Process for recovering one or more of C2, C3, or C4 olefins from the product stream of an olefin production reactor system

Abstract

A process for the recovery of olefins includes flashing at least a portion of an alkane feed stream to produce a flashed alkane feed stream; introducing the flashed alkane feed stream as a cooling medium into a cold box, a rectification system, or both; compressing and cooling the gaseous feed stream; separating the compressed and cooled feed stream into a first residual vapor stream and a first liquid residual stream; cooling the first residual vapor stream; separating the cooled first residual vapor stream into a second vapor residual stream and a second liquid residual stream; separating the first liquid residual stream into a lights removal column overhead stream and a lights removal column bottoms stream; and rectifying at least a portion of the second liquid residual stream and the lights removal column bottoms stream to produce an overhead vapor stream, a liquid recycle stream, and a bottoms liquid stream.

Description

[Technical field]

[0001] (CROSS REFERENCE TO RELATED APPLICATIONS) This application claims the benefit of U.S. Provisional Patent Application No. 63 / 322,825, filed March 23, 2022, the entire disclosure of which is incorporated herein by reference.

[0002] FIELD OF THEINVENTION FIELD OF THE DISCLOSURE

[0002] Embodiments described herein relate generally to chemical processing, and more specifically to product recovery in chemical processing. [Background technology]

[0003] Ethylene, ethane, propylene, propane, and / or heavier hydrocarbons can be recovered from a variety of gas streams including natural gas, refinery gas, synthesis gas, or combinations thereof obtained from coal, crude oil, naphtha, oil shale, steam crackers, catalytic crackers, or combinations thereof. Cryogenic expansion processes are widely used to recover condensable product gases from non-condensable or difficult to condense gases because they offer simplicity of start-up, flexibility of operation, good efficiency and reliability.

[0004] In a conventional cryogenic expansion recovery process, a pressurized feed gas stream is cooled by heat exchange with other streams in the process and / or an external refrigeration source, such as an ethylene or propylene compression-refrigeration system. As the gas stream is cooled, a liquid stream is produced at the desired C 2+ The expanded stream may be collected in one or more separators as a high pressure liquid containing some of the components. Depending on the product richness of the liquid, this liquid stream may be expanded to a lower pressure and rectified. This expansion, coupled with work extraction, reduces the temperature of the stream. Under some conditions, it may be desirable to pre-cool the pressurized liquid prior to these expansions to further reduce the temperature resulting from the expansion. The expanded stream is then rectified through a distillation column where the expanded cooled stream is distilled to remove residual methane, hydrogen, the desired C 2 Or C 3The non-condensable, or heavier products from one or more of the above are separated. Summary of the Invention

[0005] While conventional recovery processes are available to recover ethylene, ethane, propylene, propane, and / or heavier hydrocarbons from various gas streams, these processes often require external refrigeration systems, which can reduce the efficiency of recovery and increase costs.

[0006] Therefore, C with reduced capital investment 2 , C 3 There continues to be a need for processes that provide improved energy efficiency recovery of one or more of the following products: C2O, C3O4, or heavier products. These needs are met by the system and process embodiments described in this disclosure. The embodiments of the present disclosure include a process for extracting C2O from the product stream of an olefin production reactor system. 2 , C 3 , or C 4 The present disclosure is directed to a process for recovering one or more of the olefins. Disclosed herein is the use of refrigeration duty of the feed stream to an upstream alkane to alkene conversion process. For example, liquefied natural gas can be used as a feed to an alkane to alkene conversion plant. This liquefied natural gas can be utilized to cool various process streams in downstream recovery units. The disclosed process can utilize this refrigeration duty by including a lights cut tower and a rectification system downstream of the lights cut tower that generate streams that can be used as cooling media in the recovery process. Additionally, the refrigeration duty can be integrated into the cold box of the recovery system. With one or more of the cold box integration, the lights cut tower, and the two-stage rectification system, the disclosed process can achieve improved efficiency of C with less need for a larger external refrigeration system and reduced capital investment. 2 , C 3 , or C 4 One or more of the olefins can be recovered.

[0007] According to one or more embodiments disclosed herein, a method for producing a C olefin production reactor system from a product stream of the olefin production reactor system is provided. 2 , C 3 , or C 4 A process for recovering one or more of the olefins includes flashing at least a portion of an alkane feed stream of an olefin production reactor system to produce a flashed alkane feed stream, introducing the flashed alkane feed stream as a cooling medium to a cold box, a rectification system, or both, and compressing and cooling the gaseous feed stream to produce a compressed and cooled feed stream. The gaseous feed stream has at least 70 weight percent (wt%) C 2 , C 3 , and C 4 The process further includes separating the compressed and cooled feed stream into a first residual vapor stream and a first liquid residual stream, cooling the first residual vapor stream in a cold box to produce a cooled first residual stream, separating the cooled first residual stream into a second vapor residual stream and a second liquid residual stream, and separating the first liquid residual stream in a lights removal tower into a lights removal tower overhead stream and a lights removal tower bottom stream. Removal of the light components may enable the use of the flashed alkane feed stream as a cooling medium in a rectification system. The process further includes rectifying at least a portion of the second liquid residual stream and the lights removal tower bottom stream in a rectification system to produce an overhead vapor stream, a liquid recycle stream, and a bottom liquid stream.

