Processes for recovery of one or more of c 2, c 3, or c 4 olefins

Abstract

One or more of C2, C3, or C4 olefins may be recovered by a process that may include compressing and cooling a gaseous feed stream to produce a first compressed and cooled feed stream, further cooling the first compressed and cooled feed stream by heat exchange with a bottoms stream to produce a second compressed and cooled feed stream, separating the second compressed and cooled feed stream into a first residual vapor stream and a first liquid residue 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 residual vapor stream and a second liquid residue stream, and passing at least a portion of the first liquid residue stream and at least a portion of the second liquid residue stream to a fractionation system to produce at least an overhead vapor stream, a liquid recycle stream, and a bottoms stream. The gaseous feed stream may include at least 70 wt.% of a combination of C2, C3, and C4 components, and the cooling of the gaseous feed stream may be by heat exchange with a cooling fluid having a temperature of from 0 °C to 70 °C.

Description

PROCESSES FOR RECOVERY OF ONE OR MORE OF C2, C3, OR C4OLEFINSCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Provisional Application Serial No. 63 / 583,444 filed September 18, 2023, the contents of which are incorporated in their entirety herein.TECHNICAL FIELD

[0002] Embodiments described herein generally relate to chemical processing and, more particularly, to product recovery in chemical processing.BACKGROUND

[0003] Ethylene, ethane, propylene, propane, and / or heavier hydrocarbons can be recovered from a variety of gas streams including, natural gas, refinery gas, synthetic gas, or combinations thereof, obtained from coal, crude oil, naphtha, oil shale, steam cracker, catalytic cracker, or combinations thereof. The cryogenic expansion processes are widely used for recovery of condensable product gas from non-condensable or difficult to condense gas as it provides start-up simplicity, operating flexibility, good efficiency and reliability.SUMMARY

[0004] Despite conventional recovery processes available for recovering ethylene, ethane, propylene, propane, and / or heavier hydrocarbons from variety of gas streams, these processes are often relatively inefficient, requiring high heat duty costs for the cooling of the materials to condensable temperatures. Accordingly, there is an ongoing need for processes providing improved energy-efficient recovery of one or more of C2, C3, These needs may be met by embodiments of systems and processes described in the present disclosure. Embodiments of the present disclosure are directed to processes for recovery of one or more of C2, C3, or C4 olefins where the pressure in several of the streams is relatively elevated as compared with conventional methods. In particular, the pressure of the feed stream following compressing is relatively high, and the pressure of operation of a fractionation system utilized to form a bottoms stream that is heat exchanged with the feed stream is relatively high. Such configurations may enable therecovery of condensable product gas from non-condensable or difficult to condense gas. Fractionation systems at high-pressure, as described herein, generally enables lower operating temperature, thus, enabling in some embodiments crude propylene to be used as refrigerant to cool down the warm cracked gas. This result, in one or more embodiments, is less refrigerant requirement for a cold box and enablement of better heat integration.

[0005] According to one or more embodiments disclosed herein, one or more of C2, C3, or C4 olefins may be recovered by a process that may comprise compressing and cooling a gaseous feed stream to produce a first compressed and cooled feed stream, further cooling the first compressed and cooled feed stream by heat exchange with a bottoms stream to produce a second compressed and cooled feed stream, separating the second compressed and cooled feed stream into a first residual vapor stream and a first liquid residue 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 residual vapor stream and a second liquid residue stream, and passing at least a portion of the first liquid residue stream and at least a portion of the second liquid residue stream to a fractionation system to produce at least an overhead vapor stream, a liquid recycle stream, and a bottoms stream. The gaseous feed stream may comprise at least 70 wt.% of a combination of C2, C3, and C4 components, and the cooling of the gaseous feed stream may be by heat exchange with a cooling fluid having a temperature of from 0 °C to 70 °C.

[0006] It is to be understood that both the foregoing brief summary and the following detailed description present embodiments of the technology, and are intended to provide an overview or framework for understanding the nature and character of the technology as it is claimed. The accompanying drawings are included to provide a further understanding of the technology, and are incorporated into and constitute a part of this specification. The drawings illustrate various embodiments and, together with the description, serve to explain the principles and operations of the technology. Additionally, the drawings and descriptions are meant to be merely illustrative, and are not intended to limit the scope of the claims in any manner.

