Reactor system for oxidative dehydrogenation (ODH) of ethane

Abstract

An oxidative dehydrogenation (ODH) reactor system and a method of operating the ODH reactor system include providing a feed having ethane, oxygen, and a diluent to produce a reaction mixture flowing through a tube side of the ODH reactor and converting ethane to ethylene with an ODH catalyst on the tube side. Coolant is directed through the shell side of the ODH reactor to maintain the tube side at a first temperature in a first cooling section and at a second temperature in a second cooling section, where the first temperature is lower than the second temperature. The ODH reactor system may include more than one ODH reactor. For an ODH reactor system having more than one ODH reactor in series, oxygen may be injected between the ODH reactors.

Description

Technical Field

[0001] The present disclosure relates to an oxidative dehydrogenation (ODH) reactor system to improve the performance of an ODH plant for ethylene production. Background Art

[0002] Catalytic oxidative dehydrogenation of alkanes to corresponding olefins is an alternative to steam cracking. In contrast to steam cracking, oxidative dehydrogenation (ODH) can be operated at lower temperatures and does not usually produce coke. For ethylene production, ODH can provide a higher ethylene yield than steam cracking. ODH can be carried out in a reaction vessel with a catalyst for converting alkanes into corresponding olefins. Acetic acid as a by-product may be generated in the conversion of lower alkanes (e.g., ethane) to corresponding olefins (e.g., ethylene). Product olefins and by-product acetic acid can be recovered from the ODH reactor effluent separately.

[0003] Carbon dioxide is the main greenhouse gas emitted by human activities. Carbon dioxide (CO2) can be produced in various industrial and chemical plant facilities. At such facilities, more efficient use of energy can reduce CO2 emissions at the facility and thus reduce the CO2 footprint of the facility. SUMMARY OF THE INVENTION

[0005] Oxidative dehydrogenation (ODH) reactor systems and methods of operating ODH reactor systems. In operation, a feed having ethane, oxygen, and a diluent is provided to produce a reaction mixture that flows through a tube side of an ODH reactor. Ethane is converted to ethylene via an ODH catalyst on the tube side. A coolant is directed through the shell side of the ODH reactor to maintain the tube side at a first temperature in a first cooling section and at a second temperature in a second cooling section, wherein the first temperature is lower than the second temperature.

[0006] The ODH reactor system may include more than one ODH reactor. For an ODH reactor system having more than one ODH reactor in series, oxygen may be injected between the ODH reactors. Oxygen may be injected into the product effluent of the upstream ODH reactor, which is fed into the downstream ODH reactor. In an embodiment, the interstage product effluent may be cooled to accommodate oxygen injection.

[0007] The details of one or more embodiments are set forth in the accompanying drawings and the detailed description which follow. Other features and advantages will be apparent from the detailed description and drawings, and from the claims.

[0008] BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 is a diagram of an ODH plant having an ODH reactor system for dehydrogenating ethane to ethylene.

[0010] Figure 2 and 2A is a schematic diagram of an exemplary multi-tubular fixed bed reactor.

[0011] Figure 3 , 4 , 4A, 5, 6, 7, 8, 9, 10, 11 and 12 can be Figure 1 Diagram of the ODH reactor system.

[0012] Fig.13 A ternary diagram which is an example of a flammability diagram for a mixture of ethane, oxygen, and water vapor at 300°C and 500 kilopascals (kPa) absolute pressure.

[0013] Fig.14 and 15 Each is a block flow diagram of a respective method of operating an ODH reactor system having at least one ODH reactor.

[0014] Implementation Detail

[0015] Embodiments of the present technology relate to oxidative dehydrogenation (ODH) reactor systems for dehydrogenating alkanes (e.g., ethane) to corresponding olefins (e.g., ethylene). Various aspects relate to configurations of ODH reactor systems that reduce the energy consumption of ODH equipment (facilities). For example, some aspects relate to configurations that reduce the amount of dilution water vapor in the alkane feed, thereby reducing the energy consumption of the ODH equipment.

[0016] The ODH reactor can dehydrogenate ethane to ethylene via an ODH catalyst in the presence of oxygen. Ethylene can be separated from the ODH reactor effluent to produce product ethylene.

[0017] Figure 1 It is an ODH device 100 having an ODH reactor system 102 for dehydrogenating ethane to ethylene. The dehydrogenation of ethane to ethylene can be the reaction of ethane with oxygen via an ODH catalyst to produce ethylene. The ODH reactor system 102 can be a single reactor system with a unique ODH reactor (e.g., configurations 1-7 discussed below) or a multi-reactor system with more than one ODH reactor arranged in series in operation (e.g., configurations 8-13 discussed below). Additional ODH reactors can be included in parallel in configurations 1-13 to achieve the desired amount of ethylene production capacity at the ODH device. The ODH reactor can be a multi-tubular fixed bed reactor with an ODH catalyst on the tube side, and wherein a coolant (e.g., molten salt) flows on the shell side to remove reaction heat from the tube side.

[0018] In addition to configuring the ODH reactor system 102 to attempt to reduce the amount of dilution steam implemented in the feed 104 to reduce the energy consumption of the ODH plant, considerations may also include improving energy efficiency by recovering heat from the ODH reactor to generate steam 106 for the ODH plant 100. For example, heat from coolant discharged from the reactor (such as heated in the shell side) and / or heat from process effluent discharged from the ODH reactor (from the tube side) may be used to heat boiler feed water and evaporate it into steam.

[0019] The ODH reactor system 102 may have a single ODH reactor 110, or may have an additional ODH reactor 112 in series in operation. In addition, additional similarly configured ODH reactors may be included in parallel in operation to increase ethylene production capacity. For a multi-reactor system, the first ODH reactor 110 in series may discharge the effluent as a feed to the second ODH reactor 112. In certain embodiments having the ODH reactor system 102 as a multi-reactor system, the effluent 108 may be discharged from the final ODH reactor 112 in series (e.g., the second ODH reactor, the third ODH reactor, etc.). The diluent in the feed 104 reactor may include, for example, nitrogen (N2), carbon dioxide gas (CO2) or water (water vapor), or any combination thereof. If the diluent in the feed 104 includes water, the water in the effluent 108 may include unreacted dilution water and water produced in the ODH reaction in the ODH reactor.

[0020] In an embodiment, the feed 104 may include ethane and oxygen and is provided (e.g., transported in a conduit) to the ODH reactor 110. The feed 104 may include a diluent (e.g., water vapor) to place the feed 104 outside the flammability limit. The water vapor as a diluent may be labeled as dilution water vapor. In the preparation of the feed 104, energy (heating capacity) may be applied to heat or evaporate water to incorporate water vapor or water vapor into the feed 104 as dilution water vapor. The feed 104 may be characterized as a mixed feed including ethane, oxygen, and dilution water vapor.

[0021] Dilution vapor entering ODH reactor system 102 in feed 104 may be exhausted from ODH reactor system 102 in effluent 108. In processing effluent 108 downstream of reactor system 102, energy (cooling capacity) may be applied to condense the dilution vapor in effluent 108.

[0022] Significant demands for energy in the ODH plant 100 can be [1] heating water (e.g., in the feed preparation system 114) to provide dilution water vapor in the feed 104, [2] condensing the dilution water vapor in the ODH reactor effluent 108 in the downstream effluent treatment 116, and [3] separating the condensed acetic acid from the condensed water. Therefore, reducing the amount of dilution water vapor in the feed 104 can reduce energy consumption at the ODH plant 100. Techniques for reducing the amount of dilution water vapor in the feed 104 include reducing the amount of oxygen in the feed 104. Advantageously, for a feed 104 with less oxygen, less dilution water vapor places the feed 104 outside the flammability limits. See, e.g., Fig.13 .

[0023] Techniques to reduce the amount of oxygen in the feed 104 may include increasing ethylene selectivity, favoring the formation of ethylene over the formation of carbon monoxide (which consumes more stoichiometric amounts of oxygen than ethylene formation) and over the formation of carbon dioxide (which consumes more stoichiometric amounts of oxygen than ethylene formation) in the ODH reactor. Techniques to favor the formation of ethylene over the formation of carbon monoxide and carbon dioxide may include operating one or more cooling sections of the ODH reactor at lower temperatures where feasible and / or beneficial. This is because higher temperatures (of the reaction mixture and the ODH catalyst on the tube side) may more easily allow the undesirable formation of carbon monoxide and carbon dioxide.

[0024] Techniques that are not conducive to the formation of carbon monoxide and carbon dioxide may include increasing heat transfer from the tube side to the shell side in the ODH reactor (and / or increasing the efficiency of heat transfer, such as via an increased heat transfer coefficient). This can avoid or reduce the occurrence of temperature spikes on the tube side, which can favor or cause (lead to) the (unwanted) formation of carbon monoxide and carbon dioxide. Improving heat transfer can include limiting the temperature rise of a coolant (e.g., a molten salt) passing through the shell side of the ODH reactor, thereby increasing the flow rate of the coolant through the shell side to increase the value of the heat transfer coefficient. Improving heat transfer can include limiting the diameter (e.g., nominal diameter, outer diameter, or inner diameter) of the tubes in the tube bundle in the ODH reactor to increase the velocity of the reaction mixture flowing through the tube. Such techniques can give, for example, an increased Reynolds number (Re), which can increase the heat transfer coefficient. Likewise, an increased heat transfer coefficient can reduce the occurrence of temperature spikes on the tube side. Temperature spikes on the tube side may undesirably lead to the formation of more carbon monoxide and carbon dioxide (and thereby more oxygen consumption).

[0025] The formation of carbon monoxide and carbon dioxide consumes more stoichiometric amounts of oxygen than the formation of ethylene. Therefore, the formation of increased carbon monoxide and carbon dioxide can result in more oxygen in the feed 104, which undesirably results in more dilution water vapor in the feed 104. More dilution water vapor in the feed 104 may mean more energy consumption at the ODH device 100. The formation of carbon monoxide and carbon dioxide is also an undesirable reaction because ethylene is a more valuable product. Carbon monoxide and carbon dioxide are generally undesirable products. The generation of carbon dioxide can increase the CO2 footprint of the ODH device (facility) 100.

[0026] The ODH facility 100 includes a feed preparation system 114 that provides a feed 104 to the only ODH reactor 110 or the first ODH reactor 110 in the ODH reactor system 102. Again, the feed 104 may include ethane and oxygen. As mentioned, the feed 104 may include a diluent that places the feed 104 outside the flammability limit. See, e.g. Fig.13 , which depicts the flammability diagram of a mixture of ethane, oxygen, and water (steam) as a diluent.

[0027] Examples of diluents that can be used to place the feed 104 stream outside the flammability limit can include water, nitrogen, carbon dioxide, helium, argon, methane, etc. In embodiments, water is the diluent. As shown, the water as a diluent can generally be in the form of water vapor. For example, since it is relatively simple to separate water from the ODH reactor system 102 product stream (effluent) in embodiments, water vapor or evaporated water can be an attractive diluent.

[0028] The feed preparation system 114 may combine the diluent with the ethane (and oxygen) to produce the feed 104 that is delivered to the ODH reactor system 102. For example, where the diluent is water, the feed preparation system 114 may heat or evaporate the water so as to be incorporated (added) to the ethane (and oxygen) as dilution water vapor.

[0029] In an embodiment, ethane 118 (gas) and water 120 may be provided to the feed preparation system 114, and the water 120 may be incorporated into the ethane 118 as water vapor or steam to produce the feed 104. Such incorporated water 120 may be characterized or labeled as dilution water vapor. Oxygen 122 (gas) may be provided to the feed preparation system 114 for adding the oxygen 122 to the ethane 118 to produce the feed 104. In certain embodiments, some or all of the oxygen 122 may be added to a conduit that transports the feed 104 to the ODH reactor system 102.

[0030] The feed preparation equipment 124 may include a heat exchanger for heating water 118 as a liquid (and in some cases evaporating the liquid water), an ethane saturator column for saturating ethane 118 with water 120, a steam drum vessel for adding water vapor (including water 120) to ethane 118, etc. For feed dilution embodiments (e.g., in feed preparation 114) that heat water 118, medium pressure (MP) steam may be employed, which is a higher value (more expensive) steam than low pressure (LP) steam. The source of LP steam and MP steam in the ODH plant 100 may include, for example, an extraction turbine or a pressure reducing valve for HP or VHP steam.

[0031] To add water vapor to the feed 104 of the ODH reactor, embodiments may employ, for example, a dilution steam drum or a saturator tower. A dilution steam drum may be more direct in providing dilution steam, but may unfortunately rely on a higher value heat source, such as medium-pressure steam. In an embodiment, medium-pressure steam may be better used, for example, to drive a steam turbine instead. The saturator tower may saturate hydrocarbon (e.g., ethane) gas and / or oxygen with water vapor and utilize a relatively high water cycle. For examples of feed dilution, see WO published patent application number WO 2022 / 229848 entitled “Integration for Feed Dilution in Oxidative Dehydrogenation (ODH) Reactor System,” which is incorporated herein by reference in its entirety.

[0032] Components other than ethylene formed in the ODH reactor may include acetic acid, carbon dioxide, carbon monoxide, and water. Thus, the ODH device 100 may produce ethylene 126 and acetic acid 128. Carbon monoxide and carbon dioxide may be undesirably formed in the ODH reactor and discharged in the effluent 108 along with ethylene and acetic acid.

[0033] The ODH reactor (e.g., 110, 112) can produce ethylene (C2H4) as a main product and acetic acid (CH3COOH) as a value-added byproduct. The ODH reactor (e.g., 110, 112) can produce carbon monoxide (CO), carbon dioxide (CO2) and water (H2O). The reaction mechanism characterized by the reaction of ethane (C2H6) with oxygen (O2) in the ODH reactor can be explained as follows:

[0034] C2H6+0.5O2→C2H4+H2O

[0035] C2H6+1.5O2→CH3COOH+H2O

[0036] C2H6+2.5O2→2CO+3H2O

[0037] C2H6+3.5O2→2CO2+3H2O

[0038] As can be seen from the equations immediately above, the reactions that form CO and CO2 generally utilize (consume) a greater stoichiometric amount of O2 than the listed reactions that produce ethylene. Therefore, configuring the ODH reactor system 102 to increase ethylene selectivity, thereby favoring ethylene formation over CO and / or CO2 formation, can reduce the amount of O2 implemented in the feed 104. A reduction in the amount of O2 in the feed 104 can mean that less dilution water vapor is implemented in the feed 104 in order to place the feed 104 outside the flammability limits (outside the flammability envelope) (see, e.g., Fig.13 ). As discussed, less dilution water vapor in the feed 104 can mean reduced energy consumption in the ODH plant.

[0039] The product effluent 108 from the ODH reactor system 102 may include ethylene, acetic acid, carbon dioxide, carbon monoxide, water, and unreacted ethane. In addition to dilution water vapor as water in the effluent 108, the effluent 108 may also include water formed in the ODH reactor (as steam or vapor).

[0040] Treatment 116 of the effluent 108 can include condensing water and acetic acid to remove acetic acid and water from the effluent 108. The water and acetic acid can be condensed, for example, via a heat exchanger utilizing a cooling medium (e.g., cooling water, air, etc.). In some embodiments, a flash tank vessel or a quench tower vessel can facilitate separation of the condensed liquid from the effluent 108.

[0041] The condensed water and condensed acetic acid as a mixture may be processed in an acetic acid unit (e.g., having an extractor column vessel, a solvent recovery column vessel, and a water stripper column vessel) to separate byproduct acetic acid 128 and liquid water 130. In an embodiment, the water 130 may be recycled for use in the ODH device 100. For example, the water 130 discharged from the acetic acid unit may be recycled (as recycle water) for use in scrubbing process gas in effluent treatment 116 and / or as water (e.g., 120) for dilution steam in feed preparation 114, etc.

[0042] After removing condensed water and condensed acetic acid from effluent 108 to the acetic acid unit, the remainder of effluent 108 as a gas (minus condensed liquids) may include ethylene, CO, CO2, and ethane. The gas may be scrubbed in a scrubber column vessel (e.g., with liquid water such as water 130) to remove residual acetic acid vapor and residual water vapor from the gas. The gas may be subjected to separation to remove CO and CO2. The gas may be sent through a C2 splitter (ethane / ethylene splitter) (a distillation column vessel having distillation trays) to separate ethane from the gas to produce product ethylene 126.

[0043] The equipment 132 in the effluent treatment 116 may include, for example, a heat exchanger for condensing water and acetic acid from the effluent, a flash tank vessel for separating the condensed water and condensed acetic acid as a mixture from the effluent 106, and an acetic acid unit (e.g., having an extraction column vessel) for treating the mixture to separate byproduct acetic acid 128 and liquid water 130. The equipment 132 may include the scrubber vessel described above and a process gas compressor (mechanical compressor) for increasing the pressure of the gas with ethylene from the effluent 108. Other configurations and alternative equipment are also suitable.

[0044] In some embodiments, the device 132 may include a container for separating CO and CO2 (and other light components) from the gas, and a C2 splitter. In other embodiments, the device 132 does not include such equipment, and the product stream 126 is an intermediate product stream with ethylene and ethane sent for further processing. Similarly, other configurations are also applicable. For examples of processing effluents, see WO published patent application number WO 2022 / 229847 entitled "Integration for Processing Effluent of Oxidative Dehydrogenation (ODH) Reactor", which is incorporated herein by reference in its entirety.

[0045] The acetic acid unit may be a significant energy consumer in the ODH plant affected by the amount of dilution water vapor. The presence of more dilution water vapor in the effluent 108 (and condensation with the acetic acid) may mean more heating (e.g., at the water vapor reboiler in the column) and more cooling (e.g., at the overhead condenser in the column) in the acetic acid unit.

[0046] Figure 2is a diagram of an exemplary multi-tubular fixed bed reactor 200 as a container. The container is typically a cylindrical container with an elliptical or semi-elliptical head. The container can have a vertical orientation (as shown) or a horizontal orientation. The container can be a pressure vessel, which is designed and configured (e.g., with sufficient wall thickness) to apply an internal pressure of up to a specified pressure (design pressure) greater than the ambient pressure (atmospheric pressure). The pressure vessel can be rated to maintain the fluid up to the design pressure. In operation, the operating pressure in the pressure vessel can generally be maintained below the design pressure. The pressure vessel can be constructed according to formal standards or specifications, such as the American Society of Mechanical Engineers (ASME) Boiler & Pressure Vessel Code (BPVC) or the European Union (EU) Pressure Equipment Directive (PED). For an ODH reactor that is a multi-tubular fixed bed reactor, the reactor vessel and tubes can be metal, such as steel (e.g., stainless steel).

[0047] The multi-tubular fixed bed reactor 200 includes a tube side and a shell side. The tube side may be the process side (for converting process feeds into products in a flowing reaction mixture). The shell side may be the utility side (for flow of heat transfer fluid). The shell side may be similar in effect to a vessel jacket, but may be similar or analogous to the shell side of a shell and tube heat exchanger.

[0048] The multi-tubular fixed bed reactor 200 has a shell 202 and a tube bundle, which may be similar to a shell and tube heat exchanger, except that the tubes 204 have a fixed bed of catalyst. The tube bundle is a plurality of tubes 204 arranged generally in parallel. In the tube bundle, the tubes 204 may be supported and fixed in place in parallel by a tube sheet (e.g., a plate). The tube sheet may be a circular plate that is perforated so that the tubes can pass through the perforated openings.

[0049] The shell 202 wall can be a container wall. The volume of the shell 202 surrounding the longitudinal length of the tube 204 can be characterized as the shell side of the reactor 202. The shell side can be used for the flow of heat transfer fluid around the tube 204. The volume inside the tube 204 can be characterized as the tube side of the reactor 202. Figure 2A is an exploded view of a tube 204 having a tube wall 210 and a catalyst 212 disposed in the tube 204. Figure 2 In the embodiment of the present invention, the longitudinal end portion of the vessel can be considered as the tube side. In particular, the longitudinal end portion of the vessel where the process feed 206 is introduced into the tube 204 and the process product 208 is discharged from the tube 204 can be characterized as the tube side of the reactor 202.

[0050] exist Figure 2In the embodiment of the present invention, the tube 204 can be (at least partially) filled with a catalyst 212. The catalyst 212 can be a fixed bed of catalyst in the tube 204. The catalyst 212 can promote the conversion of the feed 206 into the product 208 discharged from the reactor. In operation, providing (supplying) the feed 206 to the tube side can make the reaction mixture flow through the tube 204, and wherein the reaction in the reaction mixture is promoted (activated, promoted) by the catalyst 212. The process feed 206 can enter the container through the container inlet (e.g., inlet nozzle) to the tube side. The process product 208 can be discharged from the container from the tube side through the container outlet (e.g., outlet nozzle).

[0051] Process feed 206 enters the bottom portion of the vessel. Process product 208 exits the top portion of the vessel. However, reactor 200 may be configured such that process feed 206 enters the top portion of the vessel and process product 208 exits the bottom portion of the vessel.

[0052] The heat transfer fluid 214 can enter the vessel (to the shell side) through the vessel inlet (e.g., inlet nozzle) to flow through the shell side around the tubes 204. For the case where the reaction on the tube side is an endothermic reaction, the heat transfer fluid 214 can be a heating medium to provide heat for the endothermic reaction. For the case where the reaction is carried out as an exothermic reaction on the tube side, the heat transfer fluid 214 can be a cooling medium (coolant), and wherein the heat transfer fluid 214 removes the heat of reaction.

[0053] The heat transfer fluid 214 provided to the reactor 200 and entering the shell side can be labeled as a heat transfer fluid supply. The heat transfer fluid 214 can flow around the tubes 204. Therefore, the heat transfer fluid 214 can undergo heat exchange with the process reaction mixture and catalyst 212 on the tube side. The shell side can include baffles 216 to create more turbulence of the heat transfer fluid 214 to improve (increase) heat transfer between the heat transfer fluid 214 and the tube side.

[0054] The heat transfer fluid 218 may be discharged from the reactor 200 from the shell side, such as through a vessel outlet (e.g., an outlet nozzle). The heat transfer fluid 218 discharged from the reactor 200 from the shell side may be labeled as heat transfer fluid reflux (labeled as Reflux) sent to the heat transfer fluid supply system. The composition of the heat transfer fluid 218 discharged from the reactor 200 may be the same as the composition of the heat transfer fluid 214 supplied to the reactor 200. Due to heat exchange with the reaction mixture (and catalyst 212) on the tube side, the discharged heat transfer fluid 218 may have the same composition but a different temperature than the supplied heat transfer fluid 214.

[0055] The flow of the heat transfer fluid 214 through the shell side is in a co-current flow direction with the flow of the reaction mixture on the tube side. However, the flow of the heat transfer fluid 214 through the shell side can alternatively be in a counter-current flow direction with the flow of the reaction mixture on the tube side. For example, in the illustrated embodiment, the reactor 200 can be configured with an inlet on the upper portion of the vessel for the supply of the heat transfer fluid 214 and an outlet on the lower portion of the vessel for the return of the heat transfer fluid 218.

[0056] For an ODH reactor as a multi-tubular fixed bed reactor, the heat transfer fluid 214 can generally be a coolant because the ODH reaction is exothermic. In addition, the ODH reactor can have more than one cooling section. For example, a baffle 216 or a plate can extend completely through the shell side, dividing the shell side into more than one section. Each shell side section can have an inlet for supplying a heat transfer fluid 214 and an outlet for reflux of a heat transfer fluid 218. Each shell side section can be marked as a cooling section, which keeps the reaction mixture and catalyst 212 on the tube side at a corresponding specified temperature (corresponding isotherm temperature).

[0057] Figure 1 The embodiments of the ODH reactors 110, 112 can be similar to the reactor 200. For an ODH reactor, the number of tubes 204 in the tube bundle can be in the thousands (e.g., 30,000 tubes 204). For an ODH reactor, the process feed 206 can be the feed 104 ( Figure 1 If more than one ODH reactor is used, the process feed 206 may be the effluent from an upstream ODH reactor. The process product 208 may be the effluent 108 ( Figure 1 ). If more than one ODH reactor is used, the process product 208 may be the effluent discharged as feed to a downstream ODH reactor.

[0058] As mentioned, for ODH reactors, the heat transfer fluid 214 can typically be a coolant because the reaction on the tube side is typically exothermic. Heat transfer occurs from the reaction mixture and catalyst 212 on the tube side through the tube wall 210 to the heat transfer fluid 214 flowing through the shell side. The heat transfer fluid 214 used as a coolant for the ODH reactor can be, for example, water vapor, water (including pressurized or supercritical water), oil, or molten salt, etc. Molten salt can be selected as a coolant due to its relatively high stability and due to the relatively high heat transfer coefficient value provided by the molten salt at the operating temperature of the ODH reactor (e.g., 300-500°C). Water (critical point is 374°C and 22,064kPa) or extremely high pressure steam used as the heat transfer fluid 214 will produce a relatively high pressure on the shell side, resulting in a thicker wall of the shell (container).