[0008] It should be understood that both the foregoing general description and the following detailed description present embodiments of the technology and are intended to provide an overview or framework for understanding the nature and characteristics of the claimed technology. The accompanying drawings are included to provide a further understanding of the technology, and are incorporated in and constitute a part of this specification. The drawings illustrate various embodiments and, together with the description, serve to explain the principles and operation of the technology. Additionally, the drawings and description are intended to be merely illustrative and are not intended to limit the scope of the claims in any manner.

[0009] Additional features and advantages of the techniques disclosed herein will be set forth in the detailed description which follows, and will be readily apparent in part to those skilled in the art from that description, or will be learned by practicing the techniques as described herein, including the detailed description, claims, and accompanying drawings. [Brief description of the drawings]

[0010] The following detailed description of certain embodiments of the present disclosure can be best understood when read in conjunction with the following drawings, in which like structure is indicated with like reference numerals and in which: [Figure 1] 1 illustrates a schematic depiction of a system for recovering one or more of C2, C3, or C4 olefins from a product stream of an olefin production reactor system according to one or more embodiments described herein. [Diagram 2] 1 illustrates a schematic depiction of a two-stage fractionation system for recovering one or more of C2, C3, or C4 olefins from a product stream of an olefin production reactor system according to one or more embodiments described herein.

[0011] It should be understood that the drawings are schematic in nature and do not include some of the components of fluid catalyst processing systems commonly used in the art, such as, without limitation, temperature transmitters, pressure transmitters, flow meters, pumps, valves, etc. It will be appreciated that these components are within the spirit and scope of the disclosed embodiments. However, operational components such as those described in this disclosure may be added to the embodiments described in this disclosure.

[0012] Reference will now be made in more detail to various embodiments, some of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] As used in this disclosure, a "separator" refers to any separation device or system of separation devices that at least partially separates one or more chemicals mixed in a process stream from one another. For example, a separator can selectively separate different chemical species, phases, or sized materials from one another to form one or more chemical fractions. Examples of separators include, but are not limited to, distillation columns, flash drums, knock-out drums, knock-out pots, centrifuges, cyclones, filtration devices, traps, scrubbers, expansion devices, membranes, solvent extraction devices, and the like. It should be understood that the separation processes described in this disclosure may not completely separate all of one chemical component from all of another chemical component. It should be understood that the separation processes described in this disclosure "at least partially" separate different chemical components from one another, and it should be understood that separation may include only partial separation, even if not explicitly stated. As used in this disclosure, one or more chemical components may be "separated" from a process stream to form a new process stream. Generally, a process stream enters a separator where it can be divided or separated into two or more process streams of desired composition.

[0014] As used in this disclosure, a "cold box" refers to one or more heat exchangers connected in series. The heat exchangers may include brazed heat exchangers, shell-and-tube heat exchangers, double-pipe heat exchangers, plate heat exchangers, tubular heat exchangers, fin-type heat exchangers, condensers, evaporators, boilers, or combinations thereof.

[0015] As used in this disclosure, "rectification system" refers to any rectification device or system of rectification devices that at least partially divides a volume of a mixture (gas, solid, liquid, or combinations thereof) into several smaller fractions whose composition varies according to a gradient during a phase transition.

[0016] It is further understood that a stream may be named with respect to a component of the stream, and that the component for which the stream is named may be the majority component of the stream (such as comprising from 50 weight percent (wt%), 70 wt%, 90 wt%, 95 wt%, 99 wt%, 99.5 wt%, or even 99.9 wt% to 100 wt% of the stream's contents). It is also understood that a component of a stream is disclosed as passing from one system component to another if a stream containing that component is disclosed as passing from the system component to another.

[0017] An embodiment of the present disclosure provides a process for producing C 2 H 2 O 3 from a product stream of an olefin production reactor system. 2 , C 3 , or C 4 The present invention is directed to a process for recovering one or more of the olefins. Such a process utilizes a system having certain characteristics, such as a particular orientation of the system components. Figures 1 and 2 depict such a system 10, including a cold box 111, a light removal column 117, and a fractionation system 120.

[0018] Referring now to FIG. 1, a C olefin production reactor system is provided with a product stream. 2 , C 3 , or C 4A system 10 for recovering one or more olefins is generally depicted. The system 10 generally comprises a gaseous feed stream 100 that is directly processed to recover C olefins from a product stream of an olefin production reactor system. 2 , C 3 , or C 4 One or more of the olefins are recovered.

