Power recovery from quench and dilution steam streams.

Abstract

A process for reducing the pressure of a steam stream used to reduce the temperature or pressure in a reactor. The pressure of the steam stream is reduced in a turbine to provide a low-pressure steam stream. The steam stream rotates a turbine wheel in the turbine. The turbine wheel is configured to transfer rotational motion to a generator, which then generates electricity. The low-pressure steam stream is injected into the reactor to reduce the temperature in the reactor or reduce the partial pressure of hydrocarbon vapors in the reactor. [Selected Figure] Figure 1

Description

[Technical field]

[0001] The present invention relates generally to steam streams used as diluent or quench fluids in chemical processing or refining plants, and more particularly to processes in which such steam streams are passed through turbines to reduce the pressure of the steam stream and recover energy from the pressure reduction. [Background technology]

[0002] Chemical refining and processing processes often use diluent or quench fluids that are added to help promote the reaction(s) and / or control the temperature(s). Exemplary reactors that utilize these types of vapor streams include refinery fluidized catalytic cracking "FCC" reactors and hydrotreating reactors. In reactors, the minimum temperature of the diluent or quench vapor stream is sometimes limited by the dew point of the vapor stream.

[0003] In FCC reactors, steam is added to the transport reactor to transport the catalyst, as a working fluid for feed atomization and distribution, to remove hydrocarbons from the catalyst before regeneration, and to reduce the partial pressure of low molecular weight products, thereby mitigating the equilibrium for cracking and promoting higher conversion. Steam is commonly used for dilution in process operations, and is often used to reduce the partial pressure of hydrocarbons to promote vaporization or forward reaction in molar production reactions such as FCC. The use of steam is to provide a gaseous material that is easily condensed and removed after its use. In many cases, for FCC, it is advantageous to have steam as close to the dew point as possible, since the added energy is detrimental to the performance of the unit. The flow of hot catalyst added to the reactor is limited by the maximum reactor temperature that promotes thermal cracking. Because the pressure drop from the steam supply to the reactor riser is usually high, the steam enters with a lot of superheat, which unnecessarily creates a higher reactor temperature than would be possible with a less superheated steam source. This tends to limit the circulation rate of the hot catalyst and result in less desirable thermal cracking for catalytic cracking.

[0004] In hydroprocessing reactors, the catalyst bed is often separated into multiple beds due to the highly exothermic nature of hydroprocessing and the need to quench the reaction and control the temperature. Between different reactor beds, a relatively low temperature (compared to the process) hydrogen-containing vapor stream is added to quench the reactor temperature before the process fluid enters the next bed catalyst. The use of a hydrogen-containing vapor stream requires energy as the quench stream is compressed. The throughput of a hydroprocessing unit is often limited by the flow of quench hydrogen to maintain the reactor catalyst bed temperature within a safe range.

[0005] In either conventional hydroprocessing or FCC reactors, the quench or dilution streams often pass through a control valve to control the flow of these vapor streams. While these conventional systems are likely effective for their intended purposes, the control valves result in a loss of mechanical energy. Specifically, energy removed via pressure drop is dissipated without recovery by the control valve, so energy is lost. In addition, the lost energy can represent a higher operating cost, since the energy removed is often the result of energy added to the system. This lost energy is achieved via an adiabatic pressure drop across the control valve, resulting in a minimal temperature drop versus pressure drop.

[0006] Therefore, what is needed is an effective and efficient apparatus and process for recovering this lost energy associated with such quench or dilution vapor streams, as well as a method for shifting more of the energy drop to temperature drop versus pressure drop. Summary of the Invention

[0007] The present invention provides an apparatus and process that overcomes one or more of the shortcomings associated with the prior art.

[0008] Specifically, according to the present invention, the control valve is replaced by a turbine. By using a turbine instead of a control valve, the same or more energy removal to reduce pressure is achieved with a higher temperature drop after more isentropic processes compared to a control valve. The turbine in the quench or dilute stream changes the pressure drop from adiabatic operation (valve with high outlet temperature) to isentropic operation, and energy is extracted in a manner that operates on the shaft, thereby producing a lower temperature output while optionally generating power from the pressure letdown. Alternatively, the energy can be dissipated by brakes or other devices if electrical recovery is not highly valued for process improvement.

