Hydrocarbon purification with alkali wash

Abstract

Embodiments of the present disclosure relate to hydrocarbon purification, in particular waste plastic purification using alkali wash.

Description

Technical Field

[0001] The embodiments disclosed herein relate to hydrocarbon purification, particularly hydrocarbon purification using alkaline washing solutions. Background Technology

[0002] Waste plastics are typically sent to landfills or incinerated, with only a small portion being recycled. Recycling of waste plastics can be achieved through various processes in which plastic waste is converted into solid, liquid, and / or gaseous fuels.

[0003] Hydrocarbon streams obtained during waste plastics processing may contain numerous impurities. These impurities can potentially poison the catalyst and / or impair other unit operations related to waste plastics processing. Therefore, it may be desirable to remove impurities from the hydrocarbons before using them in downstream processes. Summary of the Invention

[0004] This disclosure provides various implementation methods, including but not limited to:

[0005] A method for purifying hydrocarbons using an alkaline washing solution, the method comprising: transferring waste plastics to a depolymerization reactor; depolymerizing the waste plastics in the depolymerization reactor to provide a depolymerization reactor output; transferring the depolymerization reactor output to an extraction tower having an alkaline washing solution input; washing the depolymerization reactor output in the extraction tower to provide an extraction tower residue; transferring the extraction tower residue to a hydrogenation treatment reactor; and hydrogenating the extraction tower residue in the hydrogenation treatment reactor to provide purified hydrocarbons. Attached Figure Description

[0006] Figure 1 This is a schematic diagram of a hydrocarbon purification system utilizing alkaline washing solution according to an embodiment of this disclosure.

[0007] Figure 2 This is a schematic diagram of a system utilizing alkaline washing solution according to an embodiment of this disclosure.

[0008] Figure 3 This is a schematic diagram of a hydrocarbon purification system utilizing alkaline washing solution according to an embodiment of this disclosure. Detailed Implementation

[0009] This disclosure relates to methods and systems for the purification of waste plastics (e.g., hydrocarbons), and particularly for the purification of waste plastics using alkaline washing solutions. One or more embodiments specify that the waste plastics, such as hydrocarbon streams, are obtained during waste plastic processing. One or more embodiments specify that the waste plastics are, for example, solids before entering a depolymerization reactor.

[0010] Impurities in waste plastics (such as hydrocarbon streams made from plastic waste) can be removed using various technologies. One previously used technique for removing impurities from hydrocarbons prior to steam cracking was hydrogenation. In hydrogenation, hydrocarbons are catalytically treated at elevated temperatures in a hydrogen atmosphere to help reduce impurities.

[0011] Plastic waste, including useful hydrocarbons (which can be obtained by processing plastic waste), can also include numerous impurities such as N, S, Cl, Br, F, Si, P, and / or I. One or more embodiments specify that these impurities may also contain one or more metals. As an example, waste plastics may include impurities including heteroatoms such as chlorinated compounds, as found in polyvinyl chloride, sulfonated compounds such as tert-butylmethyl sulfide, dimethyl disulfide, dibenzothiophene, etc., and / or nitrogen compounds such as quinoline, which can be converted from nitrogen compounds into acids such as hydrochloric acid, sulfuric acid, and ammonia. When high concentrations of impurities are present, the catalyst used for hydrogenation can deactivate more rapidly. As mentioned above, these impurities can form undesirable compounds such as NH3 and / or HCl, which can lead to corrosion. Additionally, HCl can react with NH3 to form NH4Cl, which can cause clogging of downstream pipelines and / or scaling in heat exchangers. To mitigate these problems, previous hydrogenation processes have utilized large amounts of water, for example, to reduce HBr and / or NH3 in the hydrocarbons.

[0012] Hydrogenation processing facilities are designed to operate at moderate pressure levels and are not designed to tolerate large amounts of catalyst impurities, such as poisons. Therefore, it is desirable to remove poisons from waste plastics within the processing facility.