[0019] The gaseous feed stream 100 is a C olefin production reactor system product stream. 2 , C 3 , or C 4 The product stream may be from a petrochemical process or may be naphtha, natural gas liquids (NGLs), or other hydrocarbon sources from a crude oil refining operation. The product stream may include a gaseous feed stream 100. As described herein, in one or more embodiments, the gaseous feed stream 100 may be a reaction effluent of steam cracking, catalytic cracking, or both. In one or more embodiments, the gaseous feed stream 100 may include natural gas, refinery gas, syngas, or combinations thereof obtained from coal, crude oil, naphtha, oil shale, or combinations thereof. In embodiments, the gaseous feed stream 100 may be at least 70 wt%, at least 75 wt%, at least 80 wt%, or at least 85 wt% C 2 , C 3 , or C 4 In an embodiment, the gaseous feed stream 100 may contain one or more of the following components: 2 , 0.01% to 5% by weight H 2 , 0.01 wt% to 5 wt% methane, and 70 wt% to 95 wt% C 2 , C 3 , or C 4 In an embodiment, the gaseous feed stream 100 comprises ethane, propane, butane, or a combination thereof. In an embodiment, the gaseous feed stream 100 comprises 50 wt. % propane.

[0020] The gaseous feed stream 100 may be introduced into a compressor 103. The gaseous feed stream 100 may be compressed in the compressor 103 to produce a compressed feed stream 102A. The compressed feed stream 102A may be introduced into a heat exchanger 129. The C in the compressed feed stream 102A may be 2 , C 3 , or C 4 The amount of one or more of the components in the gaseous feed stream 100 may vary depending on the amount of C 2 , C 3 , or C 4 The amount of one or more of the components may be greater than the amount of the other components. The compressed feed stream 102A may be cooled in heat exchanger 129 to produce compressed and cooled feed stream 102B. In an embodiment, the compressed feed stream 102A may be cooled in heat exchanger 129 by cooling water, bottoms liquid stream 122, or both. If the compressed feed stream 102A is cooled by bottoms liquid stream 122, the cooling required in heat exchanger 129 may be provided by heating, flashing, vaporizing bottoms liquid stream 122, or a combination thereof. In an embodiment, the bottoms liquid stream 122 may be flashed prior to entering heat exchanger 129. The bottoms liquid stream 122 may be flashed to allow for a preferred cooling temperature range. When cooling is provided by vaporizing bottoms liquid stream 122, the cooling may be from 10 wt.% to 99.9 wt.%, 10 wt.% to 99 wt.%, 10 wt.% to 95 wt.%, 10 wt.% to 90 wt.%, 10 wt.% to 85 wt.%, 10 wt.% to 80 wt.%, 15 wt.% to 99.9 wt.%, 15 wt.% to 99 wt.%, 15 wt.% to 95 wt.%, 15 wt.% to 90 wt.%, 15 wt.% to 85 wt.%, %, 15% to 80% by weight, 20% to 99.9% by weight, 20% to 99% by weight, 20% to 95% by weight, 20% to 90% by weight, 20% to 85% by weight, 20% to 80% by weight, 25% to 99.9% by weight, 25% to 99% by weight, 25% to 95% by weight, 25% to 90% by weight, 25% to 85% by weight, or 25% to 80% by weight may be vaporized.

[0021] The compressed and cooled feed stream 102B may be introduced into a first separator 105. The compressed and cooled feed stream 102B may be separated into a first residual vapor stream 104A and a first liquid residual stream 106. In an embodiment, the first residual vapor stream 104A is a first residual liquid stream having between 1% and 25% by weight N 2 , 0.01% to 5% by weight H 2 , 0.01 wt% to 5 wt% methane, and 70 wt% to 95 wt% C 2 , C 3 , or C 4 The first residual vapor stream 104A may include one or more of the following components: 2 , C 3 , or C 4 The amount of one or more of the components may vary depending on the composition of the compressed feed stream 102A. 2 , C 3 , or C 4 It may be greater than the amount of one or more of the ingredients.

[0022] The first residual vapor stream 104A may be introduced into a cold box 111. The first residual vapor stream 104A may be cooled in the cold box 111 to produce a cooled first residual vapor stream 104B. In an embodiment, the cooled first residual vapor stream 104B may be a stream containing 1% to 45% by weight N 2 , 0.01% to 15% by weight H 2 , 0.01 wt% to 5 wt% methane, and 50 wt% to 95 wt% C 2 , C 3 , or C 4 It may contain one or more of the ingredients.

[0023] The cooled first residual vapor stream 104B may be introduced into a second separator 109. The cooled first residual vapor stream 104B may be separated into a second vapor residual stream 108 and a second liquid residual stream 110A. In an embodiment, the second vapor residual stream 108 is a 30 wt % to 80 wt % N 2 , 10% to 40% by weight H 2 , 5 wt% to 20 wt% methane, and 0.01 wt% to 10 wt% C 2 , C 3 , or C 4In an embodiment, the second vapor retentate stream 108 may have a temperature between −120° C. and −100° C. In an embodiment, the second liquid retentate stream 110A may have between 0.001% and 2% by weight N 2 , 0.001% to 1% by weight H 2 , 0.001% to 2% by weight of methane, and 90% to 99% by weight of C 2 , C 3 , or C 4 It may contain one or more of the ingredients.

