Methods for drying c2-c4 hydrocarbon streams

Abstract

A method for processing a mixed stream may include compressing the mixed stream to form a compressed mixed stream. The mixed stream includes one or more of C2, C3, and C4 hydrocarbons and H2O. The method may include cooling the compressed mixed stream to form a cooled mixed stream and separating the cooled mixed stream into at least a first fraction and a second fraction. The method may include at least partially drying the first fraction such that at least a portion of the H2O is removed from the first fraction to form a dried first fraction that has a lower H2O concentration than the first fraction. The method may further include compressing the dried first fraction to form a compressed dried first fraction, cooling the compressed dried first fraction to form a cooled dried first fraction, and passing the cooled dried first fraction to a separation unit.

Description

METHODS FOR PROCESSING HYDROCARBONSCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Provisional Application Serial No. 63 / 605,751 filed December 4, 2023, the contents of which are incorporated in their entirety herein.TECHNICAL FIELD

[0002] Embodiments described herein generally relate to methods and systems for processing hydrocarbons and, more specifically, to methods and systems for drying hydrocarbon streams.BACKGROUND

[0003] Various hydrocarbons, such as ethylene, ethane, propylene, propane, and heavier hydrocarbons, may be recovered from a variety of product streams obtained from chemical reactors. Cryogenic separation processes may be used to recover more condensable hydrocarbons from less condensable gasses or products.SUMMARY

[0004] In cryogenic separation processes, a mixed stream comprising hydrocarbons may be compressed and cooled by heat exchange with other process streams and / or external sources of refrigeration. As the mixed stream is cooled, streams comprising various fractions of the mixed feed stream may be collected as high pressure liquid or vapor streams. If the mixed stream comprises too much H2O (water) the H2O may freeze during one or more of the cooling steps of the cryogenic separation process. Accordingly, there is a need for methods to dry the mixed stream to avoid freezing H2O in one or more system components used in the cryogenic separation process.

[0005] Some conventional systems dry vapor and liquid fractions of the mixed stream separately, using a vapor fraction dryer and a liquid fraction dryer. Use of separate dryers for vapor and liquid fractions may result in the use of two dryer and regeneration systems as well as an oil / water separator upstream of the liquid fraction dryer to remove free water before the liquid fraction is passed to the liquid fraction dryer. Accordingly, there is a need for systems and methods for drying a mixed stream that reduces the capital cost of the drying system components.

[0006] Embodiments of the methods for processing mixed streams described herein may address one or more of these problems. For example, in one or more embodiments described herein a mixed stream may be compressed and then dried upstream of a separation unit. This may allow H2O to be removed from the mixed stream upstream of the separation unit to prevent the H2O from freezing in the cryogenic separation process. Additionally, this may allow the mixed stream to be dried in a single dryer system, which may reduce the capital cost of the system relative to conventional systems where a liquid fraction and a vapor fraction of the mixed stream are dried in separate dryer systems.

[0007] According to one or more embodiments of the present disclosure, a method for processing a mixed stream may comprise compressing the mixed stream to form a compressed mixed stream. The mixed stream comprises greater than or equal to 70 wt.% of one or more of C2, C3, and C4 hydrocarbons, and the mixed stream comprises H2O. The method may comprise cooling the compressed mixed stream to form a cooled mixed stream and separating the cooled mixed stream into at least a first fraction and a second fraction. The first fraction may comprise one or more of the C2, C3, and C4 hydrocarbons, and the second fraction may comprise one or more of the C2, C3, and C4 hydrocarbons and H2O. The method may comprise at least partially drying the first fraction such that at least a portion of the H2O is removed from the first fraction to form a dried first fraction that has a lower H2O concentration than the first fraction. The method may further comprise compressing the dried first fraction to form a compressed dried first fraction, cooling the compressed dried first fraction to form a cooled dried first fraction, and passing the cooled dried first fraction to a separation unit.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 processing a mixed stream, according to one or more embodiments disclosed herein;

[0010] FIG. 2 schematically depicts a system for processing a mixed stream comprising two compressors downstream of the dryer, according to one or more embodiments disclosed herein;

[0011] FIG. 3 schematically depicts a system for processing a mixed stream comprising two compressors upstream of the dryer, according to one or more embodiments disclosed herein;

[0012] FIG. 4 schematically depicts a system for processing a mixed stream comprising an olefin production system, according to one or more embodiments disclosed herein;

[0013] It should be understood that the drawings are schematic in nature, and do not include some components of a separation 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.