[0013] Embodiments of this disclosure specify the use of alkaline washing solutions to reduce the concentration of impurities, such as hydrocarbons, in waste plastics. The embodiments specify that, advantageously, the alkaline washing solution can replace and / or reduce water consumption from hydrocarbon purification. As disclosed herein, the alkaline washing solution can reduce the concentration of one or more components from hydrocarbon streams, such as, for example, HCl, HF, HBr, and H2S.

[0014] Figure 1 This is a schematic diagram of a hydrocarbon purification system 100 utilizing an alkaline washing solution according to an embodiment of this disclosure. As discussed herein, hydrocarbon purification may include depolymerization. The hydrocarbon purification system 100 can be used to purify hydrocarbon materials, such as waste plastics. As used herein, “waste plastics” includes raw materials as defined in ISO 18604, polymers recovered from post-consumer materials as defined in ISO 14021, and combinations thereof. Waste plastics may include alkanes, oxygen-containing compounds, nitrogen-containing compounds, chlorides, sulfur components, and combinations thereof. Waste plastics may contain significant amounts of dienes and olefins, as well as impurities such as, for example, N, O, S, and Cl.

[0015] Hydrocarbon purification system 100 may include a depolymerization section 101. The depolymerization section 101 can reduce the size of polymers, for example, by depolymerizing the polymers therein. Embodiments specify that the depolymerization section 101 may include one or more known elements, such as a pump or other known processing elements. Figure 1 Not shown in the diagram. The depolymerization section 101 may include a depolymerization reactor. The depolymerization reactor may also be referred to by terms such as a hydrodepolymerization reactor and / or a catalytic depolymerization reactor. The depolymerization reactor may be a fixed-bed reactor. The depolymerization reactor may include a depolymerization catalyst.

[0016] The depolymerization catalyst can be a supported catalyst comprising a Group VIII metal selected from the group consisting of Ni, Pd, Pt, Co, Rh, Fe, Mo, W, Ti, Cr, V, Zr, and / or Ru, and optionally a Group VIB metal selected from the group consisting of Mo and / or W, on an amorphous mineral support selected from the group consisting of alumina, silica, silica-alumina, magnesia, clay, and combinations thereof. The depolymerization catalyst may also include supported zeolites, such as, for example, SiO2, Al2O3, AlPO4, and combinations thereof.

[0017] The depolymerization reactor can be operated at temperatures ranging from 50°C to 250°C. This includes all individual values ​​and sub-ranges from 50°C to 250°C; for example, the depolymerization reactor can be operated at temperatures ranging from a lower limit of 50°C, 60°C, or 70°C to an upper limit of 250°C, 240°C, or 230°C.

[0018] Depolymerization reactors can operate at pressures ranging from 15 bar absolutes (bara) to 200 bara. This includes all individual values ​​and sub-ranges within the 15 bara to 200 bara range; for example, depolymerization reactors can operate at lower limits of 15 bara, 20 bara, or 25 bara to upper limits of 200 bara, 190 bara, or 180 bara. The combination of pressure and reactor outlet temperature can specify that a portion of the contents of the depolymerization reactor is in a liquid state.

[0019] The depolymerization section 101 may have a first input 111. The first input may comprise waste plastics, such as unpurified hydrocarbons containing one or more impurities as discussed herein. The first input may comprise solid waste plastics, such as granular or shredded waste plastics. In other words, the embodiment specifies that the first input 111 is not a liquid.

[0020] The first input 111 (e.g., waste plastic) may have various compositions. The first input 111 may include waste plastic obtained from, for example, the following: bottle caps and stoppers, milk, water or orange juice containers, detergent bottles, office automation equipment (printers, computers, copiers, etc.), white goods (refrigerators, washing machines, etc.), consumer electronics (televisions, video recorders, stereos, etc.), automotive shredder residue (the mixed material remaining after most of the metal has been separated from shredded automobiles and other metal-rich products "shredded" by metal recyclers), packaging waste, household waste, rotational molding parts (kayaks / coolers), construction waste, and industrial molding and extrusion waste, etc.