[0024] The second vapor residue stream 108 may be introduced into a cold box 111. At least a portion of the second vapor residue stream 108 may pass through the cold box 111 and then be introduced into a turbo expander / compressor 115. At least a portion of the second vapor residue stream 108 may be expanded in the turbo expander / compressor 115 to produce an expanded second vapor residue stream 112. In an embodiment, the expanded second vapor residue stream 112 may be a stream having between 40% and 90% by weight N 2 , 10% to 50% by weight H 2 , 1 wt% to 10 wt% methane, and 1 wt% to 10 wt% C 2 , C 3 Or C 4 The expanded second vapor residue stream 112 may include one or more of the components. In an embodiment, the expanded second vapor residue stream 112 may have a temperature between 0° C. and 50° C. The expanded second vapor residue stream 112 may be introduced into a cold box 111. The expanded second vapor residue stream 112 may be used as a cooling medium in the cold box 111. The expanded second vapor residue stream 112 may pass through the cold box 111 and exit the system 10 as an off-gas.

[0025] 1 , the second liquid retentate stream 110A may be introduced into a cold box 111 downstream of the first separator 105. The second liquid retentate stream 110A may be used as a cooling medium in the cold box 111. The second liquid retentate stream 110A may be cooled in the cold box 111 to produce a cooled second liquid retentate stream 110B. In an embodiment, the cooled second liquid retentate stream 110B may be cooled with 0.001 wt % to 5 wt % N 2 , 0.001% to 1% by weight H 2 , 0.001% to 1% by weight of methane, and 90% to 99% by weight of C 2 , C 3 , or C 4 It may contain one or more of the ingredients.

[0026] At least a portion of the second liquid retentate stream 140 may be introduced into the cold box 111. At least a portion of the second liquid retentate stream 140 may be introduced into the cold box 111. 2 , 0.001% to 1% by weight H 2 , 0.001% to 2% by weight of methane, and 90% to 99% by weight of C 2 , C 3 , or C 4 At least a portion of the second liquid residue stream 140 may be mixed with the liquid recycle stream 130A in the cold box 111. At least a portion of the second liquid residue stream 140 may be used as a cooling medium in the cold box 111.

[0027] 1, the first liquid residue stream 106 may be introduced into a lights removal column 117 downstream of the first separator 105. The lights removal column 117 may be disposed upstream of a two-stage rectification system. The lights removal column 117 removes N, N-dimethylformamide from the first liquid residue stream 106 upstream of the rectification system 120. 2 , H 2, methane, or combinations thereof to produce a lights removal column overhead stream 116 and a lights removal column bottoms stream 118. The second overhead stream 126A may be separated to produce various streams that may be used as cooling media in the cold box 111. In the lights removal column 117, the first liquid residue stream 106 may be separated into a lights removal column overhead stream 116 and a lights removal column bottoms stream 118. In an embodiment, the lights removal column overhead stream 116 is a stream containing 1 wt % to 30 wt % N 2 , 1% to 10% by weight H 2 , 0.01 wt% to 5 wt% methane, and 70 wt% to 95 wt% C 2 , C 3 Or C 4 The lights removal column overhead stream 116 may be mixed with the first residual vapor stream 104A in cold box 111 and then introduced into second separator 109. In embodiments, the lights removal column bottoms stream 118 may comprise at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, or at least 99.9% by weight of C 2 , C 3 , or C 4 The lights removal column bottoms stream 118 may contain less than 1 wt.%, less than 0.1 wt.%, less than 0.01 wt.%, less than 0.001 wt.%, or even less than 0.0001 wt.% N 2 , H 2 , methane, or a combination thereof. The bottoms stream 118 of the lights removal column may include H 2 The lights removal column bottoms stream 118 may be introduced to a rectification system 120.

[0028] Advantageously, removal of the light and non-condensable components by the lights removal column 117 can increase the temperature of the overhead stream 126A in the rectification system 120 to a more favorable temperature since the lightest components of the first liquid residue stream 106 are removed and not sent to the rectification system. This higher temperature overhead stream 126A can be cooled for condensation in heat exchanger 133 without the need for an external refrigeration system. Alternatively, the flashed alkane feed stream 138 may be adequate to sufficiently cool the overhead stream 126A, although an external refrigeration system may be required if the lights removal column 117 is not used.

