Reactor effluent heat recovery system

Abstract

A heat exchanger includes a housing having a longitudinal axis wherein a first portion of the housing is located on a first side of a plane passing through the housing and a second portion is located on a second side of the plane opposite the first side. A first heat transfer surface is arranged in the first portion of the housing and a second heat transfer surface is arranged in the second portion of the housing. The first and second heat transfer surfaces may be coil bundles, wherein one of the coolant streams bordering the heat transfer surfaces is a reactor feed stream. The tubes in the tube bundle have a radial spacing between the tubes that is much greater than an axial spacing between the tubes. Reactor effluent flows through the housing without substantially changing direction while the first and second heat transfer surfaces cool the effluent.

Description

BACKGROUND OF THE INVENTION TECHNICAL FIELD

[0001] The present disclosure generally relates to the integration of heat recovery and cooling of an effluent stream from a reactor in a processing system, and more particularly but not exclusively to a processing system including a coil heat exchanger for such purposes.

[0002] Description of the prior art

[0003] Various types of heat exchangers are used to recover heat from a reactor effluent stream and to further cool the reactor effluent stream separately. Heat recovery using known heat exchangers can be achieved via indirect heat exchange with a process stream to be heated for an additional downstream application or by generating steam. In most cases, the final temperature of the reactor effluent leaving the heat exchanger is still too high for downstream compression, recycle, or separation steps. Therefore, additional cooling is required using a separate unit downstream of the heat exchanger to reduce the temperature of the reactor effluent for downstream separation or compression of useful products and recycle to the reactor.

[0004] For example, U.S. Patent No. 10,962,302 describes the form and function of heat exchangers for catalytic dehydrogenation, fluid catalytic cracking, and catalytic reforming. These heat exchangers can be grouped under the general category of feed-effluent combination ("CFE") heat exchangers. In particular, this reference describes a process known as the OLEFLEX process, as shown in FIGS. 1 and Figure 2 wherein the reactor effluent is heat exchanged with a mixture of vapor feed and hydrogen-rich recycle gas and cooled from 584 degrees Celsius ("C") to 142 degrees Celsius. Although the inlet temperature of the feed gas is quite low (about 40 degrees Celsius), the heat capacity of the hot fluid relative to the cold fluid prevents the effluent gas from being cooled below 140 degrees Celsius before the temperature pinch occurs. The effluent is further cooled in a downstream cooler before compression and recycle in order to minimize the temperature before phase separation and recycle of the steam portion using a compressor.

[0005] U.S. Published Application No. 2020 / 0290939 describes a method for improving the energy conversion of the heat available in a hydrocarbon feed stream during olefin production. Specifically, Figure 3 shows a hydrocarbon feed stream and a hydrogen feed stream that are pressurized to 30 absolute bar and heated by indirect heat exchange with an expanded effluent stream from a furnace reactor. The effluent stream is cooled to 130 degrees Celsius in a feed-effluent heat exchanger and then further cooled to 30 degrees Celsius in a separate cooler downstream of the feed-effluent heat exchanger.

[0006] In the foregoing and other examples of known heat exchangers, a relatively low-pressure, high-temperature reactor effluent can be cooled by heat exchange with an incoming feed stream of the known heat exchanger. The reactor effluent is further cooled in one or more separate downstream units to effect downstream separation or compression and recycle to the reactor. For large-scale production of bulk chemicals such as ethylene, propylene, isobutylene, and others, the scale of production is such that the heat exchange equipment includes multiple units with interconnecting piping to cool the reactor effluent to a sufficient level for separation or compression and recycle.

[0007] Accordingly, the effluent stream is split and distributed to individual units before each heat exchange section, and then the components are recombined and collected before being redistributed to the next heat exchange section, and so on. Multiple changes in the flow direction result in high pressure drops and the possibility of non-uniform distribution between individual units or within individual flow channels or layers. The high pressure drop is particularly disadvantageous when downstream processing of the reactor effluent involves yield-pressure related reactions and / or when the reactor effluent is below atmospheric pressure such that a large compression ratio is required. However, known heat exchangers also have additional deficiencies and drawbacks.

[0008] In particular, the use of multiple units with interconnecting piping increases the overall cost and space requirements of the system. Due to the high cost of operating a compressor to pressurize the reactor effluent downstream of the heat exchanger, known heat exchange systems also use a large amount of electricity for recycle, which further increases the cost. Interstage coolers and / or aftercoolers between compression stages may further increase capital and operating costs. Additionally, compared to the heat recovered by steam generation, the use of known heat exchangers may limit the heat that can be recovered to heat the feed, and thereby result in a relatively large amount of greenhouse gas emissions, since steam generation during processing inherently requires burning fuel to generate steam. These and other factors of known heat exchangers reduce efficiency and result in a lower overall return on investment.

[0009] Accordingly, there is a need for a heat exchanger that overcomes the deficiencies and drawbacks of known heat exchange systems. SUMMARY OF THE INVENTION

[0010] The present disclosure generally relates to heat integration in refinery and petrochemical processes, and specifically but not exclusively to the integration of a CFE heat exchanger with downstream cooling. Embodiments of the present disclosure provide a reactor effluent cooling system that is capable of effectively cooling an effluent from a reaction system to a temperature suitable for recompression and / or separating desired products from materials to be recycled along a single axis, with substantially no change in direction and without redistributing the fluid between multiple parallel units.

[0011] Embodiments of the present disclosure may include heat exchange devices, systems, and methods, where a coil heat exchanger is configured with at least two heat transfer surfaces. The heat transfer surfaces may be provided in a variety of different shape factors or arrangements. For example, each heat transfer surface may be a corresponding plurality of coils or tube bundles. The tubes associated with each heat transfer surface define corresponding circuits for a heat transfer medium to flow through a particular portion of the heat exchanger for interaction with the effluent stream flowing through the heat exchanger. A first circuit of tubes corresponding to a first heat transfer surface may be used to recover heat from the effluent stream passing through the heat exchanger via indirect heat transfer with at least one of the feed streams, by generating steam, or via other intermediate fluids. A second circuit of tubes corresponding to a second heat transfer surface is used to further cool the effluent by indirect heat transfer with at least one additional stream without removing the effluent between the circuits. The first and second circuits are housed within a common shell, and the effluent flows through the shell from an inlet to an outlet in a direction parallel to the axis of the shell with substantially no change in direction. More than two tube circuits or tube bundles may be used. For example, a first tube circuit may cool the effluent by generating steam from boiler feed water, a second tube circuit may further cool the effluent stream and recover heat by indirectly heating the feed stream, and a third tube circuit may further cool the effluent stream by indirect heat transfer with a coolant stream. Other configurations are possible.

[0012] The first and second circuits may be arranged in such a way as to create parallel or alternating sub-circuits that can be individually activated to increase or decrease the feed or coolant flow rates according to the operating task. For example, the first circuit may be a bundle of multiple tubes, each tube having its own inlet and grouped in a tube sheet. As a result, each inlet of the tube bundle and the corresponding tube may be a corresponding sub-circuit of the first circuit. In one embodiment, the heat exchanger is provided in the shape factor of a coil heat exchanger that is configured to have two sets or bundles of coils wound around a mandrel within a single shell. Each bundle of tubes may be wound around a separate mandrel having a common axis or may be wound around a single common mandrel. The tubes are coiled with axial and radial spacing between the tubes, where the radial spacing is much greater than the axial spacing. In some embodiments, the radial spacing may be ten times or more greater than the axial spacing.

[0013] Thus, the concept of the present disclosure replaces a heat exchanger system with multiple parallel or series units and replaces the associated piping system of the system with a single heat exchanger shell that cools the reactor effluent to the desired temperature for further downstream processing with substantially no change in the direction of the effluent through the outer shell. Thus, the concept of the present disclosure reduces the total capital and operating costs of the heat exchanger system while also reducing the pressure drop in the system, thereby increasing the yield.

[0014] Additional benefits and advantages of the concepts of the present disclosure will be described in detail with reference to the accompanying drawings, or will be otherwise understood by those of ordinary skill in the relevant art after reviewing the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The present disclosure will be more fully understood by reference to the following drawings, which are for illustrative purposes only. Non-limiting and non-exhaustive embodiments are described with reference to the drawings, where like reference numerals refer to like parts throughout the various views, unless otherwise specified. The dimensions and relative positions of the elements in the drawings are not necessarily drawn to scale. For example, the shapes of various elements are selected, enlarged, and positioned to enhance the readability of the drawing. In other drawings, the dimensions and relative positions of the elements in the drawings are drawn exactly to scale. The particular shapes of the elements drawn may be selected to facilitate identification in the drawings. The drawings do not depict every aspect of the teachings disclosed herein and do not limit the scope of the claims.

[0016] Figure 1A is a schematic diagram of a known CATOFIN processing system.

[0017] Figure 1B is Figure 1A a schematic diagram of the heat recovery system of a known processing system.

[0018] Figure 2 is a schematic diagram of an embodiment of a processing system according to the present disclosure that diverts reactor effluent to a heat exchanger.

[0019] Figure 3 is a schematic diagram of an embodiment of a processing system according to the present disclosure that provides reactor effluent directly to a heat exchanger.

[0020] Figure 4A is a schematic diagram of an embodiment of a heat exchanger according to the present disclosure having a single mandrel.

[0021] Figure 4B is a schematic diagram of an embodiment of a heat exchanger according to the present disclosure having multiple individual mandrels.

