Processes for condensing one or more hydrocarbons in a purge gas

Abstract

Processes for condensing one or more hydrocarbons. In some embodiments, the process can include obtaining a liquified ethylene feed. The liquified ethylene feed can be expanded to produce an expanded ethylene feed. The expanded ethylene feed can be at a pressure and a temperature sufficient to maintain the ethylene in a liquid phase. Heat can be indirectly transferred from a purge gas obtained from an olefin polymerization process to the expanded ethylene feed to produce a heated ethylene feed and a cooled purge gas. The cooled purge gas can include one or more condensed hydrocarbon molecules and one or more gaseous hydrocarbon molecules. At least a portion of the heated ethylene feed can be introduced into a polymerization reactor of the olefin polymerization process.

Description

PROCESSES FOR CONDENSING ONE OR MORE HYDROCARBONS IN A PURGE GASCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to and the benefit of U.S. Provisional Application No.63 / 751,392 having a filing date of January 30, 2025, the disclosure of which is incorporated herein by reference in its entirety.FIELD

[0002] This disclosure relates to processes for condensing one or more hydrocarbons in a purge gas. More particularly, such embodiments relate to processes for transferring heat from a purge gas obtained from an olefin polymerization process to a liquified ethylene feed to produce a heated ethylene feed and a cooled purge gas that includes one or more condensed hydrocarbon molecules and one or more gaseous hydrocarbon molecules.BACKGROUND

[0003] Polyethylene plants vent purge gases that remove valuable components, e.g., ethylene, propylene, butene, butane, isobutene, pentane, isopentane, hexane, and / or hexene, from the system to maintain a desired pressure within the system. Condensing and returning the valuable components to the system can save on material costs, operating costs, emissions, and capital.

[0004] One process that can condense such valuable components includes expanding a supercritical ethylene feed to reduce the temperature of ethylene feed that can then be used to condense the vented valuable components. One drawback of this process is that the pressure of the supercritical ethylene feed can only be reduced down to reactor feed pressure and, therefore, the temperature the feed can be reduced to has a lower limit. Additional refrigeration machines could be added to further reduce the temperature, but that would increase the capital and operating costs. Another process that allows for further pressure reductions and colder temperatures utilizes an expander / re -compressor, but again the addition of the expander / re-compressor increases the capital and operating costs.

[0005] There is a need, therefore, for improved processes for condensing one or more hydrocarbons in a purge gas. This disclosure satisfies this and other needs.SUMMARY

[0006] Processes for condensing one or more hydrocarbons are provided. In some embodiments, the process can include obtaining a liquified ethylene feed. The liquifiedethylene feed can be expanded to produce an expanded ethylene feed. The expanded ethylene feed can be at a pressure and a temperature sufficient to maintain the ethylene in a liquid phase. Heat can be indirectly transferred from a purge gas obtained from an olefin polymerization process to the expanded ethylene feed to produce a heated ethylene feed and a cooled purge gas. The cooled purge gas can include one or more condensed hydrocarbon molecules and one or more gaseous hydrocarbon molecules. At least a portion of the heated ethylene feed can be introduced into a polymerization reactor of the olefin polymerization process.

[0007] In other embodiments, the process for upgrading one or more hydrocarbons can include steam cracking a hydrocarbon to produce a steam cracker effluent. An ethylene feed can be separated from the steam cracker effluent. The ethylene feed can be compressed and cooled to produce a liquified ethylene feed. The liquified ethylene feed can be expanded to produce an expanded ethylene feed. The expanded ethylene feed can be at a pressure and a temperature sufficient to maintain the ethylene in a liquid phase. Heat can be indirectly transferred from a purge gas obtained from an olefin polymerization process to the expanded ethylene feed to produce a heated ethylene feed and a cooled purge gas. The cooled purge gas can include one or more condensed hydrocarbon molecules and one or more gaseous hydrocarbon molecules. At least a portion of the heated ethylene feed can be introduced into a polymerization reactor of the olefin polymerization process.BRIEF DESCRIPTION OF THE DRAWINGS

[0008] FIG. 1 depicts an illustrative purge gas recovery unit for condensing one or more hydrocarbons in a purge gas by indirectly transferring heat from the purge gas to an expanded ethylene feed within one or more indirect heat exchangers, according to one or more embodiments described.

[0009] FIG. 2 depicts another illustrative purge gas recovery unit for condensing one or more hydrocarbons in a purge gas that is similar to the system shown in FIG. 1, but further includes one or more additional indirect heat exchangers configured to transfer heat from a first cooled purge gas to a liquified ethylene, according to one or more embodiments described.

[0010] FIG. 3 depicts another illustrative purge gas recovery unit for condensing one or more hydrocarbons in a purge gas that is similar to the system shown in FIG. 2, but further includes one or more third indirect heat exchanger configured to transfer heat from the liquified ethylene feed to a fluid to produce a chilled liquified ethylene feed that is introduced into the one or more second heat exchangers, according to one or more embodiments described.

[0011] FIG. 4 depicts another illustrative purge gas recovery unit for condensing one or more hydrocarbons in a purge gas that is similar to the system shown in FIG. 3 but does not include the one or more second indirect heat exchangers, according to one or more embodiments described.

[0012] FIG. 5 depicts an illustrative system for producing a steam cracker effluent, obtaining an ethylene feed therefrom, utilizing the ethylene feed to cool a purge gas vented from an olefin polymerization system, and polymerizing at least a portion of the ethylene feed in a polymerization reactor after cooling the purge gas, according to one or more embodiments described.DETAILED DESCRIPTION

[0013] Various specific embodiments, versions and examples of the invention will now be described, including preferred embodiments and definitions that are adopted herein for purposes of understanding the claimed invention. While the following detailed description gives specific preferred embodiments, those skilled in the art will appreciate that these embodiments are exemplary only, and that the invention may be practiced in other ways. For purposes of determining infringement, the scope of the invention will refer to any one or more of the appended claims, including their equivalents, and elements or limitations that are equivalent to those that are recited. Any reference to the “invention" may refer to one or more, but not necessarily all, of the inventions defined by the claims.

[0014] In this disclosure, a process is described as comprising at least one “step.” It should be understood that each step is an action or operation that may be carried out once or multiple times in the process, in a continuous or discontinuous fashion. Unless specified to the contrary or the context clearly indicates otherwise, multiple steps in a process may be conducted sequentially in the order as they are listed, with or without overlapping with one or more other steps, or in any other order, as the case may be. In addition, one or more or even all steps may be conducted simultaneously with regard to the same or different batch of material. For example, in a continuous process, while a first step in a process is being conducted with respect to a raw material just fed into the beginning of the process, a second step may be carried out simultaneously with respect to an intermediate material resulting from treating the raw materials fed into the process at an earlier time in the first step. Preferably, the steps are conducted in the order described.

[0015] Unless otherwise indicated, all numbers indicating quantities in this disclosure are to be understood as being modified by the term “about” in all instances. It should also beunderstood that the precise numerical values used in the specification and claims constitute specific embodiments. Efforts have been made to ensure the accuracy of the data in the examples. However, it should be understood that any measured data inherently contains a certain level of error due to the limitation of the technique and / or equipment used for acquiring the measurement.

[0016] Certain embodiments and features are described herein using a set of numerical upper limits and a set of numerical lower limits. It should be appreciated that ranges including the combination of any two values, e.g., the combination of any lower value with any upper value, the combination of any two lower values, and / or the combination of any two upper values are contemplated unless otherwise indicated.

[0017] The indefinite article “a” or “an,” as used herein, means “at least one” unless specified to the contrary or the context clearly indicates otherwise. Thus, embodiments using “a reactor” or “a conversion zone” include embodiments where one or two or more reactors or conversion zones are used, unless specified to the contrary or the context clearly indicates that only one reactor or conversion zone is used.

[0018] In this disclosure, “A, B, ... or a combination thereof’ means “A, B, ... or any combination of any two or more of A, B, ...” and “A, B, ..., or a mixture thereof’ means “A, B, ..., or any mixture of any two or more of A, B, ...”.

[0019] The term “hydrocarbon” means (i) any compound consisting of hydrogen and carbon atoms or (ii) any mixture of two or more such compounds in (i). The term “Cn hydrocarbon,” where n is a positive integer, means (i) any hydrocarbon compound comprising carbon atom(s) in its molecule at the total number of n, or (ii) any mixture of two or more such hydrocarbon compounds in (i). Thus, a C2 hydrocarbon can be ethane, ethylene, acetylene, or mixtures of at least two of these compounds at any proportion. A “Cm to Cn hydrocarbon” or “Cm-Cn hydrocarbon,” where m and n are positive integers and m < n, means any of Cm, Cm+1, Cm+2, ..., Cn-1, Cn hydrocarbons, or any mixtures of two or more thereof. Thus, a “C2 to C3 hydrocarbon” or “C2-C3 hydrocarbon” can be any of ethane, ethylene, acetylene, propane, propene, propyne, propadiene, cyclopropane, and any mixtures of two or more thereof at any proportion between and among the components. A “saturated C2-C3 hydrocarbon” can be ethane, propane, cyclopropane, or any mixture thereof of two or more thereof at any proportion. A “Cn+ hydrocarbon” means (i) any hydrocarbon compound comprising carbon atom(s) in its molecule at the total number of at least n, or (ii) any mixture of two or more such hydrocarbon compounds in (i). A “Cn- hydrocarbon” means (i) any hydrocarbon compound comprising carbon atoms in its molecule at the total number of at most n, or (ii) any mixture of two or moresuch hydrocarbon compounds in (i). A “Cm hydrocarbon stream” means a hydrocarbon stream consisting essentially of Cm hydrocarbon(s). A “Cm-Cn hydrocarbon stream” means a hydrocarbon stream consisting essentially of Cm-Cn hydrocarbon(s).

[0020] The term “crude” means whole crude oil as it flows from a wellhead, a production field facility, a transportation facility, or other initial field processing facility, optionally including crude that has been processed by a step of desalting, treating, and / or other steps as may be necessary to render it acceptable for conventional distillation in a refinery. Crude is presumed to contain resid. The term “crude fraction” means a hydrocarbon fraction obtained via the fractionation of crude. Non-limiting examples of crudes can be or can include, but are not limited to, Tapis, Murban, Arab Light, Arab Medium, and / or Arab Heavy.

[0021] The term “resid” refers to a bottoms cut of a crude distillation process that contains non-volatile components. Resids are complex mixtures of heavy petroleum compounds otherwise known in the art as residuum or residual or pitch. Atmospheric resid is the bottoms product produced from atmospheric distillation of crude where a typical endpoint of the heaviest distilled product is nominally 343°C, and is referred to as 343°C resid. The term “nominally,” as used herein, means that reasonable experts may disagree on the exact cut point for these terms, but by no more than + / - 55.6°C preferably no more than + / - 27.8°C. Vacuum resid is the bottoms product from a distillation column operated under vacuum where the heaviest distilled product can be nominally 566°C, and is referred to as 566°C resid.

[0022] The term “hydrocarbon-containing feed” refers to a composition that includes one or more hydrocarbons. Illustrative hydrocarbon-containing feeds can be or can include, but are not limited to, crude, gas oils, heating oil, jet fuel, diesel, kerosene, gasoline, coker naphtha, steam cracked naphtha, catalytically cracked naphtha, hydrocrackate, reformate, raffinate reformate, Fischer-Tropsch liquids and / or gases, natural gasoline, distillate, virgin naphtha, atmospheric pipestill bottoms, vacuum pipestill streams such as vacuum pipestill bottoms and wide boiling range vacuum pipestill naphtha to gas oil condensates, non-virgin hydrocarbons from refineries, vacuum gas oils, heavy gas oil, naphtha contaminated with crude, atmospheric residue, heavy residue, a C residue admixture, naphtha / residue admixture, hydrocarbon gases / residue admixture, hydrogen / residue admixtures, waxy residues, gas oil / residue admixture, relatively light alkanes, e.g., ethane, propane, butane, and / or pentane, recycle streams that can include ethane, propane, ethylene, propylene, butadiene, or a mixture thereof, one or more condensates, fractions thereof, or any mixture thereof.