[0029] At least a portion of the second liquid residue stream 110A, at least a portion of the lights removal column bottoms stream 118, or both may be introduced into a rectification system 120 to produce an overhead vapor stream 128, a liquid recycle stream 130A, and a bottoms liquid stream 122. With reference to FIGS. 1 and 2, an example of a rectification system 120 is a two-stage rectification system including a first rectification unit 121A and a second rectification unit 121B downstream of the first rectification unit 121A. The two-stage rectification system may allow for the utilization of cooling water for compression duty of the first overhead stream 120A from the first rectification unit 121A. As a result of the removal of light and non-condensable components by the lights removal column 117, the gaseous feed stream 100 may be compressed using cooling water and heat integration from the first overhead stream 120A. The use of cooling water can be beneficial for the use of heat removal refrigerant processes due to superior thermodynamic efficiency and low associated capital costs. Additionally, a two-stage rectification system can generate various streams that can be used as cooling media in the cold box. A two-stage rectification system can provide flexibility in operation and product specification adjustments.

[0030] 1 and 2, in an embodiment, at least a portion of the second liquid residue stream 110A may be introduced to a first rectification unit 121A depending on the stage composition. In an embodiment, at least a portion of the second liquid residue stream 110A may be cooled in a cold box 111 to produce a cooled second liquid residue stream 110B. The cooled second liquid residue stream 110B may be introduced to a rectification system 120. In an embodiment, the cooled second liquid residue stream 110B may be introduced to a first rectification unit 121A of a two-stage rectification system. As discussed above, the lights removal column bottoms stream 118 may be introduced to the first rectification unit 121A. At least a portion of the cooled second liquid residue stream 110B and the lights removal column bottoms stream 118 may be separated into a first overhead stream 120A and a bottom liquid stream 122. In an embodiment, where the cooled second liquid residue stream 110B is fed to the first rectification unit 121A, the cooled second liquid residue stream 110B and the lights removal column bottoms stream 118 may be separated into a first overhead stream 120A and a bottoms liquid stream 122.

[0031] In an embodiment, the first overhead stream 120A is a 0.001-1 wt. % N 2 , 0 to 1 wt% H 2 , 0.001 to 1 wt% methane, and 98 wt% to 99.9 wt% C 2 , C 3 , or C 4 The first overhead stream 120A comprises one or more of the following components: H 2 In embodiments, the bottoms liquid stream 122 may be at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, at least 99.9% by weight C 2 , C 3 , or C 4 The bottoms liquid stream 122 may contain one or more of the following components: N 2 , H 2 , methane, or combinations thereof.

[0032] The first overhead stream 120A may be partially condensed and refluxed. The temperature of the first overhead stream 120A may be controlled to utilize cooling water as a condensing agent for the gaseous feed 100. In an embodiment, the first overhead stream 120A may be cooled by a heat exchanger 131 to produce a cooled first overhead stream 120B. In an embodiment, the heat exchanger 131 may use cooling water as a cooling medium. The heat exchanger 131 may not require an external refrigeration system. The cooled first overhead stream 120B may be introduced into the third separator 125. The cooled first overhead stream 120B may be separated into a first vapor stream 123A and a first liquid stream 123B. The first liquid stream 123B may be reintroduced into the first rectification unit 121A.

[0033] 1 and 2, at least a portion of the first overhead stream 120A may be introduced into a second rectification unit 121B downstream of the first rectification unit 121A and then separated into a second overhead stream 126A and a second bottoms stream 124. In embodiments, a first vapor stream 123A comprising non-condensable components may be introduced into the second rectification unit 121B. The first vapor stream 123A may be separated into a second overhead stream 126A and a second bottoms stream 124. In embodiments, the second bottoms stream 124 may comprise at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% by weight of C 2 , C 3 , or C 4 The second bottoms stream 124 may contain one or more of the following components: 2 , 0% to 1% by weight N 2 %, and 0.001% to 1% by weight of methane. 2 , N 2 The second bottoms stream 124 may be reintroduced into the first rectification unit 121A.

[0034] The second overhead stream 126A may be partially condensed and refluxed. The temperature of the second overhead stream 126A may be controlled using the alkane feed stream 136 to meet the desired specifications of total product losses. In an embodiment, the second overhead stream 126A may be cooled by heat exchanger 133 to produce a cooled second overhead stream 126B. In an embodiment, the second overhead stream 126A may be cooled in heat exchanger 133 with the flashed alkane feed stream 138. In an embodiment, the heat exchanger 133 may be used as a refrigerant (cooling medium) as a branch of the flashed alkane feed stream 138, thereby not requiring an external refrigeration system.

[0035] The cooled second overhead stream 126B may be introduced into a fourth separator 127 and then separated into an overhead vapor stream 128 and an overhead liquid stream 132. In an embodiment, the overhead vapor stream 128 is a 1 wt. % to 10 wt. % N 2 , 0.001% to 1% by weight H 2 , 1 wt% to 10 wt% methane, and 75 wt% to 95 wt% C 2 , C 3 , or C 4 It may contain one or more of the ingredients.

[0036] Overhead vapor stream 128 may be introduced to cold box 111. Overhead vapor stream 128 may be cooled in cold box 111 to produce by-products. In an embodiment, overhead vapor stream 128 may be used as a cooling medium in cold box 111 before exiting system 10 as a by-product.