[0007] Additional features and advantages of the technology disclosed herein will be set forth in the detailed description that follows, and in part will be readily apparent to those skilled in the art from that description or recognized by practicing the technology as described herein, including the detailed description that follows, the claims, as well as the appended drawings.BRIEF DESCRIPTION OF THE DRAWINGS

[0008] The following detailed description of specific embodiments of the present disclosure can be best understood when read in conjunction with the following drawings, where like structure is indicated with like reference numerals and in which:

[0009] FIG. 1 schematically depicts a system for recovery of one or more of C2, C3, or C4 olefins, according to one or more embodiments described herein;

[0010] FIG. 2 schematically depicts a two-stage fractionation system that can be utilized in the embodiment of FIG. 1, according to one or more embodiments described herein;

[0011] FIG. 3 schematically depicts another system for recovery of one or more of C2, C3, or C4 olefins, according to one or more embodiments described herein.

[0012] It should be understood that the drawings are schematic in nature, and do not include some components of a fluidized catalyst processing system commonly employed in the art, such as, without limitation, temperature transmitters, pressure transmitters, flow meters, pumps, valves, and the like. It would be known that these components are within the spirit and scope of the present embodiments disclosed. However, operational components, such as those described in the present disclosure, may be added to the embodiments described in this disclosure.

[0013] Reference will now be made in greater detail to various embodiments, some embodiments of which are illustrated in the accompanying drawings. Whenever possible, the same reference numerals will be used throughout the drawings to refer to the same or similar parts.DETAILED DESCRIPTION

[0014] Embodiments of the present disclosure are directed to processes for recovering one or more of C2, C3, or C4 olefins from a feed stream, where the feed stream may be a product stream of an olefin production reactor system. Such processes utilize systems that have particular features, such as a particular orientation of system parts. FIGS. 1-3, as described herein, depict such a system 100, which includes a cold box 111 and a fractionation system 120.

[0015] As used in this disclosure, a “separator” or “separation device” may refer to any separation device or system of separation devices that at least partially separates one or more chemicals that are mixed in a process stream from one another. For example, a separator may selectively separate differing chemical species, phases, or sized material from one another, forming one or more chemical fractions. Examples of separators include, without limitation, 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 separation processes described in this disclosure may not completely separate all of one chemical constituent from all of another chemical constituent. It should be understood that the separation processes described in this disclosure “at least partially” separate different chemical components from one another, and that even if not explicitly stated, it should be understood that separation may include only partial separation. As used in this disclosure, one or more chemical constituents may be “separated” from a process stream to form a new process stream. Generally, a process stream may enter a separator and be divided, or separated, into two or more process streams of desired composition.

[0016] As used in this disclosure, a “cold box” may refer to multiple heat exchangers connected in series or otherwise, usually where a cooling source cools multiple streams. 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.

[0017] As used in this disclosure, a “fractionation system” may refer to any fractionation device or system of fractionation devices that at least partially divide a certain quantity of a mixture (gas, solid, liquid, or combinations thereof), during a phase transition, into a number of smaller fractions in which the composition varies according to a gradient.

[0018] It should further be understood that streams may be named for the components of the stream, and the component for which the stream is named may be the major component of the stream (such as comprising from 50 weight percent (wt. %), from 70 wt. %, from 90 wt. %, from 95 wt. %, from 99 wt. %, from 99.5 wt. %, or even from 99.9 wt. % of the contents of the stream to 100 wt. % of the contents of the stream). It should also be understood that components of astream are disclosed as passing from one system component to another when a stream comprising that component is disclosed as passing from that system component to another.

[0019] Referring now to FIG. 1, a system 100 for recovering one or more of C2, C3, or C4 olefins from a product stream of an olefin production reactor system is schematically depicted. The system 100 generally receives a gaseous feed stream 101, which may be a product stream from an olefin production system, and directly processes the gaseous feed stream 101 to recover one or more of C2, C3, or C4 olefins from a product stream of an olefin production reactor system.