[0059] Embodiments of the present technology may include specifying the diameter (e.g., nominal diameter, outer diameter, or inner diameter) of the tube 204 of the ODH reactor so that the reaction mixture has sufficient velocity through the tube 204 to promote a sufficient Reynolds number (Re) to give a satisfactory heat transfer coefficient. The flow hydraulics of the reaction mixture in the tube 204 can affect the heat transfer from the reaction mixture and the ODH catalyst 212 to the coolant on the shell side. As discussed, improved heat transfer may be detrimental to the formation of carbon monoxide and carbon dioxide in the reaction mixture flowing through the tube 204. Embodiments may include configuring the ODH reactor in response to specifying an increased ethylene selectivity (and thereby increasing ethylene selectivity) so that the tube 204 is at or less than a specified diameter.

[0060] For typical operating conditions and capacities of an ODH reactor, the diameter of the tube 204 [e.g., nominal diameter, outer diameter (OD), or inner diameter (ID)] for the ODH reactor can be specified, for example, in the range of 0.75 inches to 2.0 inches, 0.75 inches to 1.5 inches, or 0.75 inches to 1.25 inches. In an embodiment, a diameter less than 0.75 inches may make it difficult to load the catalyst 212 into the tube 204 (fill or place the catalyst 212 into the tube 204). However, in certain embodiments, a tube 204 diameter (for an ODH reactor) less than 0.75 inches can be accommodated. In an embodiment, a tube 204 diameter (for an ODH reactor) greater than 1.25 inches or greater than 1.5 inches can cause the reaction mixture to pass through the tube 204 at an insufficient rate, resulting in poor heat transfer and thereby increasing the formation of carbon dioxide and carbon monoxide. However, in certain embodiments, a tube 204 diameter (for an ODH reactor) greater than 1.5 inches can be accommodated. The following examples and related simulations consider a 1 inch tube, since the OD is 1 inch, the tube wall thickness is 0.083 inches, and the ID is 0.834 inches; a 1.25 inch tube, since the OD is 1.25 inches, the tube wall thickness is 0.120 inches, and the ID is 1.01 inches; and a 1.5 inch tube, since the OD is 1.5 inches, the tube wall thickness is 0.134 inches, and the ID = 1.232 inches. For a hypothetical example, a 2 inch tube may be, for example, 2 inches OD, 0.188 inches wall thickness, and 1.624 inches ID.

[0061] In some embodiments, the ODH reactor may have a supplemental tube bundle for superheating water vapor. In operation, the supplemental tube bundle receives water vapor (e.g., saturated water vapor). The water vapor flows through the tubes of the supplemental tube bundle and is heated by the heat transfer fluid 214. The water vapor is discharged from the supplemental tube bundle from the reactor 200 in a superheated form. The supplemental tube bundle may be adjacent to the primary tube bundle in the reactor vessel. On the other hand, the supplemental tube bundle may have a dedicated shell adjacent to or mounted on the reactor 200 vessel, and the dedicated shell is coupled to the shell side of the reactor 200 for the flow of the heat transfer fluid 214. The supplemental dedicated shell may receive a coolant slipstream from the primary shell.

[0062] Options for ODH reactor systems are presented. The example of Configuration 2 presented below can be a base case. Configurations 1 and 3-13 presented can generally be compared to Configuration 2 as a baseline case. However, the present technology is not limited to the various options and configurations as listed or characterized. Instead, various configurations including Configurations 1-13 are given as examples. Figure 3-12 can be presented relative to each other, and some include incremental differences relative to each other. Figure 3-12 For a description of the devices and operations in a given diagram, see also Figure 3-12 Discussion of other graphs.

[0063] Figure 3 is an ODH reactor system 300, which may be Figure 1 The ODH reactor system 102 of FIG. 3 is labeled Configuration 1 for comparison purposes with examples of ODH reactor systems disclosed herein.

[0064] The ODH reactor system 300 includes an ODH reactor 302 as a multi-tubular fixed bed reactor. The reactor 302 is depicted with a symbol of multiple vertical lines, which together represent the shell side and the tube side in the reactor vessel. The two diagonal lines are symbols for the flow of coolant through the shell side, which is used for heat exchange between the shell side and the tube side, and indicates a cooling section. The reactor 302 has a cooling section. The coolant system outside the reactor 302 is associated with the cooling section. The cooling section can remove the reaction heat of the exothermic reaction on the tube side to provide a reactor isotherm temperature, wherein the process reaction mixture and the ODH catalyst on the tube side are maintained at a constant temperature (e.g., in the range of 300° C. to 500° C.).

[0065] The ODH reactor 302, which is a multi-tubular fixed bed reactor, includes a tube bundle having a plurality of tubes. Figure 3In one embodiment, the diameter (e.g., nominal diameter, outer diameter, or inner diameter) of each tube is 1 inch. The interior (internal volume) of the tube can be the tube side. The shell side can be the volume in the reactor vessel along the tube bundle surrounding the tube. In an embodiment, the container wall along the straight side of the container can be the shell wall. In operation, heat transfer from the tube side (inside the tube) through the tube wall of each tube to the shell side can occur. In particular, heat transfer from the reaction mixture in the tube (flowing in the tube) and the ODH catalyst through the tube wall to the coolant flowing through the shell side can occur. In an embodiment, the coolant is a molten salt.

[0066] ODH catalyst (for example, as a fixed bed) can be arranged inside the tube. As used herein, the term "ODH catalyst" can be a catalyst known for the ODH of ethane. ODH catalyst can provide an ODH reaction in which ethane is dehydrogenated to ethylene and acetic acid as a byproduct can be formed. Low temperature ODH catalyst may be beneficial. A non-limiting example of an ODH catalyst that can be used for an ODH reactor is a low temperature ODH catalyst, which includes molybdenum (Mo), vanadium, tellurium (Te), niobium and oxygen (O), wherein the molar ratio of molybdenum to vanadium is 1:0.12 to 1:0.49, the molar ratio of molybdenum to tellurium is 1:0.01 to 1:0.30, the molar ratio of molybdenum to niobium is 1:0.01 to 1:0.30, and oxygen is present at least in an amount to satisfy the valence state of any metal element present. The molar ratio of molybdenum, vanadium, tellurium and niobium can be determined by inductively coupled plasma mass spectrometry (ICP-MS). The catalyst may be labeled a low temperature ODH catalyst in that it provides an ODH reaction at less than 450°C, less than 425°C, less than 400°C, or less than 375°C, or in a range of 300°C to 500°C, for example.

[0067] The reactor 302 vessel includes a feed inlet for feeding a feed 304 (e.g., similar to Figure 1 Feed 104 or Figure 2 The feed 206 of the reactor 302 is received into the reactor 302 to the tube side to produce a reaction mixture flowing through the tube side. In the embodiment shown, the reaction mixture flows upward through the tube. The feed inlet can be a container inlet nozzle connected to a feed conduit, and the feed conduit transports the feed 304 to the reactor 302. The feed 304 can include ethane, oxygen and a diluent. The diluent can be water vapor as a dilution water vapor.

[0068] As discussed, in connection with the ODH reaction of dehydrogenating ethane to ethylene, a byproduct formed in the reaction mixture flowing through the tube side may be acetic acid. As further mentioned, byproducts formed in the reaction mixture flowing through the tube side may also include water, CO2, and CO. Thus, the effluent 308 (e.g., which may be similar to Figure 1 The outflow 108 or Figure 2 The process products 208) may include ethylene, acetic acid, water, CO2, CO, unreacted ethane, and unreacted diluent (which may be water in an embodiment).

[0069] In order to remove the heat of reaction from the reaction mixture flowing through the tube side, the reactor system 300 may include a coolant supply system for supplying coolant 310 to the shell side of the reactor 302. The coolant 310 introduced into the shell side through the inlet nozzle on the reactor 302 container can be labeled as a coolant supply or a cold coolant (e.g., a cold salt as a coolant of a molten salt). Heat transfer from the reaction mixture and the ODH catalyst on the tube side to the coolant 310 flowing through the shell side can occur. The heated coolant 312 can be discharged from the shell side to the coolant supply system as a coolant reflux (hot coolant or hot salt as a coolant of a molten salt) from the reactor 302 (e.g., through a reactor container outlet nozzle). The coolant supply system can keep the reaction mixture and the ODH catalyst at a specified temperature. The coolant 310 and the heated coolant 312 can generally have the same composition.

[0070] The heated coolant 312 generally has a higher temperature than the supplied coolant 310. In other words, the coolant experiences a temperature increase (ΔT) across the shell side. The amount of energy (Q) received as heat by the coolant from the tube side may be Q=mc p ΔT, where Q is the energy per time [e.g., kilojoules per second (kJ / s) or kilowatts (kW)], m is the mass flow rate of the coolant per time [e.g., kilograms per second (kg / s)], and c p is the specific heat capacity of the coolant [units such as (kJ / kg)(1 / °C)], and ΔT is the temperature rise of the coolant (eg, °C). Q is the amount of heat received by the coolant to maintain the tube side (reaction mixture, ODH catalyst) at a specified temperature.

[0071] In the equation Q = mc p It can be seen from ΔT that for a given Q to maintain the tube side at a specified temperature, the temperature rise of the coolant (ΔT) and the flow rate of the coolant (m) are inversely proportional. Therefore, a lower temperature rise (ΔT) of the specified coolant gives a larger flow rate (m) of the coolant through the shell side. Conversely, a higher temperature rise (ΔT) of the specified coolant gives a lower flow rate (m) of the coolant through the shell side. The temperature rise (ΔT) of the coolant can be specified to provide a sufficient coolant flow rate (m) (for example, to provide a sufficient Reynolds number (Re)), thereby giving a satisfactory heat transfer coefficient. The flow hydraulics of the coolant flowing along the tubes on the shell side can affect the heat transfer from the reaction mixture on the tube side to the coolant.

[0072] The coolant supply system may include a coolant pump 314 (circulation pump), a control valve 316, and a coolant heat exchanger 318. The coolant pump 314 (e.g., a centrifugal pump) provides power to circulate the coolant through the shell side of the reactor 302. The suction (inlet) of the pump 314 receives the heated coolant 312 (conduit return) as the suction fluid. The pump 314 discharges the heated coolant 312 through the control valve 316 and the coolant heat exchanger 318.

[0073] A coolant heat exchanger 318 (e.g., a shell and tube heat exchanger) removes heat from the heated coolant 312 to provide the coolant 312 (coolant supply) at a desired (specified) temperature (the inlet temperature of the coolant 310 to the reactor 302). A control valve 316 regulates (modulates, adjusts, maintains, changes) the amount of heated coolant 312 flowing through the heat exchanger 318 to provide a supply of coolant 310 at a desired temperature. A bypass portion 320 of the heated coolant 312 flows through a bypass conduit that bypasses the coolant heat exchanger 318. The total flow rate of coolant in the circulation through the coolant supply system and the shell side of the reactor 302 can generally be substantially constant. The flow rate of the coolant provided by the pump 314 through the shell side will be lower at a specified higher temperature increase (ΔT) of the coolant through the shell side. The flow rate of the coolant provided by the pump 314 through the shell side will be higher at a specified lower temperature increase (ΔT) of the coolant through the shell side.

[0074] The ODH reactor 302 vessel may have an effluent outlet for discharging an effluent 308 from the ODH reactor 302. The effluent outlet may be a vessel outlet nozzle to an effluent discharge conduit for flow of the effluent 308 discharged from the reactor 302. The temperature of the discharged effluent 308 may be, for example, in the range of 300° C. to 500° C., which is comparable to the operating temperature of the ODH reactor 302 vessel (e.g., 300° C. to 500° C.).

[0075] The effluent heat exchanger 322 is disposed along the effluent discharge conduit. The heat exchanger 322 cools the effluent 308 using water 324 as a cooling medium. For example, the effluent exchanger 322 can cool the effluent 308 to a temperature in the range of 150° C. to 350° C. (or in the range of 200° C. to 300° C.). The heat exchanger 322 can be labeled as a transport line exchanger (TLE). In the depicted embodiment, the heat exchanger 322 is a water vapor generation heat exchanger so as to heat (evaporate) water 324 (e.g., liquid water) using the effluent 308 as a heating medium to generate water vapor 326 from the water 312. Thus, the effluent heat exchanger 322 can be characterized as a water vapor generation heat exchanger. The water 324 can be heated in the heat exchanger 322 using heat from the effluent 308 so as to flash (evaporate) the water 324 into water vapor 326. In alternative embodiments, the effluent heat exchanger 322 can heat (preheat) the water 312 to evaporate the water into water vapor 326 downstream. In those embodiments, the effluent heat exchanger 322 can be characterized as a preheater (e.g., a BFW preheater). The effluent heat exchanger 322 (steam generating heat exchanger) can be, for example, a shell and tube heat exchanger or a finned heat exchanger (e.g., having a tube bundle with fins), etc. The water 324 can be, for example, softened water, steam condensate, or boiler feed water (BFW), etc. The boiler feed water can be treated softened water. The effluent 308 can be cooled across the heat exchanger 322 by an amount ranging from, for example, 50° C. to 350° C.

[0076] The coolant heat exchanger 318 can also be used to generate water vapor 326 from the water 324. Thus, the coolant heat exchanger 318 can be labeled as a water vapor generating heat exchanger. Like the effluent heat exchanger 322, the coolant heat exchanger 318 can be, for example, a shell and tube heat exchanger or a finned heat exchanger (e.g., having a tube bundle with fins), etc.

[0077] In embodiments, one or both of the heat exchangers 318, 322 may heat (preheat, not evaporate) water 324 in order to evaporate the water 324 into steam 326 in a steam drum 328. In those embodiments, one or both of the heat exchangers 318, 322 may receive water 324 from a steam drum 328 or from a boiler feed water (BFW) pump and discharge heated (preheated) water 324 (typically not steam 326) to the steam drum 328.

[0078] The reactor system 300 may include a steam drum 328 vessel (e.g., a VHP steam drum) to provide water 324 to the heat exchangers 318, 322. The steam drum 328 vessel may have a horizontal orientation (as depicted) or a vertical orientation. The steam drum 328 vessel may receive water 324 from a pump (not shown) (e.g., a boiler feed pump) via a water feed conduit. The steam drum 328 vessel may have a vessel inlet nozzle to receive the water 324. The steam drum 328 may discharge the water 324 to the heat exchangers 318, 322 through a vessel outlet nozzle. The motive force for the water 324 to flow from the steam drum 328 to the heat exchangers 318, 322 (and the water vapor 326 to flow from the heat exchangers 318, 322 to the steam drum 328) may be, for example, by thermosiphoning.

[0079] In operation, the level of water 324 is maintained in the steam drum 328 vessel, such as via a level controller. The level controller may include a level control valve on a discharge conduit from a bottom portion of the steam drum 328 vessel (forming a vessel outlet nozzle for flowing water 324 to the heat exchangers 318, 322), a level sensor at the steam drum 328 vessel, an instrument transmitter for indicating the level measured by the level sensor to the control system, and control logic in the control system for controlling the level control valve to maintain the level at a set point.

[0080] In some embodiments, a small portion of the water 324 (or a slipstream of the water 324) discharged from the steam drum 328 vessel can be sent to a blowdown (e.g., sewer), as shown at 330, to prevent or reduce the accumulation of impurities (e.g., solids) in the steam drum 328 vessel. The blowdown can be intermittent.

[0081] The water vapor 326 produced by the heat exchangers 318, 322 may be directed to a water vapor drum 328. The water vapor drum 328 may have a vessel inlet nozzle to receive the water vapor 326. The water vapor 326 produced by the heat exchangers 318, 322 may be low pressure (LP) water vapor (e.g., 150 pounds per square inch gauge [psig] or less), medium pressure (MP) water vapor (e.g., in the range of 150 psig to 500 psig), high pressure (HP) water vapor (e.g., in the range of 500 psig to 900 psig), or very high pressure (VHP) water vapor (e.g., in the range of 900 psig to 1700 psig), etc. For water vapor that may be HP water vapor or VHP water vapor, the notation HP / VHP water vapor (e.g., in the range of 500 psig to 1700 psig) is used. In an embodiment, the water vapor 326 is HP / VHP water vapor. The pressure of the steam generated via the steam generating heat exchanger 310 may vary with the temperature of the effluent 308 driven by the operating temperature (ODH reaction temperature) of the ODH reactor 302. For the steam 314 as HP / VHP steam, the operating temperature in the steam drum 328 vessel may be, for example, in the range of 240°C to 330°C.

[0082] Higher pressure steam, such as greater than 500 pounds per square inch gauge (psig) or greater than 900 psig, may generally be more valuable than lower pressure steam, such as less than 500 psig or less than 150 psig. At the steam generating heat exchangers 318, 322, generating HP steam or VHP steam may generally be more beneficial (valuable) than generating MP steam or LP steam, and may thereby improve the economics of the reactor system 300 and the associated ODH equipment (facility). Steam 326 may have different applications. The use of steam by a consumer or a consumer receiving the steam may depend on the pressure of the steam. In some embodiments, the higher steam pressure of the generated steam may provide more versatility in terms of steam integration within a facility or device. For example, HP steam may be used to power a turbine connected to a compressor, while LP steam is generally used for purposes such as heating.

[0083] In operation of the steam drum 328, the water vapor 326 entering the steam drum 328 can be discharged from the top of the steam drum 328 as water vapor 326. Any liquid water 324 that flashes (evaporates) in the steam drum 328 can be discharged from the top as water vapor 326. The water vapor 326 discharged from the top of the steam drum 328 can be saturated water vapor (or slightly above saturation temperature). The steam drum 328 can have a container outlet nozzle on the upper or top portion of the steam drum 328 container for discharging the water vapor 326. The water vapor 326 (e.g., saturated water vapor or nearly saturated) can be discharged from the top of the steam drum 328 into a conduit for distribution to a user (e.g., at an ODH equipment facility).

[0084] The ODH reactor system 300 can superheat the water vapor 326 before distributing the water vapor 326 to the user. In particular, the water vapor 326 can flow through the superheater 332 heat exchanger before distribution. The water vapor 326 discharged from the superheater 332 heat exchanger is the water vapor 326 superheated by the superheater 332. The heating medium for the superheater 332 is the coolant flowing through the shell side of the reactor 302. The symbol depicted for the superheater 332 is the symbol for the heat exchanger. The heat exchanger symbol of the superheater 332 can represent a heat exchanger (e.g., a shell and tube heat exchanger or a plate fin heat exchanger) disposed outside the reactor 302, and wherein the slipstream of the coolant is directed through the superheater 332 from the shell side of the reactor 302.

[0085] The heat exchanger symbol for superheater 332 may represent an additional or supplemental tube bundle (with a dedicated surrounding shell) having a relatively small number of tubes (without an ODH catalyst). The additional tube bundle may supplement the tube side of reactor 302, and wherein water vapor 326 flows through the tubes of the additional tube bundle (second tube bundle). Coolant (slip stream) from the main shell side of reactor 302 flows through the shell side of the additional tube bundle to heat (superheat) the water vapor 326. The additional tube bundle with a dedicated shell may be mounted to the reactor 302 vessel, and the dedicated shell is coupled to the shell side of reactor 302 for the flow of coolant. The supplemental tube bundle may be a tube bundle (another tube bundle or second tube bundle) inside the reactor 302 vessel adjacent to the main tube bundle.

[0086] In operation, the additional or supplemental tube bundle receives water vapor 326 (e.g., saturated water vapor) through a water vapor inlet nozzle. The water vapor 326 flows through the tubes of the additional tube bundle and is heated by the coolant from the shell of the reactor 302. The water vapor 326 is discharged from the reactor 302 in a superheated form by the additional tube bundle. The additional or supplemental tube bundle (with a dedicated shell) mounted to the reactor 302 vessel may have an outlet (superheated water vapor outlet nozzle) for discharging the superheated water vapor 326.

[0087] The tubes of the additional or supplemental tube bundle may generally be parallel to the tubes of the main tube bundle in the main shell of the reactor 302. The additional tubes may generally be separate from the main tube bundle. The additional tubes may share the shell coolant. For additional tube bundles mounted on the exterior of the reactor 302 vessel, a slipstream of the main shell coolant may flow as the additional shell coolant.

[0088] Figure 4 is similar to Figure 3 The ODH reactor system 400 is an ODH reactor system 400 of the ODH reactor system 300, except that the only ODH reactor 402 has two cooling sections instead of a single shell or a single cooling section as in the ODH reactor 302. For a discussion of similar or identical equipment and operation, refer to Figure 3 . Figure 4A is an ODH reactor system 400A, which is Figure 4 The ODH reactor systems 400 and 400A are identical except that the coolant flows in a countercurrent (rather than cocurrent) flow direction relative to the reaction mixture flowing through the tube side. The ODH reactor systems 400 and 400A may each be Figure 1 ODH reactor system 102. For comparison of examples of ODH reactor systems disclosed herein, embodiments of ODH reactor systems 400 and 400A provide a basis for configurations 2-5. In the example analysis, configuration 2 was selected as the base case in the comparison of configurations 1-13.

[0089] The ODH reactor 402 has a first cooling section 404 and a second cooling section 406 separated by a barrier 408 on the shell side of the ODH reactor 402. For the "first" cooling section and the "second" cooling section presented in various embodiments herein, the second cooling section is operationally downstream of the first cooling section in the direction of flow of the reaction mixture in the tube. The flow of the coolant through the shell of the first cooling section can be co-current or counter-current relative to the reaction mixture flowing through the tube. The flow of the coolant through the shell of the second cooling section can be co-current or counter-current relative to the reaction mixture flowing through the tube.

[0090] The barrier 408 may be, for example, a metal plate that seals the shell side of the first cooling section 404 from the shell side of the second cooling section 406. Thus, in operation, the coolant in the first cooling section 404 is separated from the coolant in the second cooling section 408. The barrier 408 may have perforations or other openings for the tubes of the tube bundle to pass through the barrier 408 and thus for the reaction mixture to flow through the two cooling sections 404, 406.

[0091] For cooling sections where the tubes have catalyst (ODH catalyst), the cooling section in the ODH reactor can be labeled as catalyst cooling section. Figure 4, the first cooling section 404 and the second cooling section are each a catalyst cooling section. The catalyst cooling section can be used to cool the reaction mixture and the ODH catalyst on the tube side. For cooling sections where the tube does not have a catalyst (ODH catalyst), the cooling section can be labeled as a non-catalyst cooling section, where the cooling section is used to cool the reaction mixture on the tube side. For examples of using non-catalyst cooling sections, see Figure 5 The cooling section 510 and Figure 8 The cooling section 804 of the embodiment of the present invention is a cooling section 804 of the present invention. For the non-catalyst cooling section, inert particles can be arranged in the tube. In an embodiment, the use of the non-catalyst cooling section can be characterized as a coolant quench of the reaction mixture on the tube side. For the case of a coolant as a molten salt, the coolant quench can be referred to as a salt quench.

[0092] Feed 410 introduced into reactor 402 of the tube (tube side) may produce an initial reaction mixture in first cooling section 404. Feed 410 may be similar to Figure 1 The reaction mixture flows through the tube. The reaction mixture flowing in the tube flows from the first cooling section 404 through the barrier 408 into the second cooling section 406. The reaction mixture discharged from the tube (tube side) of the second cooling section 406 can provide an effluent 412 of the ODH reactor 402. The effluent 412 can be similar to Figure 1 of the outflow 108.

[0093] The first cooling section 404 and the second cooling section 406 can provide respective isotherm temperatures for the reactor 402. In particular, each cooling section 404, 406 can provide or promote respective constant temperatures of the reaction mixture and the ODH catalyst on the tube side by removing reaction heat (exotherm).

[0094] As discussed (e.g. regarding Figure 3 ), a coolant supply system for an ODH reactor may include a coolant pump (e.g., a centrifugal pump) to receive coolant from the shell side of the ODH reactor and to power the circulation of the coolant through the shell side. The coolant pump may be configured to provide a specified capacity (circulation flow rate of the coolant) based on a specified temperature increase of the coolant through the shell side. Specifying the temperature increase to be lower (e.g., in the range of 2°C to 8°C) provides a configuration of the coolant pump to provide a greater flow rate, which is conducive to improving the efficiency of heat transfer from the tube side to the shell side. The coolant supply system may include a coolant heat exchanger to cool at least a portion of the coolant to provide a desired or specified coolant supply temperature to the shell side. The coolant supply system may include a control valve (e.g., a flow control valve) to adjust the amount of coolant directed through the coolant heat exchanger in the circulation (and thereby adjust the amount of coolant bypassing the coolant heat exchanger).

[0095] The first coolant supply system 414 circulates a coolant (e.g., molten salt) through the shell side in the first cooling section 404. The first coolant system 414 provides a coolant supply to the first cooling section 404 and receives a coolant return from the first cooling section 404. The second coolant supply system 416 circulates a coolant (e.g., molten salt) through the shell side in the second cooling section 406. The second coolant system 416 provides a coolant supply to the second cooling section 406 and receives a coolant return from the second cooling section 406.