[0022] Figure 5 is a schematic diagram of the spacing between tubes in a heat exchanger according to the present disclosure.

[0023] Figure 6 is an isometric view of a heat exchanger according to the present disclosure.

[0024] Figure 7 is along Figure 6 a schematic cross-sectional view of the heat exchanger along its longitudinal axis.

[0025] Figure 8 is a schematic diagram of a processing system including a heat exchanger Figure 6 having Detailed Implementation Modes

[0026] Those of ordinary skill in the relevant art will understand that the present disclosure is merely illustrative and not limiting in any way. Other embodiments of the systems and methods of the present disclosure can be readily conceived by those skilled in the art with the assistance of the present disclosure.

[0027] Each feature and teaching disclosed herein can be used alone or in combination with other features and teachings to provide heat exchange devices, systems, and methods. Representative examples that utilize many of these additional features and teachings, either alone or in combination, are described in further detail with reference to the accompanying drawings. This detailed implementation mode is only intended to teach those skilled in the art further details for practicing various aspects of the present teaching, and is not intended to limit the scope of the claims. Therefore, the combinations of features disclosed in the detailed implementation mode may not be necessary for practicing the teaching in the broadest sense, but are merely taught to describe particularly representative examples of the present teaching.

[0028] In addition, the various features of the representative examples and dependent claims can be combined in ways that are not specifically and explicitly enumerated to provide additional useful embodiments of the present teaching. It is also expressly stated that for the purposes of the original disclosure and for the purpose of limiting the claimed subject matter, all value ranges or indications of entity groups disclose every possible intermediate value or intermediate entity. It is also expressly stated that the dimensions and shapes of the components shown in the drawings are designed to assist in understanding how to practice the present teaching, but are not intended to limit the dimensions and shapes shown in the examples in some embodiments. In some embodiments, the dimensions and shapes of the components shown in the drawings are drawn to scale and are intended to limit the dimensions and shapes of the components.

[0029] Generally speaking, the concepts of the present disclosure are used to recover heat from reactor effluents in many processes to reduce the total pressure drop, reduce the number of equipment, and increase the return on investment of the technology. The increase in the return on investment is the result of the reduction in pipeline laying and site space and the reduction in pressure drop, which can enable the reactor to operate at a lower pressure and increase the yield, or can reduce the compression costs associated with downstream separation and the recycle of the unreacted portion of the effluent. The concepts of the present disclosure can be used with any heat recovery scheme that indirectly exchanges heat between a hot effluent and a cold feed stream, followed by additional indirect cooling of the effluent with an additional stream.

[0030] While the present disclosure will continue to describe certain examples of heat exchanger systems and heat exchange devices that may be particularly advantageous for petrochemical processing and refining, such as at least for propane dehydrogenation to produce propylene, it should be understood that the concepts of the present disclosure can be applied to a wide range of technologies and industries. Specifically, the concepts of the present disclosure can be equally applied to any industry or technology that utilizes a heat exchanger and is connected to an independent additional downstream cooler, such as at least in offshore operations, refineries, power, petrochemicals, or the paper and food industries. Further, the concepts of the present disclosure can be applied to technologies and industries where it is generally advantageous to maximize heat transfer efficiency to pressure drop. Accordingly, the concepts of the present disclosure are not limited to the examples provided below.

[0031] Figure 1A and Figure 1B is a schematic diagram of a known processing system 20. Specifically, Figure 1A is a schematic diagram of a heat recovery system 22 of a CATOFIN unit. Unless the context clearly indicates otherwise, "CATOFIN" means "Catalytic Olefins" and refers to the technology of catalytic dehydrogenation of alkanes to produce olefins, including but not limited to the dehydrogenation of isobutene, n-butane, or propane to isobutene, n-butene, or propylene, respectively. Figure 1B is a schematic diagram of a heat recovery system 22 of a processing system 20, showing example locations and arrangements of aspects of the heat recovery system 22.

[0032] From Figure 1A starting, the processing system 20 includes a heat recovery system 22 having a feed effluent heat exchanger 24 and a cooler 26 downstream of the feed effluent heat exchanger 24. The heat recovery system 22 cools the reactor effluent in operation from 575 degrees Celsius to about 30 - 40 degrees Celsius by generating steam, preheating the feed in the feed - effluent heat exchanger 24, and discharging heat to the cooling water in the cooler 26. The reactor feed and the recycle stream flowing to the reactor in operation are first heated by the reactor effluent in the heat exchanger 24 and then by the feed heater 28. In one embodiment, the heat exchanger 24 and the cooler 26 are shell - and - tube devices, but with special design considerations further explained below.

[0033] Recently, with the rising fuel costs or to minimize emissions from burning fossil fuels, there is a desire to preheat the feed to 400 - 475 degrees Celsius while the effluent inlet temperature is approximately 490 degrees Celsius, sacrificing steam production to maximize heat recovery. Due to the temperatures involved, the pipes in system 20 are typically made of austenitic stainless steel. Although the recoverable heat may be limited by coking of the heat pipe plates and metallurgical considerations, generally the heat exchanger should have a very high efficiency. The required efficiency is usually expressed in terms of heat exchange "effectiveness", which is defined as the percentage of the heat transferred from the cooling fluid to the heating fluid out of the maximum possible heat recovery. In some cases, there are other limitations or requirements. For example, the Catofin process for propane or propane - butane combination dehydrogenation TM requires the reaction to be carried out under reduced pressure, so the pressure loss of the gas must be minimized as much as possible to maintain high selectivity. In one embodiment, system 20 is designed for high - recovery (low - steam) applications and the heat effectiveness is greater than 90%, which results in a high surface area requirement.

[0034] In operation, the effluent leaving the heat exchanger 24 is further cooled in a separate set of shell - and - tube effluent coolers 26 before product compression and recycle. Since the reactor operates under sub - atmospheric conditions, minimizing the pressure drop of the effluent passing through the heat recovery section is an important design factor, which can both increase the reactor throughput and minimize the compression power of the compressor 30.

[0035] Turning to Figure 1B , the heat recovery system 22 is described in more detail. The heat exchanger 24 may include a plurality of shell - and - tube heat exchangers arranged in parallel or in series, and the cooler 26 may include a plurality of shell - and - tube effluent coolers arranged in parallel or in series. The exact number and arrangement of the heat exchanger 24 and the cooler 26 can be selected based on the operating tasks of the system 20 ( Figure 1A ) and other design factors. Figure 1B It is also shown that the heat exchanger 24 and the cooler 26 are connected by rather long pipes as well as various elbows, tees, and bends. The additional length of the pipes and the additional connectors create the disadvantages of the known systems described herein, namely high pressure drop, uneven distribution and the possibility of fouling, reduced yield, increased total capital cost and the space utilized by the system, a large amount of electricity used for recycle and increased associated costs, and the generation of a large amount of emissions, etc.

[0036] There are additional design considerations and disadvantages associated with the high - recovery (low - steam) processing system 20 because the recoverable heat may be limited by coking at the heat pipe plates and metallurgical considerations, such that at least some steam generation may be required to reduce the outlet temperature. For example, referring to Figure 1A and Figure 1B, in addition to the cooler 26, the system 20 may also include a reactor effluent steam generator (“RESG”) that cools a portion of the reactor effluent from 575 degrees Celsius to approximately 295 degrees Celsius while generating high-pressure steam, such as steam at about 44 absolute bar, and the remaining portion bypasses the steam generator. The bypass around the RESG is opened, and although the RESG itself has an outlet temperature of 295 degrees Celsius, the inlet of the heat exchanger 24 is reduced to below 500 degrees Celsius after mixing.

[0037] The heat exchanger 24 is a second cooler installed after the RESG. The heat exchanger 24 cools the reactor effluent while preheating the feed entering the feed heater 28 to 400 - 475 degrees Celsius. As described above, due to the extremely low allowable pressure drop and potential fouling, the shell-and-tube heat exchanger applied in this service is designed with the effluent flowing in the tube side (hot side). Therefore, the feed is distributed in the shell side (cold side). Due to the very low heat transfer coefficient in the tube side, this arrangement results in a very large surface area requirement. Therefore, multiple parallel heat exchangers are used to meet these design considerations. The large shell-side volume poses challenges to configuring the shell side to ensure proper distribution and temperature uniformity on the wet surface.

[0038] In addition, there are special considerations for the expansion joint mechanism in the heat exchanger 24. Due to the design, operating conditions, and size of the heat exchanger 24, it may be very challenging to attempt to adopt traditional expansion joint solutions (such as flanges and bellows or internal bellows).

[0039] In addition, the shell-side flow distribution problem should be addressed to ensure uniform thermal expansion of all pipes in the tube sheet. To ensure uniform distribution of the effluent flow to the pipes, the inlet pipes of the steam generator and / or bypass mixer are configured such that the pipe elbow is at least 5 pipe diameters away from the tube sheet. This arrangement utilizes additional space while also potentially generating pressure drop. Some known examples of the heat exchanger 24 also utilize special distributor designs to minimize temperature variations on the tube sheet, which increases the cost and complexity of the system 20.