[0020] The gaseous feed stream 101 may be introduced to the system 100. The gaseous feed stream may include, or may consist of, a product stream of an olefin production reactor system. The product stream may be from a petrochemical process or naphtha from a refining operation for crude oil, natural gas liquids (NGL), or other hydrocarbon sources. As described herein, in one or more embodiments, the gaseous feed stream 101 may be a reaction effluent of steam cracking, catalytic cracking, or both. In one or more embodiments, the gaseous feed stream 101 may include natural gas, refinery gas, synthetic gas, or combinations thereof obtained from coal, crude oil, naphtha, oil shale, or combinations thereof. In embodiments, the gaseous feed stream 101 may include at least 70 wt.%, at least 75 wt.%, at least 80 wt.%, or at least 85 wt.% of one or more of C2, C3, or C4 components. In embodiments, the gaseous feed stream 101 comprises from 1 wt.% to 10 wt.% N2, from 0.01 wt.% to 5 wt.% H2, from 0.01 wt.% to 5 wt.% methane, and from 70 wt.% to 95 wt.% one or more of C2, C3, or C4 components. In embodiments, the gaseous feed stream 101 comprises ethane, propane, butane, or combinations thereof. In embodiments, the gaseous feed stream 101 comprises 50 wt.% propane.

[0021] The gaseous feed stream 101 may be introduced to the compressor 103. The gaseous feed stream 101 may be compressed in the compressor 103 to produce the compressed feed stream 102 A. The compressed feed stream 102 A may be introduced to the heat exchanger 127 and may be cooled by heat exchange with a cooling fluid 138 in heat exchanger 127. The effluent of the heat exchanger 127 is referred to as a first compressed and cooled feed stream 102B. The cooling fluid 138 may pass through the heat exchanger 127 and be warmed to form process fluid 139, having the same composition as the cooling fluid 138. The cooling fluid 138 is not necessarily limited in composition, and may be, for example, water, air, or a refrigerant. The cooling fluid 138 may have a temperature of from 0 °C to 70 °C. For example, the cooling fluid 138 may havea temperature of from 0 °C to 10 °C, from 10 °C to 20 °C, from 20 °C to 30 °C, from 30 °C to 40 °C, from 40 °C to 50 °C, from 50 °C to 60 °C, from 60 °C to 70 °C, or any combination of one or more of these ranges.

[0022] In some embodiments, the amount of one or more of C2, C3, or C4 components in the compressed feed stream 102A and / or the first compressed and cooled feed stream 102B may be greater than the amount of one or more of C2, C3, or C4 components in the gaseous feed stream 101 due to mixing with the recycling stream 135 prior to or at the compressor 103, as discussed hereinbelow in more detail.

[0023] According to embodiments, the first compressed and cooled feed stream 102B may have a pressure of from 15 barg to 100 barg. For example, the first compressed and cooled feed stream 102B may have a pressure of from 15 barg to 20 barg, from 20 barg to 25 barg, from 25 barg to 30 barg, from 30 barg to 40 barg, from 40 barg to 50 barg, from 50 barg to 75 barg, from 75 barg to 100 barg, or any combination of these ranges. For example, the first compressed and cooled feed stream 102B may have a pressure of from 15 barg to 35 barg. Without being bound by theory, it is believed that it may be beneficial to have the first compressed and cooled feed stream have a relatively high pressure (e.g., 15 barg or greater) because such relatively high pressures enable, according to one or more embodiments, a warmer fractionation column so feed refrigerant in fractionation condenser may be utilized, thus eliminating the need of an external refrigeration machine. If the pressure is too low (e.g., less than 15 barg), the external refrigeration may be needed. If pressure is too high (e.g., higher than 50 barg or 100 barg), added capital expenditure and operating expenditure may be present.

[0024] The first compressed and cooled feed stream 102B may be further cooled in the heat exchanger 129 to produce the second compressed and cooled feed stream 102C. In embodiments, the first compressed and cooled feed stream 102B may be cooled in the heat exchanger 129 by the contents of a bottoms stream 122 A, as is explained in detail hereinbelow.

[0025] Still referring to FIG. 1, in one or more embodiments, the second compressed and cooled feed stream 102C may be introduced to a first separator 105. The compressed and cooled feed stream 102B may be separated into a first residual vapor stream 104 A and a first liquid residue stream 106. In embodiments, the first residual vapor stream 104A may comprise from 1 wt.% to 25 wt.% N2, from 0.01 wt.% to 5 wt.% H2, from 0.01 wt.% to 5 wt.% methane, and from70 wt.% to 95 wt.% one or more of C2, C3, or C4 components. The amount of one or more of C2, C3, or C4 components in the first residual vapor stream 104 A may be greater than the amount of one or more of C2, C3, or C4 components in the second compressed and cooled feed stream 102C.