[0023] A "polymer" has two or more of the same or different repeating units / mer units or simply units. A "homopolymer" is a polymer having repeating units that are the same. A"copolymer" is a polymer having two or more repeating units that are different from each other. As such, the term “copolymer” includes terpolymers (a polymer having three units that are different from each other), tetrapolymers (a polymer having four units that are different from each other), and so on. The term "different" as used to refer to units indicates that the units differ from each other by at least one atom and / or are different isomerically.

[0024] The term “aqueous fluid” refers to a composition that includes water in the liquid phase, water in the vapor phase, or a mixture of water in the liquid phase and water in the vapor phase.

[0025] As used herein, in reference to Periodic Table “Groups” of Elements, the “new” numbering scheme for the Periodic Table Groups are used as in the CRC Handbook of Chemistry and Physics (David R. Lide, ed., CRC Press 81st ed. 2000).

[0026] FIG. 1 depicts an illustrative purge gas recovery unit 100 for condensing one or more hydrocarbons in a purge gas in line 1000 by indirectly transferring heat from the purge gas in line 1000 to an expanded liquid ethylene feed in line 1048 within one or more indirect heat exchangers 1050, according to one or more embodiments. A cooled purge gas via line 1002 and a heated ethylene feed via line 1052 can recovered from the indirect heat exchanger 1050.

[0027] In some embodiments, the purge gas in line 1000 can be obtained from an olefin polymerization process, e.g., a polyethylene or polypropylene polymerization process. As such, in some embodiments, the purge gas in line 1000 can have a concentration of one or more unreacted monomers, unreacted comonomers, impurities, and / or catalytic components in an amount of 500 ppmw or greater. The purge gas in line 1000 can include, but is not limited to, H2, one or more C1-C10 linear alkanes, one or more C4-C10 branched alkanes, one or more C2-C10 alkenes, N2, or any mixture thereof. In some embodiments, the purge gas in line 1000 can include one or more of H2, methane, ethane, ethylene, propane, propylene, 2-methyl propane, butane, isobutane, 1 -butene, pentane, isopentane, neopentane, pentene, hexane, 2-methylepentane, 3 -methylpentane, 2, 2, -dimethylbutane, 2,3 -dimethylbutane, 1 -hexene, heptane, 2-methylhexane, 3 -methylpentane, 2,2-dimethylpentane, 2,3-dimethylpentane, octane, nonane, decane, N2, or any mixture thereof.

[0028] In some embodiments, the purge gas in line 1000 can include 500 ppmw or greater of hydrocarbons. In at least one embodiment, the purge gas in line 1000 can include 0 % v / v to 100 % v / v of one or more unreacted monomers, unreacted comonomers, impurities, or catalytic components, e.g., 0 % v / v to 20 % v / v, 20 % v / v to 40 % v / v, 40 % v / v to 60 % v / v, 60 % v / v to 80 % v / v, or 80 % v / v to 100 % v / v. For example, the purge gas in line 1000 can include 15 % v / v to 35 % v / v ethene, 2 % v / v to 4 % v / v ethane, 10 % v / v to 40 % v / v of C4 compounds(e.g., butane, 1 -butene, 2-butene, 2methyl propane, etc.); 2 % v / v to 20 % v / v of Cs compounds (e.g., pentane, 1-pentene, 2-pentene, isopentane (i.e., 2 -methyl butane), etc.); 2 % v / v to 20 % v / v of C6 compounds (e.g., 1-hexene, 2-hexene, hexane, 2-methylpentane, etc.), or any mixture thereof. In at least one embodiment, the purge gas in line 1000 can include about 4 % v / v, 6 % v / v, 10 % v / v, or 15 % v / v to about 20 % v / v, 25 % v / v, 30 % v / v, 35 % v / v, or 40 % v / v of nitrogen.

[0029] An ethylene feed via line 1010 can be introduced into one or more compressors or compression stages 1012 to produce a compressed ethylene feed in line 1014. In some embodiments, the compressor 1012 can compress the ethylene feed in line 1010 in a single stage, two stages, three stages, four stages, or more. In some embodiments, the ethylene feed in line 1010 can be separated from a pyrolysis effluent, e.g., a steam cracker effluent. The ethylene feed in line 1010 can be ethylene or can be composed substantially of ethylene. In some embodiments, the ethylene feed in line 1010 can include at least 99 mol%, at least 99.3 mol%, at least 99.5 mol%, at least 99.7 mol%, or at least 99.9 mol% of ethylene. Other components that can be present in the ethylene feed can be or can include, but are not limited to, hydrogen, methane, ethane, or any mixture thereof.

[0030] The compressed ethylene feed via line 1014 and a heat transfer medium via line 1016 can be introduced into one or more indirect heat exchangers 1018. Heat can be transferred from the compressed ethylene feed to the heat transfer medium within the indirect heat exchanger 1018 to produce a liquified ethylene feed in line 1020 and a heated heat transfer medium in line 1022. In some embodiments, the heat transfer medium in line 1016 can be or can include, but is not limited to, ethane, ethylene, propane, propylene, or any mixture thereof.

[0031] The ethylene feed in line 1010 can be at a temperature in a range from -50°C, -45°C, -40°C, or -35°C to -30°C, -25°C, or -20°C. The liquified ethylene feed in line 1020 can be at a pressure in a range from 1,100 kPag, 1,170 kPag, 1,300 kPag, 1,400 kPag, 1,500 kPag, or 1,600 kPag to 1,700 kPag, 1,800 kPag, 1,900 kPag, 2,000 kPag, 2,070 kPag, or 2,150 kPag. For example, in some embodiments, the liquified ethylene feed in line 1020 can be at a temperature of -46°C to -25°C and a pressure of 1,170 kPag to 2,070 kPag.

[0032] In some embodiments, the liquified ethylene feed via line 1020 can be introduced into a product dram 1024 and can then via line 1026 be introduced to one or more pumps 1028 to produce a liquified ethylene feed in line 1030 that can be at a greater pressure than the liquified ethylene feed in line 1026. In other embodiments, the liquified ethylene via line 1020 can be introduced directly to the pump 1028. Said another way, the liquified ethylene feed in line 1020 and / or 1026 can be pressurized via the pump 1028.

[0033] As shown in FIG. 1, a first portion of the liquified ethylene feed can be conveyed via line 1032 to an expansion valve 1046 and a second portion of the liquified ethylene feed can be conveyed to one or more indirect heat exchangers 1060. When the liquified ethylene feed is in line 1030, the liquified ethylene feed in lines 1030, 1032, and 1034 can be at a temperature in a range from -50°C, -45°C, -40°C, or -35°C to -30°C, -25°C, or -20°C. In some embodiments, the liquified ethylene feed in line 1030, 1032, and 1034 can be at a pressure in a range from 4,750 kPag, 4,830 kPag, 4,900 kPag, 6,000 kPag, 8,000 kPag, or 9,000 kPag to 10,000 kPag, 11,000 kPag, 12,000 kPag, 13,000 kPag, 13,800 kPag, or 14,500 kPag. For example, in some embodiments, the liquified ethylene feed in line 1030, 1032, and 1034 can be at a temperature of -46°C to -25°C and a pressure of 4,960 kPag to 13,800 kPag. In some embodiments, the liquified ethylene feed in line 1030, 1032, and 1034 can be under supercritical conditions. Said another way, in some embodiments, the liquified ethylene feed in line 1030, 1032, and 1034 can be a supercritical ethylene feed.

[0034] The first portion of the liquified ethylene via line 1032 can be introduced into the expansion valve 1046 to produce the expanded liquid ethylene feed in line 1048. The second portion of the liquified ethylene feed via line 1034 and a heated heat transfer medium, e.g., an aqueous fluid, via line 1058 can be introduced into the indirect heat exchanger 1060 to produce a cooled heat transfer medium in line 1062 and a heated ethylene feed in line 1064. The heated ethylene feed in line 1064 can be in the vapor phase. Said another way, 100% of the ethylene in the heated ethylene feed in line 1064 can be in the vapor phase.

[0035] The expanded liquid ethylene feed in line 1048 can be at a temperature and a pressure sufficient to maintain the ethylene in the liquid phase. The expanded liquid ethylene feed in line 1048 can be at a temperature in a range from -50°C, -45°C, -40°C, or -35°C to -30°C, -25°C, or -20°C. The expanded liquid ethylene feed in line 1048 can be at a pressure in a range from 1,300 kPag, 1,650 kPag, 1,900 kPag, 2,150 kPag, 2,070 kPag, 2,200 kPag, or 2,500 kPag to 2,800 kPag, 3,100 kPag, 3,300 kPag 3,700 kPag, 4,000 kPag, 4,300 kPag. For example, in some embodiments, the expanded liquid ethylene feed in line 1048 can be at a temperature in a range from -46°C to -25°C and a pressure in a range from 2,070 kPag to 4,960 kPag. A temperature of the expanded liquid ethylene feed in line 1048 and the liquified ethylene feed in line 1032 can be the same. The expanded liquid ethylene feed in line 1048 can be in the liquid phase. Said another way, 100% of the ethylene in the expanded liquid ethylene feed in line 1048 can be in the liquid phase.

[0036] As noted above, the purge gas in line 1000 and the expanded liquid ethylene feed in line 1048 can be introduced into the indirect heat exchanger 1050 to produce the heatedethylene feed in line 1052 and the cooled purge gas in line 1002. The purge gas in line 1000 can be at a temperature in a range from 0°C, 10°C, 20°C, 30°C, 45°C, 60°C, or 80°C to 100°C, 110°C, 120°C, 125°C, 130°C, or 135°C. The purge gas in line 1000 can be at a pressure in a range from 500 kPag, 700 kPag, 800 kPag, or 900 kPag to 1,000 kPag, 1,100 kPag, 1,200 kPag, 1,300 kPag, 1,400 kPag, or 1,500 kPag. For example, in some embodiments, the purge gas can be at a temperature of 15°C to 25°C and a pressure of 900 kPag to 1,100 kPag.

[0037] The heated ethylene feed in line 1052 can be at a temperature in a range from -30°C, -27°C, -25°C, -20°C, or -15°C to -10°C, -5°C, 0°C 5°C, 10°C, 12°C, or 15°C. The heated ethylene feed in line 1052 can be at a pressure in a range from 1,300 kPag, 1,500 kPag, 1,750 kPag, 1,900 kPag, 2,050 kPag. 2,070 kPag, 2,200 kPag, 2,500 kPag, 2,800 kPag, 3,100 kPag, or 3,300 kPag to 3,700 kPag, 4,000 kPag, 4,300 kPag, 4,700 kPag, 4,800 kPag, 4,960 kPag, or 5,050 kPag. For example, in some embodiments, the heated ethylene feed in line 1052 can be at a temperature in a range from -30°C to -9°C and a pressure of 2,070 kPag to 4,960 kPag. The heated ethylene feed in line 1052 can be in the vapor phase. Said another way, 100% of the ethylene in the heated ethylene feed in line 1052 can be in the vapor phase.

[0038] The heated ethylene feed in line 1052 can be combined with the heated ethylene feed in line 1064 to produce a mixed or combined ethylene feed in line 1066. In some embodiments, at least a portion of the mixed or combined ethylene feed via line 1066 can be introduced into the olefin polymerization process, e.g., a polymerization reactor, from which the purge gas in line 1000 was obtained.

[0039] The cooled purge gas in line 1002 can be at a temperature in a range from -50°C, -47°C, -45°C, -43°C, or -40°C to -37°C, -35°C, -33°C, -30°C, -27°C, -25°C, or -20°C. The cooled purge gas in line 1002 can be at a pressure in a range from 500 kPag, 700 kPag, 800 kPag, 900 kPag, 1,000 kPag, 1,100 kPag, 1,200 kPag, 1,300 kPag, 1,400 kPag, or 1,500 kPag to 1,700 kPag, 2,000 kPag, 2,300 kPag, 2,500 kPag, 2,700 kPag, or 3,000 kPag. For example, in some embodiments, the cooled purge gas can be at a temperature of -45°C to -26°C and a pressure of 900 kPag to 1,100 kPag.