[0040] The cooler 26 downstream of the heat exchanger 24 cools the reactor effluent (tube side) as low as possible using a coolant (shell side), which can be an open-loop or closed-loop cooling water system, or a closed-loop ethylene glycol water cooling system or other water-based or non-water-based liquid coolant system. The reactor effluent is cooled to a temperature as close as possible to the coolant temperature to allow the reactor effluent vapor to be effectively compressed in the product gas compressor 30. Since a very low pressure drop is allowed on the effluent side, multiple units in parallel are used and preferably the same number as that of the heat exchanger 24. This arrangement results in a very low velocity in the cooling water (CW) shell side of the cooler 26 and a risk of stagnation. The effluent cooler may scale due to the low cooling water flow rate, especially when the cooling water system is not a closed loop. Due to the low temperature, carbon steel is used for the pipes; however, corrosion may occur due to the stagnation of the cooling water. As a result, techniques are utilized in the shell side of the cooler 26 to minimize stagnation, but due to the above factors, it may be very challenging to design a sufficient velocity (such as greater than 0.6 meters per second (“m / s”), or more preferably greater than 1.0 m / s).

[0041] In summary, the combination of high heat recovery and low pressure drop in the heat exchanger 24 and the cooler 26 poses challenges to the design of the shell-and-tube heat exchanger in the system 20. For example, to achieve a low pressure drop, the effluent flows in the tube side and the tube diameter is greater than 25 millimeters (“mm”). Additionally, the heat transfer resistance of the tube-side fluid is relatively large, and a large number of tubes are used, requiring multiple units in parallel to achieve effective cooling. The heat exchanger 24 requires high effectiveness, such as a countercurrent flow greater than 90%, and the exchanger is relatively long. The shell side has a large volume, generally unable to fully utilize the available shell-side pressure drop, and the shell-side distribution is poor, which may lead to uneven thermal expansion between the tubes. The system 20 may also have the additional disadvantages described above.

[0042] Figure 2 is a schematic diagram of an embodiment of the processing system 100. In one embodiment, the processing system 100 is a CATOFIN plant, which is different from the system 20 described below, but the present disclosure is not limited thereto. The system 100 includes a heat exchanger 102, a heater 104, a reactor 106, and a steam generator 108. The heat exchanger 102 is in communication with the heater 104, which is in communication with the reactor 106. The reactor 106 is operable to output an effluent, at least a portion of which is in communication with the steam generator 108. The steam generator 108 and the remaining portion of the effluent are in communication with the heat exchanger 102. In summary, the heat exchanger 102 is operable to cool the effluent from the reactor 106 by indirectly transferring heat via at least one of the reactor feed streams, by generating steam, or via other intermediate fluids to recover heat from the effluent.

[0043] Unless the context and language otherwise clearly dictate, the phrase "reactor feed stream" or "feed stream" means a chemical feedstock derived from a refined or partially refined petroleum fraction, primarily used in the manufacture of fuels, chemicals, synthetic rubber, and various plastics, and specifically includes, but is not limited to, feeds for processes to produce desired products by hydrotreating, such as turbine fuel, diesel, and other products known as middle distillates, as well as lower boiling hydrocarbon liquids, such as naphtha and gasoline, gas oils, and heavy gas oils recovered from crude oil by distillation. Examples of feedstocks for "reactor feed stream" or "feed stream" further include, but are not limited to, propane or butane for the production of olefins by catalytic dehydrogenation (CATOFIN); normal butane or a mixture of normal butane and normal butene for the production of 1,3-butadiene; heavy reformate; a transalkylation xylene or mixed xylene feed stream mixed with hydrogen for the production of para-xylene. In all cases, the feed stream may consist of fresh feed mixed with unreacted feed recycled from the separation section.

[0044] Heat exchanger 102 includes an inlet 110 and an outlet 112, with a plane 114 passing through heat exchanger 102. A first heat transfer surface 116 is disposed in a first portion 118 of heat exchanger 102 on a first side of plane 114, and a second heat transfer surface 120 is disposed in a second portion 122 of heat exchanger 102 on a second side of plane 114 opposite the first side. The first portion 118 and the second portion 122 of heat exchanger 102 may correspond to portions of the shell of heat exchanger 102 that are integrated with each other in a single integral shell, as further described below. As a result, heat exchanger 102 defines a flow path for the effluent of reactor 106 from inlet 110 to outlet 112, with the direction of the effluent essentially unchanged. The first heat transfer surface 116 and the second heat transfer surface 120 interact with the reactor effluent along the flow path through heat exchanger 102 without changing the flow direction of the reactor effluent. Such first heat transfer surface 116 and second heat transfer surface 120 may be corresponding plural coils or tube bundles that define respective first and second circuits (or sub-circuits associated with each tube) for the heat transfer medium to flow through heat exchanger 102.

[0045] In operation, a feed stream (propane feed in a non-limiting example) is conveyed along a flow line 124 and enters the heat exchanger 102 at a point above the plane 114 and interacts with the first heat transfer surface 116. Unless the language and context clearly dictate otherwise, "flow line" is interpreted to mean any structure capable of conveying a fluid and includes, but is not limited to, conduits, pipes, etc. The feed stream 123 from the flow line 124 is heated in the heat exchanger 102 by heat exchange with the reactor effluent stream via the first heat transfer surface 116 and then leaves the heat exchanger 102 via the flow line 126 and reaches the heater 104. The heater 104 is operable to raise the temperature of the feed stream from the first heat transfer surface 116 to a selected temperature for the reaction at the reactor 106. Then the heated feed stream is provided from the heater 104 to the reactor 106 via the flow line 128. As described above, the reactor 106 is operable to output an effluent along the line 130. The reactor effluent in the line 130 can be split into two parts, namely a first effluent part 130A and a second effluent part 130B. The first effluent part 130A is cooled in the steam generator 108. The second effluent part 130B bypasses the steam generator 108 along the line 132. Then the first effluent part 130A and the second effluent part 130B converge and mix downstream of the steam generator 108. The resulting converged effluent stream is provided to the inlet 110 of the heat exchanger 102.

[0046] The converged effluent stream passes through the heat exchanger 102 from the inlet 110 to the outlet 112 and is cooled by heat exchange with the first heat transfer surface 116 and then the second heat transfer surface 120 in sequence. In one embodiment, the first part 118 of the heat exchanger 102 is the upper part of the heat exchanger above the plane 114, where the heat exchanger 102 is arranged generally vertically. Thus, the converged effluent is first cooled by heat exchange with the incoming feed stream 124 via the first heat transfer surface 116. The second part 122 of the heat exchanger 104 can be the lower part of the heat exchanger 102, where the coolant stream interacts with the second heat transfer surface 120 along the lines 134, 136. After the effluent passes through the first heat transfer surface 116, the second heat transfer surface 120 cools the converged effluent. As a result, the first heat transfer surface 116 and the second heat transfer surface 120 cool the converged effluent stream in sequence in a direction parallel to the axis of the heat exchanger 102, and the direction of the converged effluent stream is substantially unchanged. After cooling, the converged effluent stream leaves the outlet 112 for further processing along the line 138.

[0047] For example, the cooled effluent in line 138 can be supplied to a compressor 140 that communicates with the outlet 112 of the heat exchanger 102. The compressor 140 communicates with a separation section 142 and drives the cooled effluent stream through the separation section 142. The separation section 142 is schematically shown in dashed lines, indicating that the separation section 142 can include various known stages, devices, and systems, such as at least Figure 1A those downstream of compressor 30 in, for separating any useful products and / or by-products along line 144 and recycling unreacted feed along recycle line 146 to mix with fresh feed such as from feed line 123 to form a feed stream provided via feed line 124 to the first heat transfer surface 116 and ultimately to the reactor 106 as described herein. As a result, the reactor feed heated at the first heat transfer surface 116 via heat transfer with the reactor effluent can include fresh feed via line 123 and recycled and unreacted feed from the separation stage 142 along line 146.

[0048] In some embodiments, in addition to the head loss associated with the heat exchanger and the straight pipe section pressure drop, the pressure change between the outlet 112 of the reactor 106 and the suction or inlet of the compressor 140 includes no more than 8 velocity heads, and preferably less than 8 velocity heads. "Velocity head" is a common method for estimating losses caused by fittings such as elbows, bends, and tees in a piping system. Table 6-6 in Section 6-18 of the 7th Edition of Perry’s Chemical Engineering handbook lists the additional frictional losses in terms of the number of velocity heads ("K") when turbulent flow passes through various fittings. The pressure drop ("DP") associated with a fitting can be calculated according to the following formula.

[0049] DP = SK x 0.5 x (density) x (velocity)^2

[0050] where SK is the sum of the number of velocity heads in the system, and the density (kg / m3) and velocity (m / s) are calculated based on the flow rate and pipe size. Thus, the pressure change or pressure drop (DP) in system 100 is mainly attributed to the heat exchanger 102, rather than the intermediate pipes and other structures, and the total sum of the velocity heads (K) resulting from the direction changes due to bends, elbows, and tees in system 100 (and other systems described herein) is less than 8.

[0051] In a non-limiting example that utilizes the heat exchanger concept of the present disclosure and with reference to Figure 8 further described, the sum of the K values is 3.5 (the K value for each of the seven long radius elbows is 0.5). In contrast, in reference to Figure 1A and Figure 1BIn the known system 20 described, due to the need to distribute fluid among multiple parallel heat exchangers 24 and then collect and redistribute the fluid to the downstream cooler 26, there are necessarily a large number of flow direction changes. For example, in Figure 1B the heat recovery system 22 and the Figure 1A system 20 including such a heat recovery system 22, there are 10 long-radius elbows (each with K = 0.5) and four branch tees (each with K = 1.0), and the total K value can be 9 velocity heads. Because the known system 20 includes such additional intermediate pipes and other aspects as described herein, the pressure change between the reactor and the compressor can be more than 1.5 times the pressure change through the heat exchangers 24 and the downstream cooler 26.