[0026] The first residual vapor stream 104 A may be introduced to a cold box 111. The first residual vapor stream 104 A may be cooled in the cold box 111 to produce the cooled first residual vapor stream 104B. In embodiments, the cooled first residual vapor stream 104B may comprise from 1 wt.% to 45 wt.% N2, from 0.01 wt.% to 15 wt.% H2, from 0.01 wt.% to 5 wt.% methane, and from 50 wt.% to 95 wt.% one or more of C2, C3, or C4 components.

[0027] The cooled first residual vapor stream 104B may be introduced to a second separator 109. The cooled first residual vapor stream 104B may be separated into a second residual vapor stream 108 and a second liquid residue stream 110A. In embodiments, the second residual vapor stream 108 comprises from 30 wt.% to 80 wt.% N2, from 10 wt.% to 40 wt.% H2, from 5 wt.% to 20 wt.% methane, and from 0.01 wt.% to 10 wt.% one or more of C2, C3, or C4 components. In embodiments, the second residual vapor stream 108 may have a temperature of from -120 °C to - 100 °C. In embodiments, the second liquid residue stream 110A may comprise from 0.001 wt.% to 2 wt.% N2, from 0.001 wt.% to 1 wt.% H2, from 0.001 wt.% to 2 wt.% methane, and from 90 wt.% to 99 wt.% one or more of C2, C3, or C4 components. The second residual vapor stream 108 may be introduced to the cold box 111 and be utilized as a coolant to form an off-gas by product stream 112.

[0028] Still referring to FIG. 1, the second liquid residue stream 110A may be introduced to the cold box 111. The second liquid residue stream 110A may act as a coolant in the cold box 111 to produce a warmed second liquid residue stream HOB. In embodiments, the warmed second liquid residue stream 110B may comprise from 0.001 wt.% to 5 wt.% N2, from 0.001 wt.% to 1 wt.% H2, from 0.001 wt.% to 1 wt.% methane, and from 90 wt.% to 99 wt.% one or more of C2, C3, or C4 components.

[0029] At least the portion of the cooled second liquid residue stream HOB, at least the portion of the first liquid residue stream 106, or both, may be introduced to the fractionation system 120 to produce at least an overhead vapor stream 128, a liquid recycle stream 130A, and a bottoms stream 122 A. Referring to FIGS. 1 and 2, one example of the fractionation system 120 is a two-stage fractionation system shown in FIG. 2, which includes the first fractionator 121Aand the second fractionator 121B downstream of the first fractionator 121A. The two-stage fractionation system may enable utilization of cooling water for compression duty of a first overhead stream 120 A from the first fractionator 121 A. As a result of removal of light and noncondensable components by the light removal column 117, the gaseous feed stream 101 may be compressed using cooling water and heat integration from the first overhead stream 120 A. Utilization of cooling water may be beneficial to the utilization of a heat rejection refrigerant process due to superior thermodynamic efficiency as well as low associated capital cost. Additionally, the two-stage fractionation system may produce various streams that may be used as cooling mediums in the cold box. The two-stage fractionation system may provide flexibility in operation and product specification adjustment.

[0030] Still referring to FIGS. 1 and 2, in embodiments, at least the portion of the cooled second liquid residue stream HOB may be introduced to the first fractionator 121 A depending on stage compositions. In embodiments, at least the portion of the second liquid residue stream 110A may be cooled in the cold box 111 to produce the cooled second liquid residue stream HOB. The cooled second liquid residue stream 110B may be introduced to the fractionation system 120. In embodiments, the cooled second liquid residue stream 110B may be introduced to the first fractionator 121A of the two-stage fractionation system. As discussed above, the first liquid residue stream 106 may be introduced to the first fractionator 121 A. At least a portion of the cooled second liquid residue stream 110B and the first liquid residue stream 106 may be separated into a first overhead stream 120 A and a bottoms stream 122 A. In embodiments, when the cooled second liquid residue stream 110B is fed to the first fractionator 121 A, the cooled second liquid residue stream 110B and the first liquid residue stream 106 may be separated into a first overhead stream 120 A and a bottoms stream 122 A.