[0037] The overhead liquid stream 132 may be split into a liquid recycle stream 130A and a liquid reflux return stream 130B. The liquid recycle stream 130A may be introduced to the cold box 111. The liquid recycle stream 130A may be used as a cooling medium in the cold box. The liquid reflux return stream 130B may be introduced to the second rectification unit 121B.

[0038] In an embodiment, the liquid recirculation stream 130A contains 0.001% to 1% by weight N 2, 0% to 1% by weight H 2 , 0.001% to 1% by weight of methane, and 90% to 99% by weight of C 2 , C 3 , or C 4 In an embodiment, the liquid recycle stream 130A may include one or more of the following components: 2 It does not have to include.

[0039] 1 and 2, at least a portion of the liquid recycle stream 130A may be introduced to the turboexpander / compressor 115. Heat may be recovered from the liquid recycle stream 130A, and at least a portion of the liquid recycle stream 130A may be compressed in the turboexpander / compressor 115 to generate the recycle stream 135. The recycle stream 135 may be introduced to the compressor 103 and compressed along with the gaseous feed stream 100.

[0040] The second bottoms stream 124 may be reintroduced into the first rectification unit 121A. Prior to being reintroduced into the first rectification unit 121A, the second bottoms stream 126 may be mixed with the first liquid stream 123B.

[0041] 1 and 2, in an embodiment, an alkane feed stream 136 may be introduced into the system 10 as a medium for heat exchange. As described herein, an "alkane feed stream" may include an amount of alkane, such as greater than 25%, 50%, 75%, or even 95% by weight. In an embodiment, the alkane feed stream 136 may be converted to the gaseous feed stream 100 by a reactor system, not shown. For example, the reactor system may dehydrogenate the alkane feed stream 136 to form the gaseous feed stream 100.

[0042] The alkane feed stream 136 may be a liquid stream that is relatively cool. In an embodiment, at least a portion of the alkane feed stream 106 may be flashed to produce a flashed alkane feed stream 138. In an embodiment, at least a portion of the alkane feed stream 136 may be flashed at a pressure of -5 pounds force per square inch (psig) (0.07 megapascals (MPa)) to 136 psig (1.04 MPa), -5 psig (0.07 MPa) to 106 psig (0.83 MPa), 5 psig (0.14 MPa) to 106 psig (0.83 MPa), 5 psig (0.14 MPa) to 136 psig (1.04 MPa), 25 psig (0.27 MPa) to The alkane feed stream 136 may be flashed to a pressure of 136 psig (1.04 MPa), 25 psig (0.27 MPa) to 106 psig (0.83 MPa), or 25 psig (0.27 MPa) to 46 psig (0.42 MPa) and vaporized at a temperature of −25° C. to −5° C., −25° C. to 0° C., −25° C. to 40° C., −20° C. to −5° C., −20° C. to 0° C., −20° C. to 40° C., −15° C. to −5° C., −15° C. to 0° C., or −15° C. to 40° C. prior to delivery to the reaction zone. For gas phase reactions at relatively low pressures, the alkane feed stream 136 may be flashed to a relatively low pressure and vaporized at refrigeration temperatures prior to delivery to the reaction zone.

[0043] The alkane feed stream 136 may be introduced to the cold box 111, the rectification system 120, or both, and may be used as a cooling medium in the cold box 111, the rectification system 120, or both. In an embodiment, the flashed alkane feed stream 138 may be introduced to the cold box 111, the rectification system 120, or both, and may be used as a cooling medium. The available refrigeration duty from the alkane feed stream 136 at these refrigeration temperatures may drive some sections of the cold box 111, eliminating the need for an external refrigeration system. In addition, the flashed alkane feed stream 138 may be used as a refrigerant in the heat exchanger 133, eliminating the need for an external refrigeration system. In such an embodiment, the refrigerant duty of the alkane feed stream 136 is essentially "free" to the system, since the alkane feed stream 136 must be heated to some degree before being converted to the gaseous feed stream 100.

[0044] From the product stream of the olefin production reactor system of the present disclosure, 2 , C 3 , C 4 The process for recovering one or more of the olefins, or a combination thereof, is advantageous in that it is advantageous in that it is more efficient than conventional recovery processes. 2 , C 3 , or C 4 In embodiments, the disclosed process may produce a higher yield of one or more of the olefins, based on the total weight of the product stream introduced into the disclosed recovery process, of 90 wt.% or more, 95 wt.% or more, 96 wt.% or more, 97 wt.% or more, 98 wt.% or more, or even 99 wt.% or more of C. 2 , C 3 , C 4 A combined yield of olefins or a combination thereof may be produced. EXAMPLES

[0045] C from the product stream of an olefin production reactor system 2 , C 3 , or C 4Various embodiments of the process and system for the recovery of one or more conversions of olefins may be further clarified by the following examples, which are to be understood as being exemplary in nature and not limiting of the subject matter of the present application.