[0052] Figure 3 is a schematic diagram of an embodiment of the processing system 200. Although the system 100 can provide the benefits and advantages described herein, additional advantages can be achieved by eliminating combustion and reducing or eliminating direct carbon dioxide emissions as in the system 200. The system 200 includes a heat exchanger 202, a heater 204, and a reactor 206 that are in fluid communication with each other. Notably, the heater 204 of the system 200 can be an electric heater and the system 200 does not include a steam generator as in the system 100. As a result, the system 200 does not utilize the combustion of carbon-containing gases and thus does not produce direct emissions of carbon dioxide during operation, which further improves the return on investment while reducing the overall environmental impact of the system 200.

[0053] In the system 200, the heat exchanger 202 can generally be similar to the heat exchanger 102 in the system 100. Briefly, the heat exchanger 202 includes an inlet 208 and an outlet 210, where a first heat transfer surface 212 is disposed above a plane 214 passing through the heat exchanger 202 in the heat exchanger 202, and a second heat transfer surface 216 is disposed below the plane 214 in the heat exchanger 202. Thus, the heat exchanger 202 has a flow path passing through the heat exchanger 202 from the inlet 208 to the outlet 210, which sequentially passes through the first heat transfer surface 212 and the second heat transfer surface 216, and the flow direction of the fluid passing through the heat exchanger 202 does not change substantially.

[0054] During operation of the system 200, the feed stream 218 enters the heat exchanger 202 above the plane 214 and interacts with the first heat transfer surface 212. In one embodiment, the feed stream 218 is a hydrocarbon feed or a hydrocarbon feed mixed with hydrogen and may consist of fresh feed mixed with recycle unreacted feed recycled from the separation section. The feed stream exits the heat exchanger 202 along line 220 and is provided to the heater 204. The heater 204 may be an electric heater having radiant heating elements mounted on a refractory-lined vessel and operable to heat the feed stream to a suitable temperature for input into the reactor 206. After the feed stream is heated by the heater 204, the feed stream is provided to the reactor 206 along line 222. The reactor 206 is operable to output the effluent directly to the inlet 208 of the heat exchanger 202 along line 224. The heat exchanger 202 cools the effluent using the feed stream 218 at the first heat transfer surface 212 and using a separate coolant stream provided along lines 226, 228 to the second heat transfer surface 216. Unless the context and language otherwise clearly dictate, the term "coolant" shall be construed broadly to mean a liquid or gas capable of being used to remove heat and includes, but is not limited to, cooling water in an open-loop or closed-loop system, ethylene glycol water in a closed-loop cooling system, or other water-based or non-water-based liquids in such coolant systems. After cooling, the effluent exits the heat exchanger 202 for further processing at 230.

[0055] Accordingly, in some embodiments, the effluent from the reactor 206 is not split into components for additional cooling but is provided directly from the reactor 206 to the heat exchanger 202. This arrangement further reduces the piping, equipment costs, site space, and pressure drop in the system 200. However, since the reactor effluent is not cooled before entering the heat exchanger 202, the effluent entering the heat exchanger 202 can have a higher temperature relative to the system 100. As a result, the feed stream 218 can likewise be heated to a higher temperature than in the system 100. In some embodiments, the higher temperature of the feed stream 218 reduces the operating load of the heater 204 and enables the use of an electric heater rather than a heater based on the combustion operation of a carbon-containing gas.

[0056] It will be appreciated that in order to minimize or even completely avoid the combustion of fuel and the generation of steam, the heat recovery efficiency is preferably very high to ensure that the maximum possible energy is extracted from the hot effluent stream. The thermal effectiveness can be defined as the heat recovered from the effluent stream divided by the theoretical maximum possible heat recovery. Figure 2 the heat exchanger 102 in Figure 3The thermal effectiveness of the heat exchanger 202 and other heat exchangers described herein will generally be higher than 85%, and preferably higher than 90%. Known systems typically include straight tubes or channels for CFE, which cannot achieve the same level of effectiveness as the concepts of the present disclosure in a single heat exchanger housing. It has been found that, compared to known solutions, using coiled tubes wound around a mandrel provides a thermal effectiveness greater than 85% in a single housing, or a significant reduction in the number of single housings, which has the benefits and advantages described herein.

[0057] Figure 4A is a schematic view of an embodiment of the heat exchanger 300. Unless otherwise provided herein, the heat exchanger 300 may be similar to the heat exchangers 102, 202 described with reference to systems 100, 200, respectively. The heat exchanger 300 includes a housing 302 that may generally be arranged vertically as Figure 4A shown. The housing 302 includes an inlet 304 and an outlet 306 to define a flow path through the housing 302. Additionally, the housing 302 has a longitudinal axis 308, which may be the vertical centerline passing through the housing 302, where the inlet 304 and the outlet 306 are centered on the axis 308. A plane 310 passes through the housing 302 and the axis 308. In one embodiment, the plane 310 is a horizontal plane passing through the housing 302 that intersects the longitudinal axis 308 passing through the housing 302 such that the plane 310 is perpendicular to the axis 308.

[0058] The plane 310 divides the housing 302 into a first portion 312A and a second portion 312B, and may be a conceptual dividing line of the housing 302 to provide additional context regarding the concepts of the present disclosure. In fact, the housing 302 is a single, integral, unified component having a continuous body including the first portion 312A and the second portion 312B. The first portion 312A of the housing 302 is the upper portion of the housing 302 on the first side or upper side of the plane 310, and the second portion 312B of the housing 302 is the lower portion of the housing 302 on the second side or lower side of the plane 310 opposite the first side. Additionally, the inlet 304 leads to the first portion 312A of the housing 302, and the second portion 312B leads to the outlet 306 of the housing 302. As a result, the flow path through the housing 302 sequentially traverses the inlet 304, the first portion 312A of the housing 302, the second portion 312B of the housing 302, and the outlet 306. Thus, the flow path is along the longitudinal axis 308 of the housing 302, and the direction of the fluid or effluent along the flow path is substantially unchanged, as generally indicated by the arrow 314.

[0059] The heat exchanger 300 also includes a first heat transfer surface 316 and a second heat transfer surface 318. In one or more embodiments, the plane 310 is a horizontal plane that passes through the housing 302 and is located between the first heat transfer surface 316 and the second heat transfer surface 318, rather than a horizontal plane that passes through the center of the housing 302, as described above. Additionally, the plane 310 can be a reference surface through which all the effluent flows with substantially no change in direction, as described herein. The first heat transfer surface 316 is disposed in a first portion 312A of the housing 302, while the second heat transfer surface 318 is disposed in a second portion 312B of the housing 302. The first heat transfer surface 316 and the second heat transfer surface 318 are schematically shown as cylinders, but in reality, the first heat transfer surface 316 and the second heat transfer surface 318 can include a plurality of coil tubes with gaps therebetween to increase the contact surface area with the effluent flowing along the flow path 314, as shown and described in more detail with reference to Figure 7 For example, in some embodiments, the first heat transfer surface 316 and the second heat transfer surface 318 can be different sets of coil tubes, each set of coil tubes containing a corresponding plurality of coil tubes arranged around a single mandrel 320, where the corresponding sets of coil tubes are spaced apart from each other along the mandrel 320.

[0060] The mandrel 320 can be aligned with the longitudinal axis 308 such that the first set of coil tubes or the plurality of first coil tubes corresponds to the first heat transfer surface 316, and the second set of coil tubes or the plurality of second coil tubes corresponds to the second heat transfer surface 318, which surrounds the mandrel 320 in a continuous tube layer centered on the longitudinal axis 308. In one embodiment, each of the plurality of coil tubes or sets of coil tubes corresponding to the first heat transfer surface 316 and the second heat transfer surface 318 can have substantially the same size or length. Additionally, the single mandrel 320 can be a continuous, integral, and uniform structure with a constant diameter along its length. The first heat transfer surface 316 and the second heat transfer surface 318 are connected to tube sheets 322, 324, 326, 328 to achieve the process scheme described herein. In particular, the tube sheets 322, 324, 326, 328 can convey a coolant or feed stream to, through, and away from the heat transfer surfaces 316, 318 to recover heat from the reactor effluent flowing along the flow path 314, as described herein.

[0061] In another embodiment, the heat exchanger 300 includes more than one mandrel 320, as Figure 4B shown. Figure 4BThe heat exchanger 300 includes at least two mandrels 320, namely a first mandrel 320A and a second mandrel 320B. Each of the first mandrel 320A and the second mandrel 320B can be arranged along an axis 308, i.e., concentric with the axis 308. Alternatively, the mandrels 320A, 320B can be parallel to the axis 308 but offset from or spaced apart from the axis 308. A coiled tube or tube bundle including a first heat transfer surface 316 can be arranged around the first mandrel 320A, and a coiled tube or tube bundle including a second heat transfer surface 318 can be arranged around the second mandrel 320B. In addition, each of the mandrels 320A, 320B can have the same or different sizes or diameters. For example, the first mandrel 320A can have a smaller diameter and a greater length than the second mandrel 320B. Other variations in the sizes of the mandrels 320A, 320B are contemplated herein.