[0096] The coolant heat exchanger in the first coolant supply system and the coolant heat exchanger in the second coolant supply system can each receive water from the steam drum (e.g., BFW) and heat the water (coolant as the heating medium) to evaporate the water to produce water vapor (e.g., HP / VHP steam). Similarly, the effluent heat exchanger receives water from the steam drum to cool the effluent 412 and thereby evaporates the water (effluent 412 as the heating medium) to produce water vapor. As discussed, the water vapor can be discharged from the steam drum for distribution to users. Also as discussed, the water vapor can be discharged in a heat exchanger associated with the cooling section (e.g., as in Figure 3 332) overheating. Figure 4 In FIG. 4 , there are two such heat exchangers associated with the first cooling section 404 and the second cooling section 406 , respectively.

[0097] The heating medium for the two superheater heat exchangers is respectively the coolant flowing through the shell side of the first cooling section 404 and the second cooling section 406. The superheater heat exchangers may each be: [1] a heat exchanger (e.g., a shell and tube heat exchanger or a plate fin heat exchanger) disposed outside the reactor 402 and in which a slipstream of the coolant is directed from the shell side through the superheater heat exchanger; [2] a second tube bundle having several tubes (without an ODH catalyst) adjacent to the main tube bundle in the reactor 402 and in which water vapor flows through those tubes so that the coolant flowing through the shell side in each cooling section 404, 406 heats (superheats) the water vapor; and / or [3] an installed additional (supplementary) tube bundle (second tube bundle) (with a dedicated surrounding shell) in which water vapor flows through the tubes (without an ODH catalyst) and the coolant (e.g., slipstream) from the main shell side of the reactor 402 flows through the shell side of the additional tube bundle to heat (superheat) the water vapor.

[0098] Typically, a steam generating heat exchanger (e.g. Figure 4 In embodiments where the heat exchanger is configured to heat (preheat, not evaporate) water in order to evaporate the water into water vapor in the steam drum, the heat exchanger may receive water from the BFW pump and discharge heated (preheated) water (typically not water vapor) to the steam drum.

[0099] The second cooling section 406 is operatively arranged at the downstream of the first cooling section 404 in the flow direction of the reaction mixture on the tube side.Thus, the oxygen concentration in the reaction mixture in the first cooling section 404 can be generally greater than the oxygen concentration in the reaction mixture in the second cooling section 406.Therefore, in the case where the availability of oxygen in the first cooling section 404 is higher, the reaction in the reaction mixture may be more prone to including the reaction producing carbon monoxide and carbon dioxide.On the contrary, oxygen has a lower concentration (less available) in the second cooling section 406.Therefore, the reaction in the reaction mixture in the second cooling section 404 may be less prone to the reaction producing carbon monoxide and carbon dioxide.The advantage that the ODH reactor has two cooling sections can be that the tube side can be operated at a lower temperature in the first cooling section 404 to reduce the reaction forming carbon monoxide and carbon dioxide in the presence of higher concentrations of oxygen. For example: (1) the reaction mixture and the ODH catalyst on the tube side in the first cooling section 404 can be maintained at a temperature in the range of 300°C to 400°C or 300°C to 450°C; and (2) the reaction mixture and the ODH catalyst on the tube side in the second cooling section 406 can be maintained at a temperature in the range of 350°C to 500°C.

[0100] Likewise, the cooling sections 404, 406 and associated coolant supply systems remove the heat of reaction (exotherm) generated in the reaction mixture on the tube side. The amount of heat removed can be varied to provide a specified isotherm temperature. The amount of cooling flowing through each cooling section can be varied to provide a specified temperature increase (e.g., in the range of 2°C to 8°C) of the coolant passing through the cooling sections 404, 406.

[0101] Figure 5 is similar to Figure 4 The ODH reactor system 500 of the ODH reactor system 400 is the same as the ODH reactor system 500 except that the only ODH reactor 502 has [1] a third cooling section (non-catalyst cooling section) which can be characterized as a coolant (salt) quench, and [2] does not use an effluent heat exchanger to cool the effluent. For a discussion of similar or identical equipment and operation, refer to Figure 3-4 The ODH reactor system 500 may be Figure 1 The ODH reactor system 102 of FIG. 5 provides a basis for Configuration 6 for purposes of comparison to examples of ODH reactor systems disclosed herein.

[0102] The ODH reactor 502 has a first cooling section 504 and a second cooling section 506 separated by a barrier 508 on the shell side of the ODH reactor 502. As discussed, the barrier 508 can be, for example, a metal plate that seals the shell side of the first cooling section 504 from the shell side of the second cooling section 506. Thus, in operation, the coolant (e.g., molten salt) in the first cooling section 504 is separated from the coolant (e.g., molten salt) in the second cooling section 506. The barrier 508 can have perforations or other openings for the tubes of the tube bundle to pass through the barrier 508, and thus for the reaction mixture to flow through the two cooling sections 504, 506.

[0103] The ODH reactor 502 has a third cooling section 510 separated from the second cooling section 506 by a barrier 512 on the shell side of the ODH reactor 502. Similar to the barrier 508, the barrier 512 (e.g., a metal plate with openings for the tubes) seals the shell side of the third cooling section 510 from the shell side of the second cooling section 506. Thus, in operation, the coolant (e.g., molten salt) in the third cooling section 510 is separated from the coolant in the second cooling section 506.

[0104] The reaction mixture flows from the second cooling section 508 through the third cooling section 510 on the tube side. The third cooling section 510 is a non-catalyst cooling section in that the tubes in the third cooling section 510 do not have a catalyst (but may have inert particles disposed therein). Therefore, the reaction in the third cooling section 510 may be limited. The purpose of the cooling section 510 may be to cool the reaction mixture flowing through the tubes in the third cooling section 510 before the reaction mixture is discharged as an effluent 514. Thus, in an embodiment, the third cooling section 510 may be implemented in place of an effluent heat exchanger that cools the effluent 514. The effluent 514 may be similar to Figure 1 The effluent 108. In an embodiment, the third cooling stage 510 may cool the effluent 514 to a temperature in the range of 150°C to 350°C (or in the range of 200°C to 300°C).

[0105] Feed 516 introduced into the reactor 502 of the tube (tube side) can produce an initial reaction mixture in the first cooling section 504. Feed 516 can be similar to Figure 1 The reaction mixture flows in the tube. The tube is guided through barriers 508 and 512. Barriers 508 and 512 are not inside the tube. The reaction mixture flows from the first cooling section 504 to the second cooling section 506 across barrier 508 in the tube. The reaction mixture flows from the second cooling section 506 to the third cooling section 510 across barrier 512 in the tube. The reaction mixture discharged from the tube (tube side) of the third cooling section 510 can provide the effluent 514 of the ODH reactor 502.

[0106] Cooling sections 504, 506 can each provide a corresponding isotherm temperature for the reactor 502. In particular, cooling sections 504, 506 can provide or promote a corresponding constant temperature of the reaction mixture and the ODH catalyst on the tube side. As mentioned, the third cooling section 510 can cool the reaction mixture so as to be discharged as an effluent 514 having a temperature in the range of 150°C to 350°C (or in the range of 200°C to 300°C). The third cooling section 510 can replace TLE, and thus more surely act as HEX, although the third cooling section 510 can be close to isothermal on the coolant (molten salt) side, but as the molten salt coolant circulates less, the coolant can have an elevated temperature. The third cooling section 510 (for example, instead of TLE) can reduce the tube side reaction mixture temperature, for example, from 450°C to 150°C-200°C.

[0107] As discussed (e.g. regarding Figure 3-4 ), a coolant supply system for an ODH reactor may include a coolant pump (e.g., a centrifugal pump) to receive coolant from the shell side of the ODH reactor and to power the circulation of the coolant through the shell side. The coolant pump may be configured to provide a specified capacity (circulation flow rate of the coolant) based on a specified temperature increase of the coolant through the shell side. Specifying the temperature increase to be lower (e.g., in the range of 2°C to 8°C) provides a configuration of the coolant pump to provide a greater flow rate, which is conducive to improving the efficiency of heat transfer from the tube side to the shell side. The coolant supply system may include a coolant heat exchanger to cool at least a portion of the coolant to provide a desired or specified coolant supply temperature to the shell side. The coolant supply system may include a control valve (e.g., a flow control valve) to adjust the amount of coolant directed through the coolant heat exchanger in the circulation (and thereby adjust the amount of coolant bypassing the coolant heat exchanger).

[0108] exist Figure 5 , a first coolant supply system circulates a coolant (e.g., molten salt) through the shell side in the first cooling section 504. The first coolant supply system provides a coolant supply to the first cooling section 504 and receives a coolant return from the first cooling section 504. A second coolant supply system circulates a coolant (e.g., molten salt) through the shell side in the second cooling section 506. The second coolant supply system provides a coolant supply to the second cooling section 506 and receives a coolant return from the second cooling section 506. A third coolant supply system circulates a coolant (e.g., molten salt) through the shell side in the third cooling section 510. The third coolant supply system provides a coolant supply to the third cooling section 510 and receives a coolant return from the third cooling section 510.

[0109] The coolant heat exchanger in the first coolant supply system and the coolant heat exchanger in the second coolant supply system may each receive water (e.g., BFW) from the steam drum and heat the water (with the coolant as the heating medium) to evaporate the water, thereby providing steam (e.g., HP / VHP steam) to the steam drum. The coolant heat exchanger in the third coolant supply system heats water (e.g., BFW) with the coolant as the heating medium to deliver the heated water to the steam drum.

[0110] As discussed, the water vapor can be discharged from the water vapor drum for distribution to users. Also as discussed, the water vapor can be heated in a heat exchanger associated with the cooling section (e.g., as in Figure 3 332) overheating. Figure 5 In FIG. 5 , there are two such heat exchangers associated with the first cooling section 504 and the second cooling section 506 , respectively.

[0111] The heating medium for the two superheater heat exchangers is respectively the coolant flowing through the shell side of the first cooling section 504 and the second cooling section 506. The superheater heat exchangers may each be: [1] a heat exchanger (e.g., a shell and tube heat exchanger or a plate fin heat exchanger) disposed outside the reactor 502 and in which a slipstream of the coolant is directed from the shell side through the superheater heat exchanger; [2] a second tube bundle having several tubes (without an ODH catalyst) adjacent to the main tube bundle in the reactor 502 and in which water vapor flows through those tubes so that the coolant flowing through the shell side in each cooling section 504, 506 heats (superheats) the water vapor; and / or [3] an installed additional (supplementary) tube bundle (second tube bundle) (with a dedicated surrounding shell) in which water vapor flows through the tubes (without an ODH catalyst) and the coolant (e.g., slipstream) from the main shell side of the reactor 402 flows through the shell side of the additional tube bundle to heat (superheat) the water vapor.

[0112] Typically, a steam generating heat exchanger (e.g. Figure 5 In embodiments where the heat exchanger is configured to heat (preheat, not evaporate) water in order to evaporate the water into water vapor in the steam drum, the heat exchanger may receive water from the BFW pump and discharge heated (preheated) water (typically not water vapor) to the steam drum.

[0113] The second cooling section 506 is operatively arranged downstream of the first cooling section 504 in the direction of flow of the reaction mixture on the tube side. Thus, the oxygen concentration in the reaction mixture in the first cooling section 504 can generally be greater than the oxygen concentration in the reaction mixture in the second cooling section 506. Therefore, in the case where the availability of oxygen in the first cooling section 504 is higher, the reaction in the reaction mixture may be more likely to include a reaction that produces carbon monoxide and carbon dioxide. In contrast, oxygen is less concentrated (less available) in the second cooling section 506. Therefore, the reaction in the reaction mixture in the second cooling section 504 may be less likely to be a reaction that produces carbon monoxide and carbon dioxide. The advantage of having two cooling sections with an ODH catalyst in the tube of the ODH reactor can be that the tube side can be operated at a lower temperature in the first cooling section 504 to reduce the reaction of forming carbon monoxide and carbon dioxide in the presence of a higher concentration of oxygen. For example: (1) the reaction mixture and the ODH catalyst on the tube side in the first cooling section 504 can be maintained at a temperature in the range of 300°C to 450°C; and (2) the reaction mixture and the ODH catalyst on the tube side in the second cooling section 506 can be maintained at a temperature of 350°C to 500°C. The third cooling section 510 is operatively arranged downstream of the second cooling section 506 in the flow direction of the reaction mixture on the tube side.

[0114] Figure 6 is similar to Figure 5 The ODH reactor system 600 of the ODH reactor system 500 is the same as the ODH reactor system 600 except that the third cooling section of the only ODH reactor 602 has an ODH catalyst and the ODH reactor system 600 includes an effluent heat exchanger to cool the effluent. For a discussion of similar or identical equipment and operation, refer to Figure 3-5 The ODH reactor system 600 may be Figure 1 ODH reactor system 102. For comparison purposes of the examples of ODH reactor systems disclosed herein, an embodiment of ODH reactor system 600 provides a basis for configuration 7. The inclusion of a third cooling section may provide better control of the ODH catalytic reaction and may thereby beneficially result in less production of CO and CO2. An increased number of cooling sections (catalyst cooling sections) may result in better selectivity for ethylene because the tube side may be operated at a lower temperature in the upstream cooling section to reduce the reaction to form CO and CO2 in the presence of higher concentrations of oxygen. Typically, the reaction mixture temperature may increase from a cooling section to the next cooling section.

[0115] When there are more cooling sections in the same ODH reactor, better performance can be achieved in an embodiment. However, the increase in the number of cooling sections can make the ODH reactor system more complicated. In some cases, the increased complexity may be undesirable. Although three or more cooling sections can be implemented in a single reactor, some embodiments can have up to two cooling sections in a single reactor. For an ODH reactor system as a multi-reactor system with two reactors in series, an example is that the first reactor has two catalyst cooling sections and an inert cooling section (salt quenching), and the second reactor in series has two catalyst cooling sections. This situation or reactor system configuration is applicable to any number of reactors in series (the last reactor has two catalyst cooling sections, and the previous stage has two catalyst cooling sections and a salt quenching section). Of course, other configurations are also applicable.

[0116] For the ODH reactor system 600, the ODH reactor 602 has a first cooling section 604, a second cooling section 606, and a third cooling section 608. The second cooling section 606 is operatively disposed downstream of the first cooling section 604 in the direction of flow of the reaction mixture. The third cooling section 608 is operatively disposed downstream of the second cooling section 606 in the direction of flow of the reaction mixture.

[0117] A barrier 610 (e.g., a metal plate with perforations for the tubes) separates the first cooling section 604 from the second cooling section 606 on the shell side of the reactor 602. A barrier 612 (e.g., a metal plate with perforations for the tubes) separates the second cooling section 606 from the third cooling section 608 on the shell side of the reactor 602. The reaction mixture flows through the tubes via the three cooling sections 604, 606, 608 on the tube side, and its flow is not affected by the barriers 610, 612. The ODH catalyst is disposed in the tubes in the three cooling sections 604, 606, 608.

[0118] The feed 614 introduced into the reactor 602 of the tube (tube side) can produce an initial reaction mixture when entering the first cooling section 604. The feed 614 can be similar to Figure 1 The reaction mixture flows through the tube. The tube is directed through barriers 610, 612. Barriers 610, 612 are not inside the tube. Likewise, the flow of the reaction mixture is not affected by barriers 610, 612. The reaction mixture flowing in the tube flows from the first cooling section 604 across barrier 610 into the second cooling section 606. The reaction mixture flows from the second cooling section 606 across barrier 612 in the tube into the third cooling section 608. The reaction mixture discharged from the tube (tube side) of the third cooling section 608 can provide an effluent 616 of the ODH reactor 602. The reaction mixture from the third cooling section 608 is discharged as an effluent 616. The effluent 616 can be similar to Figure 1 of the outflow 108.

[0119] The cooling sections 604, 606, 608 can each provide a respective isotherm temperature for the reactor 602. In particular, the cooling sections 604, 606, 608 can each provide or promote a respective constant temperature of the reaction mixture and the ODH catalyst on the tube side. For example, the temperature can range from 300° C. to 450° C. in the first cooling section 604, and can range from 350° C. to 500° C. in the cooling sections 606, 608.

[0120] As discussed (e.g. regarding Figure 3-5 ), a coolant supply system for an ODH reactor may include a coolant pump (e.g., a centrifugal pump) to receive coolant from a shell side of the ODH reactor and to power the circulation of the coolant through the shell side. The coolant pump may be configured to provide a specified capacity (circulation flow rate of the coolant) based on a specified temperature increase of the coolant through the shell side. The coolant supply system may include a coolant heat exchanger to cool at least a portion of the coolant to provide a desired or specified coolant supply temperature to the shell side. The coolant supply system may include a control valve (e.g., a flow control valve) to adjust the amount of coolant directed through the coolant heat exchanger in the circulation.

[0121] exist Figure 6 , a first coolant supply system circulates a coolant (e.g., molten salt) through the shell side in the first cooling section 604 via a coolant pump, thereby providing a coolant supply to the first cooling section 604, and receiving a coolant return from the first cooling section 604 (to the coolant pump). A second coolant supply system circulates a coolant (e.g., molten salt) through the shell side in the second cooling section 606 via a coolant pump, thereby providing a coolant supply to the second cooling section 606, and receiving a coolant return from the first cooling section 606 (to the coolant pump suction). A third coolant supply system circulates a coolant (e.g., molten salt) through the shell side in the third cooling section 608 via a coolant pump, thereby providing a coolant supply to the third cooling section 608, and receiving a coolant return from the third cooling section 608 (to the coolant pump inlet).

[0122] The corresponding coolant heat exchanger in each of the first coolant supply system, the second coolant supply system, and the third coolant supply system can each receive water (e.g., BFW) from the steam drum and heat the water (using the coolant as a heating medium) to evaporate the water, thereby providing steam (e.g., HP / VHP steam) to the steam drum. The effluent heat exchanger 618 (arranged along the effluent discharge conduit from the reactor 602) can receive water from the steam drum and heat the water (using the effluent 616 as a heating medium) to evaporate the water, thereby providing steam (e.g., HP / VHP steam) to the steam drum. Thus, the effluent heat exchanger 618 can beneficially cool the effluent 616 (remove heat from the effluent 616). In an embodiment, the effluent heat exchanger 618 can cool the effluent 616 to a temperature in the range of 150° C. to 350° C. (or in the range of 200° C. to 300° C.), for example.

[0123] As discussed, the water vapor can be discharged from the water vapor drum for distribution to users. Also as discussed, the water vapor can be heated in a heat exchanger associated with the cooling section (e.g., as in Figure 3 332) overheating. Figure 6 In FIG. 6 , there are two such heat exchangers associated with the first cooling section 604 and the second cooling section 606, respectively. A third such heat exchanger (superheater) (not shown) may also be associated with the third cooling section 608.

[0124] The heating medium for the two superheater heat exchangers is the coolant flowing through the shell side of the first cooling section 604 and the second cooling section 606. The two superheater heat exchangers can be respectively as Figure 3-5 608. As mentioned, the third superheater heat exchanger coupled to the third cooling section 608 can be similarly configured. Typically, the number of such superheater heat exchangers for the reactor system 600 can be one associated with one cooling section, two associated with two cooling sections, or three associated with three cooling sections, respectively. A coolant (e.g., molten salt) is used to superheat the water vapor.

[0125] Figure 7 is similar to Figure 3-6 The ODH reactor system 700 is similar to the ODH reactor system of FIG. 700 , except that the ODH reactor system 700 is not a single reactor system. Instead, the ODH reactor system 700 is a multi-reactor system having two ODH reactors 704, 706 arranged in series in operation. For a discussion of similar or identical equipment and operation, reference is made to FIG. Figure 3-6 The ODH reactor system 700 may be Figure 1For purposes of comparison to the examples of ODH reactor systems disclosed herein, an embodiment of ODH reactor system 700 provides the basis for configuration 8.

[0126] The first ODH reactor 702 and the second ODH reactor 704 are each a multi-tubular fixed bed reactor with two cooling sections, and the cooling section uses a coolant (such as a molten salt) on the reactor shell side to cool the reaction mixture and the ODH catalyst on the tube side. The cooling sections 710, 712, 742, 744 can each provide or promote the corresponding isotherm temperature (constant temperature) of the reaction mixture and the ODH catalyst on the tube side. For example, the tube side temperature can be maintained in the range of 300°C to 450°C in the first cooling section 710, 742, and maintained in the range of 350°C to 500°C in the second cooling section 712, 744.

[0127] The two cooling sections in each reactor 702, 704 are separated by respective barriers on the shell side (sealing the shell side between the cooling sections). The reaction mixture flows through each barrier through the tubes (on the tube side). The tubes in the four cooling sections (tube side) have ODH catalyst.

[0128] The first ODH reactor 702 is operatively disposed upstream of the second ODH reactor 704. The first ODH reactor 702 receives a feed 706, which may be similar to Figure 1 The feed 706 may advantageously have less oxygen (and therefore less dilution water vapor) because the oxygen 708 gas is injected between the reactors 702, 704. This may be an advantage of a multi-reactor system compared to a single reactor system. The feed 706 may include a sufficient amount of oxygen (or more) for the OHD reaction in the first ODH reactor 702.

[0129] The feed 706 (first reactor feed) introduced into the first ODH reactor 702 produces an initial reaction mixture that flows through the tube side. The reaction mixture (on the tube side) flows through the first cooling section 710 of the first reactor 702 and flows through the second cooling section 712 of the first reactor 702. The second cooling section 712 is operatively disposed downstream of the first cooling section 710.

[0130] The first coolant supply system 714 provides the first coolant as a coolant supply to the reactor shell side in the first cooling section 710, and receives the first coolant as a coolant return from the reactor shell side in the first cooling section 710. The second coolant supply system 716 provides the second coolant as a coolant supply to the reactor shell side in the second cooling section 712, and receives the second coolant as a coolant return from the reactor shell side in the second cooling section 712. Both the first coolant and the second coolant may be, for example, molten salt.

[0131] The first coolant supply system 714 may have a first coolant pump 718, a first coolant control valve 720, and a first coolant heat exchanger 722 that cools the first coolant using water 724 as a cooling medium. The first coolant pump 718 (e.g., a centrifugal pump), which is a first coolant circulation pump, may configure the flow rate (circulation rate) of the first coolant to produce a specified temperature increase of the first coolant passing through the shell side in the first cooling section 710. The first coolant control valve 720 (e.g., a flow control valve) may adjust the amount (flow rate) of the first coolant directed through the first coolant heat exchanger 722. The first coolant heat exchanger 722 (e.g., a shell and tube heat exchanger) may remove the reaction heat received by the first coolant in the reactor shell side so as to provide the desired supply temperature of the first coolant to the reactor shell side.

[0132] The second coolant supply system 716 may have a second coolant pump 726, a second coolant control valve 728, and a second coolant heat exchanger 730 that cools the second coolant using water 724 as a cooling medium. The second coolant pump 726 (e.g., a centrifugal pump), which is a second coolant circulation pump, may configure the flow rate (circulation rate) of the second coolant to produce a specified temperature increase of the second coolant passing through the shell side in the first cooling section 710. The second coolant control valve 728 (e.g., a flow control valve) may adjust the amount (flow rate) of the second coolant directed through the second coolant heat exchanger 730. The second coolant heat exchanger 730 (e.g., a shell and tube heat exchanger) may remove the reaction heat received by the second coolant in the reactor shell side so as to provide a desired supply temperature of the second coolant to the reactor shell side.

[0133] The first coolant heat exchanger 722 and the second coolant heat exchanger 730 may each receive water 724 from a steam drum 732 container and evaporate the water 724 into steam 734 that is sent to the steam drum 732. The water 724 is provided to the steam drum 732 from a source (not shown). For the water 724 as boiler feed water (BFW), the source may be a BFW pump.

[0134] The reaction mixture is discharged from the first ODH reactor 702 from the tube side as the effluent 736 of the first ODH reactor 702. The effluent 736 may include ethylene, acetic acid (steam), CO, CO2, water (steam), unreacted ethane, and residual oxygen. The effluent 736 may be discharged from the first ODH reactor 702 through an effluent discharge conduit. The effluent discharge conduit may transport the effluent 736 to the feed inlet of the second ODH reactor 702. Thus, the effluent discharge conduit from the first ODH reactor 702 may be used as a feed conduit for the second ODH reactor 702.

[0135] Liquid water 738 is added (injected) into the effluent 736 as water for quenching the effluent 736 to cool the effluent 736. In particular, evaporation of the added liquid water 738 in the effluent 738 consumes heat in the effluent 736 to cool the effluent 736. In other words, the sensible heat of the effluent 736 can provide latent heat of evaporation to evaporate the injected liquid water 738, thereby cooling the effluent 736. In an embodiment, the liquid water supply conduit transports the liquid water 738 to the effluent discharge conduit transporting the effluent 736. A tee pipe may connect the liquid water supply conduit with the effluent discharge conduit so as to add (inject) the liquid water 738 into the effluent 736. Water quenching via the injected liquid water 738 may cool the effluent 736 to a temperature in the range of 150° C. to 350° C. (or in the range of 200° C. to 300° C.), for example. After water quenching, O2 may be injected into the effluent 736. The purpose of cooling the effluent 736 (whether by the depicted water quench or by other cooling techniques) may be to avoid autoignition of hydrocarbons and acetic acid (which may be at or near their autoignition temperatures) with the addition of O2, and to avoid associated undesirable reactions (e.g., combustion and production of CO and CO2).