[0021] Examples of waste plastics include polyolefins such as polyethylene and polypropylene, polyesters such as polyethylene terephthalate, vinyl polymers such as polyvinyl chloride, acrylonitrile, butadiene and styrene homopolymers and interpolymers, polyesters such as polyethylene terephthalate and poly(bisphenol A carbonate), polyamides such as nylon 66, polycarbonates such as poly(bisphenol A carbonate), acrylics such as poly(methyl methacrylate), fluorocarbon polymers, polyethers, polysaccharides, silicones such as poly(dimethylsiloxane), thermoplastic elastomers such as ethylene propylene rubber, and combinations thereof.

[0022] In one or more embodiments, the waste plastic may have a concentration of 0.900 g / cm³. 3 Up to 0.990 g / cm 3 The density. This article discloses and incorporates 0.900 g / cm³. 3 Up to 0.9990 g / cm 3 All individual values ​​and sub-ranges; for example, waste plastics may have a lower limit of 0.900 g / cm³. 3 0.905g / cm 3 Or 0.910 g / cm 3 The upper limit is 0.990 g / cm³. 3 0.980 g / cm 3 Or 0.970 g / cm 3 The density can be determined according to ASTM D792.

[0023] In one or more embodiments, the waste plastic may have a melt index (I2) ranging from 0.30 dg / min to 6.00 dg / min. All individual values ​​and sub-ranges from 0.30 dg / min to 6.00 dg / min are disclosed and incorporated herein; for example, waste plastic may have a melt index (I2) from a lower limit of 0.30 dg / min, 0.80 dg / min, 1.00 dg / min, 1.25 dg / min, 1.50 dg / min, or 1.80 dg / min to an upper limit of 6.00 dg / min, 5.00 dg / min, 4.00 dg / min, 3.50 dg / min, 3.00 dg / min, or 2.80 dg / min. I2 can be determined according to ASTM D1238 (190°C, 2.16 kg).

[0024] The depolymerization section 101 may have a second input 116. The second input may contain hydrogen. The hydrogen from the second input may react with one or more impurities of unpurified hydrocarbons from the first input 111 in the presence of a depolymerization catalyst.

[0025] The partial pressure of hydrogen in the gas phase in the depolymerization reactor can be from 10 bar to 140 bar. This includes all individual values ​​and sub-ranges from 10 bar to 140 bar; for example, hydrogen can have a partial pressure from a lower limit of 10 bar, 12 bar, or 14 bar to an upper limit of 140 bar, 135 bar, or 130 bar.

[0026] The hydrocarbon purification system 100 may include an extraction section 105. The extraction section 105 may include an extraction column. Embodiments specify that the extraction section 105 may include one or more known components, such as pumps or other known processing elements. Figure 1 Not shown in the diagram. The depolymerized contents from depolymerization section 101 can be fed into extraction section 105 via depolymerization output 112. In other words, the depolymerization reactor output can be transferred to the extraction column. As used herein, the two sections are “fluidly connected” to each other as fluid moves from the first section to the second section.

[0027] Hydrocarbon purification system 100, such as an extraction tower, may include an alkaline wash feed 110 leading to an extraction section 105. As used herein, "alkaline wash feed" refers to a liquid phase composition with a pH of 8 to 14. This includes all individual values ​​and sub-ranges of 8 to 14; for example, an alkaline wash feed may have a pH from a lower limit of 8, 8.5, or 9 to an upper limit of 14, 13, 12, 11, or 10. The pH of the alkaline wash feed can be determined by known methods, such as ASTM D1067. The alkaline wash feed can be used for extraction, for example, washing the depolymerization reactor output in an extraction tower.