[0040] The cooled purge gas via line 1002 can be introduced into a vent recovery drum 1004. A gaseous or vapor phase overhead via line 1006 and a condensed or liquid phase bottoms via line 1008 can be recovered from the vent recovery drum 1004. In some embodiments, the gaseous or vapor phase overhead in line 1006 can include Ffc, N2, one or more C1-C10 linear alkanes, one or more C4-C10 branched alkanes, one or more C2-C10 alkenes, or any mixture thereof. In some embodiments, the condensed or liquid phase bottoms in line 1008 can include one or more condensed C1-C10 linear alkanes, one or more condensed C4-C10 branched alkanes,one or more condensed C2-C10 alkenes, or any mixture thereof. In some embodiments, at least a portion of the condensed or liquid phase bottoms in line 1008 can be recycled back to the olefin polymerization process, e.g., to a polymerization reactor. In some embodiments, a majority of the condensed or liquid phase bottoms in line 1008 can be recycled back to the olefin polymerization process, e.g., to a polymerization reactor.

[0041] FIG. 2 depicts another illustrative purge gas recovery unit 200 for condensing one or more hydrocarbons in a purge gas in line 2000 that is similar to the purge gas recovery unit 100 shown in FIG. 1 , but further includes one or more additional indirect heat exchangers 2040 configured to transfer heat from a first cooled purge gas in line 2001 to a liquified ethylene feed in line 2032, according to one or more embodiments. A cooled or second cooled purge gas via line 2002 and a warmed liquified ethylene feed via line 2042 can be recovered from the indirect heat exchanger 2040. The purge gas in line 2000 can have the same composition and be within the same temperature range and the same pressure range as the purge gas in line 1000 in the purge gas recovery unit 100 described above with reference to FIG. 1.

[0042] An ethylene feed via line 2010 can be introduced into one or more compressors or compression stages 2012 to produce a compressed ethylene feed in line 2014. In some embodiments, the compressor 2012 can compress the ethylene feed in line 2010 in a single stage, two stages, three stages, four stages, or more. In some embodiments, the ethylene feed in line 2010 can be separated from a pyrolysis effluent, e.g., a steam cracker effluent. As such, the ethylene feed in line 2010 can have the same composition as the ethylene feed in line 1010 in the purge gas recovery unit 100 described above with reference to FIG. 1.

[0043] The compressed ethylene feed via line 2014 and a heat transfer medium via line 2016 can be introduced into one or more indirect heat exchangers 2018. Heat can be transferred from the compressed ethylene feed to the heat transfer medium within the indirect heat exchanger 2018 to produce a liquified ethylene feed via line 2020 and a heated heat transfer medium via line 2022. The heat transfer medium in line 2016 can be the same as the heat transfer medium in line 1016 in the purge gas recovery unit 100 described above with reference to FIG. 1.

[0044] When the ethylene feed is present in line 2010, the liquified ethylene feed in line 2020 can be at a temperature in a range from -50°C, -45°C, -40°C, or -35°C to -30°C, -25°C, or -20°C. The liquified ethylene feed in line 2020 can be at a pressure in a range from 1,100 kPag, 1,170 kPag, 1,300 kPag, 1,400 kPag, 1,500 kPag, or 1,600 kPag to 1,700 kPag, 1,800 kPag, 1,900 kPag, 2,000 kPag, 2,070 kPag, or 2,150 kPag. For example, in some embodiments, theliquified ethylene feed in line 2020 can be at a temperature of -46°C to -25°C and a pressure of 1,170 kPag to 2,070 kPag.

[0045] In some embodiments, the liquified ethylene feed via line 2020 can be introduced into a product drum 2024 and can then via line 2026 be introduced to one or more pumps 2028 to produce a liquified ethylene feed in line 2030 that can be at a greater pressure than the liquified ethylene feed in line 2026. In other embodiments, the liquified ethylene feed via line 2020 can be introduced directly to the pump 2028. Said another way, the liquified ethylene feed in line 2020 and / or 2026 can be pressurized via the pump 2028.

[0046] As shown in FIG. 2, a first portion of the liquified ethylene feed via line 2032 and the first cooled purge gas via line 2001 can be conveyed to one or more indirect heat exchangers 2040 to produce a warmed liquified ethylene feed via line 2042 and a cooled or second cooled purge gas via line 2002. A second portion of the liquified ethylene feed can be conveyed via line 2034 to one or more indirect heat exchangers 2060. The second portion of the liquified ethylene via line 2034 and a heated heat transfer medium, e.g., an aqueous fluid, via line 2058 can be introduced into the indirect heat exchanger 2060 to produce a cooled heat transfer medium in line 2062 and a heated ethylene feed in line 2064. The heated ethylene feed in line 2064 can be in the vapor phase. Said another way, 100% of the ethylene in the heated ethylene feed in line 2064 can be in the vapor phase.

[0047] When the liquified ethylene feed is in line 2030, the liquified ethylene feed in lines 2030, 2032, and 2034 can be at a temperature in a range from -50°C, -45°C, -40°C, or -35°C to -30°C, -25°C, or -20°C. In some embodiments, the liquified ethylene feed in line 2030, 2032, and 2034 can be at a pressure in a range from 4,750 kPag, 4,830 kPag, 4,900 kPag, 6,000 kPag, 8,000 kPag, or 9,000 kPag to 10,000 kPag, 11,000 kPag, 12,000 kPag, 13,000 kPag, 13,800 kPag, or 14,500 kPag. For example, in some embodiments, the liquified ethylene feed in line 2030, 2032, and 2034 can be at a temperature of -46°C to -25°C and a pressure of 4,960 kPag to 13,800 kPag. In some embodiments, the liquified ethylene feed in line 2030, 2032, and 2034 can be under supercritical conditions. Said another way, in some embodiments, the liquified ethylene feed in line 2030, 2032, and 2034 can be a supercritical ethylene feed.

[0048] The first cooled purge gas in line 2001 can be at a temperature in a range from -30°C, -27°C, -25°C, -20°C, or -15°C to -10°C, -5°C, 0°C, 5°C, 10°C, 12°C, or 15°C. The first cooled purge gas in line 2001 can be at a pressure in a range from 500 kPag, 700 kPag, 800 kPag, or 900 kPag to 1,000 kPag, 1,100 kPag, 1,200 kPag, 1,300 kPag, 1,400 kPag, or 1,500 kPag. For example, in some embodiments, the first cooled purge gas in line 2001 can be at a temperature of -26°C to 9°C and a pressure of 900 kPag to 1,100 kPag.

[0049] When the liquified ethylene feed is in line 2032, the wanned liquified ethylene feed in line 2042 can be at a temperature in a range from -43°C, -41 °C, -37°C, -35°C, -33°C, -30°C, -27°C, -25°C, -20°C, or -15°C to -10°C, -5°C, 0°C 5°C, 10°C, 12°C, or 15°C. The warmed liquified ethylene feed in line 2042 can be at a pressure in a range from 4,750 kPag, 4,830 kPag, 4,900 kPag, 6,000 kPag, 8,000 kPag, or 9,000 kPag to 10,000 kPag, 11,000 kPag, 12,000 kPag, 13,000 kPag, 13,800 kPag, or 14,500 kPag. For example, in some embodiments, the warmed liquified ethylene feed in line 2042 can be at a temperature of -26°C to 9°C and a pressure of 4,960 kPag to 13,800 kPag. In some embodiments, the warmed liquified ethylene feed in line 2042 can be under supercritical conditions. Said another way, in some embodiments, the warmed liquified ethylene feed in line 2042 be a supercritical ethylene feed.

[0050] The cooled or second cooled purge gas in line 2002 can be at a temperature in a range from -50°C, -47°C, -45°C, -43°C, or -40°C to -37°C, -35°C, -33°C, -30°C, -27°C, -25°C, or -20°C. The cooled or second cooled purge gas in line 2002 can be at a pressure in a range from 500 kPag, 700 kPag, 800 kPag, or 900 kPag to 1,000 kPag, 1,100 kPag, 1,200 kPag, 1,300 kPag, 1,400 kPag, or 1,500 kPag. For example, in some embodiments, the cooled or second cooled purge gas in line 2002 can be at a temperature of -45°C to -26°C and a pressure of 900 kPag to 1,100 kPag.

[0051] The cooled or second cooled purge gas via line 2002 can be introduced into a vent recovery drum 2004 to provide a gaseous or vapor phase overhead via line 2006 and a condensed or liquid phase bottoms via line 2008. In some embodiments, the gaseous or vapor phase overhead in line 2006 can include Fb, N2, one or more C1-C10 linear alkanes, one or more C4-C10 branched alkanes, one or more C2-C10 alkenes, or any mixture thereof. In some embodiments, the condensed or liquid phase bottoms in line 2008 can include one or more condensed C1-C10 linear alkanes, one or more condensed C4-C10 branched alkanes, one or more condensed C2-C10 alkenes, or any mixture thereof. In some embodiments, at least a portion of the condensed or liquid phase bottoms in line 2008 can be recycled back to the olefin polymerization process, e.g., to a polymerization reactor.

[0052] The warmed liquified ethylene feed in line 2042 can be introduced into an expansion valve 2046 to produce an expanded liquid ethylene feed in line 2048. The expanded liquid ethylene feed via line 2048 and the purge gas via line 2000 can be introduced into the indirect heat exchanger 2050 to produce the heated ethylene feed in line 2052 and the first cooled purge gas in line 2001. The heated ethylene feed in line 2052 can be within the same temperature range and pressure range as the heated ethylene feed in line 1052 in the purge gas recovery unit100 described above with reference to FIG. 1. As such, 100% of the ethylene in the heated ethylene feed in line 2052 can be in the vapor phase.

[0053] The expanded liquid ethylene feed in line 2048 can be at a temperature and a pressure sufficient to maintain the ethylene in the liquid phase. When the warmed liquified ethylene feed is present in line 2042, the expanded liquid ethylene feed in line 2048 can be at a temperature in a range from -43°C, -41 °C, -37°C. -35°C, -33°C, -30°C, -27°C, -25°C, -20°C, or -15°C to -10°C, -5°C, 0°C 5°C, 10°C, 12°C, or 15°C. The expanded liquid ethylene feed in line 2048 can be at a pressure in a range from 1 ,300 kPag, 1 ,500 kPag, 1 ,700 kPag, 1 ,900 kPag, 2,050 kPag, 2,070 kPag, 2,200 kPag, 2,500 kPag, 2,800 kPag, 3,100 kPag, or 3,300 kPag to 3,700 kPag, 4,000 kPag, 4,300 kPag, 4,700 kPag, 4,800 kPag, 4,960 kPag, or 5.050 kPag. For example, in some embodiments, the expanded liquid ethylene feed in line 2048 can be at a temperature in a range from -26°C to -9°C and a pressure in a range from 2,070 kPag to 4,960 kPag. In some embodiments, the temperature of the expanded liquid ethylene feed in line 2048 and the wamied liquified ethylene feed in line 2042 can be the same. The expanded ethylene feed in line 2048 can be in the liquid phase. Said another way, 100% of the ethylene in the expanded liquid ethylene feed in line 2048 can be in the liquid phase.

[0054] The heated ethylene feed in line 2052 can be combined with the heated ethylene feed in line 2064 to produce a mixed or combined ethylene feed in line 2066. In some embodiments, at least a portion of the mixed or combined ethylene feed via line 2066 can be introduced into the olefin polymerization process, e.g., a polymerization reactor, from which the purge gas in line 2000 was obtained.

[0055] FIG. 3 depicts another illustrative purge gas recovery unit 300 for condensing one or more hydrocarbons in a purge gas in line 3000 that is similar to the system shown in FIG. 2, but further includes one or more third indirect heat exchangers 3036 configured to transfer heat from a liquified ethylene feed in line 3032 to a fluid in line 3035 to produce a heated fluid in line 3037 and a chilled liquified ethylene feed in line 3038 that can be introduced into one or more indirect heat exchangers 3040 that can be configured to transfer heat therefrom to a first cooled purge gas in line 3001, according to one or more embodiments. The purge gas in line 3000 can have the same composition and be within the same temperature range and the same pressure range as the purge gas in line 1000 in the purge gas recovery unit 100 described above with reference to FIG. 1.

[0056] An ethylene feed via line 3010 can be introduced into one or more compressors or compression stages 3012 to produce a compressed ethylene feed via line 3014. In some embodiments, the compressor 3012 can compress the ethylene feed in line 3010 in a singlestage, two stages, three stages, four stages, or more. In some embodiments, the ethylene feed in line 3010 can be separated from a pyrolysis effluent, e.g., a steam cracker effluent. As such, the ethylene feed in line 3010 can have the same composition as the ethylene feed in line 1010 in the purge gas recovery unit 100 described above with reference to FIG. 1.