[0136] Oxygen 708 gas may be added (injected) into the effluent 736. The amount of oxygen 708 added to the effluent 736 provides oxygen for the ODH reaction in the second ODH reactor 704. (The amount of oxygen contained in the upstream feed 706 of the first ODH reactor 702 may be sufficient for the ODH reaction of the reaction mixture in the first ODH reactor 702) In an embodiment, an oxygen supply conduit delivers the oxygen 708 gas to an effluent discharge conduit that delivers the effluent 736. A tee may connect the oxygen supply conduit to the effluent discharge conduit so that oxygen 708 is added (injected) into the effluent 736.

[0137] In the illustrated embodiment, the feed 740 provided to the second ODH reactor 704 includes the first reactor effluent 736, vaporized added liquid water 738, and added oxygen 708 gas. The effluent discharge conduit from the first ODH reactor 702 can be or be coupled to a feed conduit that is coupled to a feed inlet (e.g., a vessel inlet nozzle) of the second ODH reactor 704.

[0138] The feed 740 (second reactor feed) introduced into the second ODH reactor 704 produces an initial reaction mixture that flows through the tube side of the second ODH reactor 704. The reaction mixture flows (on the tube side) through the first cooling section 742 of the second ODH reactor 704 and through the second cooling section 744 of the second ODH reactor 702. The second cooling section 744 is operationally disposed downstream of the first cooling section 742. In the context of the ODH reactor system 100, the first cooling section 742 can be labeled as the third cooling section of the four cooling sections, and the second cooling section 744 is labeled as the fourth cooling section.

[0139] The third coolant supply system 746 provides the third coolant as a coolant supply to the shell side of the reactor 704 in the first cooling section 742, and receives the first coolant as a coolant return from the shell side of the reactor 704 in the first cooling section 710. The fourth coolant supply system 748 provides the fourth coolant as a coolant supply to the shell side of the reactor 704 in the second cooling section 744, and receives the fourth coolant as a coolant return from the shell side of the reactor 704 in the second cooling section 744. Both the third coolant and the fourth coolant can each be, for example, a molten salt.

[0140] The third coolant supply system 746 can have a third coolant pump 750, a third coolant control valve 752 and a third coolant heat exchanger 754. The third coolant heat exchanger 754 cools the third coolant using water 724 as a cooling medium. The third coolant pump 750 (e.g., a centrifugal pump) as a third coolant circulation pump can be configured to generate a specified temperature increase of the third coolant through the shell side in the first cooling section 742. The third coolant control valve 752 (e.g., a flow control valve) can adjust the amount (flow rate) of the third coolant guided through the third coolant heat exchanger 754. The third coolant heat exchanger 754 (e.g., a shell and tube heat exchanger) can remove the reaction heat received by the third coolant in the shell side of the reactor 704 so as to provide the required supply temperature of the third coolant to the shell side of the reactor 704.

[0141] The fourth coolant supply system 748 may have a fourth coolant pump 756, a fourth coolant control valve 758, and a fourth coolant heat exchanger 760 that cools the fourth coolant using water 724 as a cooling medium. The fourth coolant pump 756 (e.g., a centrifugal pump), which is a fourth coolant circulation pump, may be configured to generate a specified temperature increase of the fourth coolant through the shell side in the second cooling section 744. The fourth coolant control valve 758 (e.g., a flow control valve) may adjust the amount (flow rate) of the fourth coolant directed through the fourth coolant heat exchanger 760. The fourth coolant heat exchanger 760 (e.g., a shell and tube heat exchanger) may remove the reaction heat received by the fourth coolant in the shell side of the reactor 704 so as to provide the desired supply temperature of the second coolant to the shell side of the reactor 704.

[0142] The third coolant heat exchanger 754 and the fourth coolant heat exchanger 760 can each receive water 724 from the steam drum 732 container and evaporate the water 724 (using the coolant as a heating medium) into water vapor 734 that is sent to the steam drum 732. In addition, the effluent heat exchanger 762 can heat and evaporate the water 724 (using the effluent 764 from the second ODH reactor 704 as a heating medium) into the water vapor 734 that is sent to the steam drum 732.

[0143] The reaction mixture is discharged from the second ODH reactor 704 from the tube side as effluent 762. The effluent 762 may be similar to Figure 1 The product effluent of the effluent 108. The effluent 762 may include ethylene, acetic acid (steam), CO, CO2, water (steam or water vapor) and unreacted ethane. The effluent 762 may be discharged from the second ODH reactor 704 through an effluent discharge conduit. The effluent discharge conduit may be coupled to an effluent outlet nozzle on the second ODH reactor 704 to receive the effluent 762. The above-mentioned effluent heat exchanger 762 may be arranged along the effluent discharge conduit that conveys the effluent 764. The effluent heat exchanger 762 may cool the effluent 762 using water 724 as a cooling medium. As mentioned, the effluent heat exchanger 762 may evaporate water 724 using the effluent 762 as a heating medium to produce water vapor 734.

[0144] In an embodiment of the ODH reactor system 700, the steam 734 generated at the heat exchangers 722, 730, 754, 760, and 762 can be HP / VHP steam. Thus, the steam drum 732 vessel can be operated at HP / VHP (e.g., at a pressure in the range of 500 psig to 1700 psig). Thus, the steam 734 discharged from the steam drum 732 for distribution can be HP / VHP steam, which is typically saturated steam. Thus, the steam 734 discharged from the steam drum 732 can be, for example, at a temperature in the range of 240° C. to 330° C. (saturation temperature).

[0145] The ODH reactor system 700 can heat the water vapor 734 to above the saturation temperature to provide the water vapor 734 as superheated water vapor (HP / VHP) for distribution. In particular, the superheater heat exchangers 766, 768, 770 and 772 can receive the water vapor 734 from the steam drum 732 and heat the water vapor 734 (using the reactor shell side coolant as the heating medium) to superheat the water vapor 734. Although the superheater heat exchangers are depicted as receiving the water vapor 734 in parallel, they can be arranged in series in operation. As depicted, each heat exchanger 766, 768, 770, 772 can be associated with a corresponding cooling section 710, 712, 742, 744. The four superheater heat exchangers 766, 768, 770, 772 can each be as described above. Figure 3-6 Configured as discussed above with respect to the corresponding superheater heat exchanger.

[0146] Figure 8 is with Figure 7 The ODH reactor system 700 is the same as or similar to the ODH reactor system 800, except that the first ODH reactor 802 has a third cooling section 804 (without catalyst) instead of Figure 7 Water quenching between ODH reactors. For coolants that are molten salts, the third cooling section 804 can be characterized as salt quenching. The advantage of the third cooling section 804 can be that the heat removed from the reaction mixture can be recovered via a coolant heat exchanger to produce water vapor. In contrast, for water quenching, the removed heat may be lost in the evaporation of water. In addition, as discussed, cooling the effluent before interstage O2 addition can be beneficial in reducing the temperature of the effluent components (e.g., acetic acid) to below their autoignition temperature (if above their autoignition temperature), and thereby preventing autoignition (and the associated combustion of materials such as ethane, ethylene, acetic acid, CO, etc.).

[0147] For discussion of similar or identical equipment and operations generally with respect to ODH reactor system 800, see Figure 3-7 The ODH reactor system 800 may be Figure 1The ODH reactor system 102 of FIG. 8 provides a basis for configuration 9 for purposes of comparison to examples of ODH reactor systems disclosed herein.

[0148] The third cooling section 804 (of the first ODH reactor 802) may be a non-catalyst cooling section in that there may be no catalyst present in the tubes in the third cooling section 804 (but may have inert particles disposed therein). The third cooling section 804 and the associated fifth coolant supply system (which circulates the fifth coolant through the reactor shell side in the third cooling section 804) provide a corresponding isotherm in the sense that the reaction mixture flowing through the tubes in the third cooling section 804 is maintained at a specified temperature in the range of, for example, 150° C. to 350° C. (or in the range of 200° C. to 300° C.).

[0149] A fifth coolant heat exchanger (for a fifth coolant, such as molten salt) in a fifth coolant supply system associated with the third cooling stage 804 preheats water (e.g., BFW) to evaporate water in the steam drum. The water may be provided from a pump and is typically provided at the operating pressure (e.g., HP / VHP) of the steam drum. The water may flow from a pump (e.g., a BFW pump) through the fifth coolant heat exchanger to the steam drum.

[0150] Likewise, the water level can be maintained in the steam drum. The steam can be discharged from the steam drum for distribution to users. The steam after being discharged from the steam drum can be superheated in a superheater heat exchanger before being distributed to users, for example, as in Figure 7 As discussed.

[0151] The first ODH reactor 802 receives Figure 7 Feed 806 is the same as or similar to feed 706. Feed 806 enters the tube side of the first ODH reactor 802 to produce a flowing reaction mixture in the tube. Figure 7 As in the ODH reactor system 700 of FIG. 8 , the reaction mixture flows through the first and second cooling sections of the first reactor 802. However, in the reactor system 800, the reaction mixture additionally flows through the tube side of the third cooling section 804 of the first ODH reactor 802. Likewise, the reactor tubes in the third cooling section 804 may not have a catalyst.

[0152] The reaction mixture is withdrawn from the first ODH reactor 802 from the tube side as effluent 808 (first reactor effluent) for feeding to the tube side of the second ODH reactor 810. The effluent 808 may be similar in composition to Figure 7 effluent 736 is similar or identical to, but is generally at a lower temperature than the discharged effluent 736 due to the presence of Figure 8 The third cooling section 804 of the first ODH reactor 802 in FIG. Figure 7 As with the ODH reactor system 700 of FIG. 1 , oxygen may be injected into the effluent 808. However, this may be avoided. Figure 7 Liquid water for water quenching is injected into the effluent as in the third cooling stage 804, as the reaction mixture is removed as effluent 808. The effluent 808 plus the injected oxygen is fed as feed to the second ODH reactor 810 to produce the reaction mixture flowing through the tube side. Figure 7 As in the embodiment of the present invention, the reaction mixture flows through two cooling sections in a tube and is discharged as effluent 812 through an effluent heat exchanger. The effluent 812 can be Figure 7 The outflow 812 may be similar to the outflow 764 of Figure 1 The outflow 108. Figure 7 As in the embodiment of the present invention, the effluent heat exchanger and the four coolant heat exchangers generate steam from the water received from the steam drum and discharge the steam to the steam drum. The four superheater heat exchangers superheat the steam discharged from the steam drum for distribution.

[0153] Fig. 9 is with Figure 7 The ODH reactor system 900 is the same or similar to the ODH reactor system 700, except that the effluent heat exchanger 902 (instead of the injection water quench) cools the effluent 904 discharged from the first ODH reactor 906. The advantage of the effluent heat exchanger 902 is that the heat removed from the effluent 904 can be recovered to preheat water (e.g., BFW) to generate water vapor. In contrast, with the injection water quench, the removed heat may be lost in the evaporation of the injection water in the effluent 904.

[0154] For a discussion of similar or identical equipment and operations generally with respect to ODH reactor system 900, see Figure 3-8 The ODH reactor system 900 may be Figure 1 The ODH reactor system 102 of FIG. 1 provides a basis for configuration 10 for purposes of comparing examples of ODH reactor systems disclosed herein.

[0155] The effluent heat exchanger 902 (e.g., a shell and tube heat exchanger) can cool the effluent 904 to a specified temperature, for example, in the range of 150° C. to 350° C. (or in the range of 200° C. to 300° C.) with water (e.g., BFW). The effluent heat exchanger 902 can receive water (e.g., from a BFW pump) and heat the water (in the cooling of the effluent), which preheats the water to evaporate the water in the steam drum. The water can be provided to the effluent heat exchanger 902, typically at the operating pressure of the steam drum (e.g., HP / VHP). The water can flow from a pump (e.g., a BFW pump) through the effluent heat exchanger 902 to the steam drum.

[0156] As discussed, the water level can be maintained in the steam drum. The steam can be discharged from the steam drum for distribution to users. The steam after being discharged from the steam drum can be superheated in a superheater heat exchanger before being distributed to users, as in Figure 7 As discussed.

[0157] The first ODH reactor 906 receives Figure 7 The feed 908 is the same as or similar to the feed 706. The feed 908 enters the tube side of the first ODH reactor 906 to produce a flowing reaction mixture in the tube. Figure 7 As in the ODH reactor system 700 of FIG. 1 , the reaction mixture flows through the first and second cooling sections of the first reactor 906 and is discharged as effluent 904 (first reactor effluent). Figure 7 As in the example above, no liquid water is injected into the effluent 904. Instead, the effluent heat exchanger 902 (for the first reactor effluent not in the Figure 7 ) Cooling the effluent 904. Likewise, it may be desirable to cool the effluent 904, for example to cool any components near or above their autoignition temperatures to well below their autoignition temperatures.

[0158] The reaction mixture is withdrawn from the first ODH reactor 902 from the tube side as effluent 902 (first reactor effluent) for feeding to the tube side of the second ODH reactor 910. The effluent 904 may have Figure 7 The effluent 736 has the same or similar composition as Figure 7 As with the ODH reactor system 700 of FIG. 1 , oxygen may be injected into the effluent 904 to provide feed 912 to the second ODH reactor 910. However, again, the above may be avoided. Figure 7 Liquid water for water quenching is injected into the effluent as in the effluent heat exchanger 902 cools the effluent 904. The effluent 904 plus injected oxygen enters the second ODH reactor 910 as feed 912 to produce a reaction mixture flowing through the tube side. Figure 7 As in the embodiment of the present invention, the reaction mixture flows in a tube through two cooling sections of the second ODH reactor 910 and is discharged from the second ODH reactor 910 from the tube side through an effluent heat exchanger 916 as an effluent 914 (second reactor effluent). The effluent 914 can be Figure 7 The outflow 914 may be similar to Figure 1 The outflow 108. Figure 7As in, the effluent heat exchanger 916 and the four coolant heat exchangers generate steam from the water received from the steam drum and discharge the steam to the steam drum. The four superheater heat exchangers (as previously described) superheat the steam discharged from the steam drum for distribution.

[0159] Fig.10 is with Figure 7 The ODH reactor system 700 is the same or similar to the ODH reactor system 1000, except that the ODH reactor system 1000 has a third ODH reactor 1002 that is operationally arranged in series downstream of the second ODH reactor 1004. Thus, the ODH reactor system 1000 has three ODH reactors in series. In this embodiment of the ODH reactor system, the number "n" of ODH reactors in series may exceed three. From the performance and energy considerations of the ODH device, a larger number "n" of ODH reactors in series may be advantageous. However, a larger number "n" of ODH reactors in series may increase the operational complexity and capital cost of the ODH reactor system.

[0160] In the ODH reactor system 1000, the effluent 1006 (third reactor effluent) discharged from the third ODH reactor 1002 is similar to Figure 1 The effluent 1008 discharged from the second ODH reactor 1004 is fed to the third ODH reactor 1002. As with the effluent 1010 (first reactor effluent) discharged from the first ODH reactor 1012 in the series of three ODH reactors of the ODH reactor system 1000, liquid water (for water quench cooling) and oxygen can both be injected into the effluent 1008 (second reactor effluent).

[0161] The fifth coolant supply system (via a coolant pump) circulates the fifth coolant through the shell side in the first cooling section of the third ODH reactor 1002. The fifth coolant supply system removes heat from the circulating fifth coolant via a coolant heat exchanger (using water as the cooling medium), which also generates water vapor from water (e.g., BFW). The coolant heat exchanger receives water from a water vapor drum and discharges the generated water vapor to the water vapor drum.

[0162] As with the other coolant supply systems discussed previously, the sixth coolant supply system (via a coolant pump) circulates the sixth coolant through the shell side in the second cooling section of the third ODH reactor 1002. The sixth coolant supply system removes heat from the circulating sixth coolant via a coolant heat exchanger (using water as a cooling medium), which also generates water vapor from water (e.g., BFW). The coolant heat exchanger receives water from a steam drum and discharges the generated water vapor to the steam drum. The sixth coolant and the fifth coolant can each be, for example, a molten salt.

[0163] For a discussion of similar or identical equipment and operations generally with respect to the ODH reactor system 1000, see Figure 3-9 The ODH reactor system 1000 may be Figure 1 For purposes of comparing examples of ODH reactor systems disclosed herein, an embodiment of ODH reactor system 1000 provides a basis for configuration 11.

[0164] and Figure 7 Like the ODH reactor system 700, the first ODH reactor 1012 receives a signal similar to Figure 1 Feed 1014 of feed 104. Advantageously, feed 1014 can have less oxygen (and therefore less dilution water vapor) than a single reactor system because oxygen is injected between ODH reactors in series in a multi-reactor system. This can be a benefit of a multi-reactor system compared to a single reactor system.

[0165] The first ODH reactor 1012, the second ODH reactor 1004 and the third ODH reactor 1002 are each multi-tubular fixed bed reactors, which have two cooling sections using a coolant (such as molten salt) on the reactor shell side to cool the reaction mixture and the ODH catalyst on the tube side. The six cooling sections can each provide or promote the corresponding isotherm temperature (constant temperature) of the reaction mixture and the ODH catalyst on the tube side. For example, the tube side temperature can be maintained in the range of 300°C to 450°C in the first cooling section of each reactor, and maintained in the range of 350°C to 500°C in the second cooling section of each reactor. The two cooling sections in each ODH reactor are separated by corresponding barriers on the shell side (sealing the shell side between cooling sections). The reaction mixture flows through each barrier through the tube (on the tube side). The barrier is not inside the tube. The tubes (tube sides) in the six cooling sections have ODH catalysts.

[0166] The feed 1014 (first reactor feed) introduced into the first ODH reactor 1012 produces an initial reaction mixture flowing through the tube side. The reaction mixture (on the tube side) flows through the first cooling section of the first ODH reactor 1012 and flows through the second cooling section of the first ODH reactor 1012, which is arranged in operation downstream of the first cooling section of the first ODH reactor 1012. The reaction mixture is discharged from the first ODH reactor 1012 from the tube side as the effluent 1010 of the first ODH reactor 1012. The effluent 1010 may include ethylene, acetic acid (steam), CO, CO2, water (steam), unreacted ethane and residual oxygen. The effluent 1010 can be discharged from the first ODH reactor 1012 through an effluent discharge conduit. The effluent discharge conduit can transport the effluent 1010 to the feed inlet of the second ODH reactor 1004. Therefore, the effluent discharge conduit from the first ODH reactor 1012 can be used as a feed conduit for the second ODH reactor 1004.

[0167] Liquid water may be added (injected) into the effluent 1010 as water for quenching the effluent 1010 to cool the effluent 1010. In particular, evaporation of the liquid water added in the effluent 1010 consumes heat in the effluent 1010 to cool the effluent 1010. In other words, the sensible heat of the effluent 1010 may provide latent heat of evaporation to evaporate the injected liquid water, thereby cooling the effluent 1010. Such water quenching via the injected liquid water may cool the effluent 1010 to a temperature in the range of, for example, 150° C. to 350° C. (or in the range of 200° C. to 300° C.). In addition, oxygen may be added (injected) into the effluent 1010. The oxygen added to the effluent 1010 provides oxygen for the ODH reaction (via the ODH catalyst) in the tubes of the second ODH reactor 1004.

[0168] Thus, the feed provided to the second ODH reactor 1004 includes the first reactor effluent 1010, evaporated added liquid water, and added oxygen. The effluent discharge conduit from the first ODH reactor 1004 can be or is connected to a second reactor feed conduit, which is connected to a feed inlet (e.g., a container inlet nozzle) of the second ODH reactor 1004. This feed (second reactor feed) introduced into the second ODH reactor 1004 produces an initial reaction mixture of the second ODH reactor 1004 that flows through the tube side. The reaction mixture (on the tube side) flows through the first cooling section of the second ODH reactor 1004 and flows through the second cooling section of the second ODH reactor 1004. The second cooling section of the second ODH reactor 1004 is operationally arranged downstream of the first cooling section of the second ODH reactor 1004. In the context of an ODH reactor system, the first cooling segment of the second ODH reactor 1004 may be labeled as the third cooling segment of the six cooling segments in the three ODH reactors, and the second cooling segment of the second ODH reactor 1004 may be labeled as the fourth cooling segment of the six cooling segments in the three ODH reactors.

[0169] The reaction mixture is discharged from the second ODH reactor 1004 from the tube side as an effluent 1008 fed to the third ODH reactor 1002. The effluent 1008 may include ethylene, acetic acid (steam), CO, CO2, water (steam or water vapor) and unreacted ethane. The effluent 1008 may be discharged from the second ODH reactor 1004 through an effluent discharge conduit. The effluent discharge conduit may be connected to an effluent outlet nozzle on the second ODH reactor 1004 to receive the effluent 1008. The effluent discharge conduit may transport the effluent 1008 to the feed inlet of the third ODH reactor 1002. Therefore, the effluent discharge conduit from the second ODH reactor 1004 may be used as a feed conduit for the third ODH reactor 1002.

[0170] As between the first reactor 1012 and the second reactor 1004, liquid water and oxygen may be injected between the second reactor 1004 and the third reactor 1002. Liquid water may be added (injected) into the second reactor effluent 1008 as water to quench the effluent 1008 via evaporation of the injected water to cool the effluent 1008. This water quenching via the injected liquid water may cool the effluent 1008 to a temperature in the range of, for example, 150° C. to 350° C. (or in the range of 200° C. to 300° C.). In addition, oxygen may be added (injected) into the second reactor effluent 1008. The oxygen added to the effluent 1008 provides oxygen for the ODH reaction (via the ODH catalyst) in the tubes of the third ODH reactor 1002.

[0171] Thus, the feed provided to the third ODH reactor 1002 includes the second reactor effluent 1008, evaporated added liquid water, and added oxygen. The effluent discharge conduit from the second ODH reactor 1004 can be or is connected to a third reactor feed conduit, which is connected to a feed inlet (e.g., a vessel inlet nozzle) of the third ODH reactor 1002. The feed introduced into the third ODH reactor 1002 (the third reactor feed) produces an initial reaction mixture that flows through the tube side third ODH reactor 1002. The reaction mixture (on the tube side) flows through the first cooling section of the third ODH reactor 1002 and flows through the second cooling section of the third ODH reactor 1002.

[0172] The second cooling section of the third ODH reactor 1002 is operatively disposed downstream of the first cooling section of the third ODH reactor 1002. In the context of an ODH reactor system, the first cooling section of the third ODH reactor 1002 may be labeled as the fifth cooling section of the six cooling sections of the three ODH reactors, and the second cooling section of the third ODH reactor 1002 may be labeled as the sixth cooling section of the six cooling sections of the three ODH reactors.

[0173] The reaction mixture is discharged from the third ODH reactor 1002 from the tube side as effluent 1006 (third reactor effluent). The effluent 1006 may be similar to Figure 1 The product effluent of the effluent 108 of the reactor 1002. The effluent 1006 may include ethylene, acetic acid (steam), CO, CO2, water (steam or water vapor) and unreacted ethane. The effluent 1006 may be discharged from the third ODH reactor 1002 through an effluent discharge conduit. The effluent discharge conduit may be connected to an effluent outlet nozzle on the third ODH reactor 1002 to receive the effluent 1006. An effluent heat exchanger 1016 may be provided along the effluent discharge conduit conveying the effluent 1006. The effluent heat exchanger 1016 may cool the effluent 1006 using water (e.g., BFW) from a steam drum as a cooling medium. The effluent heat exchanger 1016 may evaporate water using the effluent 1006 as a heating medium to produce water vapor sent to the steam drum.

[0174] In an embodiment of the ODH reactor system 1000, the steam produced at the six coolant heat exchangers and the effluent heat exchanger 1016 can be HP / VHP steam. Thus, the steam drum vessel can be operated at HP / VHP (e.g., at a pressure in the range of 500 psig to 1700 psig). Thus, the steam discharged from the steam drum for distribution can be HP / VHP steam, which is typically saturated steam. Thus, the steam discharged from the steam drum can be, for example, at a temperature in the range of 240° C. to 330° C. (saturation temperature).

[0175] The ODH reactor system 1000 can heat the steam exhausted from the steam drum to above the saturation temperature to produce steam as superheated steam (HP / VHP) for distribution. In particular, six superheater heat exchangers can receive (e.g., in parallel) the steam from the steam drum and heat the steam (using the reactor shell side coolant as the heating medium) to superheat the steam. As depicted, each of the six superheater heat exchangers can be associated with a corresponding cooling section. The six superheater heat exchangers can each be as shown in FIG. Figure 3-9 The number of superheater heat exchangers may be less than six, such as in the range of 1 to 6, and may be connected in parallel as depicted, or may be connected in series with respect to the flowing water vapor being superheated. Such alternative configurations involving superheater exchangers in an ODH reactor system may be applicable to an ODH reactor system depicted herein having more than one superheater.