[0028] One or more embodiments specify that the alkaline washing solution is a solution. One or more embodiments specify that the alkaline washing solution is an aqueous solution. One or more embodiments specify that the alkaline washing solution can be prepared using an alkali (e.g., an alkaline substance). One or more embodiments specify that the alkaline washing solution can be prepared using sodium hydroxide (NaOH), potassium hydroxide (KOH), calcium hydroxide (Ca(OH)2), or combinations thereof. One or more embodiments specify that the alkaline washing solution is prepared using NaOH. The alkaline washing solution input 110 can partially extract hydrocarbons bonded to heteroatoms, such as chlorine and / or silicon, as well as the resulting inorganic substances, such as H2S, HCl, HF, and HBr.

[0029] The alkaline washing input 110 can be 20% to 150% by weight of the total weight of the depolymerized contents from the depolymerization section (e.g., the depolymerization reactor output transferred to the extraction column (depolymerized contents from the depolymerization reactor)) fed into the extraction section. This includes all individual values ​​and sub-ranges from 20 to 150; for example, the alkaline washing solution can be a lower limit of 20%, 25%, or 30% by weight of the total weight of the depolymerized contents fed into the extraction section from the depolymerization section, and an upper limit of 150%, 130%, or 110% by weight.

[0030] One or more implementation schemes specify that the internal recirculation flow can be used to control the flow rate of the alkaline washing solution entering the extraction tower.

[0031] The extraction column can operate at temperatures ranging from 150°C to 300°C. This includes all individual values ​​and sub-ranges from 150°C to 300°C; for example, the extraction column can operate at temperatures ranging from a lower limit of 150°C, 160°C, or 170°C to an upper limit of 300°C, 280°C, or 260°C.

[0032] The extraction column can operate at pressures from 15 bara to 200 bara. This includes all individual values ​​and sub-ranges from 15 bara to 200 bara; for example, the extraction column can operate at pressures from a lower limit of 15 bara, 20 bara, or 25 bara to an upper limit of 200 bara, 195 bara, or 190 bara.

[0033] The hydrocarbon purification system 100 may include a first extraction section output 119. The recovered material from the extraction column of the extraction section 105 may be sent via the first extraction section output 119 to the depolymerization section 101 and / or the heat transfer section 103.

[0034] The hydrocarbon purification system 100 may include a first diversion line 113. A portion of the recovered material (e.g., liquid) from the first extraction stage output 119 may be sent to a depolymerization stage 101 via the first diversion line 113. Different portions of the recovered material from the first extraction stage output 119 may be sent to the depolymerization stage 101 for various applications. One or more embodiments specify that, based on the total weight percentage of the recovered material in the first extraction stage output 119, 5% to 75% of the recovered material from the first extraction stage output 119 may be sent to the depolymerization stage. This includes all individual values ​​and sub-ranges from 5% to 75%; for example, based on the total weight percentage of the recovered material in the first extraction stage output 119, a lower limit of 5%, 10%, or 20% to an upper limit of 75%, 65%, or 50% of the recovered material from the first extraction stage output 119 may be sent to the depolymerization stage.

[0035] The hydrocarbon purification system 100 may include a second diversion line 114. A portion of the recovered material from the first extraction section output 119 may be sent to the heat transfer section 103 via the second diversion line 114. Different portions of the recovered material from the first extraction section output 119 may be sent to the heat transfer section 103 for various applications. One or more embodiments specify that, based on the total weight percentage of the recovered material from the first extraction section output 119, 25% to 95% of the recovered material from the first extraction section output 119 may be sent to the heat transfer section 103. This includes all individual values ​​and sub-ranges from 25% to 95%; for example, based on the total weight percentage of the recovered material from the first extraction section output, a lower limit of 25%, 35%, or 50% to an upper limit of 95%, 90%, or 80% of the recovered material from the first extraction section output 119 may be sent to the heat transfer section 103.

[0036] The hydrocarbon purification system 100 may include a second extraction stage output 102. Recovered material from the extraction column of extraction stage 105 can be sent to heat transfer stage 103 via the second extraction stage output 102. The second extraction stage output 102 can be used in place of the second diversion line 114 and / or in combination with the second diversion line. In other words, the total weight percentage of recovered material transferred from extraction stage 105 to heat transfer stage 103 can be transferred via the second diversion line 114, the second extraction stage output 102, or a combination thereof.