[0014] Reference will now be made in greater detail to various embodiments, some embodiments of which are illustrated in the accompanying drawings.DETAILED DESCRIPTION

[0015] One or more non-limiting embodiments of methods for processing a mixed feed stream are described herein. FIG. 1 depicts an embodiment of a system for processing a mixed feed stream. Embodiments of the methods for processing mixed feed streams described herein may be performed using a system as depicted in FIG. 1. However, it should be understood that the methods for processing mixed feed streams described herein are not limited to the use of the system depicted in FIG. 1. Embodiments of the methods form processing mixed feed streams described herein may be used to dry a stream comprising hydrocarbons and H2O.

[0016] Referring now to FIG. 1, a mixed stream 102 may be compressed to form a compressed mixed stream 104. In one or more embodiments, the mixed stream 102 may comprise one or more of C2, C3, and C4 hydrocarbons. In one or more embodiments, the mixed stream 102 may comprise greater than or equal to 70 wt.% C2, C3, and C4 hydrocarbons. For example, the mixed stream 102 may comprise greater than or equal to 70 wt.%, greater than or equal to 75 wt.%, greater than or equal to 80 wt.%, greater than or equal to 85 wt.%, greater than or equal to 90 wt.%, or greater than or equal to 95 wt.% of C2, C3, and C4 hydrocarbons. In one or more embodiments, the C2, C3, and C4 hydrocarbons may comprise olefins and paraffins, including but not limited to ethane, ethylene, propane, propylene, butane, and butene.

[0017] The mixed stream 102 may comprise H2O. In one or more embodiments, the mixed feed stream may comprise at least 1 mol.% H2O. For example, the mixed stream 102 may comprise at least 1 mol.%, at least 2 mol.%, or even at least 5 mol.% H2O. The mixed stream 102 may comprise H2O in vapor form. In one or more embodiments, the mixed stream 102 may be saturated with H2O. As described herein, a stream may be “saturated with H2O” when the vapor pressure of H2O in the stream is at the saturation vapor pressure. “Saturation vapor pressure” is the pressure at which vapor is in thermodynamic equilibrium with its condensed state. Without intending to be bound by theory, the saturation vapor pressure of H2O in the mixed stream 102 may depend on the temperature of the mixed stream 102.

[0018] In one or more embodiments, the mixed stream 102 may be compressed in compressor 202 to form the compressed mixed stream 104. Compressor 202 may be any suitable compressor, including but not limited to, a centrifugal compressor.

[0019] In one or more embodiments, the compressed mixed stream 104 may have a pressure from 75 psig to 300 psig. For example, without limitation the compressed mixed stream 104 may have a pressure from 75 psig to 300 psig, from 100 psig to 300 psig, from 125 psig to 300 psig, from 150 psig to 300 psig, from 175 psig to 300 psig, from 200 psig to 300 psig, from 225 psig to 300 psig, from 250 psig to 300 psig, from 275 psig to 300 psig, from 75 psig to 275 psig, from 75 psig to 250 psig, from 75 psig to 225 psig, from 75 psig to 200 psig, from 75 psig to 175 psig, from 75 psig to 150 psig, from 75 psig to 125 psig, from 75 psig to 100 psig, , or any range or combination of ranges formed from these endpoints.

[0020] In one or more embodiments, the compressed mixed stream 104 may be cooled to form a cooled mixed stream 106. The compressed mixed stream 104 may be cooled by any suitable means. For example, without limitation, the compressed mixed stream 104 may be cooled by ambient cooling or by heat exchange with a coolant stream or another process stream. In one or more embodiments, the compressed mixed stream 104 may be cooled in heat exchanger 212. The compressed mixed stream 104 may be cooled against a cooling medium in heat exchanger 212. The cooling medium may be another process stream or a coolant stream. In one or more embodiments, the cooling medium may comprise air. In some embodiments, the cooling medium may comprise water. The cooling medium may have a temperature from 10 °C to 70 °C. For example, the cooling medium may have a temperature from 10 °C to 70 °C, from 20 °C to 70 °C,from 30 °C to 70 °C, from 40 °C to 70 °C, from 50 °C to 70 °C, from 60 °C to 70 °C, from 10 °C to 60 °C, from 10 °C to 50 °C, from 10 °C to 40 °C, from 10 °C to 30 °C, from 10 °C to 20 °C, or any range or combination of ranges formed from these endpoints.