[0009] For FCC units, having the dilution stream closer to its dew point reduces the heat input in the riser and allows more heat to be added by increasing the catalyst circulation, providing more selective cracking to the desired LPG and naphtha components. For hydrotreating reactors, there is less hydrogen in the quench vapor stream, lowering the energy usage in the recycle gas compressor and / or allowing more hydrogen to be injected into the inlet of the reactor - promoting longer first bed catalyst life and higher hydrogenation in each bed, but not optimal. With a fixed hydrogen flow, the cooled hydrogen allows more hydrocarbon loading to the reactor, since more heat of reaction is cooled with the same flow of now cooled hydrogen. In addition to the above benefits, the turbine converts the removed energy into electrical energy that is utilized elsewhere. Thus, the turbine offers an additional advantage over the control valves currently used with the dilution and quench streams.

[0010] Thus, in at least one aspect, the invention can be characterized as providing a process for reducing the pressure of a steam stream used to reduce the temperature, heat load, or hydrocarbon partial pressure in a reactor by reducing the pressure of the steam stream with a turbine, rotating a turbine wheel in a turbine to provide a lower pressure steam stream, injecting a low pressure steam stream into the reactor to reduce the temperature or total heat input to the reactor, or to reduce the partial pressure of the hydrocarbon vapor in the reactor.

[0011] In another aspect, the invention may feature a process for reducing pressure of the steam stream including steam; passing the steam stream through a turbine including a turbine wheel configured to transmit rotational motion to an electrical generator; and recovering a reduced pressure steam stream from the turbine; mixing the reduced pressure steam stream with a hydrocarbon vapor to reduce the partial pressure of the hydrocarbon vapor, thereby reducing the partial pressure of the hydrocarbon vapor.

[0012] Additionally, in yet another aspect, the invention may feature a process for reducing a pressure of the steam stream used as a quench stream by providing a steam stream comprising hydrogen; passing the steam stream through a turbine comprising a turbine wheel therein, the turbine wheel being optionally configured to transfer rotational motion to an electrical generator; recovering a reduced pressure steam stream from the turbine; and controlling a temperature in a reactor with the reduced pressure steam stream from the turbine.

[0013] Further aspects, embodiments and details of the invention, all of which may be combined in any manner, are set out in the following detailed description of the invention. [Brief description of the drawings]

[0014] One or more exemplary embodiments of the invention are described below in conjunction with the following drawings.

[0015] [Figure 1] 1 illustrates an FCC reactor for use in accordance with one or more embodiments of the present invention.

[0016] [Diagram 2] 1 shows a schematic diagram of a turbine according to one or more embodiments of the present invention.

[0017] [Diagram 3] 1 illustrates a hydroprocessing reactor for use in accordance with one or more embodiments of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] As mentioned above, the present invention utilizes one or more turbines to reduce pressure and temperature through near isentropic means and optionally recover energy from the quench or dilution vapor streams in the chemical processing unit. The optionally recovered energy in the form of electrical energy is used elsewhere in the processing unit, for example. It is contemplated that power recovery turbines will be installed on these high power let-downs of hydrogen and steam to the reactor, thereby generating value from the recovered energy in addition to increasing the conversion or throughput of the reactor, reducing the specific production energy intensity by allowing lower hydrogen circulation rates, higher feed rates (throughput), or increased conversion.

[0019] With these general principles in mind, one or more embodiments of the invention are described, with the understanding that the following description is not intended to be limiting.

[0020] 1, in various aspects of the invention, a turbine is used in a dilution stream associated with an FCC unit 10. The description of the invention in the context of the particular FCC unit 10 shown is not intended to limit the invention to the details disclosed therein.

[0021] 1 generally includes a separation vessel 12, a regenerator 14, and a vertical riser 16. The FCC unit 10 circulates catalyst and contact feeds in a manner described below.

[0022] The catalyst includes any well-known catalyst used in the art of fluid catalytic cracking, such as active amorphous clay-type catalysts and / or highly active crystalline molecular sieves. Molecular sieve catalysts are preferred over amorphous catalysts because of their greatly improved selectivity to the desired products. Zeolites are the most commonly used molecular sieves in FCC processes. Preferably, the first catalyst includes a large pore zeolite, such as Y-type zeolite, an activated alumina material, a binder material including either silica or alumina, and an inert filler, such as kaolin. The catalyst additive may include a medium or smaller pore zeolite catalyst, exemplified by ZSM-5, ZSM-11, ZSM-12, ZSM-23, ZSM-35, ZSM-38, ZSM-48, and other similar materials.

[0023] FCC feedstocks include conventional FCC feedstocks and high boiling or residual feeds. The most common of the conventional feedstocks is vacuum gas oil, which is a hydrocarbon material typically having a boiling range of 343°-552°C (650°-1025°F.), and is prepared by vacuum fractionation of atmospheric residue. Heavy or residual feedstocks, i.e., boiling above 499°C (930°F.), are also suitable.