[0037] The hydrocarbon purification system 100 may include a third extraction stage output 120. The third extraction stage output 120 may be a hydrocarbon-rich output 120. For example, as... Figure 2The separator shown can be used to separate hydrocarbons and water from the extraction column output to provide a hydrocarbon-rich output 120. The third extraction stage output 120 can be removed from the hydrocarbon purification system 100.

[0038] Heat transfer section 103 may include a heat exchanger. Embodiments specify that heat transfer section 103 may include one or more known elements, such as a pump or other known processing elements. Figure 1 Not shown. The heat exchanger can operate, for example, at a temperature that allows the material fed to the heat exchanger to reach a desired temperature (250°C to 350°C). This includes all individual values ​​and sub-ranges of 250°C to 350°C; for example, the heat exchanger can operate at an inlet temperature ranging from a lower limit of 30°C, 35°C, or 40°C to an upper limit of 100°C, 90°C, or 80°C.

[0039] The heat exchanger can operate at pressures from 15 bara to 200 bara. This includes all individual values ​​and sub-ranges from 15 bara to 200 bara; for example, the heat exchanger can operate at pressures from a lower limit of 15 bara, 20 bara, or 30 bara to an upper limit of 200 bara, 190 bara, or 180 bara.

[0040] Heat transfer section 103 may include hydrogen input 107. Hydrogen from input 107 may have a partial pressure of 15 bara to 200 bara. This includes all individual values ​​and sub-ranges from 15 bara to 200 bara; for example, hydrogen from input 107 may have a partial pressure ranging from a lower limit of 15 bara, 20 bara, or 25 bara to an upper limit of 200 bara, 190 bara, or 180 bara, wherein the hydrogen from input 107 has a pressure greater than that of the heat exchanger in heat transfer section 103.

[0041] The heat transfer section 103 may include an output 106. The contents of the heat transfer section 103 may be transferred to the hydrogenation treatment section 104 via the output 106.

[0042] The implementation scheme specifies that the hydrogenation treatment section 104 may include one or more known components, such as pumps or other known processing components. Figure 1 Not shown in the diagram. The hydrogenation treatment section 104 may include a hydrogenation treatment reactor. The hydrogenation treatment reactor may be a fixed-bed reactor. The hydrogenation treatment reactor may include a hydrogenation treatment catalyst.

[0043] The hydrogenation catalyst may be a supported catalyst comprising a Group VIII metal selected from the group consisting of Ni, Pd, Pt, Co, Rh and / or Ru, and optionally a Group VIB metal selected from the group consisting of Mo and / or W, on an amorphous mineral support selected from the group consisting of alumina, silica, silica-alumina, magnesium oxide, clay and mixtures thereof.

[0044] The hydrogenation reactor can operate at temperatures ranging from 250°C to 350°C. This includes all individual values ​​and sub-ranges within the 250°C to 350°C range; for example, the hydrogenation reactor can operate at temperatures ranging from a lower limit of 250°C, 260°C, or 270°C to an upper limit of 350°C, 340°C, or 330°C. One or more embodiments specify that the hydrogenation reactor operates at a temperature higher than that of the depolymerization reactor.

[0045] The hydrogenation reactor can operate at pressures from 15 bara to 200 bara. This includes all individual values ​​and sub-ranges from 15 bara to 200 bara; for example, the hydrogenation reactor can operate at pressures from a lower limit of 15 bara, 20 bara, or 25 bara to an upper limit of 200 bara, 190 bara, or 180 bara.

[0046] The partial pressure of hydrogen in the gas phase in the hydrogenation reactor can be from 10 bar to 140 bar. This includes all individual values ​​and sub-ranges from 10 bar to 140 bar; for example, hydrogen can have a partial pressure ranging from a lower limit of 10 bar, 15 bar, or 20 bar to an upper limit of 140 bar, 130 bar, or 120 bar. One or more embodiments specify that the hydrogen in the hydrogenation reactor can have a partial pressure lower than the partial pressure of hydrogen in the depolymerization reactor.