[0021] In one or more embodiments, the pressure of the compressed mixed stream 104 may be related to the temperature of the cooling medium in heat exchanger 212. Without intending to be bound by theory, the discharge pressure of the compressed mixed stream 104 at the outlet of compressor 202 and the temperature of the cooled mixed stream 106 at the exit of heat exchanger 212 may be selected such that the hydrocarbons in the cooled mixed stream 106 may be about to condense, but not yet condensed. At such temperature and pressure conditions, water may be removed from the cooled mixed stream 106 with minimal loss of hydrocarbons.

[0022] Still referring to FIG. 1, the cooled mixed stream 106 may be separated into at least a first fraction 108 and a second fraction 110. The cooled mixed stream 106 may be separated into the first fraction 108 and the second fraction 110 in any suitable separator 222.

[0023] 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 that are mixed in a process stream from one another. For example, a separator may selectively separate differing chemical species or phases 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, 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.

[0024] In one or more embodiments, separating the cooled mixed stream 106 into at least the first fraction 108 and the second fraction 110 may occur in a flash vessel or other comparable separation device, such that the first fraction 108 is a vapor and the second fraction 110 is a liquid.

[0025] In one or more embodiments, the first fraction 108 may comprise one or more of the C2, C3, and C4 hydrocarbons. In one or more embodiments, the first fraction 108 may comprise at least 30 mol% of the C2, C3, and C4 hydrocarbons included in the mixed stream 102. For example, the first fraction 108 may comprise at least 30 mol%, at least 40 mol%, at least 50 mol%, at least 60 mol%, at least 70 mol%, at least 80 mol%, at least 90 mol%, at least 95 mol%, or even at least 99 mol% of the C2, C3, and C4 hydrocarbons included in the mixed stream 102. The first fraction 108 may comprise H2O. In one or more embodiments, the first fraction 108 may comprise at least 0.01 mol.% H2O. For example, the first fraction 108 may comprise at least 0.01 mol.%, 0.03 mol.%, at least 0.05 mol.%, at least 0.07 mol.%, at least 0.09 mol.%, or even at least 0.1 mol.% H2O. In one or more embodiments, the first fraction 108 may be saturated with H2O at the temperature and pressure conditions of the first fraction 108.

[0026] In one or more embodiments, the first fraction 108 may have a pressure from 150 psig to 300 psig. For example, without limitation the first fraction 108 may have a pressure from 150 psig to 300 psig, from 170 psig to 300 psig, from 190 psig to 300 psig, from 210 psig to 300 psig, from 230 psig to 300 psig, from 250 psig to 300 psig, from 270 psig to 300 psig, from 290 psig to 300 psig, from 150 psig to 280 psig, from 150 psig to 260 psig, from 150 psig to 240 psig, from 150 psig to 220 psig, from 150 psig to 200 psig, from 150 psig to 180 psig, from 150 psig to 160 psig, or any range or combination of ranges formed from these endpoints.

[0027] In one or more embodiments, the first fraction 108 may have a temperature from 10 °C to 70 °C. For example, the cooling medium may have a temperature from 10 °C to 70 °C, from 20 °C to 70 °C, from 30 °C to 70 °C, from 40 °C to 70 °C, from 50 °C to 70 °C, from 60 °C to 70 °C, from 10 °C to 60 °C, from 10 °C to 50 °C, from 10 °C to 40 °C, from 10 °C to 30 °C, from 10 °C to 20 °C, or any range or combination of ranges formed from these endpoints.

[0028] In one or more embodiments, the second fraction 110 may comprise H2O. In one or more embodiments, the second fraction 110 may further comprise hydrocarbons. For example, the second fraction 110 may comprise H2O and one or more of the C2, C3, and C4 hydrocarbons. In one or more embodiments, the second fraction 110 may comprise at least 50 mol%, at least 60 mol%, or at least 70 mol% H2O and one or more of the C2, C3, and C4 hydrocarbons. In some embodiments, the second fraction 110 may comprise H2O and C4+ hydrocarbons. For example, the second fraction 110 may comprise at least 50 mol%, at least 60 mol%, or at least 70 mol%H2O and C4+ hydrocarbons. Without intending to be bound by theory, as the pressure of the cooled mixed stream 106 increases, such as when the cooled mixed stream 106 is at a higher stage of compression, the mole fraction of water in the second fraction 110 may be relatively low.