[0057] The compressed ethylene feed via line 3014 and a heat transfer medium via line 3016 can be introduced into one or more indirect heat exchangers 3018. Heat can be transferred from the compressed ethylene feed to the heat transfer medium within the indirect heat exchanger 3018 to produce a liquified ethylene feed via line 3020 and a heated heat transfer medium via line 3022. The heat transfer medium in line 3016 can be the same as the heat transfer medium in line 1016 in the purge gas recovery unit 100 described above with reference to FIG. 1.

[0058] The liquified ethylene feed in line 3020 can be at a temperature in a range from -50°C, -45°C, -40°C, -35°C, -30°C, or -25°C to -20°C, -15°C, -10°C, -5°C, or 0°C. The liquified ethylene feed in line 3020 can be at a pressure in a range from 1,100 kPag, 1,170 kPag, 1,300 kPag, 1,400 kPag, 1,500 kPag, 1,600 kPag, 1,800 kPag, or 2,000 kPag to 2,500 kPag, 2,750 kPag, 3,000 kPag, 3,500 kPag, 3,600 kPag, 3,800 kPag, or 4,000 kPag. For example, in some embodiments, the liquified ethylene feed in line 3020 can be at a temperature of -46°C to -3 °C and a pressure of 1,170 kPag to 3,790 kPag.

[0059] In some embodiments, the liquified ethylene feed via line 3020 can be introduced into a product drum 3024 and can then via line 3026 be introduced to one or more pumps 3028 to produce a liquified ethylene feed in line 3030 that can be at a greater pressure than the liquified ethylene feed in line 3026. In other embodiments, the liquified ethylene feed via line 3020 can be introduced directly to the pump 3028. Said another way, the liquified ethylene feed in line 3020 and / or 3026 can be pressurized via the pump 3028.

[0060] As shown in FIG. 3, a first portion of the liquified ethylene feed in line 3030 can be introduced via line 3032 and a fluid via line 3035 can be introduced into the third indirect heat exchanger 3036 to produce a chilled liquified ethylene feed via line 3038 and a heated fluid via line 3037. In some embodiments, the fluid in line 3035 can be or can include, but is not limited to, ethane, ethylene, propane, propylene, or a mixture thereof. A second portion of the liquified ethylene feed in line 3030 can be conveyed via line 3034 to one or more indirect heat exchangers 3060. The second portion of the liquified ethylene feed via line 3034 and a heated heat transfer medium, e.g., an aqueous fluid, via line 3058 can be introduced into the indirect heat exchanger 3060 to produce a cooled heat transfer medium via line 3062 and a heated ethylene feed via line 3064. The heated ethylene in line 3064 can be in the vapor phase. Saidanother way, 100% of the ethylene in the heated ethylene feed in line 3064 can be in the vapor phase.

[0061] When the liquified ethylene feed is in line 3030, the liquified ethylene feed in lines 3030, 3032, and 3034 can be at a temperature in a range from -50°C, -45°C, -40°C, -35°C, -30°C, or -25°C to -20°C, -15°C, -10°C, -5°C, or 0°C. In some embodiments, the liquified ethylene feed in line 3030, 3032, and 3034 can be at a pressure in a range from 4,750 kPag, 4,830 kPag, 4,900 kPag, 6,000 kPag, 8,000 kPag, or 9,000 kPag to 10,000 kPag, 11,000 kPag, 12,000 kPag, 13,000 kPag, 13,800 kPag, or 14,500 kPag. For example, in some embodiments, the liquified ethylene feed in line 3030, 3032, and 3034 can be at a temperature of -46°C to -3°C and a pressure of 4,960 kPag to 13,800 kPag. In some embodiments, the liquified ethylene feed in line 3030, 3032, and 3034 can be under supercritical conditions. Said another way, in some embodiments, the liquified ethylene feed in line 3030, 3032, and 3034 can be a supercritical ethylene feed.

[0062] When the liquified ethylene feed is in line 3030, the chilled liquified ethylene feed in line 3038 can be at a temperature in a range from -105°C, -100°C, -90°C, -80°C, -70°C, -60°C, or -50°C to -40°C, -30°C, -20°C, -15°C. -10°C, -5°C, 0°C, 5°C, or 10°C. The chilled liquified ethylene feed in line 3038 can be at a pressure in a range from 4,750 kPag, 4,830 kPag, 4,900 kPag, 6,000 kPag, 8,000 kPag, or 9,000 kPag to 10,000 kPag, 11,000 kPag, 12,000 kPag, 13,000 kPag, 13,800 kPag, or 14,500 kPag. For example, in some embodiments, the chilled liquified ethylene feed in line 3038 can be at a temperature of -104°C to -8°C and a pressure of 4,960 kPag to 13,800 kPag. In some embodiments, the chilled liquified ethylene feed in line 3038 can be under supercritical conditions. Said another way, in some embodiments, the chilled liquified ethylene feed in line 3038 can be a supercritical ethylene feed.

[0063] The chilled liquified ethylene feed via line 3038 and the first cooled purge gas via line 3001 can be introduced into the indirect heat exchanger 3040 to produce a warmed liquified ethylene feed in line 3042 and a second cooled purge gas or simply cooled purge gas in line 3002. The first cooled purge gas in line 3001 can be at a temperature in a range from -43°C, -41°C, -37°C, -35°C, -33°C, -30°C, -27°C, -25°C, -20°C, or -15°C to -10°C, -5°C, 0°C, 5°C, 10°C, 12°C, or 15°C. The first cooled purge gas in line 3001 can be at a pressure in a range from 500 kPag, 700 kPag, 800 kPag, or 900 kPag to 1,000 kPag, 1,100 kPag, 1,200 kPag, 1,300 kPag, 1,400 kPag, or 1,500 kPag. For example, in some embodiments, the first cooled purge gas in line 3001 can be at a temperature of -26°C to 9°C and a pressure of 900 kPag to 1,100 kPag.

[0064] When the liquified ethylene feed is in line 3032, the wanned liquified ethylene feed in line 3042 can be at a temperature in a range from -43°C, -41 °C, -37°C, -35°C, -33°C, -30°C, -27°C, -25°C, -20°C, or -15°C to -10°C, -5°C, 0°C 5°C, 10°C, 12°C, or 15°C. The warmed liquified ethylene feed in line 3042 can be at a pressure in a range from 4,750 kPag, 4,830 kPag, 4,900 kPag, 6,000 kPag, 8,000 kPag, or 9,000 kPag to 10,000 kPag, 11,000 kPag, 12,000 kPag, 13,000 kPag, 13,800 kPag, or 14,500 kPag. For example, in some embodiments, the warmed liquified ethylene feed in line 3042 can be at a temperature of -26°C to 9°C and a pressure of 4,960 kPag to 13,800 kPag. In some embodiments, the warmed liquified ethylene feed in line 3042 can be under supercritical conditions. Said another way, in some embodiments, the warmed liquified ethylene feed in line 3042 can be a supercritical ethylene feed.

[0065] The cooled purge gas in line 3002 can be at a temperature in a range from -105°C, -100°C, -90°C, -80°C, -70°C, -60°C, or -50°C to -40°C, -30°C, -20°C, -15°C, -10°C, -5°C, 0°C, 5°C, or 10°C. The cooled or second cooled purge gas in line 3002 can be at a pressure in a range from 500 kPag, 700 kPag, 800 kPag, or 900 kPag to 1,000 kPag, 1,100 kPag, 1,200 kPag, 1,300 kPag, 1,400 kPag, or 1,500 kPag. For example, in some embodiments, the cooled or second cooled purge gas in line 3002 can be at a temperature of -104°C to -8°C and a pressure of 900 kPag to 1,100 kPag.

[0066] The cooled or second cooled purge gas via line 3002 can be introduced into a vent recovery drum 3004 to provide a gaseous or vapor phase overhead via line 3006 and a condensed or liquid phase bottoms via line 3008. In some embodiments, the gaseous or vapor phase overhead in line 3006 can include Fb, N2, one or more C1-C10 linear alkanes, one or more C4-C10 branched alkanes, one or more C2-C10 alkenes, or any mixture thereof. In some embodiments, the condensed or liquid phase bottoms in line 3008 can include one or more condensed C1-C10 linear alkanes, one or more condensed C4-C10 branched alkanes, one or more condensed C2-C10 alkenes, or any mixture thereof. In some embodiments, at least a portion of the condensed or liquid phase bottoms in line 3008 can be recycled back to the olefin polymerization process, e.g., to a polymerization reactor.

[0067] The warmed liquified ethylene feed in line 3042 can be introduced into an expansion valve 3046 to produce an expanded liquid ethylene feed in line 3048. The expanded liquid ethylene feed in line 3048 and the purge gas in line 3000 can be introduced into the indirect heat exchanger 3050 to produce a heated ethylene feed in line 3052 and the first cooled purge gas in line 3001. The heated ethylene feed in line 3052 can be within the same temperature range and pressure range as the heated ethylene feed in line 1052 in the purge gas recovery unit 100 described above with reference to FIG. 1. As such, 100% of the ethylene in the heatedethylene feed in line 3052 can be in the vapor phase. The purge gas in line 3000 can have the same composition and be within the same temperature range and the same pressure range as the purge gas line 1000 in the purge gas recovery unit 100 described above with reference to FIG. 1.

[0068] The expanded liquid ethylene in line 3048 can be at a temperature and a pressure sufficient to maintain the ethylene in the liquid phase. The expanded liquid ethylene feed in line 3048 can be at a temperature in a range from -43°C, -41 °C, -37°C, -35°C, -33°C, -30°C, -27°C, -25°C, -20°C, or -15°C to -10°C, -5°C, 0°C 5°C, 10°C, 12°C, or 15°C. The expanded liquid ethylene feed in line 3048 can be at a pressure in a range from 1,300 kPag, 1,500 kPag, 1,700 kPag, 1,900 kPag, 2,050 kPag, 2,070 kPag, 2,200 kPag, 2,500 kPag, 2,800 kPag, 3,100 kPag, or 3,300 kPag to 3,700 kPag, 4,000 kPag, 4,300 kPag, 4,700 kPag, 4,800 kPag, 4,960 kPag, or 5,050 kPag. For example, in some embodiments, the expanded liquid ethylene feed in line 3048 can be at a temperature in a range from -26°C to -9°C and a pressure in a range from 2,070 kPag to 4,960 kPag. In some embodiments, the temperature of the expanded liquid ethylene feed in line 3048 and the warmed liquified ethylene feed in line 3042 can be the same. The expanded liquid ethylene feed in line 3048 can be in the liquid phase. Said another way, 100% of the ethylene in the expanded liquid ethylene feed in line 3048 can be in the liquid phase.

[0069] The heated ethylene feed in line 3042 can be combined with the heated ethylene feed in line 3064 to produce a mixed or combined ethylene feed in line 3066. In some embodiments, at least a portion of the mixed or combined ethylene feed via line 3066 can be introduced into the olefin polymerization process, e.g., a polymerization reactor, from which the purge gas in line 3000 can be obtained.

[0070] FIG. 4 depicts another illustrative purge gas recovery unit 400 for condensing one or more hydrocarbons in a purge gas in line 4000 that is similar to the purge gas recovery unit 300 shown in FIG. 3 but does not include the second indirect heat exchanger 3040, according to one or more embodiments. An ethylene feed via line 4010 can be introduced into one or more compressors or compression stages 4012 to produce a compressed ethylene feed in line 4014. In some embodiments, the compressor 4012 can compress the ethylene feed in line 4010 in a single stage, two stages, three stages, four stages, or more. In some embodiments, the ethylene feed in line 4010 can be separated from a pyrolysis effluent, e.g., a steam cracker effluent. As such, the ethylene feed in line 4010 can have the same composition as the ethylene feed in line 1010 in the purge gas recovery unit 100 described above with reference to FIG. 1.

[0071] The compressed ethylene feed via line 4014 and a heat transfer medium via line 4016 can be introduced into one or more indirect heat exchangers 4018. Heat can be transferred from the compressed ethylene feed to the heat transfer medium within the indirect heat exchanger 4018 to produce a liquified ethylene feed via line 4020 and a heated heat transfer medium via line 4022. The heat transfer medium in line 4016 can be the same as the heat transfer medium in line 1016 in the purge gas recovery unit 100 described above with reference to FIG. 1.