[0024] Turning now to FIG. 1, the riser 16 provides a conversion zone for cracking of the hydrocarbons in the feedstock. The residence time of the feed in contact with the catalyst in the riser 16 may be 3 seconds or less. Depending on the desired product distribution, a residence time of 3 seconds or less may be preferred. A shorter residence time ensures that the desired products, once obtained, are not converted to undesirable products. Notwithstanding the foregoing, different residence times may be utilized as will be appreciated by those skilled in the art.

[0025] The feedstock is introduced into the riser 16 by one or more distributors or nozzles 19 located between an inlet 18 and the riser 16, and substantially upstream from an outlet 20. Upon entering the riser 16, the volume expansion resulting from the rapid vaporization of the feedstock increases the density of the catalyst within the riser, typically to 160 kg / m 3 (10lb / ft 3 Prior to contact with the catalyst, the feedstock typically has a temperature in the range of 149°-316° C. (300°-600° F.). Additional amounts of feedstock may be added downstream of the initial feed point in distributor 19.

[0026] The mixed catalyst and reacted feed vapor then exits the top of riser 16 through outlet 20 and is separated into a cracked product vapor stream that includes olefins and a recovery of catalyst particles that are covered with a significant amount of coke and are commonly referred to as "coked catalyst." In order to minimize the contact time of the feed with the catalyst that may promote further conversion of desired products to other undesirable products, an optional separator arrangement is used to rapidly remove the coked catalyst from the product stream.

[0027] Specifically, a swirl arm arrangement 22 at the end of the riser 16 can further enhance the initial catalyst and cracked hydrocarbon separation by imparting a tangential velocity to the effluent catalyst and cracked product vapor stream mixture. Such a swirl arm arrangement 22 is more fully described in U.S. Pat. No. 4,397,738. The swirl arm arrangement 22 is located at the top of the chamber 24 and a stripping zone 26 is located at the bottom of the chamber 24. The catalyst separated by the swirl arm arrangement 22 falls into the stripping zone 26 (described below). The cracked product vapor stream, which includes light olefins and cracked hydrocarbons including some catalyst passes through a conduit 28 to a cyclone 30. The cyclone 30 removes remaining catalyst particles from the product vapor stream to reduce the particle concentration to a very low level. The product vapor stream then exits the top of the separation vessel 12 through an outlet 32. The catalyst separated by cyclone 32 returns to separation vessel 12 through a two-legged conduit 34 into a dense bed 36 where it enters stripping zone 26 through an opening 38 .

[0028] Stripping zone 26 removes adsorbed hydrocarbons from the catalyst surface by countercurrent contact with steam. Steam enters stripping zone 26 through line 40. Any hydrocarbons removed in stripping zone 26 flow upwardly as described above. Catalyst drips into catalyst bed 42 at the bottom of chamber 24.

[0029] Some catalyst from catalyst bed 42 may be recycled to the riser 16 without first being regenerated. A second portion of the catalyst from catalyst bed 42 is regenerated in regenerator 14 before it is returned to the riser 16. The second portion of the catalyst from catalyst bed 42 is transported through coked catalyst conduit 46 to regenerator 14 at a rate regulated by control valve 48 for removal of coke.

[0030] On the regeneration side of the process, coked catalyst transferred to the regenerator 14 via coked catalyst conduit 46 undergoes the typical combustion of coke from the surface of the catalyst particles by contact with an oxygen-containing gas. The oxygen-containing gas enters the bottom of the regenerator 14 via inlet 48 and passes through a dense fluidized bed of catalyst (not shown). Flue gas, consisting primarily of carbon dioxide and possibly containing carbon monoxide, passes upwardly from the dense bed into the dilute phase of the regenerator 14. A separator such as a cyclone 50 or other means removes entrained catalyst particles from the riser flue gas before the flue gas exits the regenerator 14 through outlet 52. The combustion of coke from the catalyst particles increases the temperature of the catalyst withdrawn from the regenerator 14 in the regenerator standpipe 54.

[0031] The regenerator standpipe 54 passes the regenerated catalyst from the regenerator 14 to a mixing area 57 at a rate regulated by a control valve 56. The catalyst flow rate is typically maximized to provide the highest conversion to the desired gasoline and LPG products at the highest production rates. The catalyst provides most of the heat for the reactor, and flow is limited by the temperature in the riser. Therefore, anything that reduces the heat input to the riser allows for higher catalyst circulation rates and higher conversions or higher feed rates.