[0062] In addition, in some embodiments, the mandrels 320A, 320B are separate and distinct structures spaced apart from each other, or otherwise not in direct fluid communication with each other. In one embodiment, the mandrels 320A, 320B are optionally in such direct fluid communication via a fitting 321 schematically shown in dashed lines. In addition, in some embodiments, the first heat transfer surface 316 generally has a larger size or a greater length than the second heat transfer surface 318. As a result, the plane 310 between the first heat transfer surface 316 and the second heat transfer surface 318 can be offset or spaced apart from the center of the housing 302, such that the first part 312A and the second part 312B of the housing 302 have different sizes (i.e., the first or upper part 312A is larger than the second or lower part 312B).

[0063] Figure 4A and Figure 4B The arrangement of the heat exchanger 300 in [text not provided] has many advantages compared to known heat exchangers. In particular, the first heat transfer surface 316 and the second heat transfer surface 318 can cool the reactor effluent along the flow path 314 to a desired temperature without a separate downstream cooling unit and without substantially deviating the flow direction of the effluent from the longitudinal axis 308. As a result, the pressure drop in the reactor effluent passing through the heat exchanger 300 is significantly reduced. The reduction in pressure drop minimizes compression costs and also increases the reactor throughput that is favorable for chemical reaction selectivity at lower pressures. The reduction in pressure drop is at least partly attributed to the combination of the effluent cooling process in the same housing 302, which eliminates the piping for transporting the cooled effluent from the heat exchanger 300 to an effluent cooler, as well as the pressure drops associated with inlet losses, elbows, and tees for distributing the flow rate.

[0064] In addition, the site space and capital costs associated with the heat exchanger 300 are significantly reduced compared to known heat exchangers. This benefit is particularly evident for low-pressure effluents using large pipes, such as pipes with a diameter of 20 inches or greater. Finally, the first heat transfer surface 316 and the second heat transfer surface 318 operate as parallel or alternating heat recovery or cooling circuits in different parts of the heat exchanger 300, and their operating capacities can vary according to the operating tasks of the system incorporating the heat exchanger 300. In other words, the coolant capacity through each heat transfer surface 316, 318 can be adjusted according to the operating characteristics of the larger processing system, which optimizes coolant consumption and enables more efficient processing applications that can respond to changing demands in a wider system.

[0065] Figure 5 is a schematic illustration of the spacing between aspects of the first heat transfer surface 316 and the second heat transfer surface 318 in the heat exchanger 300 described herein. As described above, the first heat transfer surface 316 and the second heat transfer surface 318 ( Figure 4A and Figure 4B ) can be different tube bundles arranged around the longitudinal axis 308 of the housing 302. Each bundle of coils can include a corresponding plurality of tubes 330 wound around the longitudinal axis 308 of the housing 302. The number, size, and arrangement of the tubes in each bundle can be selected according to design factors. In one embodiment, the tubes 330 have a first spacing P1 in the radial direction X perpendicular to the longitudinal axis 308, and the first spacing P1 is greater than a second spacing P2 in the axial direction Y parallel and aligned with the longitudinal axis 308. In some embodiments, the first spacing P1 is on average 10 times or more greater than the average value of the second spacing P2. Thus, the ratio of the first spacing P1 to the second spacing P2 can be expressed as greater than 10:1.

[0066] The average spacings P1, P2 between the tubes 330 in each bundle of coils of certain embodiments of the first heat transfer surface 316 and the second heat transfer surface 318 ( Figure 4A and Figure 4B ) are significant because the reduction in pressure drop achievable by the heat exchanger 300 ( Figure 4A and Figure 4B ) is at least partially attributable to the external flow of the effluent between the layers with a relatively large radial spacing. In other words, the specific spacings P1, P2 described herein can further reduce the pressure drop by providing a large radial spacing between the tubes 330, which does not impede the flow of the effluent through the heat exchanger 300 ( Figure 4A and Figure 4B ) or otherwise substantially change the direction of the effluent flow through the heat exchanger 300 ( Figure 4A and Figure 4B)。The relatively small second spacing P2 increases the surface area of the tubes 330 in contact with the effluent to improve heat transfer, while not being so large as to substantially change the direction of the effluent flow away from the longitudinal axis 308. As a result, the spacings P1, P2 between the tubes 330 provide further benefits and advantages relative to conventional heat exchangers.

[0067] Figure 6 is an isometric external view of the heat exchanger 300 according to at least some embodiments of the present disclosure. An effluent stream, such as from a reactor, is provided to an inlet 304 of the housing 302, as shown by arrow 332. The effluent flows through the housing 302 in a direction parallel to the longitudinal axis 308 to an outlet 306 of the housing 302 for further downstream processing and does not substantially change in a direction relative to the longitudinal axis 308, as shown by arrow 334. Unless the context otherwise requires, when describing the direction of the effluent stream, "direction does not substantially change" means that the main flow is primarily between the layers of the coils and parallel to the axis 308. It should be understood that due to factors such as temperature devices or other protruding components, some minor deviations may occur, affecting 10% or less of the overall fluid main flow, more preferably 5% or less, but these deviations do not significantly affect the direction of the main flow. Additionally, as long as the cross-sectional changes maintain a common longitudinal axis, changes in the cross-sectional area of the main flow are not considered a "substantial change in direction" or a deviation from the direction of the main flow. Small-scale (i.e., less than the diameter of a single tube) changes in the direction of flow due to turbulence or the turbulent nature of the flow are not considered a "substantial change in direction" or a deviation from the longitudinal axis because they do not affect the overall direction of the flow. In at least some examples, when describing the direction of the effluent stream, "direction does not substantially change" means that at least 90% of the main flow, or more preferably at least 95% of the main flow, is parallel to the longitudinal axis 308 or has a parallel deviation within an acceptable range (i.e., an angle within 3 degrees of the parallel direction). In some embodiments, "substantially does not deviate from the longitudinal axis" may have a meaning similar to that provided above for "direction does not substantially change".

[0068] Arrow 336 corresponds to the introduction of a cold feed stream along line 338 into the heat exchanger 300. As Figure 6As shown, pipeline 338 is connected to the housing 302 above the plane 310, such that the cold feed stream 336 is introduced into the heat exchanger 300 above the plane 310. The cold feed stream 336 is heated via interaction with the effluent stream in the heat exchanger 300 to produce a heated feed stream. The heated feed stream is indicated by arrow 340 and exits the heat exchanger 300 along pipeline 342 near the inlet 304 or near the top of the heat exchanger 300. Thus, the cold feed stream can be provided to the bottom of the first part 312A of the housing 302 above the plane 310 and travel vertically upward along the first part 312A of the housing 302 to the top of the housing 302, and then leave the housing at 340 as the heated feed stream, thereby forming a first circulation path through the heat exchanger 300.

[0069] The second circuit through the heat exchanger 300 includes a coolant stream 344 provided to pipeline 346, which is connected to the housing at the bottom of the second part 312B of the housing 302 and below the plane 310, which also corresponds to the bottom of the housing 302 adjacent to the outlet 306. The coolant stream 344 exchanges heat with the effluent stream along the longitudinal axis 308 to produce a heated coolant stream 348. The heated coolant stream 348 exits the housing 302 via a pipeline 350 connected to the top of the second part 312B of the housing and below the plane 310. Thus, the coolant stream 344 travels vertically upward through the second part 312B of the housing 302 to complete the second circuit.

[0070] In summary, the first circuit is used to recover heat from the effluent stream via indirect heat transfer with (i) at least one of the feed streams; (ii) by generating steam; and / or (iii) by other intermediate fluids. The second circuit is used to further cool the effluent without removing the effluent by indirect heat transfer with at least one additional stream, wherein the first and second circuits and their arrangement in the heat exchanger 300 provide the benefits and advantages described herein.

[0071] Figure 7 is a schematic cross-sectional view of the first part 312A of the heat exchanger 300 along the longitudinal axis 308 of the heat exchanger 300. The heat exchanger 300 includes a mandrel 320 arranged along the longitudinal axis 308. The first heat transfer surface 316 can be a tube bundle surrounding the mandrel 320. Specifically, Figure 7Provides a representation of the winding angle of the tubes of the first heat transfer surface 316. By adjusting the winding angle relative to the horizontal plane passing through the housing 302, the total length of the tubes can vary independently of the diameter of the housing 302. For example, reducing the winding angle relative to the horizontal direction increases the tube density and tube length. The heat exchanger 300 may also include a shroud 352 located between the housing 302 and the heat transfer surfaces 316, 318. Additional tubes 354 of the heat exchanger 300 are schematically shown to illustrate the axial and radial spacing between the tubes 354, as described herein. The tubes 354 may also be arranged in concentric layers that overlap each other from the mandrel 320 to the shroud 352, with each layer separated by a spacer 356.

[0072] The heat exchanger 300 can overcome many of the deficiencies and drawbacks of the known heat exchangers discussed herein. For example, in the known system 20 ( Figure 1A and Figure 1B ), multiple individual heat exchangers 24 and coolers 26 are combined in a single housing 302 in the heat exchanger 300. The use of a single housing 302 in the heat exchanger 300 eliminates a significant amount of the piping and support structures required to connect and support multiple shell-and-tube heat exchangers in series and parallel, as in the known system 300, which provides the benefits described herein. As described above, the tube length in the heat exchanger 300 can vary independently of the diameter of the housing 302 by adjusting the winding angle. Thus, the heat exchanger 300 is more compact and has a higher overall heat transfer coefficient than known heat exchangers. The surface area for cooling is less than that of an equivalent shell-and-tube exchanger, and in some embodiments, the surface area of the heat transfer surfaces 316, 318 can be approximately one-third of the surface area in known heat exchangers. Additionally, a single flow device can also accommodate high capacities or operating tasks.