[0031] In embodiments, the first overhead stream 120A comprises from 0.001 to 1 wt.% N2, from 0 to 1 wt.% H2, from 0.001 to 1 wt.% methane, and from 98 wt.% to 99.9 wt.% one or more of C2, C3, or C4 components. The first overhead stream 120A may not include H2. In embodiments, the bottoms stream 122A may comprise at least 95 wt.%, at least 96 wt.%, at least 97 wt.%, at least 98 wt.%, at least 99 wt.%, or at least 99.9 wt.% one or more of C2, C3, or C4 components. The bottoms stream 122 A may not include N2, H2, methane, or combinations thereof.

[0032] The first overhead stream 120 A may be partially condensed and refluxed. The temperature of the first overhead stream 120 A may be controlled to enable utilizing cooling water as a condensing agent for the gaseous feed 100. In embodiments, the first overhead stream 120A may be cooled by the heat exchanger 131 to produce a cooled first overhead stream 120B. In embodiments, the heat exchanger 131 may use cooling water as a cooling medium. The heat exchanger 131 may not require external refrigeration system. The cooled first overhead stream 120B may be introduced to 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 fractionator 121 A.

[0033] Still referring to FIGS. 1 and 2, at least a portion of the first overhead stream 120A may be introduced to the second fractionator 121B downstream of the first fractionator 121 A and then separated into a second overhead stream 126A and a second bottom stream 124. In embodiments, the first vapor stream 123A including non-condensable components may be introduced to the second fractionator 121B. The first vapor stream 123A may be separated into the second overhead stream 126A and the second bottom stream 124. In embodiments, the second bottom stream 124 may comprise at least 95 wt.%, at least 96 wt.%, at least 97 wt.%, at least 98 wt.%, or at least 99 wt.% one or more of C2, C3, or C4 components. The second bottom stream 124 may further comprise from 0 wt.% to 1 wt.% H2, from 0 wt.% to 1 wt.% N2, and from 0.001 wt.% to 1 wt.% methane. The second bottom stream 124 may not include H2, N2, or both. The second bottom stream 124 may be reintroduced into the first fractionator 121 A.

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

[0035] The cooled second overhead stream 126B may be introduced to a fourth separator 127, and then separated into an overhead vapor stream 128 and an overhead liquid stream 132. Inembodiments, the overhead vapor stream 128 may comprise from 1 wt.% to 10 wt.% N2, from 0.001 wt.% to 1 wt.% H2, from 1 wt.% to 10 wt.% methane, and from 75 wt.% to 95 wt.% one or more of C2, C3, or C4 components.

[0036] The overhead vapor stream 128 may be introduced to the cold box 111. The overhead vapor stream 128 may be cooled in the cold box 111 to produce by-products 128A. In embodiments, the overhead vapor stream 128 may be used as a cooling medium in the cold box 111 before existing the system 100 as by-products.

[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 fractionator 121B.

[0038] In embodiments, the liquid recycle stream 130A may comprise from 0.001 wt.% to 1 wt.% N2, from 0 wt.% to 1 wt.% H2, from 0.001 wt.% to 1 wt.% methane, and from 90 wt.% to 99 wt.% one or more of C2, C3, or C4 components. In embodiments, the liquid recycle stream 130A may not include H2. The 135 liquid recycle stream 130A may be passed through a valve to release pressure and form liquid recycle stream 130B. Still referring to FIGS. 1 and 2, at least a portion of the liquid recycle stream 130B may be passed through the cold box 111 to form a cooled liquid recycle stream 135. The cooled liquid recycle stream 130B may be combined with the gaseous feed stream 101 upstream or at the compressor 103.

[0039] The second bottom stream 124 may be re-introduced to the first fractionator 121 A. Prior to re-introducing to the first fractionator 121 A, the second bottom stream 126 may be mixed with the first liquid stream 123B.

[0040] According to embodiments, the fractionation system 120 may operate at a pressure of from 15 barg to 100 barg. For example, the fractionation system 120 may operate at a pressure of from 15 barg to 20 barg, from 20 barg to 25 barg, from 25 barg to 30 barg, from 30 barg to 40 barg, from 40 barg to 50 barg, from 50 barg to 75 barg, from 75 barg to 100 barg, or any combination of these ranges. For example, the fractionation system 120 may operate at a pressure of from 15 barg to 35 barg. In such embodiments, one, two, or all three of the overhead vapor stream 128, the liquid recycle stream 130A, and the bottoms stream 122 A may have a pressure offrom 15 barg to 100 barg, or any subrange of pressure as described hereinabove. Without being bound by theory, it is believed that it may be beneficial to have the fractionation system 120 operate at a relatively high pressure (e.g., 15 barg or greater) because such relatively high pressures enable, according to one or more embodiments, a warmer fractionation column so feed refrigerant in fractionation condenser may be utilized, thus eliminating the need of an external refrigeration machine. If the pressure is too low (e.g., less than 15 barg), the external refrigeration may be needed. If pressure is too high (e.g., higher than 50 barg or 100 barg), added capital expenditure and operating expenditure may be present.