[0032] In mixing zone 57, regenerated catalyst is mixed with the catalyst directly from catalyst bed 42. A fluidizing gas passes from conduit 58 into mixing vessel 56. The fluidizing gas contacts the catalyst and maintains it in a fluidized state as it moves up through riser 16 and into contact with the feedstock as described above. Often the fluidizing gas is steam. In addition to fluidizing the catalyst, the steam helps to reduce the partial pressure of the hydrocarbons in riser 16, driving the catalyzed reaction toward desired products (as opposed to undesirable by-products).

[0033] In a conventional FCC unit, a control valve is used to reduce the pressure of the steam in conduit 58 before it is sent to FCC unit 10. The present invention uses a turbine 60 in an isentropic expansion to reduce the pressure of the steam in conduit 58 before passing the steam to FCC unit 10, resulting in a lower energy content of the steam compared to steam controlled by an adiabatic process control valve. An exemplary turbine 60 is shown in FIG.

[0034] 2, the turbine 60 includes a turbine wheel 62 with blades 64 configured to transmit or transfer rotational motion generated by a flow of steam passing through the turbine wheel 62 to a generator 66. The generator 66 generally includes a first winding 68 in communication with the turbine wheel 62 and a second winding 70 surrounding the first winding 68. As is known, rotation of the first winding 68 relative to the second winding 70 generates an electric current. Although not so illustrated, the generator 66 may include a permanent magnet in place of one of the windings 68, 70. Such generators are well known in the art.

[0035] The turbine 60 may also include a processor 72 configured to measure the amount of electricity generated by the turbine 60, and a transmitter 74 to transmit information related to the amount of electricity generated by the turbine 60 to a computer 76 at a control center 78. The particular configuration of the turbine 60 is not essential to the practice of the present invention, provided that the turbine 60 provides the desired pressure reduction and conversion of energy from reduced pressure to electricity. Exemplary turbines and further details are described in U.S. Patent Nos. 4,625,125; 4,694,189; 4,754,156; and 9,203,969, all of which are incorporated herein by reference.

[0036] Thus, in some embodiments, the process according to the invention includes directing a portion of the gas process stream through one or more variable resistance turbines to control the flow rate of the gas process stream and, optionally, generate power therefrom; controlling the pressure and temperature of the gaseous process stream so that the gas leaving the power recovery turbine remains in the gas phase; and measuring or controlling the flow rate to vary the resistance through the turbine, or both, using variable nozzle turbines, inlet variable guide vanes, or directly coupled variable electrical loads, to name a few. Also, the resistance to rotation of the variable resistance turbine can be varied by an external variable load electrical circuit that is in a magnetic field from a magnet or magnets that rotate on the turbine. The more load placed on the circuit, the higher the resistance to rotation of the turbine. This in turn gives more pressure drop across the turbine, slowing the flow of the process stream. An algorithm in the device can also calculate the actual flow through the device by measuring the turbine RPM and the load on the circuit. The resistance to rotational flow can also be varied by variable position inlet guide vanes. In some embodiments, power is generated via a power recovery turbine with variable resistance to flow enabled by either guide vanes or a variable load on the power generation circuit. Algorithms for calculating actual flow using guide vane position, power output and RPM can be used.

[0037] Thus, steam from conduit 58 enters turbine 60 at an inlet and rotates turbine wheel 62, thereby reducing the pressure and temperature of the steam and extracting energy from the steam. Resulting low pressure steam 59 from an outlet of turbine 60 is injected into riser 16 to reduce the partial pressure of the hydrocarbon vapor therein. The desired temperature of the steam at the outlet of turbine 60 is preferably within 15° C. of the dew point of the reduced pressure steam. It is also contemplated that turbine 60 may be utilized in place of a control valve in association with nozzle 19 and / or in conjunction with stripping steam line 40.

[0038] With reference to FIG. 3, it is also contemplated that the turbine may be used in conjunction with the quench stream, for example, in a hydroprocessing reactor 100. As used herein, the term "hydroprocessing" may refer to processing one or more hydrocarbons in the presence of hydrogen and may include hydrotreating and / or hydrocracking. As used herein, the term "hydrocracking" may refer to the process breaking or decomposing at least one long-chain hydrocarbon into lower molecular weight hydrocarbons in the presence of hydrogen and at least one catalyst. As used herein, the term "hydroprocessing" may refer to a process that includes contacting a hydrocarbon feedstock with hydrogen gas in the presence of one or more suitable catalysts for removing heteroatoms such as sulfur, nitrogen, and metals from the hydrocarbon feedstock. In hydroprocessing, some hydroprocessing processes are specifically designed to saturate aromatics, so that hydrocarbons with double and triple bonds may be saturated, and aromatics may also be saturated.