[0073] The heat exchanger 300 is more compact than an equivalent shell-and-tube heat exchanger, which results in a significant reduction in the size and number of devices. Additionally, replacing multiple exchangers (in series and parallel) with a single housing can reduce piping, structural, and installation costs. By eliminating the interconnecting piping and taking advantage of the spacing between the pipes as Figure 7 shown, the pressure drop from the effluent mixing point downstream of the steam generator to the compressor can be reduced by approximately 3 to 5 kPa. It has been found that approximately half of this reduction in pressure drop comes from reducing the pipe length, elbows, tees, and bends in the system, while the other half comes from eliminating the combined pressure drop of the multiple heat exchangers 24 and coolers 26 in the system 20 ( Figure 1A and Figure 1B ).

[0074] The lowest pressure drop is likely to occur in the shell side (i.e., Figure 7The arrow marked as effluent (shell). In the heat exchanger 300, the effluent flows outside the tube 354, which is arranged in concentric layers separated by spacers 356. By placing the cooler feed in the tube 354, the hot end tube sheet temperature is reduced by about 30 degrees Celsius, which effectively reduces the maximum metal design temperature by the same amount. Therefore, at the maximum temperature limit (due to material limitations or concerns about coking deposits), higher heat recovery efficiency can be achieved compared to placing the effluent in the pipeline. The layers of the pipeline also form a "channel" for the vapor flow, and the channel is relatively large. As Figure 7 shown, the radial spacing between the layers (the outer diameter distance between the tubes) can be more than ten times larger than the axial spacing because there is only a minimum axial spacing between the individual tubes in each layer. This tube layout minimizes the risk of blockage and provides a relatively large open area orthogonal to the flow, which can allow the flow to pass through the layers with substantially no change in the direction of the effluent flow, as described herein.

[0075] In the heat exchanger 300, the coolant can be cooling water, and its flow rate inside the tube (i.e., about 1.5 to 2 meters per second ("m / s")) can be much higher than that of known shell-and-tube exchangers (less than 0.7 m / s). The higher speed is expected to be beneficial for promoting higher heat transfer and higher shear stress at the tube wall to provide self-cleaning. In addition, the cooling water will be discharged, thereby reducing or eliminating the possibility of stagnant zones inside the tube. The tube material can be stainless steel, which will further reduce corrosion.

[0076] In known shell-and-tube configurations, the effluent flows parallel through all coolers to maintain low pressure. The cooling water inevitably has to flow parallel through all three exchangers, otherwise the effluent cannot be cooled to the required temperature. If the available cooling water flow rate is limited, this process may result in a very low shell-side velocity. In the heat exchanger 300, the tube winding angle can be flexibly increased to accommodate the low water velocity. Additionally, if the cooling flow is restricted for some reason during operation, the cooling water can also be isolated through a subset or sub-circuit of the available tubes of the heat exchanger 300, as described herein, to maintain a high water flow velocity in the remaining tubes.

[0077] As described above, the feed outlet temperature can be limited to 450 degrees Celsius to minimize the risk of coking at the tube sheet. This temperature can also set the maximum heat recovery limit. The fluid in contact with the tube sheet tends to be at the current tube sheet temperature, so the metal temperature should also be considered. The tube sheet temperature is mainly determined by the temperature of the tube-side fluid. For known shell-and-tube designs, such as in the heat exchanger 24, the tube-side fluid is the hot effluent, so the tube sheet will be close to 490 degrees Celsius.

[0078] For the heat exchanger 300, the tube-side fluid can be a cold feed, such that the average temperature of the tube sheet is relatively low. For a feed temperature of 450 degrees Celsius and an effluent temperature of 490 degrees Celsius, the average tube sheet temperature is reduced from 487 degrees Celsius to 451 degrees Celsius. The reduction in the tube sheet temperature of the heat exchanger 300 enables a higher feed outlet temperature.

[0079] Figure 8 is a schematic view of a processing system 301 that includes the heat exchanger 300. Specifically, provided Figure 8 to demonstrate the reduction in footprint, equipment, connections, support structure, and other advantages of the heat exchanger 300 relative to the known system 20. As Figure 8 shown, multiple heat exchangers 24 and coolers 26 of the system 20 ( Figure 1A and Figure 1B ) are replaced by a single heat exchanger 300 to provide the advantages described herein. This arrangement significantly reduces the piping system of the system 301 relative to the system 20, while also reducing the pressure drop and providing other advantages described herein.

[0080] In view of the foregoing, one or more embodiments of a heat exchanger system can be generally described as including: a shell having a longitudinal axis, wherein a first portion of the shell is located on a first side of a plane passing through the shell, and a second portion of the shell is located on a second side of the plane opposite the first side; a first heat transfer surface in the first portion of the shell; a second heat transfer surface in the second portion of the shell; a feed stream in communication with the first heat transfer surface; a heater in communication with the first heat transfer surface, operable to heat the feed stream output from the first heat transfer surface; a coolant stream in communication with the second heat transfer surface; a reactor in communication with the heater, operable to output an effluent stream to a heat exchanger configured to cool the effluent stream passing through the shell along the longitudinal axis of the shell.

[0081] In one embodiment, the feed stream is a reactor feed and the coolant stream is water, ethylene glycol water, or an aqueous coolant.

[0082] In one embodiment, the coolant stream is cooling water in an open-loop cooling system.

[0083] In one embodiment, the coolant stream is ethylene glycol water in a closed-loop cooling system.

[0084] In one embodiment, the coolant stream is an aqueous or non-aqueous liquid coolant in an open-loop or closed-loop cooling system.

[0085] In one embodiment, the shell of the heat exchanger is arranged vertically and the longitudinal axis is the vertical centerline passing through the shell.

[0086] In one embodiment, the plane is a horizontal plane passing through the shell between the first heat transfer surface and the second heat transfer surface.

[0087] The heat exchanger system may also include a first mandrel extending through at least a first portion of the housing and a second mandrel extending through at least a second portion of the housing.

[0088] In one embodiment, the first mandrel and the second mandrel extend along the longitudinal axis of the housing from the first portion of the housing to the second portion of the housing.

[0089] In one embodiment, the first heat transfer surface is a plurality of first coils arranged around the first mandrel.

[0090] In one embodiment, the second heat transfer surface is a plurality of second coils arranged around the second mandrel.

[0091] In one embodiment, the heat exchanger system also includes a single mandrel extending along the longitudinal axis of the housing.

[0092] In one embodiment, the first heat transfer surface and the second heat transfer surface are respectively a plurality of coils arranged around the single mandrel.

[0093] In one embodiment, the heat exchanger is configured to cool the effluent stream with substantially no change in the direction of the effluent stream.

[0094] In one embodiment, the heat exchanger is configured to cool the effluent stream with substantially no deviation from the longitudinal axis.

[0095] In one embodiment, the heat exchanger system also includes a compressor in communication with the heat exchanger, wherein the cooled effluent from the heat exchanger is supplied to the compressor, and the pressure change between the outlet of the reactor and the suction inlet of the compressor includes no more than 8 velocity heads associated with elbows, tees, bends or other fittings and no more than 1.5 times the pressure drop associated with the heat exchanger.

[0096] One or more embodiments of the system may be generally described as including: a heat exchanger including a housing having an inlet and an outlet aligned with a longitudinal axis extending through the housing from the inlet to the outlet along the longitudinal axis; a first mandrel disposed along the longitudinal axis of the housing; a first heat transfer surface in the housing being a plurality of first coils arranged around the first mandrel, a second mandrel being disposed along the longitudinal axis of the housing, and a second heat transfer surface in the housing being a plurality of second coils arranged around the second mandrel; a feed stream in communication with the first heat transfer surface; a heater in communication with the first heat transfer surface operable to heat the feed stream from the first heat transfer surface; a reactor in communication with the heater operable to output an effluent stream to the inlet of the housing, the first heat transfer surface and the second heat transfer surface being operable to cool the effluent stream along a flow path.

[0097] In one embodiment, the first heat transfer surface and the second heat transfer surface are operable to cool the effluent stream with substantially no change in the direction of the effluent stream along the flow path.

[0098] In one embodiment, the first heat transfer surface is operable to exchange heat with the effluent stream from the reactor to heat the feed stream, and coolant is provided to the second heat transfer surface.

[0099] In one embodiment, the shell includes a first portion on a first side of a plane passing through the shell and a second portion on a second side of the plane opposite the first side, and the feed stream enters the heat exchanger in the first portion of the shell.

[0100] In one embodiment, the shell of the heat exchanger is arranged vertically, the longitudinal axis is the vertical centerline passing through the shell, and the plane is a horizontal plane passing through the center of the shell.

[0101] In one embodiment, the shell of the heat exchanger is arranged vertically, the longitudinal axis is the vertical centerline passing through the shell, and the plane is located between the first heat transfer surface and the second heat transfer surface.

[0102] In one embodiment, the effluent stream is divided into a first portion and a second portion, and the system further includes a steam generator in communication with the reactor and operable to cool the first portion of the effluent stream.

[0103] In one embodiment, the second portion of the effluent stream bypasses the steam generator.

[0104] In one embodiment, the first portion and the second portion of the effluent stream merge downstream of the steam generator and are provided to the inlet of the heat exchanger.