[0029] Still referring to FIG. 1, the first fraction 108 may be at least partially dried such that at least a portion of the H2O is removed from the first fraction 108 to form a dried first fraction 112 that has a lesser H2O concentration than the first fraction 108. In one or more embodiments, the dried first fraction 112 may comprise less than or equal to 100 ppm H2O. For example, the dried first fraction 112 may comprise less than or equal to 100 ppm, less than or equal to 90 ppm, less than or equal to 80 ppm, less than or equal to 70 ppm, less than or equal to 60 ppm, less than or equal to 50 ppm, less than or equal to 40 ppm, less than or equal to 30 ppm, less than or equal to 20 ppm, less than or equal to 10 ppm, less than or equal to 5 ppm, or even less than or equal to less than or equal to 1 ppm H2O.

[0030] In one or more embodiments, the first fraction 108 may be at least partially dried in a dryer 232. Dryer 232 may be any suitable dryer. In one or more embodiments, the dryer 232 may comprise one or more columns packed with an adsorbent. The adsorbent may comprise any material suitable for removing water from the first fraction 108. In one or more embodiments, the adsorbent may comprise a molecular sieve. In some embodiments, the dryer 232 may comprise multiple packed columns in parallel. In such embodiments, one or more packed columns may be used to dry the first fraction 108 while one or more remaining packed columns may be regenerated.

[0031] Without intending to be bound by theory, the temperature and pressure of the first fraction 108, when introduced to the dryer 232, may approach the temperature and pressure of the dew point of the desired hydrocarbon product, such that a significant portion of the desired hydrocarbon product does not condense. For example, at least 70 mol%, at least 75 mol%, at least 80 mol%, 85 mol%, 90 mol%, 95 mol%, or even 99 mol% of the desired hydrocarbon product may not condense. As described herein, a “dew point” of a hydrocarbon is a point at which that hydrocarbon begins to condense. For example, without limitation, if C3 hydrocarbons are the desired hydrocarbon product, then the temperature and pressure of the first fraction 108 may be adjusted to approach a dew point of the C3 hydrocarbons, such that a significant amount of the C3 hydrocarbons do not condense. Without intending to be bound by theory, if the pressure of the first fraction is too high (e.g. greater than 300 psig), then desired hydrocarbon products maycondense by a significant amount. However, if the pressure of the first fraction 108 is too low (e.g., less than 75 psig) then the volumetric flow of the first fraction 108 may be too great, resulting in a relatively large and expensive dryer 232 to remove a sufficient amount of water from the first fraction 108. For example, if the volumetric flow of the first fraction 108 is too great, then the size of the dryer 232 necessary to remove enough water to produce a dried first fraction 112 having a concentration of less than 100 ppm H2O may be so large that the use of such a dryer may be cost prohibitive.

[0032] Still referring to FIG. 1, the dried first fraction 112 may be compressed to form a compressed dried first fraction 114. The dried first fraction 112 may be compressed in second compressor 204. The second compressor 204 may be any suitable compressor, including but not limited to, a centrifugal compressor.

[0033] In one or more embodiments, the compressed dried first fraction 114 may be cooled to form a cooled dried first fraction 116. The compressed dried first fraction 114 may be cooled by any suitable means. For example, without limitation, the compressed dried first fraction 114 may be cooled by ambient cooling or by heat exchange with a coolant stream or another process stream. In one or more embodiments, the compressed dried first fraction 114 may be cooled in heat exchanger 214. The compressed dried first fraction 114 may be cooled against a cooling medium in heat exchanger 214. The cooling medium may be another process stream or a coolant stream. In one or more embodiments, the cooling medium may comprise air. In some embodiments, the cooling medium may comprise water. The cooling medium may have a temperature from 10 °C to 70 °C. For example, the cooling medium may have a temperature from 10 °C to 70 °C, from 20 °C to 70 °C, from 30 °C to 70 °C, from 40 °C to 70 °C, from 50 °C to 70 °C, from 60 °C to 70 °C, from 10 °C to 60 °C, from 10 °C to 50 °C, from 10 °C to 40 °C, from 10 °C to 30 °C, from 10 °C to 20 °C, or any range or combination of ranges formed from these endpoints.