[0176] Fig.11 is with Fig.10 The ODH reactor system 1000 is the same or similar to the ODH reactor system 1100, except that no water quenching is performed between the ODH reactors, and instead a coolant (e.g., molten salt) quenching is performed in each of the first ODH reactor and the second ODH reactor. In particular, the first ODH reactor system and the second ODH reactor each have a third cooling section without a catalyst. For a discussion of the third cooling section without a catalyst, see, e.g., Figure 5 and Figure 8 . The third cooling section (non-catalyst cooling section) in each of the first and second ODH reactors removes heat from the reaction mixture on the tube side via a circulating coolant on the shell side. The third cooling section can cool the reaction mixture to a temperature in the range of, for example, 150°C to 300°C (or in the range of 200°C to 300°C). For a coolant that is a molten salt, the third cooling section can be characterized as implementing a salt quench. An advantage of the third cooling section can be that the heat removed from the reaction mixture can be recovered to heat water (e.g., preheat BFW) to produce water vapor via a coolant heat exchanger. In contrast, for a reactor such as Figure 7 and Fig.10 The water in the reactor is quenched and the removed heat may be lost in the evaporation of the water.

[0177] For a discussion of similar or identical equipment and operations generally with respect to the ODH reactor system 1100, see Figure 3-10 The ODH reactor system 1100 may be Figure 1 An embodiment of an ODH reactor system 1100 provides a basis for configuration 12 for purposes of comparing examples of ODH reactor systems disclosed herein.

[0178] The third cooling section (non-catalyst cooling section) of the first ODH reactor is operationally located downstream of the second cooling section of the first ODH reactor. The seventh coolant supply system (via a coolant circulation pump) circulates the seventh coolant through the shell side in the third cooling section of the first ODH reactor. The seventh coolant heat exchanger (using water as a cooling medium) removes heat from the circulating seventh coolant and thereby heats (e.g., preheats) water so as to evaporate water (e.g., BFW) into water vapor in a steam drum (e.g., HP / VHP). The seventh coolant heat exchanger can be configured to evaporate water, partially evaporate water, or heat water without evaporating in a heat exchanger. The illustrated embodiment is to heat (preheat) water in a heat exchanger without significant evaporation. The seventh coolant heat exchanger receives water from a pump (e.g., a BFW pump).

[0179] The third cooling section (non-catalyst cooling section) of the second ODH reactor is operationally located downstream of the second cooling section of the second ODH reactor. An eighth coolant supply system (via a coolant circulation pump) circulates the eighth coolant through the shell side in the third cooling section of the second ODH reactor. An eighth coolant heat exchanger (using water as a cooling medium) removes heat from the circulating eighth coolant and thereby heats the water so as to evaporate the water (e.g., BFW) into water vapor (e.g., HP / VHP) in a water vapor drum. The eighth coolant heat exchanger can be configured to evaporate water, partially evaporate water, or heat water without evaporating in a heat exchanger. The illustrated embodiment is to heat (preheat) water in a heat exchanger without significant evaporation. The eighth coolant heat exchanger receives water from a pump (e.g., a BFW pump).

[0180] The seventh coolant and the eighth coolant can each be, for example, a molten salt. In the context of the ODH reactor system 1100, the third cooling section of the first ODH reactor can be labeled as the seventh cooling section of the eight cooling sections in the three ODH reactors, and the third cooling section of the second ODH reactor can be labeled as the eighth cooling section of the eight cooling sections in the three ODH reactors.

[0181] Likewise, the level of water can be maintained in the steam drum. The steam can be discharged from the steam drum for distribution to users. The steam after being discharged from the steam drum can be superheated in a superheater heat exchanger (discussed previously) before being distributed to users.

[0182] The first ODH reactor receives Fig.10 The feed enters the tube side of the first ODH reactor to produce a flowing reaction mixture in the tube. The reaction mixture flows through the first, second and third cooling sections of the first ODH reactor. The reaction mixture is taken as an effluent (first reactor effluent) (similar to Figure 8The effluent 808) is discharged from the tube side from the first ODH reactor for feeding to the tube side of the second ODH reactor. The effluent can be similar in composition to Fig.10 effluent 1008 is similar or identical to, but is generally at a lower temperature than the discharged effluent 1008 due to the presence of Fig.11 The two quench cooling stages may be characterized by replacing the water quench to cool the reactor effluents of the first ODH reactor and the second ODH reactor prior to the addition of O2.

[0183] exist Fig.11 In the process, oxygen may be injected into the first reactor effluent, such as Fig.10 However, it is possible to avoid Fig.10 Liquid water for water quenching is injected into the first reactor effluent as in the third cooling stage of the first ODH reactor, because the third cooling stage of the first ODH reactor cools the reaction mixture discharged as the first reactor effluent. Generally, for the case of O2 injection, water injection can be implemented if the interstage effluent temperature is relatively high. The three cooling techniques (water quenching, salt quenching, and HEX between two reactors) that produce a cooled interstage effluent before adding O2 can be used alone or in combination.

[0184] The first reactor effluent plus the injected oxygen enters the second ODH reactor as a feed to produce a reaction mixture that flows through the tube side. The reaction mixture flows through the three cooling sections of the second ODH reactor in the tube and is discharged from the second ODH reactor as an effluent (second reactor effluent). Oxygen can be injected into the second reactor effluent. The second reactor effluent plus the injected oxygen enters the third ODH reactor as a feed to produce a reaction mixture that flows through the tube side of the two cooling sections of the third ODH reactor. The reaction mixture can be discharged from the tube side of the third ODH reactor as an effluent (third reactor effluent), and the effluent can be similar to Figure 1 The effluent 108. The effluent can be cooled in the effluent heat exchanger using water as a cooling medium, and the water evaporates into water vapor using the heat from the effluent, and the water vapor is sent to the steam drum. In the ODH reactor system 1100, six superheater heat exchangers (as shown) superheat the water vapor discharged from the steam drum for distribution to users.

[0185] Fig.12 is with Fig.10The ODH reactor system 1000 is the same or similar to the ODH reactor system 1200, except that effluent heat exchangers 1202, 1204 (rather than injection water quenching) cool the effluent discharged from the first ODH reactor and the second ODH reactor, respectively. The effluent heat exchangers 1202, 1204 can have the advantage that heat removed from the effluent can be recovered to preheat water (e.g., BFW) to generate water vapor. In contrast, with injection water quenching, the removed heat may be lost in the evaporation of injection water in the effluent.

[0186] For a discussion of similar or identical equipment and operations generally with respect to ODH reactor system 1200, see Figure 3-11 The ODH reactor system 1200 may be Figure 1 For purposes of comparison to the examples of ODH reactor systems disclosed herein, an embodiment of ODH reactor system 1200 provides a basis for configuration 13.

[0187] The effluent heat exchangers 1202, 1204 (e.g., shell and tube heat exchangers) can each cool the respective effluents to a specified temperature, for example, in the range of 150°C to 350°C (or in the range of 200°C to 300°C) with water (e.g., BFW). The effluent heat exchangers 1202, 1204 can receive water (e.g., from a BFW pump) and heat the water (in the cooling of the effluent), which preheats the water to evaporate the water in the steam drum. The water can be provided to the heat exchangers 1202, 1204, typically at the operating pressure of the steam drum (e.g., HP / VHP). The water can flow from a pump (e.g., a BFW pump) through the heat exchangers 1202, 1204 to the steam drum.

[0188] exist Fig.12 In, such as about Fig.10 As discussed, the six coolant heat exchangers in the coolant supply system and the third reactor effluent heat exchanger can evaporate water (e.g., BFW) from the steam drum (as a cooling medium) to produce steam that is sent to the steam drum. As also discussed, the liquid level of water can be maintained in the steam drum. The steam can be discharged from the steam drum for distribution to users. The steam after being discharged from the steam drum can be superheated in a superheater heat exchanger (as depicted) before being distributed to users, as discussed with respect to the previous figures.

[0189] As discussed, for ODH reactor systems (e.g. Figure 1 102) of the process feed (e.g. Figure 1 104), may contain dilution water vapor along with the ethane and oxygen to keep the feed mixture outside the flammability limits.

[0190] Fig.13 is an example of a flammability diagram 1300 for a mixture of ethane, oxygen, and water vapor at 300°C and 500 kilopascals (kPa) absolute pressure. The flammability diagram 1300 is a ternary diagram having an ethane axis with associated horizontal grid lines 1302 for the molar concentration of ethane in the mixture in mole %, an oxygen axis with associated diagonal grid lines 1304 for the molar concentration of oxygen in the mixture in mole %, and a water vapor axis with associated diagonal grid lines 1306 for the molar concentration of oxygen in the mixture in mole %. The area (region) between the upper flammability limit (UFL) 1308 and the lower flammability limit (LFL) 1310 is the flammability zone, meaning that mixtures of those compositions in this zone are flammable. The area of ​​the curve outside the flammability limits is non-flammable and may be the desired operating zone (outside the flammability zone). Line 1312 represents an oxygen to ethane molar ratio of 3.5 for combustion of all ethane.

[0191] As a contingency in the operation of the ODH reactor system, the maximum concentration of oxygen in the feed can be specified at a margin 1314 (e.g., 1-5 mole %) less than the oxygen concentration at UFL 1308. As depicted, margin 1314 is a line parallel to the line of UFL 1308. Margin 1314 is the amount of oxygen mole % outside the flammability zone - specifically, the margin outside the upper flammability limit (UFL 1308). By increasing the concentration of dilution water vapor, the oxygen concentration can be reduced from the oxygen concentration UFL 1308 to margin 1314. Table 1 shows the oxygen concentration based on the oxygen concentration at UFL 1308. Fig.13 (flammability diagram at 300° C. and 500 kPa). The margins 1314 considered tabulated are no margin, 1 mol % less, 2 mol % less, 3 mol % less, 4 mol % less, and 5 mol % less.

[0192] Table 1. Based on Fig.13 Oxygen target in the mixture (feed)

[0193]

[0194]

[0195] Fig.14The present invention is a method 1400 of operating an ODH reactor system having an ODH reactor. The ODH reactor is a multi-tubular reactor having a tube side and a shell side. The tube side may include a tube for the reaction mixture to flow. The shell side may include a volume around the tube (outside) in the reactor for the coolant to flow around the tube. The ODH reactor includes a first cooling section and a second cooling section, which may be separated by a barrier on the shell side. The second cooling section may be operationally located downstream of the first cooling section relative to the flow direction of the reaction mixture flowing through the tube side. The ODH reactor may have a flow barrier separating the first cooling section and the second cooling section on the shell side so that the first coolant and the second coolant do not combine on the shell side.

[0196] At box 1402, the method includes providing a feed including ethane, oxygen and a diluent (e.g., water as water vapor) to produce a reaction mixture flowing through the tube side of the ODH reactor. The diluent can be water, CO2, N2, argon, helium or methane, or any combination thereof. The presence of a diluent including these above-mentioned diluents can keep the feed outside the flammability limit. For example, the feed can include water (diluted water vapor) as a diluent, thereby keeping the feed outside the flammability limit. Providing the feed to the tube side can be providing the feed to the inlet of the tube (of the tube bundle) of the ODH reactor. The tube can have an ODH catalyst disposed therein.

[0197] At box 1404, the method includes dehydrogenating ethane to ethylene in the reaction mixture (via ODH catalyst) on the tube side. The ODH reaction can include dehydrogenating ethane to ethylene in the tube via ODH catalyst in the presence of oxygen in the reaction mixture. The reaction of ethane and oxygen in the reaction mixture can include the first overall reaction of dehydrogenating ethane to ethylene, the second overall reaction of producing acetic acid (and water), the third overall reaction of producing carbon monoxide (and water) and the fourth overall reaction of producing carbon dioxide (and water). These four overall reactions can each be a representation with an intermediate reaction embedded therein. These four reactions are simplified representations of the overall reaction, which can be characterized as the yield type (overall reaction) of the reaction, wherein each reaction has an associated reaction chain. The method can include specifying the ethylene selectivity of the improvement by favoring the first overall reaction to exceed the third overall reaction and the fourth overall reaction, wherein the first overall reaction consumes less stoichiometric oxygen than each of the third overall reaction and the fourth overall reaction.

[0198] At box 1406, the method includes flowing a first coolant through the shell side in the first cooling section, thereby maintaining the reaction mixture (and / or ODH catalyst) in the first cooling section at a first temperature, such as in the range of 300°C to 450°C, 350°C to 450°C, 300°C to 400°C, or 300°C to 375°C. The first coolant can be, for example, a molten salt. As understood by those of ordinary skill in the art, a molten salt can be a salt that is solid at standard temperature and pressure but enters a liquid phase due to an increased temperature. A molten salt can be a class of ionic liquids that are solid at ambient temperature. Molten salts (e.g., fluoride salts, chloride salts, nitrate salts, etc.) can be a heat transfer fluid used as a coolant for an ODH reactor.

[0199] At block 1406, the method includes flowing a second coolant (e.g., molten salt) through the shell side in the second cooling section, thereby maintaining the reaction mixture (and / or ODH catalyst) in the second cooling section at a second temperature, wherein the first temperature is lower than the second temperature. The second temperature can be, for example, in the range of 350° C. to 500° C. or in the range of 375° C. to 450° C. The ODH reactor can have a third cooling section (e.g., Figure 6 ) up to "n" cooling stages.

[0200] The method includes cooling the reaction mixture (and / or ODH catalyst) to a first temperature in a first cooling section via a first coolant flowing through the shell side in the first cooling section, and cooling the reaction mixture (and / or ODH catalyst) to a second temperature in a second cooling section via a second coolant flowing through the shell side in the second cooling section. The shell side is used for the flow of the first coolant and the second coolant around the tube. The second coolant and the first coolant can both be molten salts and have the same composition.

[0201] The method may include specifying a first temperature lower than a second temperature so as to favor dehydrogenating ethane to ethylene over reactions that produce carbon dioxide in the reaction mixture and over reactions that produce carbon monoxide in the reaction mixture, thereby increasing ethylene selectivity. Maintaining the first temperature lower than the second temperature may increase ethylene selectivity in response to specifying and increasing ethylene selectivity, thereby reducing the amount of oxygen in the feed to reduce the amount of water in the feed. In addition, the ODH reactor of the present invention having more than two cooling sections may produce more benefits to reaction performance and better selectivity to ethylene.

[0202] In a given cooling section, the temperature of the reaction mixture and the ODH catalyst can be substantially the same. The temperature difference between the reaction mixture and the ODH catalyst can be, for example, less than 1°C or less than 2°C. The flow of the coolant on the shell side cools the reaction mixture and the ODH catalyst. In steady state, the temperature of the coolant can be similar to the temperature of the reaction mixture and the ODH catalyst.

[0203] At block 1408, the method includes maintaining a temperature rise of the first coolant through the first cooling section below a first threshold. The first threshold may be, for example, in the range of 2° C. to 8° C. The method includes maintaining a temperature rise of the second coolant through the second cooling section below a second threshold. The second threshold may be, for example, in the range of 2° C. to 8° C. These specified thresholds may determine the amount of molten salt circulation.

[0204] The method may include specifying that the temperature increase of the first coolant be maintained below a first threshold and the temperature increase of the second coolant be maintained below a second threshold so as to favor the dehydrogenation of ethane to ethylene over the reaction that produces carbon dioxide and over the reaction that produces carbon monoxide, thereby increasing ethylene selectivity. Such maintaining the temperature increase of the first coolant below the first threshold and the temperature increase of the second coolant below the second threshold may be responsive to specifying an increase in ethylene selectivity and increasing ethylene selectivity, thereby reducing the amount of oxygen in the feed to reduce the amount of water in the feed.

[0205] At block 1410, the method may include discharging an effluent from the ODH reactor, the effluent comprising ethylene, acetic acid, water, carbon dioxide, and carbon monoxide. In particular, the method may include discharging a reaction mixture as an effluent from the ODH reactor.

[0206] At block 1412, the method may include heating water (e.g., BFW) with at least one of a first coolant discharged from the ODH reactor, a second coolant discharged from the ODH reactor, or an effluent discharged from the ODH reactor. In an embodiment, water vapor is generated from the water by heating the water with at least one of the first coolant, the second coolant, or the effluent to evaporate the water.

[0207] At box 1414, the method may include flowing the generated water vapor to a water vapor drum and from the water vapor drum through a superheater heat exchanger (e.g., one superheater heat exchanger for each cooling section of the ODH reactor). There may be one superheater heat exchanger for each cooling section. There may be more than one superheater in series and / or parallel for each cooling section. The superheater heat exchanger may be a heat exchanger (e.g., a shell and tube heat exchanger) disposed adjacent to (but not mounted on) the ODH reactor. Coolant from the ODH reactor shell may be directed through the superheater heat exchanger as a heating medium. Alternatively, the superheater heat exchanger may be a supplemental tube bundle within the reactor shell or an additional tube bundle mounted on the ODH reactor (with a dedicated shell), and wherein the dedicated shell shares coolant with the ODH reactor shell.

[0208] At box 1416, the method may include flowing a third coolant through the shell side in the third cooling section of the ODH reactor, thereby maintaining the reaction mixture on the tube side in the third cooling section at a third temperature, wherein the third temperature is lower than the second temperature. The third cooling section (if used) is operationally downstream of the second cooling section in the flow direction of the reaction mixture, and is separated from the second cooling section by the second flow barrier on the shell side. In an embodiment, the third cooling section may be a catalyst cooling section or a non-catalyst cooling section. If it is a catalyst cooling section, the temperature of the coolant may be the highest (maximum) among the three cooling sections. If it is a non-catalyst coolant section, such as a coolant (salt) quenching section, the temperature of the reaction mixture and the coolant may be the smallest (lowest) among the three cooling sections. As a non-catalyst cooling section (without a catalyst, but may have inert particles inside the tube) of the third cooling section (if used), it can be used to cool the reaction mixture so as to be discharged as a reactor effluent, rather than using TLE to cool the effluent.

[0209] According to box 1412 and box 1416, the method may include heating water (e.g., BFW) with at least one of a first coolant discharged from the ODH reactor, a second coolant discharged from the ODH reactor, a third coolant discharged from the ODH reactor, or an effluent discharged from the ODH reactor. In an embodiment, the tube side in the third cooling section does not include a catalyst, and the effluent is not used to heat the water (e.g., BFW). In other embodiments, the tube side in the third cooling section does not include a catalyst, and the effluent is used to heat the water (e.g., BFW).

[0210] The method may include, in response to specifying an increase in ethylene selectivity, configuring the ODH reactor so that the tube is at or less than a specified diameter (e.g., nominal diameter, outer diameter, or inner diameter), thereby increasing the ethylene selectivity. The specified diameter is equal to or less than a diameter (e.g., nominal diameter, outer diameter, or inner diameter) of, for example, 1.5 inches or 1.25 inches, wherein the linear velocity of the reaction mixture in the tube is in the range of 150 centimeters per second (cm / s) to 500 cm / s, and wherein the gas hourly space velocity of the reaction mixture over the ODH catalyst in the tube is in the range of 1,500 hours. -1 (hr -1 ) to 10,000hr -1 range.

[0211] Fig.15The present invention is a method 1500 of operating an ODH reactor system having a first ODH reactor and a second ODH reactor that are arranged in series in operation, and each is a multi-tubular fixed bed reactor having a shell side and a tube side. The first ODH reactor and the second ODH reactor each have a first cooling section and a second cooling section. The first ODH reactor and the second ODH reactor may each have a flow barrier on the shell side that separates the first cooling section and the second cooling section. For the first ODH reactor and the second ODH reactor, the second cooling section may be located operationally downstream of the first cooling section in the flow direction of the reaction mixture flowing through the tube side, and separated from the first cooling section by the flow barrier on the shell side.

[0212] At block 1502, the method includes providing a feed comprising ethane, oxygen (oxygen gas), and a diluent (eg, water vapor) to a first ODH reactor. This may produce a reaction mixture that flows through the tube side of the first ODH reactor.

[0213] At block 1504, the method includes dehydrogenating ethane to ethylene via an ODH catalyst in a reaction mixture flowing on the tube side of each of the first ODH reactor and the second ODH reactor.As discussed, additional reactions may occur in the reaction mixture.

[0214] At box 1506, the method includes flowing a coolant (e.g., molten salt) through the shell side in the first cooling section and the second cooling section of each of the first ODH reactor and the second ODH reactor, thereby cooling the ODH catalyst on the tube side. This can cool the reaction mixture and the ODH catalyst on the tube side of each of the first ODH reactor and the second ODH reactor. The shell side can be used for the flow of coolant to cool the ODH catalyst on the tube side. The cooling of the ODH catalyst can involve (1) maintaining the ODH catalyst (and / or reaction mixture) on the tube side in the first cooling section of the first ODH reactor at a temperature lower than the temperature of the ODH catalyst (and / or reaction mixture) on the tube side in the second cooling section of the first ODH reactor, and (2) maintaining the ODH catalyst (and / or reaction mixture) on the tube side in the first cooling section of the second ODH reactor at a temperature lower than the temperature of the ODH catalyst (and / or reaction mixture) on the tube side in the second cooling section of the second ODH reactor. The temperature of the ODH catalyst and the reaction mixture in the first cooling section of each of the first ODH reactor and the second ODH reactor can be, for example, in the range of 300°C to 450°C. The temperature of the ODH catalyst and the reaction mixture in the second cooling section of each of the first ODH reactor and the second ODH reactor can be, for example, in the range of 350° C. to 500° C. In a given cooling section, the temperature of the reaction mixture and the ODH catalyst can be substantially the same. The temperature difference between the reaction mixture and the ODH catalyst can be, for example, less than 1° C. or less than 2° C. In steady state, the temperature of the coolant can be similar to the temperature of the reaction mixture and the ODH catalyst.

[0215] At block 1508, the method includes maintaining a temperature rise of the coolant through each of the first cooling section and the second cooling section of each of the first ODH reactor and the second ODH reactor below a threshold. The threshold may be, for example, in the range of 2°C to 8°C.

[0216] At box 1510, the method includes heating water (e.g., BFW) with coolant discharged from at least one of the first cooling section of the first ODH reactor, the second cooling section of the first ODH reactor, the first cooling section of the second ODH reactor, or the second cooling section of the second ODH reactor, wherein the heated water evaporates the water into water vapor or preheats the water to evaporate (vaporize) the water into water vapor in a water vapor drum.

[0217] At box 1512, the method includes discharging a first effluent from the first ODH reactor to a second ODH reactor. In particular, the method may include discharging the first effluent from the first ODH reactor as a feed to the tube side of the second ODH reactor. The first effluent includes ethylene, acetic acid, water, carbon dioxide, carbon monoxide, and unreacted ethane.

[0218] At block 1514, the method includes cooling the first effluent. For example, the method may include injecting liquid water into the first effluent, thereby evaporating the liquid water via heat from the first effluent to cool the first effluent. Instead of (or in addition to) the liquid water injection, the method may include cooling the first effluent with boiler feed water as a cooling medium through a heat exchanger (e.g., operatively disposed between the first reactor and the second reactor), thereby evaporating the boiler feed water into steam or heating the boiler feed water so as to evaporate the boiler feed water into steam in a steam drum.

[0219] Instead of (or in addition to) liquid water injection and / or heat exchangers for cooling the first effluent, the method may include indirect or upstream cooling of the first effluent. In other words, the first ODH reactor may have a third cooling section (e.g., without an ODH catalyst in the tube) to cool the reaction mixture in the tube before discharging the reaction mixture as the first effluent. Thus, in order to cool the first effluent, the method may include flowing a coolant through the shell side in the third cooling section of the first ODH reactor, thereby cooling the reaction mixture on the tube side in the third cooling section, wherein the third cooling section is operationally located downstream of the second cooling section of the first ODH reactor in the flow direction of the reaction mixture and is separated from the second cooling section by a second flow barrier on the shell side. In an embodiment, the tube side in the third cooling section (if used) of the first ODH reactor (in which the reaction mixture flows) does not include a catalyst. In an embodiment, the tubes in the third cooling section may have non-catalyst particles with relatively high thermal conductivity to facilitate or increase heat removal.

[0220] At block 1516, the method includes injecting oxygen into the first effluent. In particular, the method may include injecting oxygen into the first effluent between the first ODH reactor and the second ODH reactor.

[0221] The method includes discharging a second effluent from the second ODH reactor. The second effluent includes ethylene, acetic acid, water, carbon dioxide, and carbon monoxide.

[0222] In line with block 1510, the method may include generating water vapor via heat from at least one of a coolant discharged from the first ODH reactor, a coolant discharged from the second ODH reactor, a first effluent discharged from the first ODH reactor, or a second effluent discharged from the second ODH reactor. The method may include flowing the water vapor through another tube bundle (without an ODH catalyst) associated with the first ODH reactor or the second ODH reactor or both, so as to heat the water vapor with the coolant flowing on the shell side, thereby superheating the water vapor. The tubes may be in a separate shell and tube heat exchanger adjacent to the ODH reactor, and the shell and tube heat exchanger receives / returns coolant (as a heating medium) from / to the ODH reactor shell. Alternatively, the tubes may be a supplementary (additional) tube bundle within the ODH reactor shell, or a supplementary (additional) tube bundle within a dedicated shell (which is adjacent to or mounted on the ODH reactor) that receives (and returns) a slipstream of coolant (molten salt) from the ODH reactor shell. Water vapor (eg, at approximately saturation) may flow from the steam drum through these additional tubes. Superheating of the water vapor may be raising the temperature of the water vapor above the saturation temperature of the water vapor.