[0072] When the ethylene feed is present in line 4010, the liquified ethylene feed in line 4020 can be at a temperature in a range from -50°C, -45°C, -40°C, -35°C, -30°C, or -25°C to -20°C, -15°C, -10°C, -5°C, or 0°C. The liquified ethylene feed in line 4020 can be at a pressure in a range from 1,100 kPag, 1,170 kPag, 1,300 kPag, 1,400 kPag, 1,500 kPag, 1,600 kPag, 1,800 kPag, or 2,000 kPag to 2,500 kPag, 2,750 kPag, 3,000 kPag, 3,500 kPag, 3,600 kPag, 3,800 kPag, or 4,000 kPag. For example, in some embodiments, the liquified ethylene feed in line 4020 can be at a temperature of -46°C to -3°C and a pressure of 1,170 kPag to 3,790 kPag.

[0073] In some embodiments, the liquified ethylene feed via line 4020 can be introduced into a product drum 4024 and can then via line 4026 be introduced to one or more pumps 4028 to produce a liquified ethylene feed in line 4030 that can be at a greater pressure than the liquified ethylene feed in line 4026. In other embodiments, the liquified ethylene feed via line 4020 can be introduced directly to the pump 4028. Said another way, the liquified ethylene feed in line 4020 and / or 4026 can be pressurized via the pump 4028.

[0074] As shown in FIG. 4, a first portion of the liquified ethylene feed in line 4030 can be introduced via line 4032 and a fluid via line 4035 can be introduced into one or more indirect heat exchangers 4036 to produce a chilled liquified ethylene feed via line 4038 and a heated fluid via line 4037. In some embodiments, the fluid in line 4035 can be or can include, but is not limited to, ethane, ethylene, propylene, propylene, or a mixture thereof. A second portion of the liquified ethylene feed in line 4030 can be conveyed via line 4034 to one or more indirect heat exchangers 4060. The second portion of the liquified ethylene feed via line 4034 and a heated heat transfer medium, e.g., an aqueous fluid, via line 4058 can be introduced into the indirect heat exchanger 4060 to produce a cooled heat transfer medium via line 4062 and a heated ethylene feed via line 4064. The heated ethylene feed in line 4064 can be in the vapor phase. Said another way, 100% of the ethylene in the heated ethylene feed in line 4064 can be in the vapor phase.

[0075] When the liquified ethylene feed is in line 4030, the liquified ethylene feed in lines 4030, 4032, and 4034 can be at a temperature in a range from -50°C, -45°C, -40°C, -35°C, -30°C, or -25°C to -20°C, -15°C, -10°C, -5°C, or 0°C. In some embodiments, the liquified ethylene feed in line 4030, 4032, and 4034 can be at a pressure in a range from 4,750 kPag, 4,830 kPag, 4,900 kPag, 6,000 kPag, 8,000 kPag, or 9,000 kPag to 10,000 kPag, 11,000 kPag, 12,000 kPag, 13,000 kPag, 13,800 kPag, or 14,500 kPag. For example, in some embodiments, the liquified ethylene feed in line 4030, 4032, and 4034 can be at a temperature of -46°C to -3°C and a pressure of 4,960 kPag to 13,800 kPag. In some embodiments, the liquified ethylene feed in line 4030, 4032, and 4034 can be under supercritical conditions. Said another way, in some embodiments, the liquified ethylene feed in line 4030, 4032, and 4034 can be a supercritical ethylene feed.

[0076] When the liquified ethylene feed is in line 4030, the chilled liquified ethylene feed in line 4038 can be at a temperature in a range from -105°C, -100°C, -90°C, -80°C, -70°C, -60°C, or -50°C to -40°C, -30°C, -20°C, -15°C, -10°C, -5°C, 0°C, 5°C, or 10°C. The chilled liquified ethylene feed in line 4038 can be at a pressure in a range from 4,750 kPag, 4,830 kPag, 4,900 kPag, 6,000 kPag, 8,000 kPag, or 9,000 kPag to 10,000 kPag, 11,000 kPag, 12,000 kPag, 13,000 kPag, 13,800 kPag, or 14,500 kPag. For example, in some embodiments, the chilled liquified ethylene feed in line 4038 can be at a temperature of -104°C to -8°C and a pressure of 4,960 kPag to 13,800 kPag. In some embodiments, the chilled liquified ethylene feed in line 4038 can be under supercritical conditions. Said another way, in some embodiments, the chilled liquified ethylene feed in line 4038 can be a supercritical ethylene feed.

[0077] The chilled liquified ethylene feed via line 4038 can be introduced into an expansion valve 4046 to produce an expanded liquid ethylene feed in line 4048. The expanded liquid ethylene feed in line 4048 can be at a temperature and a pressure sufficient to maintain the ethylene in the liquid phase. When the chilled liquified ethylene feed is present in line 4038, the expanded liquid ethylene feed in line 4048 can be at a temperature in a range from -105 °C, -100°C, -90°C, -80°C, -70°C, -60°C, or -50°C to -40°C, -30°C, -20°C, -15°C, -10°C, -5°C, 0°C, 5°C, or 10°C. The expanded liquid ethylene feed in line 4048 can be at a pressure in a range from 1,300 kPag, 1,500 kPag, 1,750 kPag, 1,900 kPag, 2,070 kPag, 2,200 kPag, or 2,500 kPag to 2,700 kPag, 2,900 kPag, 3,100 kPag, 3,300 kPag, 3,500 kPag, 3,700 kPag, 4,000 kPag, 4,300 kPag, 4,500 kPag, 4,700 kPag, 4,800 kPag, 4,960 kPag, or 5,050 kPag. For example, in some embodiments, the expanded liquid ethylene feed in line 4048 can be at a temperature in a range from -105°C to 10°C and a pressure in a range from 1,300 kPag to 5,050 kPag. A temperature of the expanded liquid ethylene feed in line 4048 and the chilled liquified ethylene feed in line 4038 can be the same. The expanded liquid ethylene feed in line 4048 can be inthe liquid phase. Said another way, 100% of the ethylene in the expanded liquid ethylene feed in line 4048 can be in the liquid phase.

[0078] The purge gas in line 4000 and the expanded liquid ethylene feed in line 4048 can be introduced into the indirect heat exchanger 4050 to produce a heated ethylene feed in line 4052 and a cooled purge gas in line 4002. The heated ethylene feed in line 4052 can be within the same temperature range and pressure range as the heated ethylene feed in line 1052 in the purge gas recovery unit 100 described above with reference to FIG. 1. As such, 100% of the ethylene in the heated ethylene feed in line 4052 can be in the vapor phase. The purge gas in line 4000 can have the same composition and be within the same temperature range and the same pressure range as the purge gas in line 1000 in the purge gas recovery unit 100 described above with reference to FIG. 1.

[0079] The heated ethylene feed in line 4052 can be combined with the heated ethylene feed in line 4064 to produce a mixed or combined ethylene feed in line 4066. In some embodiments, at least a portion of the mixed or combined ethylene feed via line 4066 can be introduced into the olefin polymerization process, e.g., a polymerization reactor, from which the purge gas in line 4000 was obtained.

[0080] The cooled purge gas in line 4002 can be at a temperature in a range from -105°C, -100°C, -90°C, -80°C, -70°C, -60°C, or -50°C to -40°C, -30°C, -20°C, -15°C, -10°C, -5°C, 0°C, 5°C, or 10°C. The cooled purge gas in line 4002 can be at a pressure in a range from 500 kPag, 700 kPag, 800 kPag, or 900 kPag to 1,000 kPag, 1,100 kPag, 1,200 kPag, 1,300 kPag, 1,400 kPag, or 1,500 kPag. For example, in some embodiments, the cooled purge gas can be at a temperature of -104°C to -8°C and a pressure of 900 kPag to 1,100 kPag.

[0081] The cooled purge gas via line 4002 can be introduced into a vent recovery drum 4004. A gaseous or vapor phase overhead via line 4006 and a condensed or liquid phase bottoms via line 4008 can be recovered from the vent recovery drum 4004. In some embodiments, the gaseous or vapor phase overhead in line 4006 can include Fh, N2, one or more C1-C10 linear alkanes, one or more C4-C10 branched alkanes, one or more C2-C10 alkenes, or any mixture thereof. In some embodiments, the condensed or liquid phase bottoms in line 4008 can include one or more condensed C1-C10 linear alkanes, one or more condensed C4-C10 branched alkanes, one or more condensed C2-C10 alkenes, or any mixture thereof. In some embodiments, at least a portion of the condensed or liquid phase bottoms in line 4008 can be recycled back to the olefin polymerization process, e.g., to a polymerization reactor or a purge bin.

[0082] FIG. 5 depicts an illustrative system 500 for producing a steam cracker effluent in line 5016, obtaining an ethylene feed therefrom in line 1010, utilizing the ethylene feed in line1010 to cool a purge gas in line 1000 vented from an olefin polymerization system 5020, and polymerizing at least a portion of the ethylene feed in line 1010 in a polymerization reactor 5022 after cooling the purge gas in line 1000, according to one or more embodiments. As shown in FIG. 5, the system 500 includes the purge gas recovery unit 100 for condensing one or more hydrocarbons in the purge gas in line 1000 by indirectly transferring heat from the purge gas in line 1000 to the expanded liquid ethylene feed in line 1048 within the indirect heat exchanger 1050. It should be understood that, in other embodiments, the system 500 can include the purge gas recovery unit 200, 300, or 400 described above with reference to FIGS.2-4.

[0083] The system 500 also includes a steam cracking system 5001 that includes a steam cracker 5010 and a steam cracker effluent recovery facility 5018 that can provide the ethylene feed via line 1010 for use in the purge gas recovery unit 100. The polymerization system 5020 can include a polymerization reactor 5022, one or one or more discharge tanks 5024, one or more compressors or compression stages 5026, 5028 (two are shown), one or more heat exchangers 5030, 5032, 5034 (three are shown), and one or more purge bins 5036.

[0084] A hydrocarbon-containing feed via line 5002 and an aqueous fluid via line 5004 can be mixed, blended, combined, or otherwise contacted to produce a mixture via line 5006. In some embodiments, the mixture can include about 10 wt% to about 95 wt% of the aqueous fluid, based on a combined weight of the hydrocarbon-containing feed and the aqueous fluid. The mixture in line 5006 can be heated, e.g., to a temperature of about 200°C to about 585°C, to produce a heated mixture. For example, the mixture in line 5006 can be heated in a convection section 5012 of the steam cracker 5010 to produce the heated mixture via line 5008. In some embodiments, the heated mixture in line 5008 can be in the vapor phase and can be introduced into one or more radiant tubes 5011 located within a radiant section 5014 of the steam cracker 5010 to produce the steam cracker effluent via line 5016. The steam cracker effluent via line 5016 can be introduced into the steam cracker effluent recovery facility 5018 to obtain the ethylene feed via line 1010 therefrom.

[0085] In some embodiments, the heated mixture in line 5008 can include liquid phase hydrocarbons and gaseous phase hydrocarbons. In such embodiment, the heated mixture can be introduced into one or more separators or separation stages to obtain a vapor phase or overhead product and a liquid phase or bottoms product therefrom. The vapor phase or overhead product can be introduced into the radiant tube(s) 5011 and the liquid phase or bottoms product can be further processed via well-known processes. Illustrative separation or separation stages that can be used to obtain the vapor phase or overhead product and the liquidphase or botoms product from the heated mixture in line 5008 can be or can include the separators and / or other equipment disclosed in U.S. Patent Nos. 7,138,047; 7,090,765; 7,097,758; 7,820,035; 7,311,746; 7,220,887; 7,244,871; 7,247,765; 7,351,872; 7,297,833; 7,488,459; 7,312,371; 6,632,351; 7,578,929; and 7,235,705.