[0034] Still referring to FIG. 1, in one or more embodiments, the cooled dried first fraction 116 may be passed to a separation unit 300. The separation unit 300 may be any separation unit suitable for separating the dried first fraction into one or more streams. Embodiments of separation units 300 that may be suitable are described in WO 2023 / 183791 Al, the entirety of which is incorporated by reference herein. In one or more embodiments, the cooled dried first fraction 116may be separated into one or more vapor and liquid streams in the separation unit 300. In one or more embodiments, the separation unit 300 may be a cryogenic separation unit. A cryogenic separation unit may comprise one or more heat exchangers 218 positioned within a cold box 500 and one or more separators 310. In one or more embodiments, passing the dried first fraction to the separation unit 300 comprises passing at least a portion of the dried first fraction 112 to one or more heat exchangers 218 positioned within the cold box 500.

[0035] As used in this disclosure, a “cold box” refers to an insulated enclosure that may house one or more system components. The cold box may be insulated to minimize heat transfer between the system components and the environment. In one or more embodiments, one or more heat exchangers 218 may be positioned within a cold box 500. In some embodiments, multiple heat exchangers may be positioned in series within a cold box. The heat exchangers may include a brazed heat exchanger, a shell and tube heat exchanger, double pipe heat exchanger, plate heat exchanger, tubular heat exchanger, fin type heat exchanger, condensers, evaporators, boilers, or combinations thereof.

[0036] In a cryogenic separation process, a process stream, such as the cooled dried first fraction 116, may be cooled by heat exchange with other process streams and / or external sources of refrigeration in the one or more heat exchangers 218 positioned within the cold box 500. The one or more separators 310 may be used to separate more condensable hydrocarbons from less condensable gasses, such as carbon dioxide and hydrogen.

[0037] In one or more embodiments, the method may comprise separating the cooled dried first fraction 116 at a temperature of less than or equal to 0 °C in the separation unit 300. For example, the cooled dried first fraction 116 may be separated at a temperature of less than or equal to 0 °C, less than or equal to -10 °C, less than or equal to -20°C, less than or equal to -30 °C, less than or equal to -40 °C, less than or equal to -50 °C, less than or equal to -60 °C, less than or equal to -70 °C, less than or equal to -80 °C, less than or equal to -90 °C, or even less than or equal to - 100 °C.

[0038] Without intending to be bound by theory, removing H2O from the cooled dried first fraction 116 before separating the cooled dried first fraction 116 in the separation unit 300 at a temperature of less than or equal to 0 °C may prevent H2O from freezing within the separation unit 300. H2O included in the stream introduced to the separation unit 300 may freeze in variouspieces of equipment within the separation unit 300. For example, H2O may freeze in one or more heat exchangers positioned within the cold box in separation unit 300. This may damage the process equipment in the separation unit 300, such as the one or more heat exchangers, or reduce the efficiency of the separation unit 300. Removing water from the stream fed to the separation unit 300 may prevent damage to system components in the separation unit 300 and may improve the efficiency of the separation unit 300.

[0039] In one or more embodiments, the method for processing the mixed stream 102 may further comprise compressing and cooling the cooled dried first fraction 116 upstream of the separation unit 300. Referring now to FIG. 2, the cooled dried first fraction 116a may be passed to separator 224. The cooled dried first fraction 116a may be separated into a light fraction 116b and a heavy fraction 116c. In one or more embodiments, the separator 224 may be a vapor / liquid separator. In such embodiments, the light fraction 116b may be a vapor fraction, and the heavy fraction 116c may be a liquid fraction. The light fraction 116b may be passed to a third compressor 206. The third compressor 206 may be any suitable compressor, including but not limited to, a centrifugal compressor. The light fraction 116b may be compressed in the third compressor 206 to form a compressed fraction 118.