[0041] Referring now to FIG. 1, the bottoms stream 122A may undergo some processing prior to being utilized as a heat exchange fluid with the first compressed and cooled feed stream 102B in the heat exchanger 129. It should be understood that the “bottoms stream” is described with reference numbers 122A, 122B (in FIG. 2 only), 122C, and 122D, and that these streams all generally have the same composition but may have different temperature and / or pressure.

[0042] In one or more embodiments, the pressure of the bottoms stream 122A may be reduced upstream of its heat exchange with the first compressed and cooled feed stream 102B. As depicted in FIG. 1 a pressure release mechanism 137, such as a valve or flash vessel, may be utilized to reduce the pressure of the bottoms stream 122 A, such that bottoms stream 122 A has a greater pressure than the bottoms stream 122C (downstream of the pressure release mechanism 137). In such embodiments, reducing the pressure of the bottoms stream may at least partially vaporize the bottoms stream 102 A such that the bottoms stream 102 A includes both liquid and gas phase materials. According to some embodiments, from 10 wt.% to 99.9 wt.%, from 10 wt.% to 99 wt.%, from 10 wt.% to 95 wt.%, from 10 wt.% to 90 wt.%, from 10 wt.% to 85 wt.%, from 10 wt.% to 80 wt.%, from 15 wt.% to 99.9 wt.%, from 15 wt.% to 99 wt.%, from 15 wt.% to 95 wt.%, from 15 wt.% to 90 wt.%, from 15 wt.% to 85 wt.%, from 15 wt.% to 80 wt.%, from 20 wt.% to 99.9 wt.%, from 20 wt.% to 99 wt.%, from 20 wt.% to 95 wt.%, from 20 wt.% to 90 wt.%, from 20 wt.% to 85 wt.%, from 20 wt.% to 80 wt.%, from 25 wt.% to 99.9 wt.%, from 25 wt.% to 99 wt.%, from 25 wt.% to 95 wt.%, from 25 wt.% to 90 wt.%, from 25 wt.% to 85 wt.%, or from 25 wt.% to 80 wt.% of the bottoms stream 122C may be vaporized.

[0043] According to embodiments, the bottoms stream 122C exchanges heat with the first compressed and cooled feed stream 102B, which cools the first compressed and cooled feedstream 102B and heats the bottoms stream 122C to from bottoms stream 122D (downstream of the heat exchanger 129. The bottoms stream 122D may be separated into at least two streams (not shown in FIG. 1).

[0044] Now referring to FIG. 3, a system that is almost identical in all respects to that of FIG. 1 is depicted, where the difference is the inclusion of an additional heat exchange step utilized on the bottoms stream 122A to form bottoms stream 122B (which is cooler than bottoms stream 122A). As depicted, the bottoms stream 122A may be passed through heat exchanger 146, where the bottoms stream 122A is heat exchanged with process stream 142, forming bottoms stream 122B (cooler than bottoms stream 122 A) and process stream 144 (warmer than process stream 142). Such heat exchange by process stream 142 may be upstream of the reducing of the pressure at the pressure release mechanism 137.

[0045] According to one or more embodiments, the process stream 142 may be an alkane feed stream that is fed to an olefin production process, which forms the gaseous feed stream as its product stream. For example, process stream 142 may be passed to an olefin production process, such as passed directly to a reactor or through one or more process units such as separators, heat exchangers, etc. before being passed to a reactor. Such alkane production process may utilizes catalytic or non-catalytic cracking and / or dehydrogenation. For example, the process stream 142 may comprise natural gas, or other alkane rich streams. In some embodiments, the process stream 142 may include one or more recycled components from the olefin production process as well as purely feedstock materials such as natural gas.