[0223] In order to reduce DS consumption, the amount of oxygen consumption should be reduced. When considering the four reactions listed above, the lowest oxygen demand is for ethylene production (0.5 moles of O2 per mole of ethane), and the highest oxygen demand is for CO2 generation (3.5 moles of O2 per mole of ethane). Therefore, in order to reduce O2 consumption, the selectivity to ethylene should be increased. In addition, increasing the selectivity to acetic acid is more desirable than forming CO or CO2.

[0224] The ODH reactor design (and operation) can be configured to achieve higher ethylene selectivity (and higher acetic acid selectivity). The specified ODH reactor design is a multi-tubular fixed bed reactor, in which the tubes are filled with catalyst. In operation, the process gas passes through the tubes, and a coolant flows on the shell side, removing the heat of reaction. Due to the operating temperatures (which are typically in the range of 300° C. to 500° C.), molten salts are specified as coolants in the following embodiments. Typically, molten salts can provide higher stability at high temperatures and better heat transfer coefficients than other heat transfer fluids.

[0225] Configurations 1-13 are presented as embodiments and are not intended to limit the present technology. Alternative or other variations are applicable, as shown in the overall disclosure of this article. Specific exemplary data are applied to configurations 1-13 in the following examples. Other exemplary data are applicable to configurations 1-13. In the discussion of configurations 1-13 of ODH reactor systems, reactors can be referred to as stages. In particular, a single reactor system can be referred to as a single-stage reactor system or a 1-stage reactor system, and a multi-reactor system can be referred to as a multi-stage reactor system (e.g., a 2-stage reactor system, a 3-stage reactor system, etc.). For example, a 2-stage reactor system is an ODH reactor system having two ODH reactors connected in series in operation. A 3-stage reactor system in an ODH reactor system has three ODH reactors connected in series in operation. The phrase "between stages" or the word "interstage" refers to between ODH reactors. Between the first stage and the second stage refers to between the first ODH reactor and the second ODH reactor. Between the second stage and the third stage refers to between the second ODH reactor and the third ODH reactor. The effluent heat exchanger that cools the effluent discharged from the reactor in a single reactor system or from the terminal (final) reactor in a multi-reactor system can be labeled as a transfer line exchanger (TLE). Interstage cooling of the effluent can be provided by (1) water quenching via liquid water injection, (2) by a heat exchanger using water as a coolant (this option is represented by the acronym HEX), or (3) by salt quenching (using the coolant as molten salt) of the reaction mixture in the reactor terminal cooling section before discharging the interstage effluent from the reactor. The HEX of the final effluent (non-interstage) can be labeled as TLE. For cooling sections in which the tube has a catalyst (ODH catalyst), the cooling section in the ODH reactor can be labeled as a catalyst cooling section. The catalyst cooling section can be used to cool the reaction mixture and the ODH catalyst on the tube side. For cooling sections in which the tube does not have a catalyst (ODH catalyst) (but can have inert particles disposed in the tube), the cooling section can be characterized as a non-catalyst cooling section for cooling the reaction mixture on the tube side. The coolant as a molten salt can be simply referred to as salt.

[0226] Presented below are descriptions and basics for thirteen exemplary configurations (Configurations 1-13) of an ODH reactor system. Figure 3-12 The implementation of the ODH reactor system in provides the basis for configurations 1-13: Configuration 1 ( Figure 3 ), configurations 2, 3, 4, and 5 ( Figure 4 ), Configuration 6( Figure 5 )、Configuration 7( Figure 6 )、Configuration 8( Figure 7 )、Configuration 9( Figure 8 )、Configuration 10( Fig. 9 )、Configuration 11( Fig.10 )、Configuration 12( Fig.11 ) and configuration 13( Fig.12 ). However, the corresponding figures are not limited to the specific embodiments in the configurations presented. The figures provide a general basis for the number of reactors, the number of cooling sections, and water heating. On the contrary, specific embodiments such as pipe size (diameter), coolant as molten salt, temperature or temperature increase value, etc. do not limit the figures for this configuration. An initial description is given immediately below as an overview of configurations 1-13.

[0227] Configuration 1 is a single reactor (1 stage) with one catalyst cooling section (1 section), 1 inch tubes, and a temperature rise of less than 5°C on the coolant side. The coolant is used to generate HP / VHP steam and superheat the generated HP / VHP steam (500 psig to 1700 psig). The reactor effluent can be cooled in the TLE after the reactor against BFW (which preheats or evaporates BFW for HP / VHP steam generation).

[0228] Configurations 1, 2 and 7 are 1 stage with 1, 2 or 3 catalyst cooling sections respectively. The number of catalyst cooling sections can be extended to n sections, which can provide better performance in the reaction.

[0229] Configurations 2 and 3 are 1 stage with 2 catalyst cooling sections. The temperature rise on the coolant side in the 2 catalyst cooling sections is less than 5°C and about 15°C, respectively. Other temperature rise values ​​of the coolant can be implemented. In terms of reaction performance related to the coolant flow rate, a temperature rise of 2-8°C (e.g., 5°C) may be more favorable than higher values, such as exceeding 8°C (e.g., 15°C). A larger ΔT may mean less coolant (e.g., molten salt) circulation, which results in a lower Reynolds number (Re) and thus a lower heat transfer coefficient (HTC). An important parameter for improving ODH reactor performance (higher ethylene selectivity and lower CO / CO2 selectivity) is heat removal capability.

[0230] Configurations 2, 4, and 5 are 1 stage with 2 catalyst cooling sections. Configurations 2, 4, and 5 have tube diameters of 1 inch, 1.25 inches, and 1.5 inches, respectively. Other tube sizes may be implemented. In general, smaller tubes may have better (improved) heat removal capabilities due to higher Re and thus higher HTC inside the tubes, which may lead to better reactor performance.

[0231] Configuration 2 is a 1 stage with 2 catalyst cooling sections and HP / VHP steam generation in the TLE after the reactor. Configuration 6 is a 1 stage with 2 catalyst cooling sections, and a third cooling section (non-catalyst cooling section with inert particles in the tubes) as a low temperature cooling section, where the tube side reaction mixture (gas) is cooled (temperature dropped) and the coolant (molten salt) preheats the vaporized BFW to produce HP / VHP steam. The difference between configuration 2 (with TLE) and configuration 6 (coolant quench section) is the TLE vs. coolant (e.g. molten salt) quench.

[0232] Configuration 8 is a 2-stage reactor system with 2 catalyst cooling sections per stage and with oxygen (O2) interstage injection. Liquid water is injected interstage to evaporate and use the latent heat of evaporation to reduce the temperature of the reactor effluent from the first stage (before O2 interstage injection) to a temperature in the range of 200°C to 300°C. This can further promote the reduction of the risk of spontaneous combustion of hydrocarbons and other combustible gases. The 2-stage reactor system separates O2 between the two stages. In this way, the first stage receives less O2 than in a 1-stage reactor system, and thus requires much less dilution steam (DS) than the 1-stage reactor system configuration.

[0233] Configuration 9 is a 2-stage reactor system with 2 catalyst cooling sections per stage and with O2 interstage injection. Similar to the single reactor in Configuration 6, the first reactor (stage) in Configuration 9 has an inert (non-catalyst) cooling section with coolant (cold molten salt as salt quench) at the end of the first reactor to cool the tube side gas before O2 injection. The coolant (colder molten salt) preheats BFW or produces HP / VHP water vapor. The first reactor has three cooling sections (molten salt cooling sections): two cooling sections are used to cool the catalytic reaction, and the third cooling section is used to cool the tube side gas before leaving the reactor.

[0234] Configuration 10 is a 2-stage reactor system with 2 catalyst cooling sections per stage and with O2 interstage injection. Instead of water quench or molten salt quench, a heat exchanger (HEX) cools the reactor effluent from the first stage and recovers heat to preheat BFW or generate HP / VHP steam. As discussed herein in the context of quenching, the phrase salt quench refers to molten salt quench (coolant molten salt in the shell of the ODH reactor).

[0235] Configurations 11, 12, and 13 are 3-stage reactor systems with 2 catalyst cooling sections per stage and O2 interstage injection. Water quenching, salt quenching, or HEX can be used between stages, or cooling of the reactor effluent prior to O2 injection as discussed above (Configurations 8, 9, and 10). Combinations of these techniques can be used. Applicability can be extended to n-stage reactors.

[0236] For the specific embodiments in configurations 1-7, some characteristics of the stage 1 reactor system include an O2 target of 6-10 mol% in the feed, a water / O2 molar ratio in the feed of 6-12, a linear velocity on the tube side of 150 cm / s to 500 cm / s, and a gas hourly space velocity (GHSV) over the ODH catalyst on the tube side of 1,500-10,000 hr -1 . This feature may depend on temperature and pressure. This feature may be considered under feed conditions of the ODH reactor (e.g., 200-350°C and 300-600 kPa absolute pressure). Observations on configurations 1-7 (1-stage reactor system) include: (a) more than 1 catalyst cooling section will improve ethylene selectivity and reduce the total feed flow to the reactor, and thus the reactor is smaller; (b) smaller tube diameters are generally better for ethylene selectivity because smaller diameters improve (increase) heat transfer coefficients (HTC) and heat removal, and thereby prevent or reduce the occurrence of spikes in peak temperatures (higher peak temperatures will generally lead to more undesirable reactions); (c) higher temperature rise on the coolant side may have a negative impact on heat removal and reactor size, possibly due to less coolant (salt) circulation that may result in less HTC; and (d) having a salt quench section is more efficient than TLE for the overall size of the reactor (however, salt quenching increases the complexity of the reactor design, i.e., one more cooling section [molten salt section]).

[0237] For the specific embodiments in configurations 8-10 (2-stage reactor system), some features of the 2-stage reactor system include: an O2 target of 6-10 mol% for the feed to the first stage reactor, an O2 target of 6-10 mol% for the feed to the second stage reactor, a water / O2 molar ratio of 1.5-3.5 for the first stage reactor, a line velocity of 250 cm / s to 600 cm / s for the first stage reactor, and a line velocity of 100 cm / s to 400 cm / s for the second stage reactor, and a GHSV of 2,000-6,000 hr for the combined two stages -1 , the GHSV of the first-stage reactor is 5,000-30,000hr -1 , and the GHSV of the second reactor is 2,000-10,000hr -1. These characteristics may be affected by the feed temperature and feed pressure, which are considered to be 200-350°C and 300-600 kPa absolute pressure for the feed to the first stage, and 150-300°C and 300-500 kPa absolute pressure for the feed to the second stage. The tube side temperature (including the reaction mixture and / or ODH catalyst) (and typically the shell side temperature) in the first cooling section of each stage (reactor) can be, for example, in the range of 300-450°C. The tube side temperature (including the reaction mixture and / or ODH catalyst) (and typically the shell side temperature) in the second cooling section of each stage (reactor) can be, for example, in the range of 350-500°C. An observation of the 2-stage reactor system is that for the HEX at the interstage or the salt quenching of the reaction mixture discharged at the interstage, the first reactor is larger and the second reactor is smaller than if water quenching is adopted at the interstage. Typically, the second reactor is typically larger than the first reactor, including when water quenching is adopted. However, in embodiments, for HEX and salt quench vs. water quench, the first reactor may be larger for HEX and salt quench than for water quench. In embodiments, for HEX and salt quench, the second reactor may be smaller than for water quench.

[0238] For the specific embodiments in configurations 11-13 (3-stage reactor system), the 3-stage reactor system includes an O2 target of 6-10 mol% for the feed to each of the first stage reactor, the second stage reactor, and the third stage reactor. The vast majority of the O2 in each stage should be consumed. The O2 at the discharge of each stage can be, for example, less than 0.1 mol%. The water / O2 molar ratio of the first stage reactor is 0.5-2.5, and there is usually no water / O2 molar ratio target for subsequent stages because DS is not usually added between stages. If there is an interstage water quench, its purpose is not to dilute but to quench the effluent. For quenching, sufficient water can be added to reduce the effluent temperature to, for example, 200-300°C. Additional features of these 3-stage reactor systems include a linear velocity of 250-700 cm / s for the first stage reactor, 100-450 cm / s for the second stage reactor, and 50-350 cm / s for the third stage reactor, and a GHSV of 2,000-6,000 hr for the combined three stages -1 , for the first stage reactor, GHSV is 5,000-60,000hr -1 , for a 2-stage reactor, GHSV is 5,000-30,000hr -1 , and for a 3-stage reactor, GHSV is 2,000-10,000hr -1These features may be affected by the feed temperature and feed pressure, which are considered for the first stage reactor at 200 - 350 °C and 300 - 600 kPa absolute pressure, for the second stage reactor at 150 - 300 °C and 200 - 500 kPa absolute pressure, and for the third stage reactor at 150 - 300 °C and 200 - 500 kPa absolute pressure.

[0239] For the embodiments in configurations 8 - 13 (2 - stage reactor system or 3 - stage reactor system), observations of the multi - reactor system include, for salt quench or HEX between stages, a larger first reactor, a larger second reactor, and a smaller third reactor than if water quench were implemented between stages. From 2 - stage to 3 - stage, the reactor sizes can change. Generally, the size of the first reactor < the second reactor < the third reactor <... < the nth reactor. If quench water is used, the size of the last reactor is larger compared to HEX and salt quench. If quench water is used, the size of the reactor before the last one is generally smaller compared to the cases of HEX and salt quench. Additional observations of the multi - reactor system include (a) less O2 enters the first stage and much less DS requirement compared to a 1 - stage (single reactor) system; (b) the first reactor is smaller than the terminal (final) reactor (and smaller than the single reactor in a 1 - stage system); (c) more stages result in slightly lower ethylene selectivity (ethylene selectivity of 1 - stage > 2 - stage > 3 - stage >... > n - stage); (d) more stages result in higher acetic acid (AA) selectivity (AA selectivity of 1 - stage < 2 - stage < 3 - stage <... < n - stage); (e) more stages result in lower CO / CO2 selectivity (CO / CO2 selectivity of 1 - stage > 2 - stage > 3 - stage >... > n - stage); (f) salt quench and HEX between stages can contribute to steam generation, while water quench generally has no liquid water evaporation and no heat recovery; (g) for salt quench or HEX at the inter - stage, more DS is implemented at the mixed feed of the first reactor compared to water quench (because in water quench, liquid water is added to the second or third reactor, which helps with dilution); (h) any combination of salt quench / HEX / water quench can be used for inter - stage cooling of the reactor effluent; and (i) with salt quench or HEX, more stages result in more HP / VHP steam generation. The present disclosure covers 1 - stage, 2 - stage, 3 - stage reactor systems that can be extended to an n - stage reactor system. The present disclosure covers 1, 2, or 3 catalyst cooling sections per stage of the reactor (which can be extended to n catalyst cooling sections).

[0240] One embodiment is a method of operating an ODH reactor system, including providing a feed comprising ethane, oxygen and a diluent (e.g., water vapor) to produce a reaction mixture flowing through the tube side of the ODH reactor, the ODH reactor being a multi-tubular reactor having a tube side and a shell side, wherein the ODH reactor comprises a first cooling section and a second cooling section. The method includes dehydrogenating ethane to ethylene (in the reaction mixture) via an ODH catalyst on the tube side. The method includes flowing a first coolant (e.g., a molten salt) through the shell side in the first cooling section, thereby maintaining the reaction mixture in the first cooling section at a first temperature (e.g., in the range of 300°C to 450°C). The method includes flowing a second coolant (e.g., a molten salt) through the shell side in the second cooling section, thereby maintaining the reaction mixture in the second cooling section at a second temperature (e.g., in the range of 350°C to 500°C), wherein the first temperature is lower than the second temperature. The ODH reactor may have a flow barrier on the shell side separating the first cooling section and the second cooling section, so that the first coolant and the second coolant are not combined on the shell side. The second cooling section may be located downstream of the first cooling section in the flow direction of the reaction mixture. Likewise, the second cooling section may be separated from the first cooling section by a flow barrier on the shell side. The method includes maintaining the temperature rise of the first coolant passing through the first cooling section below a first threshold value (e.g., in the range of 2°C to 8°C), and maintaining the temperature rise of the second coolant passing through the second cooling section below a second threshold value (e.g., in the range of 2°C to 8°C). The method may include discharging an effluent from the ODH reactor. The effluent may include ethylene, acetic acid, water, carbon dioxide, and carbon monoxide. The method may include heating water with at least one of the first coolant discharged from the ODH reactor, the second coolant discharged from the ODH reactor, or the effluent discharged from the ODH reactor. In an embodiment, water (e.g., BFW) is heated by at least one of the first coolant, the second coolant, or the effluent to evaporate water, thereby generating water vapor from the water. If so, the method may include causing water vapor to flow through the tubes of a heat exchanger to heat water vapor with the first coolant or the second coolant or both flowing on the shell side, thereby superheating the water vapor, wherein the water comprises boiler feed water, and the superheated water vapor is discharged from the heat exchanger.

[0241] The method may include flowing a third coolant through the shell side in a third cooling section of the ODH reactor, thereby maintaining the reaction mixture on the tube side in the third cooling section at a third temperature, wherein the third temperature is lower than the second temperature, wherein the third cooling section is operationally located downstream of the second cooling section in the direction of flow of the reaction mixture and is separated from the second cooling section by a second flow barrier on the shell side. The method may include heating water with at least one of the first coolant discharged from the ODH reactor, the second coolant discharged from the ODH reactor, the third coolant discharged from the ODH reactor, or the effluent discharged from the ODH reactor. In an embodiment, the tube side in the third cooling section does not include a catalyst, and in certain embodiments, the effluent is not used to heat the water.

[0242] Another embodiment is a method of operating an ODH reactor system, comprising providing a feed comprising ethane and oxygen to a tube of an ODH reactor having an ODH catalyst disposed therein, wherein the feed comprises water (e.g., in the form of water vapor) as a diluent, thereby maintaining the feed outside the flammability limit. The method includes dehydrogenating ethane to ethylene in a tube via an ODH catalyst in the presence of oxygen in a reaction mixture. The ODH reactor is a multi-tubular fixed bed reactor having a tube side and a shell side, wherein the tube side has a tube for the reaction mixture to flow. The ODH reactor has a first cooling section and a second cooling section that is operationally located downstream of the first cooling section in the flow direction of the reaction mixture. The first cooling section and the second cooling section can be separated by a flow barrier on the shell side. The method includes cooling the ODH catalyst to a first temperature (e.g., in the range of 300° C. to 450° C.) in a first cooling section via a first coolant flowing through a shell side in the first cooling section, and cooling the ODH catalyst to a second temperature (e.g., in the range of 350° C. to 500° C.) in a second cooling section via a second coolant flowing through a shell side in the second cooling section, wherein the first temperature is lower than the second temperature. The method may include maintaining the first temperature lower than the second temperature in response to specifying an increase in ethylene selectivity and increasing ethylene selectivity, thereby reducing the amount of oxygen in the feed to reduce the amount of water in the feed.

[0243] The method may include specifying a first temperature below a second temperature so as to favor dehydrogenating ethane to ethylene over reactions that produce carbon dioxide in the reaction mixture and over reactions that produce carbon monoxide in the reaction mixture, thereby increasing ethylene selectivity. The method includes maintaining a temperature increase of a first coolant passing through a first cooling section below a first threshold value (e.g., in the range of 2°C to 8°C) and maintaining a temperature increase of a second coolant passing through a second cooling section below a second threshold value (e.g., in the range of 2°C to 8°C). The method may include specifying that the temperature increase of the first coolant is maintained below a first threshold value and the temperature increase of the second coolant is maintained below a second threshold value so as to favor dehydrogenating ethane to ethylene over reactions that produce carbon dioxide and over reactions that produce carbon monoxide, thereby increasing ethylene selectivity. Maintaining the temperature increase of the first coolant below the first threshold value and the temperature increase of the second coolant below the second threshold value may be responsive to specifying an increase in ethylene selectivity and increasing ethylene selectivity, thereby reducing the amount of oxygen in the feed to reduce the amount of water in the feed.

[0244] The reaction of ethane and oxygen in the reaction mixture can include the following reactions: a first overall reaction including dehydrogenation of ethane to ethylene, a second overall reaction to produce acetic acid, a third overall reaction to produce carbon monoxide, and a fourth overall reaction to produce carbon dioxide. The method can include specifying an increased selectivity for ethylene by favoring the first overall reaction over the third overall reaction and the fourth overall reaction, wherein the first overall reaction consumes a less stoichiometric amount of oxygen than each of the third overall reaction and the fourth overall reaction.

[0245] The method may include discharging the reaction mixture as an effluent from the ODH reactor, wherein the effluent comprises ethylene, acetic acid, water, carbon dioxide, carbon monoxide, and unreacted ethane. The method may include heating boiler feed water with at least one of the first coolant, the second coolant, or the effluent. In an embodiment, the boiler feed water is heated to evaporate the boiler feed water, thereby generating water vapor from the boiler feed water. The method may include configuring the ODH reactor in response to specifying an increase in ethylene selectivity so that the tube having is at or less than a specified diameter, thereby improving ethylene selectivity. The specified diameter may be, for example, a diameter of 1.25 inches (e.g., a nominal diameter, an outer diameter, or an inner diameter), wherein the linear velocity of the reaction mixture in the tube is in the range of 150 cm / s to 500 cm / s, and wherein the gas hourly space velocity of the reaction mixture through the ODH catalyst in the tube is 1,500 hours. -1 (hr -1 ) to 10,000hr -1 range.

[0246] Another embodiment is an ODH reactor system, which includes an ODH reactor (multi-tubular fixed bed reactor), and the ODH reactor has a first cooling section and a second cooling section separated by a flow barrier on the shell side. The ODH reactor includes a tube side with an ODH catalyst to receive a feed comprising ethane, oxygen and water vapor, so that ethane is dehydrogenated to ethylene in the reaction mixture, and discharges an effluent comprising ethylene, acetic acid, water, carbon dioxide, carbon monoxide and unreacted ethane. The water vapor in the feed can serve as a diluent so that the feed is placed outside the flammability limit. The ODH reactor can be configured to produce acetic acid in the reaction mixture on the tube side. Ethane dehydrogenation to ethylene can be the first total reaction of ethane and oxygen on the tube side. The ODH reactor of the configuration can provide a reaction of ethane and oxygen on the tube side in the reaction mixture, and the reaction includes a second total reaction producing acetic acid, a third total reaction producing carbon monoxide and a fourth total reaction producing carbon dioxide.

[0247] Relative to the flow of the reaction mixture, the second cooling section can be operationally located downstream of the first cooling section. The shell side is configured to receive a first coolant (e.g., molten salt) into the first cooling section so as to maintain the temperature of the ODH catalyst on the tube side in the first cooling section at a first temperature (e.g., in the range of 300°C to 450°C), and to receive a second coolant (e.g., molten salt) into the second cooling section so as to maintain the temperature of the ODH catalyst on the tube side in the second cooling section at a second temperature (e.g., in the range of 350°C to 500°C), wherein the first temperature is lower than the second temperature. Similarly, the second cooling section can be operationally located downstream of the first cooling section in the flow direction of the reaction mixture. The ODH reactor system includes a first coolant supply system having a pump so as to provide the first coolant to the first cooling section and to maintain the temperature increase of the first coolant passing through the first cooling section below a first threshold value (e.g., in the range of 2°C to 8°C). The ODH reactor system includes a second coolant supply system having a pump so as to provide the second coolant to the second cooling section and to maintain the temperature increase of the second coolant passing through the second cooling section below a second threshold value (e.g., in the range of 2°C to 8°C). The ODH reactor system includes a first heat exchanger to heat the first water (e.g., BFW) with the first coolant for water vapor generation of the first water. The water vapor generation may involve a first heat exchanger configured to evaporate the first water into water vapor. The ODH reactor system may include a steam drum to receive the water vapor from the first heat exchanger and discharge the water vapor. Alternatively, the first heat exchanger that heats the first water may be a first heat exchanger configured to heat the first water to preheat the first water so as to evaporate the first water in the steam drum.

[0248] The ODH reactor system may include a second heat exchanger to heat the second water (e.g., BFW) with the second coolant discharged from the second cooling section for water vapor generation of the second water. The ODH reactor system may include a third heat exchanger to heat the third water (e.g., BFW) with the effluent for water vapor generation of the third water. Finally, the ODH reactor may have a third cooling section that is operationally located downstream of the second cooling section relative to the flow of the reaction mixture so as to receive the third coolant into the shell side. The third cooling section may be separated from the second cooling section by a second flow barrier on the shell side.