[0046] Example 1 Example 1 was conducted using an integrated separation train process model in Aspen Plus for the capture system depicted in Figures 1 and 2, where a Gulf Coast propane feedstock was provided. Table 1 shows the temperatures, pressures and mass fraction ratios of the streams depicted in Figures 1 and 2.

[0047] [Table 1]

[0048] [Table 2]

[0049] [Table 3]

[0050] As shown in Example 1, C 2 , C 3 , or C 4 was recovered in an energy efficient manner by utilizing a cold box, a lights removal column, and a two-stage rectification system. Example 1 further used liquefied natural gas as feed to an alkane to alkene conversion plant and utilized liquefied natural gas to cool various process streams in downstream recovery units.

[0051] According to a first aspect of the present disclosure, a method for producing a C olefin production reactor from a product stream of an olefin production reactor system is provided. 2 , C 3 , or C 4A process for recovering one or more of the olefins includes flashing at least a portion of an alkane feed stream of an olefin production reactor system to produce a flashed alkane feed stream, introducing the flashed alkane feed stream as a cooling medium to a cold box, a rectification system, or both, and compressing and cooling the gaseous feed stream to produce a compressed and cooled feed stream. The gaseous feed stream has at least 70 weight percent (wt%) C 2 , C 3 , and C 4 The process further includes separating the compressed and cooled feed stream into a first residual vapor stream and a first liquid residual stream, cooling the first residual vapor stream in a cold box to produce a cooled first residual stream, separating the cooled first residual stream into a second vapor residual stream and a second liquid residual stream, and separating the first liquid residual stream in a lights removal tower into a lights removal tower overhead stream and a lights removal tower bottoms stream. Removal of the light components may enable the use of the flashed alkane feed stream as a cooling medium in a rectification system. The process further includes rectifying at least a portion of the second liquid residual stream and the lights removal tower bottoms stream in a rectification system to produce an overhead vapor stream, a liquid recycle stream, and a bottoms liquid stream.

[0052] A second aspect of the disclosure may include the first aspect, where the rectification system may include a two-stage rectification system. The process may further include rectifying at least a portion of the second liquid residue stream and the lights removal column bottoms stream in a first rectification apparatus into a first overhead stream and a bottoms liquid stream, and rectifying at least a portion of the first overhead stream in a second rectification apparatus downstream from the first rectification apparatus into a second overhead stream and a second bottoms stream.

[0053] A third aspect of the present disclosure may include either the first or second aspect and further includes cooling the first overhead stream to produce a cooled first overhead stream; separating the cooled first overhead stream into a first vapor stream and a first liquid stream; introducing the first vapor stream into the second rectification unit; and reintroducing the first liquid stream and the second bottoms stream into the first rectification unit.

[0054] A fourth aspect of the present disclosure can include any of the first to third aspects, and further includes cooling the second overhead stream in a heat exchanger, separating the cooled second overhead stream into an overhead vapor stream and an overhead liquid stream, and splitting the overhead liquid stream into a liquid recycle stream and a liquid reflux return stream.

[0055] A fifth aspect of the present disclosure can include any of the first to fourth aspects, further including cooling the second overhead stream in a heat exchanger by heat exchange with a flashed alkane feed stream.

[0056] A sixth aspect of the present disclosure can include any of the first to fifth aspects, further including cooling at least a portion of the overhead vapor stream in a cold box to produce by-products.

[0057] A seventh aspect of the present disclosure may include any of the first to sixth aspects, and further includes introducing the liquid reflux return stream into the second rectification unit; introducing a liquid recycle stream into a cold box, where the liquid recycle stream is used as a cooling medium in the cold box; compressing at least a portion of the liquid recycle stream to generate a recycle stream; and introducing the recycle stream into the compressor for compression with the gaseous feed stream.

[0058] An eighth aspect of the present disclosure may include any of the first to seventh aspects, 2 , H 2 , methane, or a combination thereof from the first liquid residue stream in a lights removal tower to produce a lights removal tower overhead stream and a lights removal tower bottoms stream.

[0059] A ninth aspect of the present disclosure may include any of the first to eighth aspects, and further includes cooling at least a portion of the second liquid residue stream in a cold box to produce a cooled second liquid residue stream, and introducing the cooled second liquid residue stream into the rectification system.

[0060] A tenth aspect of the present disclosure may include any of the first to ninth aspects, further including introducing at least a portion of the second liquid residue stream into a cold box, where the second liquid residue stream is used as a cooling medium in the cold box.

[0061] An eleventh aspect of the present disclosure may include any of the first to tenth aspects, further including introducing a second vapor residue flow into the cold box, where the second vapor residue flow is used as a cooling medium in the cold box.

[0062] A twelfth aspect of the present disclosure may include any of the first to eleventh aspects, and further includes expanding at least a portion of the second vapor residue stream to generate an expanded second vapor residue stream, and introducing the expanded second vapor residue stream into a cold box, where the expanded second vapor residue stream is used as a cooling medium.