[0039] As shown in Figure 3, the hydroprocessing reactor 100 used in accordance with the present invention is a multiple fixed bed vessel 101 that includes multiple catalyst beds 102, 104, 106, 108 separated from one another by pre-bed spaces 112, 114, 116 (also called quench zones), as is known. In an exemplary embodiment, each of the catalyst beds 102, 104, 106, 108 contains a hydroprocessing catalyst. Hydroprocessing catalysts are well known and typically include molybdenum (Mo), tungsten (W), cobalt (Co), and / or nickel (Ni) on a support comprised of gamma-alumina. The particular type of hydroprocessing catalyst is not essential to the understanding or practice of the present invention.

[0040] As shown, feed stream 118 is introduced into hydroprocessing reactor 100. Although feed stream 118 is shown as being introduced at the top of vessel 101, it is contemplated that feed stream 118 may be split and injected into hydroprocessing reactor 100 at multiple locations, such as prebed spaces 112, 114, 116, etc.

[0041] The hydrogen-containing stream 120 is also split into multiple streams into hydrogen-rich streams 122, 124, 126, 128. Preferably, the hydrogen-containing stream 120 is an H2-rich stream. As used herein, the term "rich" may mean an amount of a compound or species of compound in a stream that is typically at least 50% by volume, preferably 70% by volume. The hydrogen-containing stream 120 may contain recycled hydrogen from the hydroprocessing reactor 100, or a combination of recycled and make-up hydrogen.

[0042] The first hydrogen-rich stream 122 is combined with the feed stream 118 (before or after injection into the vessel 101). The remaining hydrogen-rich streams 124, 126, 128 are used as quench streams 130, 132, 134 and are injected into the pre-bed spaces 112, 114, 116 of the hydroprocessing reactor 100. Turbines 60a, 60b, 60c are used to reduce the pressure of the quench streams 130, 132, 134. These turbines 60a, 60b, 60c are, for example, the turbine 60 shown in FIG. 2. Each of the turbines 60a, 60b, 60c may be in communication with a temperature sensor 136 configured to measure the temperature of one of the pre-bed spaces 112, 114, 116 and relay the temperature to the turbines 60a, 60b, 60c to regulate the flow of the respective quench streams 130, 132, 134.

[0043] Thus, the hydrogen-rich streams 124, 126, 128 enter the turbines 60a, 60b, 60c, respectively, and rotate turbine wheels therein (see FIG. 2), thereby reducing the pressure and temperature of the hydrogen-rich streams 124, 126, 128 and extracting energy from the hydrogen-rich streams 124, 126, 128. The low pressure and temperature quench streams 130, 132, 134 are injected into the pre-bed spaces 112, 114, 116 of the reactor 100 to control the temperature of the catalyst beds 104, 106, 108 within the reactor 100.

[0044] In both the FCC unit 10 and the hydroprocessing reactor 100, the flow rate of steam coming from the turbine 60 can be adjusted to change the process conditions of the FCC unit 10 and the hydroprocessing reactor 100. For example, the flow rate of steam in the riser 16 is adjusted to allow for changes in the hydrocarbon partial pressure and catalyst circulation rate in the riser 16. Similarly, the flow rates of the quench streams 130, 132, 134 may be adjusted to change the temperature of the catalyst beds 104, 106, 108 in the reactor 100. Thus, when changing these process conditions, the changes are contemplated to be "slow controls" in which the desired changes occur at a relatively slow pace.

[0045] For example, with respect to the hydroprocessing reactor 100, it is contemplated that the response time to reach halfway (i.e., 50% of the difference) between the new (or target) temperature in the hydroprocessing reactor 100 and the original (or starting) temperature in the hydroprocessing reactor 100 is at least 1 second, or more, such as 10 seconds, when the new (or target) temperature differs from the original (or starting) temperature by at least 10%. In other words, when the new temperature of the reactor differs from the current temperature in the reactor, the turbine provides a process that requires at least 1 second, at least 10 seconds, at least 1 minute, at least 10 minutes, or 1 hour or more for half of the change to be completed.

[0046] Similarly, for FCC unit 10, the response time to reach halfway (i.e., 50% of the difference) between the new (or target) hydrocarbon partial pressure in FCC unit 10 and the original (or starting) hydrocarbon partial pressure in FCC unit 10 is also contemplated to be at least 1 second, at least 10 seconds, at least 1 minute, at least 10 minutes, or 1 hour or more when the new (or target) hydrocarbon partial pressure differs from the original (or starting) hydrocarbon partial pressure by at least 10%. One skilled in the art will be able to determine the process conditions and response times for dynamic processes related to the present invention.