[0086] The steam cracking conditions within the radiant section 5014 of the steam cracker 5010 can include, but are not limited to, one or more of: exposing the heated combined mixture to a temperature (as measured at a radiant outlet of the steam cracker) of > 400°C, e.g., a temperature of about 700°C, about 800°C, or about 900°C to about 950°C, about 1 ,000°C, or about 1050°C, a pressure of about 100 kPa-absolute to about 600 kPa- absolute, and / or a steam cracking residence time of about 0.01 seconds to about 5 seconds. In some embodiments, the heated combined mixture can be steam cracked according to the processes and systems disclosed in U.S. Patent Nos. 6,419,885; 7,993,435; 9,637,694; and 9,777,227; U.S. Patent Application Publication Nos. 2018 / 0170832; 2021 / 0340450; 2021 / 0380892; 2021 / 0388275; 2023 / 0151283; 2024 / 0247194; and 2024 / 0247193; and International Patent Application Publication No. WO 2018 / 111574. The steam cracker effluent in line 5016, at an outlet of the radiant tube(s) 5011, can be at a temperature of > 400°C, e.g., a temperature of about 700°C, about 800°C, or about 900°C to about 950°C, about l,000°C, or about 1050°C.

[0087] The steam cracker effluent recovery facility 5018 can include a number of separation steps. For example, the recovery facility 5018 can include a primary fractionator that can separate a process gas overhead, a steam cracker naphtha side stream, a steam cracker gas oil side stream, a steam cracker quench oil side stream, and a steam cracker tar bottoms from the steam cracker effluent in line 5016. In other embodiments, a tar knock-out drum can be located between the steam cracker and the primary fractionator that can separate the steam cracker tar from the steam cracker effluent such that a bottoms fraction obtained from the primary fractionator can be the steam cracker quench oil. In some embodiments, the steam cracker effluent 5016 can be cooled, e.g., via one or more transfer line exchangers and / or via direct contact with a cooling medium, prior to introduction into the recovery facility 5018. In some embodiments, the steam cracker effluent in line 5016 can be at a temperature in a range from 150°C, 160°C, 175°C, or 200°C to 250°C, 275°C, 300°C, 315°C, 325°C, or 350°C when introduced into the recovery facility 5018.

[0088] The process gas can include, for example, molecular hydrogen and C1-C5+ hydrocarbons, e.g., C1-C9 hydrocarbons. In some embodiments, the process gas can be or can include, but is not limited to, molecular hydrogen, one or more C1-C5 alkanes, one or more C2-C5 alkenes, and one or more contaminants, or a mixture thereof. The process gas can bedirected to a light hydrocarbon recovery system for recovering light (e.g., C2 to C4) olefins, among other products, co-products, and by-products. The process gas can be compressed, cooled, and further separated and / or subjected to additional processing in various process units such as an amine tower, a caustic tower, a sulfur removal unit, arsine removal units, and / or an acetylene converter. From the process gas the ethylene feed in line 1010 can be obtained. Separation of the steam cracker effluent into various products is well known in the art and many different configurations can be used to obtain a suitable ethylene feed in line 1010. In some embodiments, suitable separation systems that can be used to obtain the ethylene feed in line 1010 can include those described in U.S. Patent Application Publication Nos.2016 / 0376511; 2023 / 0091233; 2023 / 0151283; and 2023 / 0203386.

[0089] During normal operation, the gas phase polymerization system 5020 includes continuous addition of a catalyst via line 5038, ethylene monomer via line 1066 (which can be obtained from purge gas recovery unit 100), and optionally one or more comonomers and / or hydrogen via line 5040, to a fluidized bed 5042 in the polymerization reactor 5022 under a set of polymerization conditions and withdrawing a polyethylene or a heterophasic copolymer of propylene or impact copolymer product via line 5044 therefrom. In some embodiments, during normal operation, at least two of the ethylene monomer via line 1066, the condensed or liquid phase bottoms in line 1008, and the one or more comonomers and / or hydrogen via line 5040 can be mixed or otherwise combined with one another and introduced via line 5025 into the polymerization reactor 5022 as a mixed or combined reactor feed below a fluid distributor plate (“plate”) 5023 disposed within the polymerization reactor 5022. In some embodiments, the reactor feed in line 5025 can be in a two phase (gas and liquid) flow. In such embodiments, the wt% liquid can be in a range from 5 wt% up to 50 wt%, based on the total weight of the reactor feed in line 5025. In other embodiments, the reactor feed in line 5025 can be substantially in the gas or vapor phase.

[0090] The reactor 5022 can be in fluid communication with the discharge tank 5024, compressor 5026, heat exchanger 5030, purge bin 5036, and purge gas recovery unit 100. The polymerization system 5020 can also include more than one reactor 5022 arranged in series, parallel, or configured independent from the other reactors, each reactor having its own associated discharge tank(s) 5024, compressor(s) 5028, 5026, heat exchanger(s) 5030, 5032, 5034, purge bin(s) 5036, or purge gas recovery unit(s) 100 or alternatively, sharing any one or more of the associated discharge tank(s) 5024, compressor(s) 5028, 5026, heat exchanger(s) 5030, 5032, 5034, purge bin(s) 5036, or purge gas recovery unit(s) 100. For simplicity andease of description, the polymerization system 5020 will be further described in the context of a single reactor train.

[0091] The reactor 5022 can include a cylindrical section 5046, a transition section 5048, and a velocity reduction zone or dome 5050. The cylindrical section 5046 is disposed adjacent the transition section 5048. The transition section 5048 can expand from a first diameter that corresponds to the diameter of the cylindrical section 5046 to a larger diameter adjacent the dome 5050. The location or junction at which the cylindrical section 5022 connects to the transition section 5048 is referred to as the “neck” or the “reactor neck.” The dome 5050 can have a bulbous shape. One or more cycle fluid lines 5052 and vent lines 5054 can be in fluid communication with the dome 5050. The reactor 5022 can include the fluidized bed 5042 in fluid communication with the dome 5050. In general, the height to diameter ratio of the cylindrical section 5046 can vary in the range of from about 2:1 to about 5:1. The range, of course, can vary to larger or smaller ratios and depends, at least in part, on the desired production capacity and / or reactor dimensions. The cross-sectional area of the dome 5050 can be within the range of from about 2 to about 3 or as high as 4 multiplied by the cross-sectional area of the cylindrical section 5046.

[0092] The velocity reduction zone or dome 5050 can have a larger inner diameter than the fluidized bed 5042. As the name suggests, the velocity reduction zone 5050 can slow the velocity of the gas due to the increased cross-sectional area. This reduction in gas velocity allows particles entrained in the upward moving gas to fall back into the bed, allowing primarily only gas to exit overhead of the reactor 5022 via cycle fluid line 5052.

[0093] The ethylene feed via line 1066 can be introduced to the polymerization system 5020 at any point. For example, the ethylene feed via line 1066 can be introduced to the cylindrical section 5046, the transition section 5048, the velocity reduction zone 5050, to any point within the cycle fluid line 5052, or any combination thereof. FIG. 1 depicts the ethylene feed via line 1066 entering the cycle fluid in line 5052 after the heat exchanger 5030, however the ethylene feed via line 1066 can be implemented in one or more alternative locations, e.g., before the heat exchange 5030 or before the compressor 5026. The catalyst feed via line 5038 can be introduced to the polymerization system 5020 at any point. For example, the catalyst feed via line 5038 can be introduced to the fluidized bed 5042 within the cylindrical section 5046. Additional feed lines (not shown) can be utilized and located at any of the points just mentioned with respect to feed line 1066; any one or more of these feed lines can be used to convey monomer(s), induced condensing agents (ICA(s)), inert carrier gases such as nitrogen, or the like to the cycle gas flowing through the system. Induced condensing agents refer to one ormore inert condensable fluids that are readily volatile liquid hydrocarbons, which can be selected from saturated hydrocarbons containing from 2 to 10 carbon atoms, such as 3 to 10 carbon atoms. Some suitable saturated hydrocarbons include propane, n-butane, isobutane, n-pentane, isopentane, neopentane, n-hexane, isohexane, and other saturated Ce hydrocarbons, n-heptane, n-octane and other saturated C7 and Cs hydrocarbons or mixtures thereof.

[0094] During normal operation, e.g., polymer production, under a given set of operating conditions the fluidized bed may be maintained at essentially a constant height by withdrawing a portion of the bed via line 5044 as polymer product at the rate of formation of the particulate polymer product. Since the rate of heat generation during polymerization is directly related to the rate of product formation, in some embodiments, a temperature rise of the fluid across the reactor (the difference in temperature between reactor feed line 1066 and exit cycle fluid via line 5052) can be indicative of the rate of particulate polymer formation at a constant fluid velocity if no or negligible vaporizable liquid is present in the inlet fluid. The temperature rise of the fluid across the reactor, e.g., the temperature of the cycle gas exiting the reactor minus the temperature of the cycle gas introduced to the reactor, can be referred to as “DT” or “AT.” A normal or typical DT for the reactor during polymer production can range from a low of about 5°C, about 10°C, or about 15°C to a high of about 40°C, about 50°C, or about 55°C. In other embodiments, the difference in temperature between the reactor feed in line 5025 and a temperature within the middle of the fluidized bed 5042 can be used to determine or otherwise estimate the rate of product formation.

[0095] The cycle fluid via line 5052 can be compressed in the compressor 5026 and passed through the heat exchanger 5030 where heat can be exchanged between the cycle fluid and a heat transfer medium. For example, during normal operating conditions a cool or cold heat transfer medium via line 5029 can be introduced to the heat exchanger 5030 where heat can be transferred from the cycle fluid in line 5052 to produce a heated heat transfer medium via line 5031 and a cooled cycle fluid in line 5052. After cooling, all or a portion of the cycle fluid via line 5052 can be returned to the reactor 5022. The cooled cycle fluid in line 5052 can absorb the heat of reaction generated by the polymerization reaction within the reactor 5022. In some embodiments, the heat exchanger 5030 can be a shell and tube heat exchanger. If desired, several heat exchangers can be employed, in series, parallel, or a combination of series and parallel, to lower or increase the temperature of the cycle fluid in stages. In some embodiments, the compressor 5026 can compress the cycle fluid in line 5052 in a single stage, two stages, three stages, four stages, or more.

[0096] In some embodiments, the cycle gas via line 5052 can be returned to the reactor 5022 and to the fluidized bed 5042 through the fluid distributor plate 5023. The plate 5023 can be installed at the inlet to the reactor 5022 to prevent polymer particles from settling out and agglomerating into a solid mass and to prevent liquid accumulation at the bottom of the reactor 5022 as well to facilitate easy transitions between processes which contain liquid in the cycle stream 5052 and those which do not and vice versa. Although not shown, the cycle gas via line 5052 can be introduced into the reactor 5022 through a deflector disposed or located intermediate an end of the reactor 5022 and the distributor plate 5023.

[0097] The catalyst feed via line 5038 can be introduced to the fluidized bed 5042 within the reactor 5022 through one or more injection nozzles (not shown) in fluid communication with line 5038. The catalyst feed can be introduced via line 5038 as pre-formed particles in one or more liquid or gas carriers (e.g., a catalyst slurry or particles in a gas such as nitrogen). Suitable carriers can include mineral oil and / or liquid or gaseous hydrocarbons including, but not limited to, propane, butane, isopentane, hexane, heptane octane, or mixtures thereof.

[0098] The product withdrawn via line 5044 from the reactor 5022 can be introduced into the discharge tank 5024. Fluid via line 5056 can be separated from the product recovered via line 5044 from the reactor 5022. The fluid can include unreacted monomer(s), hydrogen, induced condensing agents (ICAs), and / or inerts, such as ethane and / or ethylene. The separation of the fluid can be accomplished when fluid and / or product leave the reactor 5022 and enter the product discharge tank 5024. Although not shown a valve can be located between the reactor 5022 and the discharge tank 5024, a valve can be located in line 5056 between the discharge tank 5024 and the reactor 5022, and a valve can be located in line 5058 between the discharge tank 5024 and the purge bin 5036. Such valves can be used to introduce polymer product into the discharge tank, remove gaseous components therefrom and polymer product therefrom, as is well known in the art.

[0099] The conditions for polymerization within the reactor 5022 can vary depending, at least in part, on the particular monomers, catalyst(s), catalyst system(s), and equipment availability. The specific conditions are known or readily derivable by those skilled in the art. For example, the temperature within the reactor is typically within a range from 70°C to 110°C. The pressure within the reactor 5022 is typically within a range of from 1,000 kPag or 1,500 kPag to 2,200 kPag or 2.600 kPag, for example. In some embodiments, suitable gas phase polymerization systems and process conditions can include those described in U.S. Patent Nos.5,352,749; 5,405,922; 5,436,304; 5,462,999: and 7,858,719; and U.S. Patent Application Publication Nos. 2021 / 0189023; and 2024 / 0209124.