[0040] In one or more embodiments, the compressed fraction 118 may be cooled to form a cooled fraction 120. The compressed fraction 118 may be cooled by any suitable means. For example, without limitation, the compressed fraction 118 may be cooled by ambient cooling or by heat exchange with a coolant stream or another process stream. In one or more embodiments, the compressed fraction 118 may be cooled in heat exchanger 218. The compressed fraction 118 may be cooled against a cooling medium in heat exchanger 218. The cooling medium may be another process stream or a coolant stream. In one or more embodiments, the cooling medium may comprise air. In some embodiments, the cooling medium may comprise water. The cooling medium may have a temperature from 10 °C to 70 °C. For example, the cooling medium may have a temperature from 10 °C to 70 °C, from 20 °C to 70 °C, from 30 °C to 70 °C, from 40 °C to 70 °C, from 50 °C to 70 °C, from 60 °C to 70 °C, from 10 °C to 60 °C, from 10 °C to 50 °C, from 10 °C to 40 °C, from 10 °C to 30 °C, from 10 °C to 20 °C, or any range or combination of ranges formed from these endpoints. Still referring to FIG. 2, the cooled fraction 120 may be passed to the separation unit 300.

[0041] In one or more embodiments, the method for processing the mixed stream 102 may further comprise compressing and cooling the mixed stream upstream of the compressing the mixed stream that forms the compressed mixed stream 104. Referring now to FIG. 3, mixed stream 102 may be passed to compressor 208. Compressor 208 may be upstream of compressor 202. Compressor 208 may be any suitable compressor, including but not limited to, a centrifugal compressor. The mixed stream 102 may be compressed in compressor 208 to form compressed stream 102a.

[0042] In one or more embodiments, compressed stream 102a may be cooled to form cooled stream 102b. The compressed stream 102a may be cooled by any suitable means. For example, without limitation, the compressed stream 102a may be cooled by ambient cooling or by heat exchange with a coolant stream or another process stream. In one or more embodiments, the compressed stream 102a may be cooled in heat exchanger 216. The compressed stream 102a may be cooled against a cooling medium in heat exchanger 216. The cooling medium may be another process stream or a coolant stream. In one or more embodiments, the cooling medium may comprise air. In some embodiments, the cooling medium may comprise water. The cooling medium may have a temperature from 10 °C to 70 °C. For example, the cooling medium may have a temperature from 10 °C to 70 °C, from 20 °C to 70 °C, from 30 °C to 70 °C, from 40 °C to 70 °C, from 50 °C to 70 °C, from 60 °C to 70 °C, from 10 °C to 60 °C, from 10 °C to 50 °C, from 10 °C to 40 °C, from 10 °C to 30 °C, from 10 °C to 20 °C, or any range or combination of ranges formed from these endpoints.

[0043] Still referring to FIG. 3, the cooled stream 102b may then be passed to separator 226.The cooled stream 102b may be separated into a light fraction 102c and a heavy fraction 102d. In one or more embodiments, the separator 226 may be a vapor / liquid separator. In such embodiments, the light fraction 102c may be a vapor fraction, and the heavy fraction 102d may be a liquid fraction. The light fraction 102c may be passed to compressor 202. The light fraction 102c may be compressed to form the compressed mixed stream 104. Compressed mixed stream 104 may be further processed to form the dried first fraction 112, as described hereinabove, and the dried first fraction 112 may be passed to the separation unit 300.

[0044] In one or more embodiments, one or more compressors may be positioned downstream of the dryer 232. For example, as depicted in FIG. 2, compressor 204 and compressor206 are positioned downstream of dryer 232. In one or more embodiments, one or more compressors may be positioned upstream of the dryer 232. For example, as depicted in FIG. 3, compressor 208 and compressor 202 are positioned upstream of the dryer 232. In one or more embodiments, one or more compressors may be positioned upstream of dryer 232 and one or more compressors may be positioned downstream of dryer 232. For example, in one or more embodiments, two compressors (such as compressor 208 and compressor 202 of FIG. 3) may be positioned upstream of dryer 232 and two compressor (such as compressor 204 and compressor 206 of FIG. 2) may be positioned downstream of dryer 232. The number of compressors positioned upstream of dryer 232 is not necessarily limited. For example, in one or more embodiments, 1, 2, 3, 4, or even 5 compressors may be positioned upstream of dryer 232. Likewise the number of compressors positioned downstream of the dryer is not necessarily limited. For example, in one or more embodiments, 1, 2, 3, 4, or even 5 compressors may be positioned downstream of the dryer 232.