[0047] Thus, if slow control response of the turbine is an issue, the use of the turbine is restricted to slow response or "loose" control point applications. Slow response applications contemplate that the response time to reach half (i.e., 50% of the difference) from an original (or starting) steady state condition to a new (or target) steady state condition (e.g., temperature, pressure, flow rate) is at least 1 second, or more, e.g., 10 seconds, at least 1 minute, at least 10 minutes, or 1 hour or more, when the new (or target) condition differs from the original (or starting) condition by at least 10%.

[0048] Additionally, it is further contemplated that chemical processing units used in the present process, such as FCC unit 10 or hydroprocessing reactor 100, will utilize a process control system.

[0049] The process control systems described in connection with the embodiments disclosed herein may be implemented or run on a computer with a general purpose processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general purpose processor may be a microprocessor, or the processor may be any conventional processor, controller, microcontroller, or state machine. A processor may also be a combination of computing devices, such as a combination of a DSP and a microprocessor, two or more microprocessors, or any other combination of the foregoing.

[0050] The steps of a process associated with the process control system may be embodied in an algorithm directly contained in hardware, in a software module executed by a processor, or a combination of the two. The software module may reside in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, a hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art. An exemplary storage medium is in communication with the processor, which reads information from the storage medium and writes information to the storage medium. This includes the storage medium being integral to the processor or being integral to the processor. The processor and the storage medium may reside in an ASIC. The ASIC may reside in a user terminal. Alternatively, the processor and the storage medium may reside as separate components in a user terminal. These devices are merely intended to be illustrative, non-limiting examples of computer-readable storage media. The processor and storage medium or memory also typically communicate with hardware (e.g., ports, interfaces, antennas, amplifiers, signal processors, etc.) that enables wired or wireless communication between different components, computer processors, such as between input channels, processors of control logic, output channels within a control system, and operator stations in a control center.

[0051] In communication with the computers and processors refers to the ability to send and receive information or data. The transmission of data or information can be wireless (e.g., by Wi-Fi or Bluetooth) or wired (e.g., using an Ethernet RJ45 cable or a USB cable). In the case of wireless transmission, a wireless transceiver (e.g., a Wi-Fi transceiver) is in communication with each processor or computer. The transmission can be at the request of the computer, upon request from the computer, or automatically in other ways. Data can be pushed, pulled, fetched, etc. in any combination, or can be sent and received in any other way.

[0052] Thus, in accordance with the present invention, it is contemplated that the process control system receives information on the amount of electricity generated by the turbines 60. The turbines determine the amount of electricity generated, or alternatively, the process control system receiving the information determines the amount of electricity generated. In either configuration, the amount of electricity generated by the turbines 60 is displayed on at least one display screen 80 (e.g., in communication with a computer 76 in a control center 78). If the processing unit includes multiple turbines 60, it is further contemplated that the processing control system receives information associated with the amount of electricity generated by each of the turbines 60. The processing control system determines the total power generated based on the information associated with each of the turbines 60 and displays the total power generated. The total power generated may be displayed instead of or in addition to the display of the power generated by the individual turbines 60.

[0053] As mentioned above, the recovery of electricity is based on the need to remove energy from the stream that has already been added to the stream in the processing unit. Therefore, the process according to the present invention is contemplated to provide for the various process conditions associated with the processing unit to be adjusted to initially lower the energy added to the steam. The process control system is contemplated to receive information associated with the throughput of the processing unit and determine a target power generation value for the turbine 60, since electricity typically represents the energy added to the entire processing unit. The determination of the target power generation value may be made when the electricity is at or near a predetermined level. Thus, the process control system analyzes one or more changes to the various process conditions associated with the processing unit to lower the amount of energy recovered by the turbine 60. Preferably, the process conditions are adjusted without adjusting the throughput of the processing unit. This allows the processing unit to have the same output but a lower operating input. The process control software can calculate and display the difference between the target power generation value and the total power generated on at least one display screen 80. EXAMPLES

[0054] In a simulated embodiment of the present invention, it was determined that the quench temperature of a hydroprocessing reactor could be reduced by 5-10°C by using a turbine 60 instead of a control valve. This could reduce the hydrogen demand requirement for the quench stream by up to 5%, or decapsulate the hydrocarbon feed rate by a similar amount. Another option would be to use this reduction in quench hydrogen demand to shift hydrogen to the reactor inlet. Additionally, or alternatively, the reduction in quench hydrogen demand would reduce the power consumption of the recycle gas compressor used in conjunction with the hydrogen-containing gas stream. In an FCC unit, the use of a turbine 60 instead of a control valve would allow the catalyst-to-oil (feedstock) ratio to be increased with an increase in yield (as opposed to an increase in undesirable by-products), increasing the profitability of the FCC unit or allowing more feed while maintaining a constant catalyst-to-oil ratio.