[0105] In one embodiment, the heat exchanger system further includes a compressor in communication with the outlet of the heat exchanger, wherein the cooled effluent from the outlet heat exchanger is supplied to the compressor, and the pressure change between the reactor outlet and the compressor suction inlet includes no more than 8 velocity heads associated with elbows, tees, bends, or other fittings and is no more than 1.5 times the pressure drop between the inlet and the outlet of the heat exchanger shell.

[0106] One or more embodiments of the method may generally include: providing a feed stream to a first heat transfer surface in a first portion of a heat exchanger shell, the first heat transfer surface being a plurality of first coils disposed on a first mandrel within the shell; providing the feed stream from the first heat transfer surface to a reactor; providing a cooling stream to a second heat transfer surface in a second portion of the heat exchanger shell, wherein the first portion of the shell is on a first side of a plane passing through the shell and the second portion of the shell is on a second side of the plane passing through the shell opposite the first side, and the second heat transfer surface is a plurality of second coils disposed around a second mandrel within the shell; providing an effluent stream from the reactor to an inlet of the first portion of the shell; causing the effluent stream to flow along a flow path through the shell, the flow path flowing from the inlet of the first portion of the shell to an outlet of the second portion of the shell along a longitudinal axis of the shell; and cooling the effluent stream along the flow path using the first heat transfer surface and the second heat transfer surface.

[0107] In one embodiment, cooling the effluent stream includes cooling the effluent stream using the first heat transfer surface and the second heat transfer surface, and the direction of the effluent stream along the flow path is substantially unchanged.

[0108] In one embodiment, the shell is disposed vertically, the longitudinal axis is a vertical centerline passing through the shell, and the plane is a horizontal plane passing through the center of the shell, and the flow path is along the longitudinal axis of the shell.

[0109] In one embodiment, providing the effluent stream from the reactor to the inlet of the first portion of the shell includes dividing the effluent stream into a first portion and a second portion, passing the first portion through a steam generator, bypassing the steam generator with the second portion, combining the first portion and the second portion of the effluent stream downstream of the steam generator, and providing the combined effluent stream to the inlet of the first portion of the shell.

[0110] The method may further include, after providing the feed stream to the first heat transfer surface, providing the feed stream from the first heat transfer surface to a heater, heating the feed stream with the heater, and providing the heated feed stream to the reactor.

[0111] In one embodiment, providing the effluent stream from the reactor to the inlet of the first portion of the shell includes providing the effluent stream directly from the reactor to the inlet.

[0112] The method may further include providing the cooled effluent stream from the heat exchanger to a compressor, wherein the pressure change between the outlet of the reactor and the suction inlet of the compressor includes no more than 8 velocity heads associated with elbows, tees, bends, or other fittings and is not greater than 1.5 times the pressure drop between the inlet and the outlet of the heat exchanger shell.

[0113] One or more embodiments of the system can generally be summarized as including: a heat exchanger including a housing having a longitudinal axis, a first portion of the housing being on a first side of a plane passing through the housing, a second portion of the housing being on a second side of the plane opposite the first side, one or more mandrels disposed along the longitudinal axis of the housing, a first heat transfer surface in the first portion of the housing, and a second heat transfer surface in the second portion of the housing; a feed stream in communication with the first heat transfer surface; a heater in communication with the first heat transfer surface and operable to heat the feed stream exiting the first heat transfer surface; a coolant stream in communication with the second heat transfer surface; a reactor in communication with the heater and operable to output an effluent stream to the heat exchanger, the heat exchanger being configured to cool the effluent stream passing through the housing along the longitudinal axis of the housing; and a compressor in communication with the heat exchanger.

[0114] In one embodiment, the cooled effluent from the heat exchanger is supplied to the compressor, and the pressure change between the outlet of the reactor and the inlet of the compressor includes no more than 8 velocity heads associated with elbows, tees, bends, or other fittings and no more than 1.5 times the pressure drop associated with the effluent stream passing through the heat exchanger.

[0115] In one embodiment, the first heat transfer surface and the second heat transfer surface are respective pluralities of coils disposed around one or more mandrels.

[0116] In one embodiment, the one or more mandrels include a first mandrel extending through at least the first portion of the housing and a second mandrel extending through at least the second portion of the housing.

[0117] In one embodiment, the first heat transfer surface is a plurality of first tubes disposed around the first mandrel, and the second heat transfer surface is a plurality of second tubes disposed around the second mandrel.

[0118] The foregoing description of the illustrated embodiments, including what is described in the abstract, is not intended to be exhaustive or to limit the implementations to the precise forms disclosed. Although specific embodiments and examples are described herein for illustrative purposes, various equivalent modifications can be made without departing from the spirit and scope of the present disclosure, as will be recognized by those of ordinary skill in the relevant art. The teachings of the various embodiments provided herein can be applied outside of a heat exchanger environment and are not limited to the exemplary heat exchanger systems, methods, and apparatuses generally described above.

[0119] Many of the methods described herein can be performed with variations. For example, many methods can include additional acts, omit some acts, and / or perform acts in an order different from that shown or described.

[0120] In the foregoing description, certain specific details are set forth in order to provide a thorough understanding of the various embodiments of the present disclosure. However, one of ordinary skill in the art will understand that the present disclosure may be practiced without these specific details. In other instances, well-known structures associated with heat exchangers, devices, and methods have not been described in detail to avoid unnecessarily obscuring the description of the embodiments of the present disclosure.

[0121] Certain words and phrases used in this specification are set forth below. As used throughout this document, including the claims, unless otherwise indicated, the singular forms "a," "an," and "the" include plural referents. Any feature and element described herein can be singular, e.g., a shell can refer to one shell. The terms "comprising" and "including" and their derivatives mean including but not limited to. The phrases "associated with" and "associated therewith" and their derivatives can mean: including, being included within, interconnected with, containing, being contained within, connected to or connected with, coupled to or coupled with, communicable with, cooperating with, interlacing, juxtaposing, adjacent, being bound to or bound with, having, having the property of, and so on. Other definitions of certain words and phrases are provided throughout the present disclosure.

[0122] The use of ordinal numbers such as first, second, third, etc. does not necessarily imply an ordering meaning of sequence, but may only distinguish multiple instances of an act or similar structure or material.

[0123] Throughout this specification, the claims, and the drawings, unless the context clearly dictates otherwise, the following terms take the meanings explicitly associated herein. The term "herein" refers to the specification, the claims, and the drawings associated with this application. The phrases "in one embodiment," "in another embodiment," "in various embodiments," "in some embodiments," "in other embodiments," and their other derivatives refer to one or more features, structures, functions, limitations, or characteristics of the present disclosure and are not limited to the same or different embodiments unless the context clearly dictates otherwise. As used herein, the term "or" is an inclusive "or" operator and is equivalent to the phrase "A or B, or both" or "A or B or C, or any combination thereof," and lists with additional elements are treated similarly. The term "based on" is not exclusive and allows for additional features, functions, aspects, or limitations not described unless the context otherwise clearly indicates. Additionally, throughout the specification, the meanings of "a" and "the" include singular and plural references.

[0124] In general, unless otherwise specified, the materials used to manufacture the present invention and / or its components may be selected from suitable materials such as composite materials, ceramics, plastics, metals, polymers, thermoplastics, elastomers, plastic compounds, etc., either individually or in any combination.

[0125] For purposes of explanation, the foregoing description uses specific terms and formulas to provide a thorough understanding of the disclosed embodiments. It will be apparent to those skilled in the art that practicing the present invention does not require specific details. Embodiments have been selected and described in order to best explain the principles of the disclosed embodiments and their practical application, thereby enabling others skilled in the art to utilize the disclosed embodiments and various embodiments with various modifications suitable for the particular purposes contemplated. Accordingly, the foregoing disclosure is not intended to be exhaustive or to limit the invention to the precise forms disclosed, and those skilled in the art will recognize that, given the above teachings, many modifications and variations are possible.

[0126] As used herein, the terms “top,” “bottom,” “upper,” “lower,” “above,” “below,” “over,” “under,” “left,” “right,” and other similar derivatives take their common meaning as directions or position indicators, e.g., gravity pulls an object downward, and left refers to the direction west when facing north in a basic direction scheme. These terms do not limit the possible orientations that are explicitly disclosed, implicitly disclosed, or inherently disclosed in the present disclosure, and unless the context clearly dictates otherwise, any aspect of an embodiment of the present disclosure may be arranged in any orientation.

[0127] As used herein, the term “substantially” is interpreted to include the ordinary error range or manufacturing tolerances resulting from minor differences and variations in manufacturing. Unless the context clearly dictates otherwise, relative terms such as “about,” “substantially,” and other derivatives, when used to describe a value, quantity, amount, or dimension, generally refer to a value, quantity, amount, or dimension within plus or minus 5% of the specified value, quantity, amount, or dimension. It should also be understood that any specific dimensions provided herein for components or features are for illustrative purposes only in reference to the various embodiments described herein, and thus, unless the context clearly dictates otherwise, dimensions greater than or less than the stated dimensions are clearly contemplated in the present disclosure.

[0128] In view of the foregoing detailed description, these and other changes may be made to the embodiments. In general, in the following claims, the terms used should not be construed to limit the claims to the specific embodiments disclosed in this specification and the claims, but should be construed to include all possible embodiments and the full scope of equivalents of the ownership of this claim. Accordingly, the breadth and scope of the disclosed embodiments should not be limited by any of the above embodiments, but should be defined only in accordance with the appended claims and their equivalents.