[0046] According to embodiments, the heat exchange of the process stream 142 with the bottoms stream 122 A may at least partially vaporize the process stream 142 to form process stream 144. Without being bound by theory, according to one or more embodiments, partial vaporization of the process stream 142 may be beneficial by removing heat from the process stream 142, enabling enhanced cooling to the first compressed and cooled feed stream 102B, and / or by reducing energy use in downstream separations such a depropanizer.

[0047] According to embodiments, the cooling duty for the cold box 111 may be provided by local or non-local grid electricity. Alternatively, the cold duty for the cold box 111 may be provided by a cooling medium, such as natural gas. In some embodiments, the natural gas may be utilized as a feedstock for olefin production, and may be used to cool the products of this processwhile being warmed, which is needed for the relatively high reaction temperatures needed to generally produce olefins.

[0048] A process for recovery of one or more of C2, C3, C4 olefins, or combinations of these, from a product stream of an olefin production reactor system of the present disclosure may produce greater yield of one or more of C2, C3, or C4 olefins, compared to a conventional recovery process. In embodiments, the process of the present disclosure may produce a combined yield of C2, C3, C4 olefins, or combinations of these, of greater than or equal to 90 wt.%, greater than or equal to 95 wt.%, greater than or equal to 96 wt.%, greater than or equal to 97 wt.%, greater than or equal to 98 wt.%, or even greater than or equal to 99 wt.%, based on the total weight of the product stream introduced to the recovery process of the present disclosure.EXAMPLES

[0049] The various embodiments of processes and systems disclosed herein will be further clarified by the following examples. The examples are illustrative in nature, and should not be understood to limit the subject matter of the present disclosure.

[0050] Example 1

[0051] Example 1 was conducted using an integrated separation train process model in Aspen Plus for the recovery system depicted in FIG. 1. Tables 1A-1D show a temperature, a pressure, and a mass fraction ratio of streams depicted in FIG. 1.Table 1ATable IBTable 1CTable ID

[0052] Example 2

[0053] Example 1 was conducted using an integrated separation train process model in Aspen Plus for the recovery system depicted in FIG. 1. Tables 2A-2D show a temperature, a pressure, and a mass fraction ratio of streams depicted in FIG. 1.Table 2ATable 2BTable 2C

[0054] Numerous aspects are disclosed herein. A first aspect is a process for recovery of one or more of C2, C3, or C4 olefins, the process comprising: compressing and cooling a gaseous feed stream to produce a first compressed and cooled feed stream, wherein the gaseous feed stream comprises at least 70 wt.% of a combination of C2, C3, and C4 components, wherein the cooling of the gaseous feed stream is by heat exchange with a cooling fluid having a temperature of from 0 °C to 70 °C; further cooling the first compressed and cooled feed stream by heat exchange with a bottoms stream to produce a second compressed and cooled feed stream; separating the second compressed and cooled feed stream into a first residual vapor stream and a first liquid residue 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 residual vapor stream and a second liquid residue stream; passing at least a portion of the first liquid residue stream and at least a portion of the second liquid residue stream to a fractionation system to produce at least an overhead vapor stream, a liquid recycle stream, and a bottoms stream.

[0055] Another aspect is any previous aspect or combination of previous aspects, further comprising reducing the pressure of the bottoms stream upstream of its heat exchange with the first compressed and cooled feed stream.

[0056] Another aspect is any previous aspect or combination of previous aspects, wherein reducing the pressure of the bottoms stream at least partially vaporizes the bottoms stream.

[0057] Another aspect is any previous aspect or combination of previous aspects, further comprising heat exchanging the bottoms stream with a process stream.

[0058] Another aspect is any previous aspect or combination of previous aspects, wherein the heat exchanging with the process stream is upstream of the reducing of the pressure of the bottoms stream.

[0059] Another aspect is any previous aspect or combination of previous aspects, wherein the process stream is an alkane feed stream fed to an olefin production process that forms the gaseous feed stream.

[0060] Another aspect is any previous aspect or combination of previous aspects, wherein the heat exchanging of the process stream with the bottoms stream at least partially vaporizes the process stream.

[0061] Another aspect is any previous aspect or combination of previous aspects, wherein the first compressed and cooled feed stream has a pressure of from 15 barg to 100 barg.

[0062] Another aspect is any previous aspect or combination of previous aspects, wherein the fractionation system operates at a pressure of from 15 barg to 100 barg.