[0055] Thus, not only does the present invention recover energy that is typically lost, but the present invention also provides benefits to the process conditions underlying the treatment unit.

[0056] It should be appreciated and understood by those skilled in the art that various other components, such as valves, pumps, filters, coolers, etc., are not shown in the drawings because the details of the same are within the knowledge of those skilled in the art and the description of the same is not considered necessary to practice or understand the embodiments of the present invention. Specific Embodiments

[0057] While the following description will be given in conjunction with specific embodiments, it will be understood that this description is intended to be illustrative, but not limiting, of the foregoing description and appended claims.

[0058] A first embodiment of the invention is a process for reducing the pressure of a steam stream used to reduce the temperature, heat load, or hydrocarbon partial pressure in a reactor, the process comprising: reducing the pressure of the steam stream in a turbine to provide a lower pressure steam stream; rotating a turbine wheel in the turbine; and injecting the low pressure steam stream into the reactor to reduce the temperature in the reactor or reduce the partial pressure of the hydrocarbon vapor in the reactor. An embodiment of the invention is one, any, or all of the previous embodiments to the first embodiment of this paragraph, further comprising increasing the feed rate to the reactor by extracting energy from the steam stream to mitigate a hot bottle neck. An embodiment of the invention is one, any, or all of the previous embodiments to the first embodiment of this paragraph, further comprising the turbine wheel configured to transfer rotational motion to a generator, the process further comprising generating electricity with the turbine. An embodiment of the invention is any one, any or all of the previous to the first embodiment of this paragraph, further comprising receiving information from the turbine on the amount of electricity generated by the turbine and displaying the amount of electricity generated by the turbine on at least one display screen. An embodiment of the invention is any one, any or all of the previous to the first embodiment of this paragraph, further comprising maintaining a throughput of the reactor while adjusting at least one process parameter of the reactor. An embodiment of the invention is any one, any or all of the previous to the first embodiment of this paragraph, further comprising maintaining a throughput of the reactor while adjusting at least one process parameter of the reactor. An embodiment of the invention is any one, any or all of the previous to the first embodiment of this paragraph, further comprising determining a total power generated based on the amount of electricity generated by the turbine and displaying the total power generation value on at least one display screen. An embodiment of the invention is any one, any or all of the previous to the first embodiment of this paragraph, further comprising receiving information from the turbine on the amount of electricity generated by the turbine and displaying the amount of electricity generated by the turbine on at least one display screen. An embodiment of the invention is any one, any or all of the previous to the first embodiment of this paragraph, further comprising maintaining a throughput of the reactor while adjusting at least one process parameter of the reactor. An embodiment of the present invention is one, any or all of the preceding embodiment of this paragraph through the first embodiment of this paragraph, wherein the reactor comprises a hydroprocessing reactor and the steam stream comprises a hydrogen stream.

[0059] A second embodiment of the present invention is a process for reducing the pressure of a steam stream used to adjust the partial pressure of a hydrocarbon vapor, the process comprising: providing a steam stream comprising steam; and passing the steam stream through a turbine, the turbine comprising a turbine wheel in the turbine, to reduce the partial pressure of the hydrocarbon vapor by mixing the reduced pressure steam stream with the hydrocarbon vapor. An embodiment of the present invention is any one, any or all of the previous embodiment to the second embodiment of this paragraph, in which the reduced pressure steam stream is injected into the FCC reactor to reduce the partial pressure of the hydrocarbon vapor in the FCC reactor. An embodiment of the present invention is any one, any or all of the previous embodiment to the second embodiment of this paragraph, further comprising recovering electricity generated in the turbine. An embodiment of the present invention is any one, any or all of the previous embodiment to the second embodiment of this paragraph, further comprising adjusting one or more process conditions for the FCC reactor based on the cooling load provided by the turbine. An embodiment of the invention is any one, any or all of the previous embodiment to the second embodiment of this paragraph, where the outlet temperature is within 15° C. of the dew point of the reduced pressure vapor stream. An embodiment of the invention is any one, any or all of the previous embodiment to the second embodiment of this paragraph, where the response time to reach 50% of the difference between the partial pressure and the original partial pressure when the partial pressure changes by at least 10% from the original partial pressure is at least 1 second. An embodiment of the invention is any one, any or all of the previous embodiment to the second embodiment of this paragraph, where the change response time to reach 50% of the difference between the partial pressure and the original partial pressure when the partial pressure changes by at least 10% from the original partial pressure is at least 10 seconds.