Claims

1. A system comprising: a heat exchanger comprising: a housing having a longitudinal axis, wherein a first portion of the housing is located on a first side of a plane passing through the housing, and a second portion of the housing is located on a second side of the plane opposite the first side; a first heat transfer surface in the first portion of the housing; and a second heat transfer surface in the second portion of the housing; a feed stream in communication with the first heat transfer surface; a heater in communication with the first heat transfer surface and operable to heat the feed stream output from the first heat transfer surface; a coolant stream in communication with the second heat transfer surface; and a reactor in communication with the heater and operable to output an effluent stream to the heat exchanger, the heat exchanger being configured to cool the effluent stream passing through the housing along the longitudinal axis of the housing.

2. The system according to claim 1, wherein the feed stream is a reactor feed and the coolant stream is water, ethylene glycol water or an aqueous coolant.

3. The system according to claim 1, wherein the housing of the heat exchanger is arranged vertically and the longitudinal axis is a vertical center line passing through the housing.

4. The system according to claim 3, wherein the plane is a horizontal plane passing through the housing between the first heat transfer surface and the second heat transfer surface.

5. The system according to claim 1, further comprising: a first mandrel extending through at least a first portion of the housing; and a second mandrel extending through at least a second portion of the housing.

6. The system according to claim 5, wherein the first mandrel and the second mandrel extend along the longitudinal axis of the housing from the first portion of the housing to the second portion of the housing.

7. The system according to claim 5, wherein the first heat transfer surface is a plurality of first coils arranged around the first mandrel.

8. The system according to claim 7, wherein the second heat transfer surface is a plurality of second coils arranged around the second mandrel.

9. The system according to claim 1, further comprising: a single mandrel extending along the longitudinal axis of the housing.

10. The system according to claim 9, wherein the first heat transfer surface and the second heat transfer surface are respective plurality of coils arranged around the single mandrel.

11. The system according to claim 1, wherein the heat exchanger is configured to cool the effluent stream while the direction of the effluent stream is substantially unchanged.

12. The system according to claim 1, wherein the heat exchanger is configured to cool the effluent stream while the direction of the effluent stream is substantially not deviated from the longitudinal axis.

13. The system according to claim 1, further comprising: A compressor in communication with the heat exchanger, wherein the cooled effluent from the heat exchanger is supplied to the compressor, and the pressure change between the outlet of the reactor and the suction inlet of the compressor includes no more than 8 velocity heads associated with elbows, tees, bends, or other fittings, and no more than 1.5 times the pressure drop associated with the heat exchanger.

14. The system according to claim 1, wherein the coolant flow is cooling water in an open-loop cooling system.

15. The system according to claim 1, wherein the coolant flow is ethylene glycol water in a closed-loop cooling system.

16. The system according to claim 1, wherein the coolant flow is an aqueous or non-aqueous liquid coolant in an open-loop cooling system or a closed-loop cooling system.

17. A system comprising: A heat exchanger comprising: A housing having an inlet and an outlet aligned with a longitudinal axis passing through the housing to define a flow path through the housing from the inlet to the outlet along the longitudinal axis; A first mandrel disposed along the longitudinal axis of the housing; A first heat transfer surface in the housing, which is a plurality of first coils arranged around the first mandrel; A second mandrel disposed along the longitudinal axis of the housing; and A second heat transfer surface in the housing, which is a plurality of second coils around the second mandrel; A feed stream in communication with the first heat transfer surface; A heater in communication with the first heat transfer surface, operable to heat the feed stream from the first heat transfer surface; and A reactor in communication with the heater, operable to output an effluent stream to the inlet of the housing, and the first heat transfer surface and the second heat transfer surface are operable to cool the effluent stream along the flow path.

18. The system according to claim 17, wherein the first heat transfer surface and the second heat transfer surface are operable to cool the effluent stream while the direction of the effluent stream along the flow path is substantially unchanged.

19. The system according to claim 17, wherein the first heat transfer surface is operable to heat the feed stream by heat exchange with the effluent stream from the reactor, and coolant is supplied to the second heat transfer surface.

20. The system according to claim 17, wherein the housing includes a first portion on a first side of a plane passing through the housing and a second portion on a second side of the plane opposite the first side, and wherein the feed stream enters the heat exchanger in the first portion of the housing.

21. The system according to claim 20, wherein the housing of the heat exchanger is arranged vertically, wherein the longitudinal axis is the vertical center line passing through the housing, and the plane is a horizontal plane passing through the center of the housing.

22. The system according to claim 20, wherein the housing of the heat exchanger is arranged vertically, wherein the longitudinal axis is the vertical center line passing through the housing, and the plane is located between the first heat transfer surface and the second heat transfer surface.

23. The system according to claim 17, wherein the effluent stream is divided into a first portion and a second portion, and the system further comprises: A steam generator in communication with the reactor and operable to cool the first portion of the effluent stream.

24. The system according to claim 23, wherein the second portion of the effluent stream bypasses the steam generator.

25. The system according to claim 24, wherein the first portion and the second portion of the effluent stream merge downstream of the steam generator and are provided to the inlet of the heat exchanger.

26. The system according to claim 17, which further comprises: A compressor in communication with the outlet of the heat exchanger, wherein the cooled effluent from the outlet heat exchanger is supplied to the compressor, and the pressure change between the outlet of the reactor and the suction inlet of the compressor includes no more than 8 velocity heads associated with elbows, tees, bends or other fittings and is no more than 1.5 times the pressure drop between the inlet and the outlet of the shell of the heat exchanger.

27. A method, which comprises: Providing a feed stream to a first heat transfer surface in a first portion of a shell of a heat exchanger, the first heat transfer surface being a plurality of first coils arranged around a first mandrel in the shell; Providing the feed stream from the first heat transfer surface to a reactor; Providing a cooling stream to a second heat transfer surface in a second portion of the shell of the heat exchanger, wherein the first portion of the shell is on a first side of a plane passing through the shell and the second portion of the shell is on a second side of the plane passing through the shell opposite the first side, and the second heat transfer surface is a plurality of second coils arranged around a second mandrel in the shell; Providing the effluent stream from the reactor to an inlet of the first portion of the shell; Causing the effluent stream to flow along a flow path through the shell, the flow path extending along a longitudinal axis of the shell from the inlet of the first portion of the shell to an outlet of the second portion of the shell; And Cooling the effluent stream along the flow path using the first heat transfer surface and the second heat transfer surface.

28. The method according to claim 27, wherein cooling the effluent stream comprises cooling the effluent stream using the first heat transfer surface and the second heat transfer surface while the direction of the effluent stream along the flow path is substantially unchanged.

29. The method according to claim 27, wherein the shell is arranged vertically, wherein the longitudinal axis is a vertical centerline passing through the shell and the plane is a horizontal plane passing through the center of the shell and the flow path extends along the longitudinal axis of the shell.

30. The method according to claim 27, wherein providing the effluent stream from the reactor to the inlet of the first portion of the shell comprises: Dividing the effluent stream into a first portion and a second portion; Causing the first portion to pass through a steam generator; Bypass the second portion around the steam generator; Converge the first portion and the second portion of the effluent stream downstream of the steam generator; And Provide the converged effluent stream to the inlet of the first portion of the housing.

31. The method according to claim 27, further comprising, after providing the feed stream to the first heat transfer surface: Provide the feed stream from the first heat transfer surface to a heater; Heat the feed stream with the heater; and Provide the heated feed stream to the reactor.

32. The method according to claim 27, wherein providing the effluent stream from the reactor to the inlet of the first portion of the housing comprises providing the effluent stream directly from the reactor to the inlet.

33. The method according to claim 27, further comprising, after cooling the effluent stream: Provide a cooled effluent stream from the heat exchanger to a compressor, wherein the pressure change between the outlet of the reactor and the suction inlet of the compressor comprises no more than 8 velocity heads associated with elbows, tees, bends, or other fittings and is no more than 1.5 times the pressure drop between the inlet and the outlet of the housing of the heat exchanger.

34. A system comprising: A heat exchanger comprising: A housing having a longitudinal axis, wherein a first portion of the housing is on a first side of a plane passing through the housing and a second portion of the housing is on a second side of the plane opposite the first side; One or more mandrels disposed along the longitudinal axis of the housing; A first heat transfer surface in the first portion of the housing; and A second heat transfer surface in the second portion of the housing; A feed stream in communication with the first heat transfer surface; A heater in communication with the first heat transfer surface and operable to heat the feed stream output from the first heat transfer surface; A coolant stream in communication with the second heat transfer surface; A reactor in communication with the heater and operable to output an effluent stream to the heat exchanger, the heat exchanger being configured to cool the effluent stream passing through the housing along the longitudinal axis of the housing; and A compressor in communication with the heat exchanger.

35. The system according to claim 34, wherein the cooled effluent from the heat exchanger is supplied to the compressor, and the pressure change between the outlet of the reactor and the suction inlet of the compressor comprises no more than 8 velocity heads associated with elbows, tees, bends, or other fittings.

36. The system according to claim 35, wherein the pressure change is no more than 1.5 times the pressure drop associated with the effluent stream passing through the heat exchanger.

37. The system according to claim 34, wherein the first heat transfer surface and the second heat transfer surface are respective plural coils disposed around the one or more mandrels.

38. The system according to claim 34, wherein the one or more mandrels include a first mandrel extending through at least the first portion of the housing and a second mandrel extending through at least the second portion of the housing.

39. The system according to claim 38, wherein the first heat transfer surface is a plurality of first tubes arranged around the first mandrel, and the second heat transfer surface is a plurality of second tubes arranged around the second mandrel.

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