[0100] The term “catalyst system” includes at least one “catalyst component” and at least one “activator,” alternately at least one co-catalyst. The catalyst system can also include other components, such as supports, and is not limited to the catalyst component and / or activator alone or in combination. The catalyst system can include any number of catalyst components in any combination as described, as well as any activator in any combination as described.

[0101] The term “catalyst component” or “catalyst compound” includes any compound that, once appropriately activated, is capable of catalyzing the polymerization or oligomerization of olefins. The catalyst component may include at least one Group 3 to Group 12 atom and optionally at least one leaving group bound thereto. The term “leaving group” refers to one or more chemical moieties bound to the metal center of the catalyst component that can be abstracted from the catalyst component by an activator, thereby producing the species active towards olefin polymerization or oligomerization. Suitable activators are described in detail below. In some embodiments, the catalyst compound can be or can include, but is not limited to, metallocene catalyst compounds or conventional-type catalyst compounds.

[0102] Suitable metallocene catalyst compounds can be or can include, but are not limited to, those described in U.S. Patent Nos.: 7,179,876; 7,169,864; 7.157,531; 7,129,302; 6,995,109; 6,958,306; 6,884748; 6,689,847; 5,026,798; 5,703,187; 5,747,406; 6,069,213; 7,244,795; 7,579,415; U.S. Patent Application Publication No. 2007 / 0055028; and WO Publication Nos.: WO 97 / 22635; WO 00 / 699 / 22; WO 01 / 30860; WO 01 / 30861; WO 02 / 46246; WO 02 / 50088; WO 04 / 022230; WO 04 / 026921; and WO 06 / 019494. Conventional-type catalyst compounds include Ziegler-Natta catalysts and Phillips-type chromium catalyst that are well known in the art. Examples of conventional-type transition metal catalysts include those disclosed in U.S. Patent Nos.: 4,077,904; 4,115,639; 4,124,532; 4,302,565; 4.302,566; 4,482,687; 4,564,605; 4,721,763; 4,879,359; 4,960,741; and 5,763,723.

[0103] As used herein, the terms “activator” refers to any compound or combination of compounds, supported or unsupported, which can activate a catalyst compound or component, such as by creating a cationic species of the catalyst component. For example, this can include the abstraction of at least one leaving group (the “X” group in the single site catalyst compounds described herein) from the metal center of the catalyst compound / component. Activators can include Lewis acids such as cyclic or oligomeric poly(hydrocarbylaluminum oxides) and so called non-coordinating activators (“NCA”) (alternately, “ionizing activators” or “stoichiometric activators”), or any other compound that can convert a neutral metallocene catalyst component to a metallocene cation that is active with respect to olefin polymerization. Illustrative Lewis acids include, but are not limited to, aluminoxane (e.g., methylaluminoxane“MAO”), modified aluminoxane (e.g., modified methylaluminoxane “MMAO” and / or tetraisobutyldialuminoxane “TIBAO”), and alkylaluminum compounds. Ionizing activators (neutral or ionic) such as tri (n-butyl)ammonium tetrakis(pentafluorophenyl)boron may be also be used. Further, a trisperfluorophenyl boron metalloid precursor may be used. Any of those activators / precursors can be used alone or in combination with the others. There are a variety of methods for preparing aluminoxane and modified aluminoxanes known in the art.

[0104] The catalyst compositions can include a support material or carrier. As used herein, the terms “support” and “carrier” are used interchangeably and are any support material, including a porous support material, for example, talc, inorganic oxides, and inorganic chlorides. The catalyst component(s) and / or activator(s) can be deposited on, contacted with, vaporized with, bonded to, or incorporated within, adsorbed or absorbed in, or on, one or more supports or carriers. Other support materials can include resinous support materials such as polystyrene, functionalized or crosslinked organic supports, such as polystyrene divinyl benzene polyolefins or polymeric compounds, zeolites, clays, or any other organic or inorganic support material and the like, or mixtures thereof.

[0105] Inorganic oxide supports can be or can include, but are not limited to, Group 2, 3, 4, 5, 13 or 14 metal oxides. Exemplary supports include silica, which may or may not be dehydrated, fumed silica, alumina, silica-alumina and mixtures thereof. Other useful supports include magnesia, titania, zirconia, magnesium chloride, montmorillonite, phyllosilicate, zeolites, talc, clays, and the like. Also, combinations of these support materials may be used, for example, silica-chromium, silica-alumina, silica-titania and the like. Additional support materials may include those porous acrylic polymers described in EP 0 767 184, which is incorporated herein by reference.

[0106] The polymer product(s) produced in the reactor can be or include any type of polymer or polymeric material. For example, the polymer product can include homopolymers of olefins (e.g., homopolymers of ethylene or propylene), and / or copolymers, terpolymers, and the like of olefins, particularly ethylene, and at least one other olefin. Illustrative polymers can include, but are not limited to, polyolefins, polyamides, polyesters, polycarbonates, polysulfones, polyacetals, polylactones, acrylonitrile-butadiene-styrene polymers, polyphenylene oxide, polyphenylene sulfide, styrene-acrylonitrile polymers, styrene maleic anhydride, polyimides, aromatic polyketones, heterophasic copolymers of propylene, impact copolymers, or mixtures of two or more of the above. Suitable polyolefins can include, but are not limited to, polymers comprising one or more linear, branched or cyclic C2 to C40 olefins, such as polymers comprising ethylene copolymerized with one or more C3 to C40 olefins, suchas a C3 to C20 alpha olefin, more such as C3 to C10 alpha-olefins. Exemplary polyolefins include, but are not limited to, polymers comprising ethylene including but not limited to ethylene copolymerized with a C to C10 olefin, such as a C to C10 alpha olefin, more such as propylene and or butene.

[0107] The product obtained via line 5058 from the discharge tank 5024 can be introduced into the purge bin 5036. Alternatively, the product via line 5058 can be introduced to a plurality of separation units, in series, parallel, or a combination of series and parallel, to further separate gases and / or liquids from the product. The purge bin 5036 can receive the product via line 5058, in which a plurality of gas stripping streams within the purge bin 5036 can direct one or more purge vent streams via line 5060 to the purge gas recovery unit 100. Additionally, the purge bin 5036 can receive the product via line 5058 and recover one or more polymer products, via exit line 5062. Additionally, the purge bin 5036 can direct one or more purge gases, e.g., hydrogen, to a hydrogen recovery plant, such as a blue hydrogen plant, via line 5064. The gas stripping streams utilized within the purge bin 5036 can be or can include, but are not limited to, hydrogen, nitrogen, argon, helium, ethane, methane, ethylene, propane, or propylene; alternately any one or more of the gas stripping streams can have substantially no nitrogen, argon, or helium (e.g., 100 ppm or less such as 10 ppm or less such as 0 ppm, on basis of either mass or volume, of nitrogen and / or argon), but can include any one or more of the other just-listed gases. In some embodiments, the gas stripping stream utilized in the purge bin 5036 can include nitrogen recovered from the recovery unit 100 with or without the use of one or more membrane separation units. In some embodiments, recovered nitrogen can include 50 % v / v to 99 % v / v of nitrogen with the balance including one or more Ci to C10 hydrocarbons.

[0108] The purge vent stream in line 5060 can have the same composition as the purge gas in line 1000 described above with reference to FIG. 1. The purge vent stream via line 5060 can be introduced to the heat exchanger 5032. During normal operating conditions a hot or warm purge vent stream via line 5060 can be introduced to the indirect heat exchanger 5032 where heat can be transferred from the hot or warm purge vent stream to a heat transfer medium via the indirect heat exchanger 5032. The heat transfer medium may include any suitable material that is capable of absorbing the heat emitted by the hot or warm purge vent stream. For example, and without limitation, the heat transfer medium can include chilled water capable of absorbing the heat from the purge vent stream. As a further example, the heat exchanger 5032 can include a shell and tube exchanger that utilizes cool water as a cooling medium. As a further example, the heat exchanger 5032 can include a refrigeration system and / or a plate and frame / spiral system.

[0109] The heat exchanger 5032 can produce a purge vent stream in line 5070 that can be at a temperature of 15°C, 20°C, 25°C, 30°C. or 35°C to 40°C, 45°C, 50°C, 55°C, or 60°C. Without being bound by theory, when the purge vent stream in line 5060 is cooled, the pressure will drop. As such, the purge vent stream in line 5070 can be sent to the compressor 5028 from the heat exchanger 5032 to allow for a controlled temperature increase downstream. The compressor 5028 can compress the purge vent stream to produce a compressed purge gas via line 5072. The compressed purge gas in line 5072 can be at a pressure in a range from 500 kPag, 700 kPag, 800 kPag, 900 kPag, 1,000 kPag, 1,100 kPag, 1,200 kPag, 1,300 kPag, 1,400 kPag, or 1,500 kPag to 1,700 kPag, 2,000 kPag, 2,300 kPag, 2,500 kPag, 2,700 kPag, or 3,000 kPag. In some embodiments, the compressor 5028 can compress the purge vent stream in line 5070 in a single stage, two stages, three stages, four stages, or more.

[0110] During compression of the purge vent stream within the compressor 5028, the temperature of the purge gas can be maintained below a predetermined maximum temperature. The maximum temperature can be based, at least in part, on the particular make-up or composition of the purge gas product in line 5060. For example, if the purge vent stream includes catalytic components such as triethylaluminum (TEAL) and one or more olefins, the predetermined maximum temperature could be less than about 140°C, e.g., less than 125°C or less than 120°C, because if the purge gas product is heated to a higher temperature, polymerization could be initiated within the compressor 5028. Depending, at least in part, on the particular composition of the purge vent stream, e.g., the presence of catalytic components and / or the concentration of catalytic components in the purge vent stream, the temperature of the purge vent stream can be maintained below 150°C, below 140°C, below 130°C, below 125°C, below 120°C, below 115°C, below 110°C, or below 100°C during compression.

[0111] The compressor 5028 can compress the purge vent stream in line 5070 at any desired pressure ratio, e.g., any desired ratio of the pressure of the purge vent stream introduced to the compressor 5028 compared to the pressure of the compressed purge gas recovered from the compressor 5028. For example, the purge vent stream in line 5070 can have a pressure of about 20 kPag or 25 kPag to 30 kPag or 40 kPag entering the compressor 5028, in which the compressed purge gas in line 5072 exiting the compressor 5028 can have a pressure of about 385 kPag. The compressor 5028 can compress the purge vent stream at a pressure ratio ranging from about 1:2 to about l:20ie.g., about 1:2, about 1:4, about 1:5, about 1:7, or about 1:10 to about 1:12, about 1:15, about 1:17, or about 1:20. Without being bound by theory, the pressure ratio within the compressor 5028 can be based, at least in part, on the desired pressure of thecompressed purge gas, the type of compressor, the desired predetermined maximum temperature of the compressed purge gas after compression, or any combination thereof.

[0112] The compressed purge gas in line 5072 can have a temperature that is based on the amount of compression in compressor 5028 and the temperature of the purge vent stream in line 5070. As the purge vent stream in line 5070 is compressed within the compressor 5028, the partial pressure of the unreacted monomers, unreacted comonomers, impurities, and catalytic components increases. As such, the potential for polymerization initiating increases, requiring control of the maximum temperature of the compressed purge gas in line 5072. By controlling the pressure ratio of the compressor 5028, the temperature of the compressed purge gas in line 5072 can be controlled, in which a temperature that is below the maximum temperature can be produced, limiting polymerization in the compressor 5028 and in line 5072.

[0113] The compressed purge gas in line 5072 can be introduced to the heat exchanger 5034. In some embodiments, the heat exchanger 5034, which can also be referred to as an interchanger, can include a series of diverters or valves capable of directing or redirecting the compressed purge gas in line 5072. In some embodiments, the heat exchanger 5034 can receive the compressed gas via line 5072, where the compressed gas in line 5072 can be at a temperature in a range from 90°C to 140°C and a pressure of 400 kPag to 2,450 kPag, and receive the gaseous or vapor phase overhead in line 1006 from the purge gas recovery unit 100, where the gaseous or vapor phase overhead in In line 1006 can be at a temperature in a range from -50°C to -20°C and a pressure in a range of 500 kPag to 1 ,500 kPag, where the compressed gas can be cooled while concurrently warming the gaseous or vapor phase overhead.