[0249] Yet another embodiment is a method of operating an ODH reactor system. The ODH reactor system includes a first ODH reactor and a second ODH reactor, each of which is a multi-tubular fixed bed reactor having a shell side and a tube side. The first ODH reactor and the second ODH reactor each have a first cooling section and a second cooling section. The first ODH reactor and the second ODH reactor may each have a flow barrier separating the first cooling section and the second cooling section on the shell side. The second ODH reactor is arranged in series downstream of the first ODH reactor in operation. The method includes providing a feed comprising ethane, oxygen and a diluent (e.g., water vapor) to the first ODH reactor, and dehydrogenating ethane to ethylene via an ODH catalyst in a reaction mixture flowing on the tube side of each of the first ODH reactor and the second ODH reactor. The method includes flowing a coolant (e.g., a molten salt) through the shell side in the first cooling section and the second cooling section of each of the first ODH reactor and the second ODH reactor, thereby cooling the reaction mixture and the ODH catalyst on the tube side. The method includes maintaining the temperature increase of the coolant in each of the first cooling section and the second cooling section of each of the first ODH reactor and the second ODH reactor below a threshold value (e.g., 2°C to 8°C). The cooling of the reaction mixture may include: maintaining the reaction mixture on the tube side in the first cooling section of the first ODH reactor at a temperature lower than the temperature of the reaction mixture on the tube side in the second cooling section of the first ODH reactor; and maintaining the reaction mixture on the tube side in the first cooling section of the second ODH reactor at a temperature lower than the temperature of the reaction mixture on the tube side in the second cooling section of the second ODH reactor. In an embodiment, the temperature of the reaction mixture in the first cooling section of each of the first ODH reactor and the second ODH reactor is in the range of 300°C to 450°C, and the temperature of the reaction mixture in the second cooling section of each of the first ODH reactor and the second ODH reactor is in the range of 350°C to 500°C.

[0250] The method includes discharging a first effluent from a first ODH reactor to a second ODH reactor, the first effluent comprising ethylene, acetic acid, water, carbon dioxide, carbon monoxide and unreacted ethane. The method includes injecting oxygen into the first effluent. The method may include cooling the first effluent upstream of injecting oxygen into the first effluent, or cooling the reaction mixture discharged from the first ODH reactor as the first effluent in a third cooling section in the first ODH reactor, or a combination thereof. The method may include injecting liquid water into the first effluent, thereby evaporating the liquid water via heat from the first effluent to cool the first effluent. The method may include cooling the first effluent through a heat exchanger using boiler feed water as a cooling medium, thereby evaporating the boiler feed water into water vapor or heating the boiler feed water so that the boiler feed water is evaporated into water vapor in a steam drum.

[0251] The method may include heating water with a coolant discharged from at least one of the first cooling section of the first ODH reactor, the second cooling section of the first ODH reactor, the first cooling section of the second ODH reactor, or the second cooling section of the second ODH reactor, wherein the heated water evaporates the water into water vapor or preheats the water so as to evaporate the water into water vapor in a water vapor drum. For the first ODH reactor and the second ODH reactor, the second cooling section may be defined as being located operationally downstream of the first cooling section in the flow direction of the reaction mixture and separated from the first cooling section by a flow barrier on the shell side. The method may include flowing a coolant through the shell side in the third cooling section of the first ODH reactor, thereby cooling the reaction mixture on the tube side in the third cooling section, wherein the third cooling section is located operationally downstream of the second cooling section of the first ODH reactor in the flow direction of the reaction mixture and separated from the second cooling section by a second flow barrier on the shell side. In an embodiment, the tube side stream in the third cooling section of the first ODH reactor does not contain a catalyst. The method may include discharging a second effluent from the second ODH reactor, the second effluent comprising ethylene, acetic acid, water, carbon dioxide, and carbon monoxide. The method may include generating water vapor via heat from at least one of a coolant discharged from the first ODH reactor, a coolant discharged from the second ODH reactor, a first effluent discharged from the first ODH reactor, or a second effluent discharged from the second ODH reactor. Finally, the method may include heating the water vapor with a coolant from the first ODH reactor or the second ODH reactor or both, thereby superheating the water vapor.

[0252] Another embodiment is a method of operating an ODH reactor system, including providing a feed comprising ethane, oxygen and a diluent to a first ODH reactor having a tube side and a shell side to produce a first reaction mixture flowing through the tube side. The feed may have a diluent (e.g., water vapor) so that the feed is kept outside the flammability limit. The method includes dehydrogenating ethane to ethylene in the first reaction mixture flowing through the tube side via an ODH catalyst on the tube side, wherein the first ODH reactor has a first cooling section and a second cooling section that is operationally located downstream of the first cooling section. In an embodiment, the first cooling section and the second cooling section are separated by a flow barrier on the shell side. The method includes causing a first coolant to flow through the shell side in the first cooling section, thereby maintaining the ODH catalyst in the first cooling section at a first temperature. The method includes causing a second coolant to flow through the shell side in the second cooling section, thereby maintaining the ODH catalyst in the second cooling section at a second temperature. The method includes specifying a first temperature lower than a second temperature to facilitate the ethylene selectivity in the first reaction mixture in the first cooling section. The method may include specifying a temperature rise of the first coolant through the first cooling section to be below a first threshold value to favor ethylene selectivity in the first reaction mixture; and specifying a temperature rise of the second coolant through the second cooling section to be below a second threshold value to favor ethylene selectivity in the first reaction mixture. The method may include maintaining a temperature rise of the first coolant through the first cooling section below a first threshold value, wherein the first temperature is less than the second temperature; and maintaining a temperature rise of the second coolant through the second cooling section below a second threshold value. The method may include discharging the first reaction mixture from a tube side to a second ODH reactor as a first effluent from the first ODH reactor to produce a second reaction mixture flowing through the second ODH reactor.

[0253] The method may include cooling the first effluent by injecting liquid water into the first effluent or by a heat exchanger using boiler feed water as a cooling medium. The method may include injecting oxygen into the first effluent, wherein the first effluent discharged from the first ODH reactor contains ethylene, acetic acid, water, carbon dioxide, carbon monoxide and unreacted ethane. The method may include causing a third coolant to flow through the shell side in the third cooling section of the first ODH reactor, thereby cooling the first reaction mixture on the tube side in the third cooling section, wherein the third cooling section is operationally located downstream of the second cooling section and is separated from the second cooling section by a second flow barrier on the shell side. The method may include injecting oxygen into the first effluent. In an embodiment, the tube side in the third cooling section (of the first ODH reactor) does not contain a catalyst. The method may include heating water with at least one of the first coolant discharged from the first cooling section, the second coolant discharged from the second cooling section, or the first effluent, thereby promoting the production of water vapor from the water. In an embodiment, the heating of water (e.g., boiler feed water) to facilitate the generation of steam from water involves heating water to evaporate the water into steam or preheating water to evaporate the water into steam in a steam drum. The method may include heating the steam with a first coolant from the shell side of the first cooling section or with a second coolant from the shell side of the second cooling section, or both, thereby superheating the steam.

[0254] The method may include dehydrogenating ethane to ethylene in a second reaction mixture flowing through the tube side of the second ODH reactor via an ODH catalyst on the tube side of the second ODH reactor, wherein the second ODH reactor has a third cooling section and a fourth cooling section. The second ODH reactor may be a multi-tubular fixed bed reactor having a tube side and a shell side, and the second reaction mixture flows through the tube side of the second ODH reactor. The method may include discharging the second reaction mixture from the second ODH reactor as a second effluent. The method may include flowing a third coolant through the shell side of the second ODH reactor in the third cooling section, thereby maintaining the ODH catalyst in the third cooling section at a third temperature; and flowing a fourth coolant through the shell side in the fourth cooling section, thereby maintaining the ODH catalyst in the fourth cooling section at a fourth temperature, wherein the fourth temperature is greater than the third temperature. The method may include maintaining the temperature increase of the third coolant passing through the third cooling section below a third threshold; and maintaining the temperature increase of the fourth coolant passing through the second cooling section below a fourth threshold. The method may include heating water with at least one of a first coolant discharged from the first cooling section, a second coolant discharged from the second cooling section, a third coolant discharged from the third cooling section, a fourth coolant discharged from the fourth cooling section, the first effluent, or the second effluent, wherein the heating of the water evaporates the water into water vapor or preheats the water to evaporate the water into water vapor in a water vapor drum.

[0255] Another embodiment is an ODH reactor system, which includes a first ODH reactor (multi-tubular fixed bed reactor), the first ODH reactor having a first cooling section and a second cooling section separated by a flow barrier on the first shell side. The second cooling section is located downstream of the first cooling section in operation. The first ODH reactor includes a first tube side with an ODH catalyst to receive a feed comprising ethane, oxygen and water vapor, so that ethane is dehydrogenated to ethylene in the first reaction mixture, and the first effluent comprising ethylene, acetic acid, water, carbon dioxide, carbon monoxide and unreacted ethane is discharged to the second ODH reactor through a first effluent discharge conduit. The water vapor in the feed can act as a diluent to place the feed outside the flammability limit. The first ODH reactor includes a first shell side so that a first coolant is received in the first cooling section so that the temperature of the ODH catalyst in the first cooling section is maintained at a first temperature, and a second coolant is received in the second cooling section so that the temperature of the ODH catalyst in the second cooling section is maintained at a second temperature, wherein the first temperature is lower than the second temperature. The ODH reactor system includes a second ODH reactor (multi-tube fixed bed reactor) having a third cooling section and a fourth cooling section separated by a flow barrier on the second shell side. The fourth cooling section is located downstream of the third cooling section in operation. The second ODH reactor includes a second tube side with an ODH catalyst to receive a first effluent so as to dehydrogenate ethane into ethylene in the second reaction mixture, and discharge the second effluent through a second effluent discharge conduit. The second ODH reactor includes a second shell side so as to receive a third coolant in the third cooling section so as to maintain the temperature of the ODH catalyst in the third cooling section at a third temperature, and to receive a fourth coolant in the fourth cooling section so as to maintain the temperature of the ODH catalyst in the fourth cooling section at a fourth temperature, wherein the third temperature is lower than the fourth temperature. In an embodiment, the first temperature and the third temperature are each in the range of 300°C to 450°C, and the second temperature and the fourth temperature are each in the range of 350°C to 500°C.

[0256] The ODH reactor system may include a first coolant supply system having a pump to provide a first coolant to a first cooling section and maintain a temperature rise of the first coolant through the first cooling section below a first threshold; a second coolant supply system including a pump to provide a second coolant to a second cooling section and maintain a temperature rise of the second coolant through the second cooling section below a second threshold; a third coolant supply system including a pump to provide a third coolant to the first cooling section and maintain a temperature rise of the third coolant through the third cooling section below a third threshold; and a fourth coolant supply system including a pump to provide a fourth coolant to a fourth cooling section and maintain a temperature rise of the fourth coolant through the fourth cooling section below a second threshold. In an embodiment, the first threshold and the second threshold are in the range of 2°C to 8°C. In an embodiment, the first coolant and the second coolant are each or include a molten salt.

[0257] The ODH reactor system may include an oxygen supply conduit to inject oxygen into the first effluent flowing through the first effluent discharge conduit. The ODH reactor system may include a water injection conduit to inject liquid water into the first effluent flowing through the first effluent discharge conduit to cool the first effluent. The ODH reactor system may include a heat exchanger arranged along the first effluent discharge conduit to cool the first effluent with water, thereby heating the water to produce water vapor from the water. The first ODH reactor may have a fifth cooling section operationally located downstream of the second cooling section to cool the first reaction mixture flowing through the first tube side in the fifth cooling section, wherein the fifth cooling section and the second cooling section are separated by a second flow barrier on the first shell side. In an embodiment, the first tube side in the fifth cooling section does not have an ODH catalyst or other catalyst.

[0258] The ODH reactor system may include a heat exchanger to heat water with the first coolant discharged from the first cooling section to produce water vapor from the water. The ODH reactor system may have a superheater heat exchanger to heat water vapor with the first coolant from the first shell side or with the second coolant from the first shell side or both to superheat the water vapor. The ODH reactor system may include a heat exchanger to heat water with the second coolant discharged from the second cooling section to produce water vapor from the water. The ODH reactor system may have a heat exchanger to heat water with the third coolant discharged from the third cooling section to produce water vapor from the water. The ODH reactor system may have a heat exchanger to heat water with the fourth coolant discharged from the fourth cooling section to produce water vapor from the water. The ODH reactor system may have a heat exchanger arranged along the second effluent discharge conduit to heat water with the second effluent to produce water vapor from the water. The first ODH reactor may be configured to produce acetic acid from ethane in the first reaction mixture flowing through the first tube side. The second ODH reactor is configured to produce acetic acid from ethane in the second reaction mixture flowing through the second tube side. Example

[0259] The examples (for configurations 1-13) cover reactions carried out with low temperature ODH catalysts (MoVNbTeOx discussed previously) at temperatures of 300-450°C in an ODH reactor to produce mainly ethylene with high selectivity. In order to remain outside the flammability envelope of the ethane-oxygen mixture, a diluent is used. Evaporated water can be used as a diluent to achieve staying outside the flammability envelope. Based on the pressure and temperature of the mixed feed of the reactor, the target oxygen concentration can be different. The present disclosure includes reactor designs and set configurations with different levels and different reactor cooling schemes for comparison. In the configuration, HP / VHP steam is produced via cooling the hot coolant (hot molten salt) discharged from different reactor sections. The comparative figures (values) presented below are for illustrative purposes to show the relative advantages or disadvantages of one configuration relative to another configuration. Configurations 1-13 as several configurations of reactor systems and reactor designs are summarized as follows, and tabulated data (see Tables 2-4) are taken into account. Configuration 2 is selected as the base case in the comparison.

[0260] Through Siemens Process Systems Engineering (PSE) The platform software (gPROMS ProcessBuilder version 1.3.1) takes into account the reactor design. V10 was used for process simulation. SR-POLAR equation of state was used for simulation. Aspen The software is available from Aspen Technology, Inc., headquartered in Bedford, Massachusetts, USA.

[0261] Configuration 1( Figure 3 Embodiment) is a 1-stage reactor with 1 catalyst cooling section, 1 inch tubes and <5°C temperature rise in the coolant (salt). A TLE is included after the reactor for HP / VHP water vapor generation or BFW preheating. This can be characterized as the simplest configuration for building a reactor; however, since there is only one cooling section, it requires as high a dilution as possible. It is a relatively large reactor per unit of ethylene production. This reactor requires about 65% more tubes than Configuration 2 (baseline), with about 35% more tube length, which means about 125% more catalyst. This translates into a longer residence time or a smaller GHSV compared to Configuration 2. The selectivity for ethylene and AA is lower than Configuration 2, while the CO / CO2 selectivity is much higher. This means more molten salt to cool the reactor and more water vapor generation. Due to the higher dilution requirements and poorer performance compared to Configuration 2, the CO2 intensity (mass ratio) of this ODH unit (entire unit) (e.g., tons of CO2 emitted / ton of ethylene produced) is about 50% higher than Configuration 2.

[0262] Configuration 2( Figure 4 Embodiments) are 1 stage reactors with 2 catalyst cooling sections, 1 inch tubes, and <5°C temperature rise in molten salt, and TLE after the reactor for HP / VHP steam generation or BFW preheat. Again, in the comparison of Configurations 1-13, Configuration 2 is arbitrarily the base case. As noted above, Configuration 2 generally has much better performance than Configuration 1.

[0263] Configuration 3( Figure 4Embodiment) is a 1 stage reactor with 2 catalyst cooling sections, 1 inch tubes and about 15°C temperature rise in the coolant (molten salt) across each of the two cooling sections, and a post-reactor TLE for HP / VHP steam generation or BFW preheat. Thus, the basis of Configuration 3 is the same as Configuration 2, except that the temperature rise of the salt is 15°C instead of <5°C. The results of Configuration 3 show that the temperature rise of the coolant (molten salt in this case) of the increased reactor should generally be limited. The greater the temperature rise, the less molten salt circulation, resulting in a reduced heat transfer coefficient (HTC). Compared to Configuration 2, this will result in about 9% lower ethylene and AA selectivity and 9% more CO / CO2 selectivity. To achieve the same ethylene production, the number of tubes will be more than doubled, and the length of the tubes will be about 140% longer, which means about 420% more catalyst than Configuration 2. This can be translated into a longer residence time or a smaller GHSV compared to Configuration 2. Due to the high dilution requirements and the poorer performance compared to Configuration 2, the CO2 intensity of the entire device is about 40% higher than Configuration 2.

[0264] Configuration 4( Figure 4 Embodiment) has a 1-stage reactor with 2 catalyst cooling sections, 1.25 inch tubes and <5°C temperature rise in molten salt, and a TLE after the reactor for HP / VHP steam generation or BFW preheating. The basics are the same as Configuration 2, except that 1.25 inch tubes are used instead of 1 inch tubes. This shows that although larger tubes can be used for reactor design, heat removal and performance are not as effective as the smaller tubes in Configuration 2. The larger tubes have lower HTC and poorer heat removal inside the tubes. This will result in slightly lower ethylene and AA selectivities, and slightly higher CO / CO2 selectivities compared to Configuration 2. To achieve the same ethylene production, the number of tubes should be 20% less (easier to build) and the length of the tubes should be about 35% longer and the catalyst should be about 65% more than Configuration 2. This can translate into longer residence time or smaller GHSV compared to Configuration 2. Due to the slightly higher dilution requirements and slightly worse performance compared to Configuration 2, the CO2 intensity of this ODH plant is about 5% higher than Configuration 2, which is very comparable. However, the lower amount of catalyst makes Configuration 2 more attractive.

[0265] Configuration 5( Figure 4Embodiment) has a 1 stage reactor with 2 catalyst cooling sections, 1.5 inch tubes and <5°C temperature rise in molten salt and TLE after the reactor for HP / VHP steam generation or BFW preheat. This shows that although larger tubes can be used for the reactor design, the heat removal and performance are not as effective as the smaller tubes (Configurations 2 and 4). The larger tubes have lower HTC and poorer heat removal inside the tubes. This will result in about 5% lower ethylene and AA selectivity and 5% more CO / CO2 selectivity compared to Configuration 2. To achieve the same ethylene production, the number of tubes should be 20% less (easier to build) and the length of the tubes is almost twice as long, which means about 265% more catalyst than Configuration 2. This can translate into longer residence time or smaller GHSV compared to Configuration 2. Due to the high dilution requirements and poor performance compared to Configuration 2, the CO2 intensity of the ODH plant is about 25% higher than Configuration 2.

[0266] Configuration 6( Figure 5 Embodiment) is a 1-stage reactor with 2 catalyst cooling sections and 1 non-catalyst cooling section for BFW heating or V / HP steam generation, 1 inch tubes and a temperature rise of <5°C in molten salt. This means that instead of a TLE after the reactor, another cooling section with molten salt circulation is added to the end portion of the reactor, and the hot molten salt is used to preheat boiler feed water (BFW) or generate HP / VHP steam. For this third non-catalyst cooling section, this increases the length of the reactor and generally does not affect other aspects of the reactor design or performance compared to configuration 2.

[0267] Configuration 7( Figure 6 Embodiment) is a 1-stage reactor with 3 catalyst cooling sections, 1-inch tubes, <5°C temperature rise in molten salt, and a TLE after the reactor for HP / VHP steam generation or BFW preheat. This shows that adding additional cooling sections will generally improve reactor performance because the reaction can generally be carried out in a more temperature-controlled manner. Compared to Configuration 2, this will result in slightly higher ethylene selectivity at the expense of smaller AA / CO / CO2 selectivity. To achieve the same ethylene production, the number of tubes should be 10% less and 10% shorter, which means about 20% less catalyst than Configuration 2. Compared to Configuration 2, this can translate into shorter residence time or greater GHSV. The CO2 intensity of this ODH unit is slightly lower than Configuration 2 due to less dilution requirements and better performance compared to Configuration 2. Configuration 7 shows that the number of catalyst cooling sections can be extended to "n"; however, this will increase the complexity of reactor design and manufacturing.

[0268] Configuration 8( Figure 7Embodiment) is a 2-stage reactor system with 2 catalyst cooling sections in each stage, 1 inch tubes, <5°C temperature rise in molten salt, interstage water quenching, interstage oxygen addition, and TLE after the second reactor for HP / VHP steam generation or BFW preheating. Again, this configuration is a two-stage reactor system. All ethane, a portion of oxygen, and water diluent enter the first reactor with 2 catalyst cooling sections. The first reactor converts almost all of the oxygen entering (fed to) the first reactor. The effluent from the first reactor is quenched with liquid water to reduce the temperature of the gas (effluent). Oxygen is then added. When oxygen is added, the addition of quench water will prevent sudden spontaneous combustion of the gas components (ethylene, ethane, AA, CO). One of the main ideas of the 2-stage reactor is to split the oxygen between the two stages. This will reduce the oxygen in the first stage and therefore reduce the dilution water requirements for the first stage and the entire reactor system. Because in the second stage, the water already added to the first stage plus the produced water is still in the mixture, no additional dilution is required.

[0269] This 2-stage reactor system with interstage water quenching and interstage addition will result in slightly lower ethylene selectivity; however, it will increase AA selectivity by more than 2% and reduce CO / CO2 selectivity compared to Configuration 2. To achieve the same ethylene production, the first stage reactor is much smaller than the second stage reactor. For the first stage, the number of tubes should be 65% less and 60% shorter than Configuration 2. On the other hand, for the second stage, the number of tubes should be 30% more and 15% shorter than the single reactor of Configuration 2. The second stage reactor is relatively large, but comparable to a single-stage reactor (Configuration 2). Compared to Configuration 2 with a 1-stage reactor, the total catalyst in the 2-stage reactor is approximately 25% more. The residence time of the first stage is very short, while the second stage has a residence time comparable to that of the reactor in Configuration 2. Due to much less dilution requirements and slightly better performance compared to Configuration 2, the CO2 intensity of this ODH device is 40% lower than Configuration 2.

[0270] Configuration 9( Figure 8Embodiment) is a 2-stage reactor system with 2 catalyst cooling sections in each stage, 1 inch tubes, <5°C temperature rise in molten salt, 1 non-catalyst cooling section at the end of the 1st stage, oxygen at the interstage, and a TLE after the second reactor for HP / VHP steam generation or BFW preheating. Similar to configuration 8, but instead of quenching the effluent from the 1st stage reactor with quench water, an additional cooling section that is a non-catalyst cooling section is added to the end of the first stage reactor. This means that the first stage has two catalyst cooling sections with molten salt circulation and one non-catalyst cooling section with molten salt circulation. This additional section will increase the complexity of the design and manufacture of the 1st reactor, but can significantly improve the heat recovery from the effluent of the first stage reactor. In configuration 8, the quench water evaporates and no heat recovery is performed. Instead, the hot molten salt from this third cooling section in configuration 9 preheats the BFW or produces HP / VHP steam.

[0271] Configuration 9 has a slightly lower ethylene selectivity than Configuration 8; however, it will slightly increase AA selectivity and reduce CO / CO2 selectivity compared to Configuration 8. To achieve the same ethylene production, the first stage reactor is much smaller than the second stage reactor. For the first stage, the number of tubes should be 60% less and 40% shorter than the only reactor in Configuration 2. However, it is larger than the first stage reactor of Configuration 8. On the other hand, for the second stage, the number of tubes should be 20% more and 15% shorter than the only reactor in Configuration 2. The second stage reactor is relatively comparable to the single-stage reactor (Configuration 2). However, the second stage of Configuration 9 is smaller than the second stage reactor of Configuration 8. The second reactor (stage 2 reactor) has about 15% more total catalyst than the only reactor in Configuration 2 (stage 1 reactor). The residence time of the first stage is very short, while the second stage has a residence time comparable to that of Configuration 2. Due to much lower dilution requirements and significant heat recovery from the effluent of the first stage reactor, as well as slightly better performance compared to Configuration 2, the CO2 intensity of the entire device is 55% lower than Configuration 2 and nearly 10% lower than Configuration 8.

[0272] Configuration 10( Fig. 9 Embodiment) is a 2-stage reactor system with 2 catalyst cooling sections in each stage, 1 inch tubes, <5°C temperature rise in molten salt, HEX quenching at the interstage, oxygen addition at the interstage, and a TLE after the second reactor for HP / VHP steam generation or BFW preheat. Similar to configuration 10, but instead of the third cooling section in the first stage reactor, a HEX is employed between the two stages. After the entire reactor system, this HEX is similar to a TLE and can be used for BFW preheat or HP / VHP steam generation. There is generally no difference between the performance of configuration 10 and configuration 9.