[0045] Without intending to be bound by theory, positioning the dryer upstream of the separation unit 300 may allow a single dryer 232 to be used in the process for separating the mixed stream 102. In some convention systems, dryers are included within the separation unit 300. In such conventional systems, one dryer may be used to dry a liquid fraction and a second dryer may be used to dry a vapor fraction of the stream introduced to the separation unit 300. Additionally, in such conventional systems, an oil / water separator is included upstream of the liquid fraction dryer to remove free water in the liquid fraction before it is passed to the liquid fraction dryer. In the embodiments described herein, positioning the dryer 232 upstream of the separation unit 300 may allow a single dryer to be used, in contrast with the multiple dryers used in the conventional systems. This may reduce the capital cost of the systems described herein by allowing for the use of a single dryer and eliminating the need for an oil / water separator upstream of the liquid fraction dryer in conventional systems.

[0046] In one or more embodiments, the methods for processing mixed feed streams described herein may further comprise producing an olefin production system product stream comprising greater than or equal to 70 wt.% of one or more of C2, C3, and C4 hydrocarbons and contacting the olefin production system product stream with water to cool the olefin production product stream to form the mixed stream 102.

[0047] Referring now to FIG. 4, an olefin production system product stream 402 may be produced in an olefin production system 400. The olefin production system product stream 402 may comprise greater than or equal to 70 wt.% of one or more of C2, C3, and C4 hydrocarbons. For example, the olefin production system product stream 402 may comprise greater than or equal to 70 wt.% C2, C3, and C4 hydrocarbons. For example, the mixed stream 102 may comprise greater than or equal to 70 wt.%, greater than or equal to 75 wt.%, greater than or equal to 80 wt.%, greater than or equal to 85 wt.%, greater than or equal to 90 wt.%, or greater than or equal to 95 wt.% of C2, C3, and C4 hydrocarbons. In one or more embodiments, the C2, C3, and C4 hydrocarbons may comprise olefins and paraffins, including but not limited to ethane, ethylene, propane, propylene, butane, and butene.

[0048] Olefin production system 400 may be any system suitable for producing olefins. In one or more embodiments, olefin production system 400 may include a system for dehydrogenating paraffins. For example, without limitation, the olefin production system may include a system for dehydrogenating paraffins as described in U.S. Patent No. 10,590,048, the entirety of which is incorporated by reference herein.

[0049] In one or more embodiments, the olefin production system product stream 402 may have a temperature from 50 °C to 500 °C. For example, the olefin production system product stream 402 may have a temperature from about 50 °C to about 500 °C, from about 100 °C to about 500 °C, from about 150 °C to about 500 °C, from about 200 °C to about 500 °C, from about 250 °C to about 500 °C, from about 300 °C to about 500 °C, from about 450 °C to about 500 °C, from about 50 °C to about 450 °C, from about 50 °C to about 400 °C, from about 50 °C to about 350 °C, from about 50 °C to about 300 °C, from about 50 °C to about 250 °C, from about 50 °C to about 200 °C, from about 50 °C to about 150 °C, from about 50 °C to 100 °C, or any range or combination of ranges formed from these endpoints.

[0050] In one or more embodiments, the olefin production system product stream 402 may be cooled by contacting the olefin production system product stream 402 with water to cool the olefin production system product stream 402. The water may be liquid or vapor water. Still referring to FIG. 4, the olefin production system product stream 402 may be contacted with water in any suitable vessel. For example, the olefin production system product stream 402 may be contacted with water in a quench tower 410. Contacting the olefin production system productstream 402 with water may cool the olefin production system product stream 402 to form the mixed stream 102. Without intending to be bound by theory, cooling the olefin production system product stream 402 by contacting the olefin production system product stream 402 with water may result in a mixed stream 102 comprising C2, C3, and C4 hydrocarbons and H2O as described hereinabove. Furthermore, cooling the olefin production system product stream 402 by contacting the olefin production system product stream 402 with water may saturate the stream with water, resulting in a mixed stream 102 comprising C2, C3, and C4 hydrocarbons that may be saturated with H2O, as described hereinabove.