[0060] A third embodiment of the present invention may be characterized as providing a process for reducing the pressure of a steam stream used as a quench stream, the process comprising: providing a steam stream comprising hydrogen; passing the steam stream through a turbine, the turbine comprising a turbine wheel within the turbine, recovering a reduced pressure steam stream from the turbine; and reducing the pressure of the steam stream used as a quench stream by controlling the temperature in the reactor with the reduced pressure steam stream from the turbine. An embodiment of the present invention is any one, any or all of the previous embodiments to the third embodiment of this paragraph, wherein the reactor comprises a hydroprocessing reactor. An embodiment of the present invention is any one, any or all of the previous embodiments to the third embodiment of this paragraph, further comprising determining a cooling load for the turbine and adjusting one or more process conditions of the hydroprocessing reactor based on the cooling load for the turbine. An embodiment of the present invention is any one, any or all of the previous embodiments to the third embodiment of this paragraph, further comprising adjusting process conditions of the steam stream to achieve a desired hydroprocessing reactor temperature. An embodiment of the present invention is any one, any or all of the previous embodiment to the third embodiment of this paragraph, wherein a reduced pressure steam flow is injected into the reactor to regulate the temperature of at least one catalyst bed. An embodiment of the present invention is any one, any or all of the previous embodiment to the third embodiment of this paragraph, wherein the response time to reach 50% of the difference between the temperature in the reactor and the original temperature in the reactor is at least 1 second when the temperature in the reactor changes by at least 10% from the original temperature in the reactor. An embodiment of the present invention is any one, any or all of the previous embodiment to the third embodiment of this paragraph, wherein the response time to reach 50% of the difference between the temperature in the reactor and the original temperature in the reactor is at least 10 seconds ...

[0061] Without further elaboration, it is believed that, using the preceding description, one skilled in the art can utilize the present invention to its fullest extent, readily ascertain the essential characteristics of the present invention, and make various changes and modifications to the present invention to adapt it to various uses and conditions without departing from the spirit and scope of the present invention. The preceding preferred specific embodiments are therefore to be construed as merely illustrative, and are not limitative of the remainder of the disclosure in any way, but are intended to cover various modifications and equivalent arrangements falling within the scope of the appended claims.

[0062] Above, all temperatures are set forth in degrees Celsius and all parts and percentages are by weight unless otherwise stated.

[0063] Although at least one exemplary embodiment has been presented in the foregoing detailed description, it should be understood that numerous variations exist. It should also be understood that the exemplary embodiment or exemplary embodiments are merely examples, and are not intended to limit the scope, applicability, or configuration of the present invention in any manner. Rather, the foregoing detailed description provides those skilled in the art with a convenient guide for implementing the exemplary embodiments, and it is understood that various changes may be made in the function and arrangement of elements described in the exemplary embodiments without departing from the scope of the invention as set forth in the appended claims and their legal equivalents.

Claims

1. 1. A process for reducing the pressure of a vapor stream used to reduce the temperature or heat load in a reactor, comprising: reducing the pressure of the steam stream in a turbine to provide a low pressure steam stream, the steam stream comprising hydrogen; rotating a turbine wheel within the turbine; injecting the low pressure vapor stream and the feed stream into the reactor and reducing the temperature within the reactor; a first feed stream split from said feed stream and a first vapor stream split from said vapor stream are injected into a space above a first prebed space of said reactor.

2. 10. The process of claim 1 further comprising increasing the feed rate of the stream to the reactor by extracting energy from the vapor stream to mitigate a hot neck.

3. the turbine wheel is configured to transmit rotational motion to a generator, the process further comprising: The process of claim 1 including generating electricity with the turbine.

4. receiving information from the turbine relating to an amount of electricity generated by the turbine; The process of claim 3 further comprising: displaying on at least one display screen an amount of electricity generated by the turbine.

5. 5. The process of claim 4, further comprising maintaining a throughput of the reactor while adjusting at least one process parameter of the reactor.

6. the reactor comprises a plurality of turbines each configured to generate electricity; The process is determining a total power generation value based on an amount of electricity produced by the turbine; and displaying said total power generation value on said at least one display screen.

7. 2. The process of claim 1, wherein a second feed stream split from the feed stream and a second lower pressure steam stream split from the steam stream and reduced in pressure by the turbine are injected into the first pre-bed space.

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