[0063] The subject matter of the present disclosure has been described in detail with reference to specific embodiments. It should be understood that any detailed description of an element or feature of an embodiment does not necessarily mean that the element or feature is essential to the particular embodiment or any other embodiment. Moreover, it should be apparent to those skilled in the art that various modifications and changes can be made to the described embodiments without departing from the spirit and scope of the claimed subject matter.

[0064] It should be noted that one or more of the claims below utilize the term "wherein" as a transitional phrase. For purposes of defining the present technology, it should be noted that this term is introduced into the claims as an open-ended transitional phrase used to introduce a recitation of a series of features of a structure, and should be interpreted in a similar manner to the more commonly used open-ended preamble term "comprising." When a first component is described as "comprising" a second component, it should be understood that in some embodiments, it is intended that the first component "consists of" or "consists essentially of" the second component.

[0065] It should be understood that any two quantitative values ​​assigned to a characteristic may constitute a range for that characteristic, and all combinations of ranges formed from all stated quantitative values ​​for a given characteristic are contemplated in this disclosure.

Claims

1. from the product stream of the olefin production reactor system ２ , C ３ , or C ４ 1. A process for recovering one or more of the olefins, comprising: flashing at least a portion of the alkane feed stream of the olefin production reactor system to produce a flashed alkane feed stream; introducing said flashed alkane feed stream as a cooling medium into a cold box, a rectification system, or both; compressing and cooling the gaseous feed stream to produce a compressed and cooled feed stream, wherein the gaseous feed stream has at least 70 weight percent (wt%) C ２ , C ３ , and C ４ generating a mixture of the ingredients; separating the compressed and cooled feed stream into a first residual vapor stream and a first liquid residual stream; cooling the first residual vapor stream in the cold box to produce a cooled first residual stream; separating the cooled first residue stream into a second vapor residue stream and a second liquid residue stream; separating the first liquid residue stream in a lights removal column into a lights removal column overhead stream and a lights removal column bottoms stream, wherein removal of light components enables the use of the flashed alkane feed stream as a cooling medium in the rectification system; rectifying at least a portion of said second liquid residue stream and said bottoms stream of said lights removal column in said rectification system to produce an overhead vapor stream, a liquid recycle stream, and a bottoms liquid stream.

2. the rectification system comprises a two-stage rectification system, and the process comprises: rectifying at least a portion of the second liquid residue stream in a first rectification apparatus, rectifying at least a portion of the bottoms stream of the lights removal column, or both, into a first overhead stream and a bottoms liquid stream; 2. The process of claim 1, further comprising: fractionating at least a portion of the first overhead stream into a second overhead stream and a second bottoms stream in a second fractionator downstream of the first fractionator.

3. cooling the first overhead stream to produce a cooled first overhead stream; separating the cooled first overhead stream into a first vapor stream and a first liquid stream; introducing said first vapor stream into said second rectification apparatus; 3. The process of claim 1 or 2, further comprising reintroducing said first liquid stream and said second bottoms stream into said first rectification unit.

4. cooling the second overhead stream in a heat exchanger; separating the cooled second overhead stream into an overhead vapor stream and an overhead liquid stream; and dividing the overhead liquid stream into the liquid recycle stream and a liquid reflux return stream.

5. 5. The process of any one of claims 1 to 4, further comprising cooling the second overhead stream in a heat exchanger by heat exchange with the flashed alkane feed stream.

6. 6. The process of any one of claims 1 to 5, further comprising cooling at least a portion of the overhead vapor stream in the cold box to produce by-products.

7. introducing said liquid reflux return stream into said second rectification apparatus; introducing the liquid recirculation stream into the cold box, the liquid recirculation stream being used as a cooling medium in the cold box; compressing at least a portion of the liquid recycle stream to generate a recycle stream; The process of any one of claims 1 to 6, further comprising introducing the recycle stream into a compressor for co-compression with the gaseous feed stream.

8. N ２ , H ２ 8. The process of claim 1, further comprising removing light components comprising benzene, methane, or a combination thereof from the first liquid residue stream in a lights removal column to produce the lights removal column overhead stream and the lights removal column bottoms stream.

9. cooling at least a portion of the second liquid retentate stream in the cold box to produce a cooled second liquid retentate stream; The process of any one of claims 1 to 8, further comprising: introducing the cooled second liquid residue stream into the rectification system.

10. 10. The process of claim 1, further comprising introducing at least a portion of the second liquid residue stream into the cold box, wherein the second liquid residue stream is used as a cooling medium in the cold box.

11. 11. The process of claim 1, further comprising introducing the second vapor residue stream into the cold box, wherein the second vapor residue stream is used as a cooling medium in the cold box.

12. expanding at least a portion of the second vapor residue stream to produce an expanded second vapor residue stream; 12. The process of claim 1, further comprising: introducing the expanded second vapor residue stream into the cold box, wherein the expanded second vapor residue stream is used as a cooling medium in the cold box.

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