[0051] Still referring to FIG. 4, in one or more embodiments, the mixed stream 102 may be compressed in compressor 202 and cooled in heat exchanger 212 as described hereinabove. The cooled mixed stream 106 may be separated into the first fraction 108 and the second fraction 110. In one or more embodiments, at least a portion of the second fraction 110 may be recycled to the quench tower 410. The second fraction 110 may supply at least a portion of the water used in the quench tower 410. It should be noted that in one or more embodiments the quench tower 410 may be fluidly connected to additional sources of water.EXAMPLES

[0052] Various embodiments of the processes and systems for separating a mixed feed stream will be further clarified in the following Examples. The Examples are illustrative in nature, and should not be understood to limit the subject matter of the present disclosure.Example 1

[0053] Example 1 was conducted using an integrated process model in Aspen plus for the compression system depicted in FIG. 1. Table 1 shows temperatures, pressures, and mole fractions of streams depicted in FIG. 1. The numbering of the streams included in Table 1 is consistent with the numbering of the streams in FIG. 1 and the numbering used throughout the detailed description.Table 1.Table 1 cont.

[0054] As shown in Example 1, the water may be removed from a mixed stream 102 using a separator 222 and a dryer 232, by the methods described hereinabove. As shown in Example 1, substantially all of the water present in the mixed stream 102 was removed by the separator 222 and the dryer 232. Specifically, the cooled dried first fraction 116 comprised 0.0 mol% water.

[0055] 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.”

[0056] 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 of” or “consists essentially of” that second component. Additionally, the term “consisting essentially of” is used in this disclosure to refer to quantitative values that do not materially affect the basic and novel characteristic(s) of the disclosure. For example, a chemical composition “consisting essentially of’ a particular chemical constituent or group of chemical constituents should be understood to mean that the composition includes at least about 99.5% of a that particular chemical constituent or group of chemical constituents.

[0057] 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.

[0058] 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.

Claims

CLAIMS1. A method for processing a mixed stream, the method comprising: compressing the mixed stream to form a compressed mixed stream, wherein the mixed stream comprises greater than or equal to 70 wt.% of one or more of C2, C3, and C4 hydrocarbons, and wherein the mixed stream comprises H2O; cooling the compressed mixed stream to form a cooled mixed stream; separating the cooled mixed stream into at least: a first fraction comprising one or more of the C2, C3, and C4 hydrocarbons andH2O; and a second fraction comprising one or more of the C2, C3, and C4 hydrocarbons andH2O; and at least partially drying the first fraction such that at least a portion of the H2O is removed from the first fraction to form a dried first fraction that has a lower H2O concentration than the first fraction; compressing the dried first fraction to form a compressed dried first fraction; cooling the compressed dried first fraction to form a cooled dried first fraction; and passing the cooled dried first fraction to a separation unit.

2. The method of claim 1, further comprising compressing and cooling the cooled dried first fraction upstream of the separation unit.

3. The method of claim 1 or 2, further comprising compressing and cooling the mixed stream upstream of the compressing of the mixed stream that forms the compressed mixed stream.

4. The method of any one of claims 1 to 3, wherein passing the cooled dried first fraction to the separation unit comprises passing at least a portion of the cooled dried first fraction to one or more heat exchangers positioned within a cold box.

5. The method of any one of claims 1 to 4, further comprising separating the cooled dried first fraction at a temperature of less than or equal to 0 °C.

6. The method of any one of claims 1 to 5, further comprising: producing an olefin production system product stream comprising the greater than or equal to 70 wt.% of one or more of C2, C3, and C4 hydrocarbons; and contacting the olefin production system product stream with water to cool the olefin production system product stream and form the mixed stream.

7. The method of any one of claims 1 to 6, wherein the mixed stream comprises at least 1 mol.% of H2O.

8. The method of any one of claims 1 to 7, wherein the first fraction comprises at least 0.01 mol.% H2O.

9. The method of any one of claims 1 to 8, wherein the second fraction comprises at least 50 mol% H2O and one or more of the C2, C3, and C4+ hydrocarbons.

10. The method of any one of claims 1 to 9, wherein the second fraction comprises at least 50 mol.% H2O and C4+ hydrocarbons.

11. The method of any one of claims 1 to 10, wherein the dried first fraction comprises less than or equal to 100 ppm H2O.

12. The method of any one of claims 1 to 11, wherein the separating of the cooled mixed stream is by a flash vessel such that the first fraction is a vapor and the second fraction is a liquid.

13. The method of any one of claims 1 to 12, wherein a pressure of the first fraction is from75 psig to 300 psig.

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