[0063] Another aspect is any previous aspect or combination of previous aspects, further comprising separating the bottoms stream into at least two streams downstream of its heat exchange with the first compressed and cooled feed stream.

[0064] Another aspect is any previous aspect or combination of previous aspects, wherein the fractionation system comprises a two-stage fractionation system.

[0065] Another aspect is any previous aspect or combination of previous aspects, further comprising passing at least a portion of the second residual vapor stream and at least a portion of the second liquid residue stream through the cold box as coolants.

[0066] Another aspect is any previous aspect or combination of previous aspects, further comprising passing the overhead vapor stream through the cold box.

[0067] Another aspect is any previous aspect or combination of previous aspects, further comprising passing the liquid recycle stream through the cold box

[0068] Another aspect is any previous aspect or combination of previous aspects, further comprising combining the liquid recycle stream with the gaseous feed stream.

[0069] The subject matter of the present disclosure has been described in detail and by reference to specific embodiments. It should be understood that any detailed description of a component or feature of an embodiment does not necessarily imply that the component or feature is essential to the particular embodiment or to any other embodiment. Further, it should be apparent to those skilled in the art that various modifications and variations can be made to the described embodiments without departing from the spirit and scope of the claimed subject matter.

[0070] It is noted that one or more of the following claims utilize the term “wherein” as a transitional phrase. For the purposes of defining the present technology, it is noted that this term is introduced in the claims as an open-ended transitional phrase that is used to introduce a recitation of a series of characteristics of the structure and should be interpreted in like manner as the more commonly used open-ended preamble term “comprising.” It should be understood that where a first component is described as “comprising” a second component, it is contemplated that, in some embodiments, the first component “consists” or “consists essentially of’ that second component.

[0071] It should be understood that any two quantitative values assigned to a property may constitute a range of that property, and all combinations of ranges formed from all stated quantitative values of a given property are contemplated in this disclosure.

Claims

CLAIMS1. A process for recovery of one or more of C2, C3, or C4 olefins, the process comprising: compressing and cooling a gaseous feed stream to produce a first compressed and cooled feed stream, wherein the gaseous feed stream comprises at least 70 wt.% of a combination of C2, C3, and C4 components, and wherein the cooling of the gaseous feed stream is by heat exchange with a cooling fluid having a temperature of from 0 °C to 70 °C; further cooling the first compressed and cooled feed stream by heat exchange with a bottoms stream to produce a second compressed and cooled feed stream; separating the second compressed and cooled feed stream into a first residual vapor stream and a first liquid residue 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 residual vapor stream and a second liquid residue stream; passing at least a portion of the first liquid residue stream and at least a portion of the second liquid residue stream to a fractionation system to produce at least an overhead vapor stream, a liquid recycle stream, and a bottoms stream.

2. The process of any preceding claim, further comprising reducing the pressure of the bottoms stream upstream of its heat exchange with the first compressed and cooled feed stream.

3. The process of claim 2, wherein reducing the pressure of the bottoms stream at least partially vaporizes the bottoms stream.

4. The process of any preceding claim, further comprising heat exchanging the bottoms stream with a process stream.

5. The process of claim 4, wherein the heat exchanging with the process stream is upstream of the reducing of the pressure of the bottoms stream.

6. The process of claim 4, wherein the process stream is an alkane feed stream fed to an olefin production process that forms the gaseous feed stream.

7. The process of claim 6, wherein the heat exchanging of the process stream with the bottoms stream at least partially vaporizes the process stream.

8. The process of any preceding claim, wherein the first compressed and cooled feed stream has a pressure of from 15 barg to 100 barg.

9. The process of any preceding claim, wherein the fractionation system operates at a pressure of from 15 barg to 100 barg.

10. The process of any preceding claim, further comprising separating the bottoms stream into at least two streams downstream of its heat exchange with the first compressed and cooled feed stream.

11. The process of any preceding claim, wherein the fractionation system comprises a two- stage fractionation system.

12. The process of any preceding claim, further comprising passing at least a portion of the second residual vapor stream and at least a portion of the second liquid residue stream through the cold box as coolants.

13. The process of any preceding claim, further comprising passing the overhead vapor stream through the cold box.

14. The process of any preceding claim, further comprising passing the liquid recycle stream through the cold box.

15. The process of any preceding claim, further comprising combining the liquid recycle stream with the gaseous feed stream.

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