[0273] Configuration 11( Fig.10Embodiment) is a 3-stage reactor system with 2 catalyst cooling sections, 1 inch tubes, <5°C temperature rise in molten salt, water quenching at the interstage, oxygen addition at the interstage, and TLE after the third reactor for HP / VHP steam generation or BFW preheating in each stage. This is similar to configuration 8, but with a third reactor. All ethane, a portion of the oxygen and water diluent enter the first reactor (with 2 catalyst cooling sections), which converts almost all of the oxygen. The effluent from the first reactor is quenched with water liquid to reduce the temperature of the gas (effluent). Oxygen is then added at the interstage between the first and second reactors. When oxygen is added, the addition of quenching water will prevent sudden spontaneous combustion of the gas components (ethylene, ethane, AA, CO). The effluent passes through the second stage in a similar manner to the first stage. The effluent from the second stage is quenched again with quenching water, oxygen is then added, and it enters the third stage. The main idea of ​​the third reactor (3-stage reactor) is to share the oxygen between the three stages. This will reduce the oxygen in the first stage and therefore reduce the dilution water requirements for the first stage and the entire reactor system. Because the water that was added to the first stage is still in the mix in the second and third stages, no additional dilution is required.

[0274] This 3-stage reactor system with water quench and oxygen interstage will result in lower ethylene selectivity; however, it increases AA selectivity by about 4% and decreases CO / CO2 selectivity compared to Configuration 2. It shows the same trend from 2 stages (Configuration 8) to 3 stages. AA selectivity is improved, and ethylene, CO / CO2 selectivity decreases. To achieve the same ethylene production, the first stage reactor is much smaller than the second and third stage reactors. The second stage is also much smaller than the third stage. For the first stage, the number of tubes should be 80% less and 70% shorter than Configuration 2. For the second stage, the number of tubes should be 40% less and 55% shorter than Configuration 2. On the other hand, for the third stage, the number of tubes should be 60% more than Configuration 2 but about 30% shorter. Compared to Configuration 2, the third reactor (3-stage reactor) has about 40% more total catalyst, and even more than Configuration 8. The residence time of the first and second stages is very short, while the third stage has a residence time comparable to that of the second stage of Configuration 2 and Configuration 8. Due to much less dilution requirements and slightly better performance compared to Configuration 2, the CO2 intensity of the entire plant is 50% lower than Configuration 2, which is 10% better (lower) than Configuration 8. This suggests that adding stages will improve the overall performance of the ODH plant. However, moving from stage 1 to stage 2 reduces the CO2 intensity by 40%, and the increment from stage 2 to stage 3 is only 10%, which may make stage 2 more attractive. Adding another stage will increase the capital and operating costs of the plant and the complexity of the reactor design and manufacture.

[0275] Configuration 12( Fig.11) is a 3-stage reactor system with 2 catalyst cooling sections in each stage, 1 inch tubes, <5°C temperature rise in molten salt, 1 non-catalyst cooling section at the end of the first and second stages, oxygen injection at the interstage, and a TLE after the third reactor for HP / VHP steam generation or BFW preheating. Similar to configuration 11, but instead of quenching the effluent from the 1st and 2nd stage reactors with quench water, an additional non-catalyst cooling section is added to the 1st and 2nd stage reactors. This means that the first and second stages have two catalyst cooling sections with molten salt circulation and one non-catalyst cooling section with molten salt circulation. This additional section will increase the complexity of the design and manufacture of the first and second reactors, but will significantly improve the heat recovery from the effluent of the first and second stage reactors. In configuration 11, the quench water is evaporated and no heat recovery is performed. In contrast, for configuration 12, the hot molten salt from the third cooling section is used to preheat BFW or V / HP steam generation.

[0276] In addition, configuration 12 has a slightly lower ethylene selectivity than configurations 2, 9, and 11; however, it will slightly increase AA selectivity and decrease CO / CO2 selectivity compared to configurations 2, 9, and 11. To achieve the same ethylene production, the first stage reactor is much smaller than the second and third stage reactors. In addition, the second stage is much smaller than the third stage. For the first stage, the number of tubes should be 75% less and 55% shorter than configuration 2. For the second stage, the number of tubes should be 25% less and 45% shorter than configuration 2. On the other hand, for the third stage, the number of tubes should be 40% more but about 35% shorter than in configuration 2. The total catalyst of the 3-stage reactor (third reactor) is about 15% more than that of configuration 2, but is similar to the 2-stage reactor (second reactor) of configuration 9. The residence time of the 1st and 2nd stages is very short, while the third stage has a residence time comparable to that of configuration 2. Due to much lower dilution requirements and higher heat recovery from the effluents of the 1st and 2nd stage reactors, as well as slightly better performance compared to Configurations 2 and 9, the CO2 intensity of this ODH plant is 70% lower than Configuration 2, almost 15% lower than Configuration 9, and 20% lower than Configuration 11. Thus, adding additional stages will improve the overall performance of the ODH plant in terms of CO2 intensity.

[0277] Configuration 13( Fig.12 ) is a 3-stage reactor system with 2 catalyst cooling sections in each stage, 1 inch tubes, <5°C temperature rise in molten salt, HEX quench at interstage, oxygen addition at interstage, and TLE after the third reactor for HP / VHP steam generation or BFW preheat. Similar to configuration 12, but instead of the third cooling section in the 1st and 2nd stage reactors, HEX is used between stages (see Fig.12). These HEXs are similar to TLE after the entire reactor system and can be used for BFW preheating or HP / VHP steam generation. There is generally no difference between the performance of Configuration 13 and Configuration 12.

[0278] Table 2 is the data of configuration 1-7, which is a single reactor system with a single ODH reactor. ΔT coolant is the temperature rise (temperature rise) of the coolant (molten salt) through each cooling section. For configuration 2 as the base case, the number of tubes (#), tube length, active catalyst (ODH catalyst), space-time yield (STY) and total flow rate are specified as 100%, and the remaining configurations are expressed as a percentage of 100% relative to configuration 2. The total mass flow rate is the total mass flow rate (mass / time) of the feed (ethane, oxygen and dilution water vapor) of the ODH reactor. Configuration 6 does not use TLE because the third cooling section in configuration 6 is a non-catalyst cooling section. Before the reaction mixture is discharged as effluent, the non-catalyst cooling section cools the reaction mixture with a coolant (molten salt), and wherein the cooling can be marked as salt quenching. The symbol Δ of ethane conversion refers to the absolute percentage difference between the listed values ​​and the ethane conversion of configuration 2. Similarly, the symbol Δ of the three rows of selectivity under ethane conversion indicates that the listed values ​​are the absolute percentage differences with the given conversion of configuration 2. The O2 / ethane mass ratio and the water / ethane mass ratio are used for the feed of the ODH reactor, and the water is the dilution water vapor. The amount of ethane feed (mass / time) is the same in all configurations 1-7. Finally, although the tube diameter in various applications can be an outer diameter (OD), an inner diameter (ID), or a nominal diameter, the specified values ​​of the diameters in Table 2 are ODs for simulation. In these embodiments used for simulation, a 1-inch tube has an OD of 1 inch, a wall thickness of 0.083 inches, and an ID of 0.834 inches; a 1.25-inch tube has an OD of 1.25 inches, a wall thickness of 0.120 inches, and an ID of 1.01 inches; and a 1.5-inch tube has an OD of 1.5 inches, a wall thickness of 0.134 inches, and an ID of 1.232 inches.

[0279] Table 2. Data for configurations 1-7

[0280]

[0281]

[0282] 1. All configurations compared to configuration 2.

[0283] 2. Δ vs configuration 2 (eg, ethane conversion Δ of configuration 1 = ethane conversion of configuration 1 minus ethane conversion of configuration 2).

[0284] 3. Section 3 replaces the TLE and non-catalyst molten salt cooling section.

[0285] 4. The third section is the third catalyst molten salt cooling section.

[0286] Table 3 is the data of configuration 8-13. As discussed, configuration 8-13 is a multi-reactor system with more than one ODH reactor (stage). All configurations 8-13 have the same amount (mass / time) of ethane fed to the ODH reactor system (particularly fed to the first ODH reactor). All configurations 8-13 have 1 "tubes (where 1" is the outer diameter (OD) of the tube used for simulation), TLE after the final ODH reactor, and a temperature rise of <5°C of the coolant molten salt through each cooling section in the ODH reactor. The number (#) of cooling sections for each stage is given. For example, the 3 / 2 listed for configuration 9 means three cooling sections in the first reactor (first stage) and two cooling sections in the second reactor (second stage). For the only ODH reactor in configuration 2 as the base case, the number (#) of tubes, tube length, active catalyst (ODH catalyst), space-time yield (STY), and total flow are specified as 100%, and the corresponding values ​​for configuration 8-13 ODH reactors are percentages relative to 100% of configuration 2. The total mass flow rate is the total flow rate (mass / time) of the feed (ethane, oxygen, and dilution water vapor) to the first ODH reactor, the oxygen injected interstage, and any water injected at the interstage (for water quench configurations 8 and 11). As with Table 2, the Δ sign for ethane conversion (for the multi-reactor system) means that the value listed is the absolute percentage difference from the ethane conversion of the single reactor system of configuration 2. Similarly, the Δ sign for selectivity means that the value listed is the absolute percentage difference from the given conversion for configuration 2. The O2 / ethane mass ratio is the mass ratio of total oxygen (fed to the first ODH reactor plus interstage injection) to the ethane fed to the first ODH reactor. The water / ethane mass ratio is the mass ratio of water (dilution water vapor) in the feed to the first ODH reactor (and any interstage injected liquid water for water quenching purposes in configurations 8 and 11) to the ethane fed to the first ODH reactor.

[0287] Table 3. Data for configuration 8-13

[0288]

[0289]

[0290] 1. All configurations compared to configuration 2.

[0291] 2. # of tubes and tube lengths for each stage (compare more than 1 stage reactor to configuration 2 with one stage reactor).

[0292] 3. Δ vs Configuration 2 (eg, ΔC2 conversion of Configuration 8 = overall C2 conversion of Configuration 8 minus C2 conversion of Configuration 2).

[0293] Table 4 gives the results for configurations 1-13. The first row is the configuration number. Configurations 1-7 are ODH reactor systems with one ODH reactor (single reactor system). Configurations 8-13 are ODH reactor systems with more than one ODH reactor (multiple reactor systems). In particular, configurations 8-10 have two ODH reactors in series (two-stage reactor system), and configurations 11-13 have three ODH reactors in series (three-stage reactor system).

[0294] The second row in Table 4 is the main duty (heat) requirement of the ODH unit, which is a combination of the heat requirement of (1) dilution steam generation for the reactor feed and (2) solvent recovery in the acetic acid unit. Solvent recovery in the AA unit may consume more energy due to the presence of more water. The more dilution steam, the greater the cooling requirement for the condensed water / AA after the reactor system. More dilution steam also provides more water in AA to the AA unit. Therefore, more solvent is used to separate AA from water, and thus more heat is used for the reboiler of the solvent recovery column, and more cooling requirement for the condenser of the solvent recovery column.

[0295] The third row is the primary cooling requirement in the ODH plant, which is a combination of (1) the cooling requirement for condensation (including condensed water) in the reactor effluent and (2) the cooling requirement for solvent recovery in the acetic acid unit. The fourth row in Table 2 is the reactor HP / VHP steam production. The fifth row is the mass ratio (e.g., kg / kg) of the LP / MP steam requirement of the ODH plant to the HP / VHP steam produced at the reactor system. The sixth row is the CO2 intensity (venting and non-venting) of the ODH plant, which is CO2 emissions produced / ethylene production.

[0296] In Table 4, the load demand, cooling demand, water vapor generation, and CO2 intensity are assigned to 100% for Configuration 2 as the base case, and the remaining configurations have percentages relative to 100% of Configuration 2. The load demand and cooling demand (and thus CO2 intensity) of the two-stage reactor system are significantly reduced compared to the one-stage reactor system because less oxygen (and thus less dilution water vapor) is fed to the first reactor in the two-stage reactor system.

[0297] Table 4. Results of configurations 1-13

[0298]

[0299] 1. Total load demand (LP / MP steam) of major load demand areas (dilution steam generation and acetic acid solvent recovery section) vs. Configuration 2.

[0300] 2. Total cooling demand (air cooler or cooling water) for major cooling demand areas (reactor effluent cooling and acetic acid solvent recovery section) vs. Configuration 2.

[0301] 3. HP / VHP steam generation vs. configuration 2 of reactor system.

[0302] 4. “LP / MP steam demand of ODH plant” versus “HP / VHP steam generated by reactor system”.

[0303] 5. CO2 intensity of ODH plant (tons of CO2 produced [emitted and non-emitted] per ton of ethylene production) vs. Configuration 2.

[0304] In general, for these configurations, any combination of water quench, HEX quench, or non-catalyst salt quench for the effluent of each stage of the reactor may be employed. In addition, ethane or water vapor may be added between stages. Furthermore, the salt flow may be co-current or counter-current relative to the process flow inside the tubes (see, e.g., Figure 4 and 4A ). In a configuration with more than one stage, each stage can be co-current or counter-current. This means, for example, that if the first stage is co-current, the second stage can be co-current or counter-current, or if the first stage is counter-current, the second stage can be co-current or counter-current.

[0305] The following may be benefits of embodiments of the present technology. A TLE after the only or final reactor may help recover more heat. Additional cooling sections at the end of each stage as non-catalyst sections may also help recover heat for HP / VHP steam generation.

[0306] Adding more catalyst cooling sections will improve the performance of the reactor to produce more ethylene and AA and less undesirable CO / CO2. It can help control the reaction temperature. In the first cooling section of the reactor, most of the oxygen can be consumed, and in the next section of the reactor, the remaining oxygen can be consumed while maintaining good selectivity to the desired products.

[0307] Limiting the temperature rise in the salt to about 5°C can improve the overall performance of the reactor in terms of producing more desired products. Allowing a higher temperature rise for the salt in each cooling section generally means less molten salt circulation, which will reduce the overall HTC on the molten salt side and result in poorer heat removal from the reaction inside the tubes.

[0308] Smaller tubes provide better reactor performance in terms of desired products. It will improve the HTC inside the tubes (on the tube side) and thereby improve (increase) heat removal from the inside of the tubes.

[0309] Adding additional stages (additional reactors) to the ODH reactor system to create a 2-stage system or a 3-stage system (or an n-stage system where n=3+) will help to distribute the oxygen between the stages and reduce the dilution requirements of the reactor system (for the first stage), which will improve the efficiency of the entire plant. Less dilution water vapor means less energy consumption for the ODH plant. The generation of dilution water vapor requires energy. Downstream, the steam water in the reactor system effluent (along with AA) is condensed to the AA unit. This means energy consumed by condensing water from the reactor effluent and the AA unit.

[0310] Water quenching can be used as an effective technique to cool the reactor effluent between stages before adding oxygen. HEX quenching or an additional non-catalyst salt quenching stage at the end of each stage may be more efficient than water quenching due to the heat recovery using molten salt or HEX quenching. This additional heat recovery will improve the performance of the entire plant in terms of energy and CO2 intensity compared to water quenching.

[0311] A number of implementations have been described, however, it will be appreciated that various modifications can be made without departing from the spirit and scope of the disclosure.

Claims

1. A method of operating an oxidative dehydrogenation (ODH) reactor system, the method comprising: providing a feed comprising ethane, oxygen, and a diluent to produce a reaction mixture flowing through a tube side of an ODH reactor, the ODH reactor being a multi-tubular reactor having a tube side and a shell side, wherein the ODH reactor comprises a first cooling section and a second cooling section; Dehydrogenation of ethane to ethylene in the reaction mixture via an ODH catalyst on the tube side; flowing a first coolant through the shell side in the first cooling section, thereby maintaining the reaction mixture in the first cooling section at a first temperature; flowing a second coolant through the shell side in the second cooling section to thereby maintain the reaction mixture in the second cooling section at a second temperature, wherein the first temperature is lower than the second temperature; maintaining a temperature increase of the first coolant passing through the first cooling section below a first threshold; and The temperature rise of the second coolant passing through the second cooling section is maintained below a second threshold value.

2. The method of claim 1, wherein the first temperature is in the range of 300°C to 450°C, the second temperature is in the range of 350°C to 500°C, the first threshold is in the range of 2°C to 8°C, and the second threshold is in the range of 2°C to 8°C, wherein the first coolant and the second coolant each comprise a molten salt, and wherein the diluent comprises water vapor.

3. The method according to claim 1, comprising: discharging an effluent from the ODH reactor, the effluent comprising ethylene, acetic acid, water, carbon dioxide, and carbon monoxide, wherein the ODH reactor comprises a flow barrier on the shell side, the flow barrier separating the first cooling section from the second cooling section such that the first coolant and the second coolant do not combine on the shell side; as well as The water is heated using at least one of a first coolant discharged from the ODH reactor, a second coolant discharged from the ODH reactor, or an effluent discharged from the ODH reactor.

4. The method of claim 3, wherein water vapor is generated from the water by heating the water to evaporate the water via at least one of the first coolant, the second coolant, or the effluent.

5. The method according to claim 4, comprising: flowing water vapor through tubes of a heat exchanger so as to heat the water vapor with the first coolant or the second coolant or both flowing on the shell side, thereby superheating the water vapor, wherein the water comprises boiler feed water; and The superheated water vapor is discharged from the heat exchanger.

6. The process of claim 1, discharging an effluent from the ODH reactor, the effluent comprising ethylene, acetic acid, water, carbon dioxide, and carbon monoxide, wherein a second cooling section is operatively located downstream of a first cooling section in the direction of flow of the reaction mixture, and wherein the second cooling section is separated from the first cooling section by a flow barrier on the shell side.

7. The method according to claim 6, comprising: flowing a third coolant through the shell side in a third cooling section of the ODH reactor, thereby maintaining the reaction mixture on the tube side in the third cooling section at a third temperature, wherein the third temperature is lower than the second temperature, wherein the third cooling section is operatively downstream of the second cooling section in the direction of flow of the reaction mixture and is separated from the second cooling section by a second flow barrier on the shell side; as well as The water is heated with at least one of a first coolant discharged from the ODH reactor, a second coolant discharged from the ODH reactor, a third coolant discharged from the ODH reactor, or an effluent discharged from the ODH reactor.

8. The process of claim 7, wherein the tube side in the third cooling section contains no catalyst and wherein no water is heated with the effluent.

9. A method of operating an oxidative dehydrogenation (ODH) reactor system, the method comprising: providing a feed comprising ethane and oxygen to tubes of an ODH reactor, the tubes comprising an ODH catalyst disposed therein, wherein the feed comprises water as a diluent, thereby maintaining the feed outside flammability limits; Dehydrogenating ethane to ethylene in a reaction mixture in the presence of oxygen via an ODH catalyst in a tube, wherein the ODH reactor comprises: a multitubular fixed bed reactor having a tube side and a shell side, the tube side comprising tubes for the flow of the reaction mixture, and wherein the ODH reactor comprises a first cooling section and a second cooling section operatively located downstream of the first cooling section in the flow direction of the reaction mixture; cooling the ODH catalyst to a first temperature in the first cooling section via a first coolant flowing through the shell side in the first cooling section, and cooling the ODH catalyst to a second temperature in the second cooling section via a second coolant flowing through the shell side in the second cooling section, wherein the first temperature is lower than the second temperature; maintaining a temperature increase of the first coolant passing through the first cooling section below a first threshold; and The temperature rise of the second coolant passing through the second cooling section is maintained below a second threshold value.

10. The method of claim 9, wherein the first cooling section and the second cooling section are separated by a flow barrier on the shell side, wherein the first temperature is in the range of 300°C to 450°C and the second temperature is in the range of 350°C to 500°C, wherein the threshold value of the first cooling section is in the range of 2°C to 8°C and the threshold value of the second cooling section is in the range of 2°C to 8°C, and wherein the water in the feed comprises water vapor.

11. The method according to claim 9, comprising: specifying the first temperature to be lower than the second temperature to favor the dehydrogenation of ethane to ethylene over the production of carbon dioxide in the reaction mixture and over the production of carbon monoxide in the reaction mixture, thereby increasing ethylene selectivity; as well as Maintaining the temperature rise of the first coolant below a first threshold and maintaining the temperature rise of the second coolant below a second threshold is specified to favor the dehydrogenation of ethane to ethylene over the reaction that produces carbon dioxide and over the reaction that produces carbon monoxide, thereby increasing ethylene selectivity.

12. The method of claim 9, wherein the reaction of ethane and oxygen in the reaction mixture comprises a first overall reaction comprising dehydrogenating ethane to ethylene, a second overall reaction to produce acetic acid, a third overall reaction to produce carbon monoxide, and a fourth overall reaction to produce carbon dioxide.

13. The method of claim 12, comprising specifying an increase in ethylene selectivity by favoring a first overall reaction over a third overall reaction and a fourth overall reaction, wherein the first overall reaction consumes a less stoichiometric amount of oxygen than each of the third overall reaction and the fourth overall reaction.

14. The method of claim 13, comprising discharging the reaction mixture as an effluent from the ODH reactor, the effluent comprising ethylene, acetic acid, water, carbon dioxide, carbon monoxide, and unreacted ethane, wherein maintaining the first temperature below the second temperature is responsive to specifying an increase in ethylene selectivity, and increasing ethylene selectivity thereby reducing the amount of oxygen in the feed to reduce the amount of water in the feed.

15. The method of claim 14, comprising heating boiler feed water with at least one of the first coolant, the second coolant, or the effluent, wherein maintaining the temperature rise of the first coolant below a first threshold and maintaining the temperature rise of the second coolant below a second threshold is responsive to specifying an increase in ethylene selectivity and increasing ethylene selectivity, thereby reducing the amount of oxygen in the feed to reduce the amount of water in the feed.

16. The method of claim 15, wherein heating boiler feed water causes the boiler feed water to evaporate, thereby generating steam from the boiler feed water.

17. The method of claim 13, comprising configuring the ODH reactor to have tubes at or less than a specified diameter in response to specifying an increased ethylene selectivity, thereby increasing the ethylene selectivity.

18. The method of claim 17, wherein the specified diameter is 1.25 inches, wherein the linear velocity of the reaction mixture in the tube is in the range of 150 centimeters per second (cm / s) to 500 cm / s, and wherein the gas hourly space velocity of the reaction mixture over the ODH catalyst in the tube is in the range of 1,500 hours. -1 (hr -1 ) to 10,000hr -1 range.

19. An oxidative dehydrogenation (ODH) reactor system comprising: An ODH reactor comprising a first cooling section and a second cooling section separated by a flow barrier on the shell side, wherein the ODH reactor is a multi-tube fixed bed reactor comprising: a tube side having an ODH catalyst to receive a feed comprising ethane, oxygen, and water vapor to dehydrogenate the ethane to ethylene in a reaction mixture and to discharge an effluent comprising ethylene, acetic acid, water, carbon dioxide, carbon monoxide, and unreacted ethane; a shell side that receives a first coolant into the first cooling section to maintain the temperature of the ODH catalyst in the first cooling section at a first temperature, and receives a second coolant into the second cooling section to maintain the temperature of the ODH catalyst in the second cooling section at a second temperature, wherein the first temperature is lower than the second temperature, wherein the second cooling section is operatively downstream of the first cooling section in the direction of flow of the reaction mixture; a first coolant supply system including a pump to provide the first coolant to the first cooling section and to maintain a temperature rise of the first coolant passing through the first cooling section below a first threshold; a second coolant supply system including a pump to provide the second coolant to the second cooling section and to maintain a temperature rise of the second coolant passing through the second cooling section below a second threshold; as well as A first heat exchanger heats first water with a first coolant for water vapor generation of the first water.

20. The system of claim 19, wherein the first temperature is in the range of 300°C to 450°C, the second temperature is in the range of 350°C to 500°C, the first threshold is in the range of 2°C to 8°C, and the second threshold is in the range of 2°C to 8°C, wherein water vapor in the feed acts as a diluent to place the feed outside of flammability limits, and wherein the ODH reactor is configured to produce acetic acid in the reaction mixture on the tube side.

21. The system of claim 19, wherein the water vapor generation comprises a first heat exchanger configured to evaporate the first water into water vapor.

22. The system of claim 21, comprising a steam drum to receive the steam from the first heat exchanger and to discharge the steam.

23. The system of claim 19, wherein the first heat exchanger for heating the first water comprises a first heat exchanger configured to preheat the first water for evaporating the first water in a steam drum, and wherein the first water comprises boiler feed water.

24. The system of claim 19, comprising a second heat exchanger that heats second water with a second coolant exhausted from the second cooling stage for water vapor generation of the second water, wherein dehydrogenating ethane to ethylene comprises a first overall reaction of ethane with oxygen on the tube side, and wherein the ODH reactor is configured to produce a reaction of ethane with oxygen in the reaction mixture on the tube side, the reactions comprising a second overall reaction to produce acetic acid, a third overall reaction to produce carbon monoxide, and a fourth overall reaction to produce carbon dioxide.

25. The system of claim 24, comprising a third heat exchanger for heating third water with the effluent for water vapor generation of the third water, wherein the first coolant and the second coolant each comprise molten salt.

26. The system of claim 19, wherein the second cooling section is operatively located downstream of the first cooling section relative to the flow of the reaction mixture, and wherein the ODH reactor comprises a third cooling section operatively located downstream of the second cooling section relative to the flow of the reaction mixture so as to receive a third coolant into the shell side, the third cooling section being separated from the second cooling section by a second flow barrier on the shell side.

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