[0114] A cooled compressed gas can be recovered via line 1000 from the heat exchanger 5034 and introduced to the purge gas vent recovery unit 100, i.e., heat exchanger 1050, as described above with reference to FIG. 1. As described above, the cooled compressed gas in line 1000 can be at a temperature in a range from0°C, 5°C, 10°C, or 15°Cto 20°C, 25°C, 30°C, or 35°C and at a pressure in a range from 500 kPag, 700 kPag, 800 kPag, or 900 kPag to 1,000 kPag, 1,100 kPag, 1,200 kPag, 1,300 kPag, 1,400 kPag, or 1,500 kPag. For example, in some embodiments, the cooled compressed gas in line 1000 can be at a temperature of 15°C to 25°C and a pressure of 900 kPag to 1,100 kPag.

[0115] A heated gaseous or vapor phase overhead via line 5074 can be recovered from the heat exchanger 5034. In some embodiments, at least a portion of the heated gaseous or vapor phase overhead in line 5074 can be recycled via line 5076 to the reactor 5022, e.g., to the velocity reduction zone or dome 5050. Alternatively, at least a portion of the heated gaseous or vapor phase overhead in line 5074 can be introduced to the cycle line 5052 (not shown). Insome embodiments, at least a portion of the heated gaseous or vapor phase overhead in line 5074 can be recycled via line 5078 to the purge bin 5036. In some embodiments, the heated gaseous or vapor phase overhead in line 5074 that can be recycled to the reactor 5022, the cycle line 5052, and / or the purge bin 5036 can be compressed such that the heated gaseous or vapor phase overhead in line 5076 can be at a sufficient pressure to enable recycle of the heated gaseous or vapor phase overhead in line 5074. In some embodiments, at least a portion of the heated gaseous or vapor phase overhead in line 5074 can be removed via line 5080 from the system 500, e.g., sent to flare.

[0116] In some embodiments, the condensed or liquid phase bottoms in line 1008 recovered from the vent recovery drum 1004 can be recycled to the polymerization reactor 5022. For example, at least a portion of the condensed or liquid phase bottoms via line 1008 can be recycled to the reactor 5022 by introducing the condensed or liquid phase bottoms via line 1008 to the cycle line 5052 between the heat exchanger 5030 and the reactor 5022. It should be understood, that the condensed or liquid phase bottoms in line 1008 can be recycled to any location in the cycle line 5052 and / or directly into the reactor 5022. In some embodiments, at least a portion of the condensed or liquid phase bottoms in line 1008 can be removed from the process, e.g., sent to flare and / or utilized in some other process, and / or sold as a product. Examples:

[0117] The foregoing discussion can be further described with reference to the following non-limiting examples.

[0118] Comparative Example - a purge gas recovery unit, as disclosed in FIG. 2A of U.S. Patent No. 5,391,656, is evaluated via a simulation. This process flow utilizes ethylene at a temperature of 0°C to 25°C and a pressure of 6,890 kPag to 11,000 kPag to cool the purge gas. This process flow does not allow for liquified ethylene to be provided to the purge gas recovery unit and represents how stream 112 (Figure 2A) is introduced into the purge gas recovery unit. The simulation assumes the use of a world-scale steam cracker and two collocated polyethylene plants. The ethylene to be condensed in the steam cracker effluent is at a pressure of 1,900 kPag with an approximately 2.8°C subcool achieving a temperature of -31.6°C. The ethylene is pumped to a pipeline pressure of approximately 12,400 kPag. All of the ethylene is heated to a pipeline temperature of approximately 21.1 °C at ambient conditions either via heat integration or ambient heating. The ethylene is provided to the polyethylene plant where a side stream (approximately 60 T / hr) is taken and sent to the purge gas recovery unit, i.e., heat exchanger 108 in FIG. 2 A. The remainder of the ethylene is sent to the ethylene vaporizer.The vaporized ethylene condenses C2 / C4 / C5 molecules that can be recovered. This process, however, fails to recover approximately 2,300 kg / hr to 2,700 kg / hr of vent material per train.

[0119] Inventive Example - a purge gas recovery unit 100, as described above with reference to FIGS. 1 and 5, is evaluated via a simulation. By not heating the ethylene in line 1032 to pipeline temperature, the ethylene can condense additional molecules in the heat exchanger 1050, thus saving operating cost from not having to replace those molecules. The simulation assumes the use of a world-scale steam cracker and two collocated polyethylene plants. The ethylene to be condensed in the steam cracker effluent is at a pressure of 1,900 kPag with an approximately 2.8°C subcool achieving a temperature of -31.6°C. The ethylene is pumped to a pipeline pressure of approximately 12,400 kPag. A side stream (~ 35T / hr) is pulled from the main flow and sent directly via line 1032 to the heat exchanger 1050 in the purge gas recovery unit 100. The remaining ethylene is heated to a pipeline temperature of approximately 21.1°C in heat exchanger 1060. The side stream in line 1032 is split evenly to each of the two polyethylene plants. Note that the side stream needed in line 1032 is less as the sensible heat from the liquid ethylene additionally provides cooling duty. The side stream is reduced in pressure to 3,280 kPag via the expansion valve 1046 to allow for complete vaporization in the heat exchanger 1050. At 3,280 kPag, the -31.6°C ethylene has approximately 23.1 °C of subcool. The vaporized ethylene condenses C2 / C4 / C5 molecules that can be recovered. This process would result in losses of 2,200 kg / hr to 2,400 kg / hr of vent material per train. An improvement of 100 kg / hr to 300 kg / hr per train over the process disclosed in U.S. Patent No. 5,391,656.

[0120] Various terms have been defined above. To the extent a term used in a claim is not defined above, it should be given the broadest definition persons in the pertinent art have given that term as reflected in at least one printed publication or issued patent. Furthermore, all patents, test procedures, and other documents cited in this application are fully incorporated by reference to the extent such disclosure is not inconsistent with this application and for all jurisdictions in which such incorporation is permitted.

[0121] While the foregoing is directed to embodiments of the present invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow.

Claims

CLAIMS:What is claimed is:

1. A process for condensing one or more hydrocarbons, comprising:obtaining a liquified ethylene feed;expanding the liquified ethylene feed to produce an expanded ethylene feed, wherein the expanded ethylene feed is at a pressure and a temperature sufficient to maintain the ethylene in a liquid phase;indirectly transferring heat from a purge gas obtained from an olefin polymerization process to the expanded ethylene feed to produce a heated ethylene feed and a cooled purge gas comprising one or more condensed hydrocarbon molecules and one or more gaseous hydrocarbon molecules; andintroducing at least a portion of the heated ethylene feed into a polymerization reactor of the olefin polymerization process.

2. The process of claim 1 , wherein a temperature of the liquified ethylene feed and the expanded ethylene feed is the same.

3. The process of claim 1 or claim 2, wherein 100% of the heated ethylene feed is in a gaseous phase.

4. The process of any one of claims 1 to 3, wherein;the liquified ethylene feed is obtained, andthe one or more condensed hydrocarbon molecules comprise one or more of Ci-Cio linear alkanes, one or more of C4-C10 branched alkanes, one or more of C2-C10 alkenes, or a mixture thereof.

5. The process of claim 4, wherein the ethylene in the liquified ethylene feed is produced in a steam cracker.

6. The process of any one of claims 1 to 5, further comprising separating the one or more condensed hydrocarbon molecules from the one or more gaseous hydrocarbon molecules in the cooled purge gas.

7. The process of claim 6, further comprising recycling at least a portion of the one or more condensed hydrocarbon molecules to the polymerization reactor.

8. The process of claim 6 or claim 7, further comprising recycling at least a portion of the one or more gaseous hydrocarbon molecules to the polymerization reactor, a purge bin in fluid communication with the polymerization reactor, or a combination thereof.

9. The process of any one of claims 1 to 8, wherein the cooled purge gas is a first cooled purge gas, the process further comprising:indirectly transferring heat from the first cooled purge gas to the liquified ethylene feed to produce a second cooled purge gas comprising one or more additional condensed hydrocarbon molecules and a heated liquified ethylene feed, wherein the heated liquified ethylene feed is expanded to produce the expanded ethylene feed.

10. The process of 9, further comprising indirectly transferring heat from the liquified ethylene feed to a fluid to produce a chilled liquified ethylene feed and a heated fluid, wherein the heat indirectly transferred from the first cooled purge gas is indirectly transferred to the chilled liquified ethylene feed to produce the second cooled purge gas and the heated liquified ethylene feed.

11. The process of any one of claims 1 to 8, further comprising indirectly transferring heat from the liquified ethylene feed to a fluid to produce a chilled liquified ethylene feed and a heated fluid, wherein the chilled liquified ethylene feed is expanded to produce the expanded ethylene feed.12 The process of claim 10 or claim 11, wherein the fluid comprises ethylene.

13. The process of any one of claims 1 to 12, wherein the liquified ethylene feed is a supercritical ethylene feed, and wherein the supercritical ethylene feed is expanded to produce the expanded ethylene feed.

14. A process for upgrading one or more hydrocarbons, comprising:steam cracking a hydrocarbon to produce a steam cracker effluent; separating an ethylene feed from the steam cracker effluent;compressing and cooling the ethylene feed to produce a liquified ethylene feed; expanding the liquified ethylene feed to produce an expanded ethylene feed, wherein the expanded ethylene feed is at a pressure and a temperature sufficient to maintain the ethylene in a liquid phase;indirectly transferring heat from a purge gas obtained from an olefin polymerization process to the expanded ethylene feed to produce a heated ethylene feed and a cooled purge gas comprising one or more condensed hydrocarbon molecules and one or more gaseous hydrocarbon molecules; andintroducing at least a portion of the heated ethylene feed into a polymerization reactor of the olefin polymerization process.

15. The process of claim 14, wherein a temperature of the liquified ethylene feed and the expanded ethylene feed is the same.

16. The process of claim 15, further comprising pumping the liquified ethylene feed to produce a supercritical ethylene feed, wherein the supercritical ethylene feed is expanded to produce the expanded ethylene feed.

17. The process of claim 16, wherein a temperature of the supercritical ethylene feed and the expanded ethylene feed is the same.

18. The process of any one of claims 14 to 17, wherein 100% of the heated ethylene feed is in a gaseous phase.

19. The process of any one of claims 14 to 18, wherein:the ethylene feed is separated from the steam cracker effluent, andthe one or more condensed hydrocarbon molecules comprise one or more of Ci-Cio linear alkanes, one or more of C4-C10 branched alkanes, one or more of C2-C10 alkenes, or a mixture thereof.

20. The process of any one of claims 14 to 19, further comprising separating the one or more condensed hydrocarbon molecules from the one or more gaseous hydrocarbon molecules in the cooled purge gas.

21. The process of claim 20, further comprising recycling at least a portion of the one or more condensed hydrocarbon molecules to the polymerization reactor.

22. The process of claim 20 or claim 21, further comprising recycling at least a portion of the one or more gaseous hydrocarbon molecules to the polymerization reactor, a purge bin in fluid communication with the polymerization reactor, or a combination thereof.

23. The process of any one of claims 14 to 22, wherein the cooled purge gas is a first cooled purge gas, the process further comprising:indirectly transferring heat from the first cooled purge gas to the liquified ethylene feed to produce a second cooled purge gas comprising one or more additional condensed hydrocarbon molecules and a heated liquified ethylene feed, wherein the heated liquified ethylene feed is expanded to produce the expanded ethylene feed.

24. The process of claim 23, further comprising indirectly transferring heat from the liquified ethylene feed to a fluid to produce a chilled liquified ethylene feed and a heated fluid, wherein the heat indirectly transferred from the first cooled purge gas is indirectly transferred to the chilled liquified ethylene feed to produce the second cooled purge gas and the heated liquified ethylene feed.

25. The process of any one of claims 14 to 22, further comprising indirectly transferring heat from the liquified ethylene feed to a fluid to produce a chilled liquified ethylene feed and a heated fluid, wherein the chilled liquified ethylene feed is expanded to produce the expanded ethylene feed.

26. The process of claim 24 or claim 25, wherein the fluid comprises ethylene.

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