[0047] Hydrogenation section 104 may include output 108. The hydrogenated (e.g., hydrotreating) contents of hydrogenation section 104 may be transferred out of hydrogenation section 104 via output 108, for example, to a downstream process, such as a flow cracker. Output 108 may be a purified hydrocarbon stream. One or more embodiments specify that the purified hydrocarbon stream contains saturated hydrocarbons, such as alkanes. As an example, the purified hydrocarbon stream may contain C2 to C34 hydrocarbons. 25 Saturated hydrocarbons.

[0048] Figure 2 This is a schematic diagram of the extraction section utilizing an alkaline washing solution according to an embodiment of this disclosure. Figure 2 Provided Figure 1 A more detailed view of the extraction section 105 shown.

[0049] like Figure 1 The depolymerized contents from depolymerization section 101 can be input into extraction section 105 via output 112. For example... Figure 2 As shown, output 112 can be transferred to heat transfer unit 250. Heat transfer unit 250 can specify that the contents of output 112 are at a temperature between 150°C and 300°C before entering extraction column 252. This includes all individual values ​​and sub-ranges of 150°C to 300°C; for example, heat transfer unit 250 can specify that the contents of output 112 are at a temperature between a lower limit of 150°C, 160°C, or 170°C and an upper limit of 300°C, 280°C, or 260°C before entering extraction column 252.

[0050] One or more embodiments specify that the heat transfer unit 250 can be optional; for example, the contents of the output 112 can be determined according to... Figure 2 The upstream processes, not shown, are at temperatures ranging from 150°C to 400°C.

[0051] The contents of the output 112, which can be heated by the heat transfer unit 250, can be transferred to the extraction column 252. One or more embodiments specify that the contents of the output 112 can be transferred to the lower section of the extraction column 252. The extraction column 252 can be used for liquid-liquid extraction. The extraction column 252 can include different known configurations for various applications. The extraction can be referred to as “reactive extraction” because the alkaline washing solution can react with one or more impurities in the extraction column.

[0052] like Figure 2 As shown, the alkaline washing liquid input 110 can be transferred to the extraction column 252. One or more embodiments specify that the contents of the alkaline washing liquid input 110 can be transferred to the upper section of the extraction column 252. A number of processing units can be used to transfer the heat associated with the alkaline washing liquid input 110. The number of processing units can be used to specify the temperature of the alkaline washing liquid input 110 upon entering the extraction column 252 as ranging from 150°C to 300°C. This includes all individual values ​​and sub-ranges from 150°C to 300°C; for example, the heater 250 can specify the temperature of the alkaline washing liquid input 110 upon entering the extraction column 252 as ranging from a lower limit of 150°C, 160°C, or 170°C to an upper limit of 300°C, 280°C, or 260°C.

[0053] like Figure 2 As shown, heat transfer unit 254 can be used to transfer heat to alkaline washing liquid input 110. Water-rich extraction tower output 256 can be used to transfer heat, for example, from heat transfer unit 254 to alkaline washing liquid input 110. Water-rich extraction tower output 256 can be discharged by gravity, for example, at the bottom portion of extraction tower 252.

[0054] like Figure 2As shown, after leaving heat transfer unit 254, the water-rich extraction column output 256 can be transferred to heat transfer unit 258. The water-rich extraction column output 256 leaving heat transfer unit 254 can be at a temperature from 30°C to 85°C. This includes all individual values ​​and sub-ranges from 30°C to 85°C; for example, the water-rich extraction column output leaving the heat transfer unit can be at a temperature from a lower limit of 30°C, 35°C, or 40°C to an upper limit of 85°C, 75°C, or 65°C.

[0055] The heat transfer unit 258 can specify that the output 256 of the water-rich extraction tower can be at a temperature from 15°C to 65°C. This includes all individual values ​​and sub-ranges from 15°C to 65°C; for example, the heat transfer unit 258 can specify that the output of the water-rich extraction tower is at a temperature from a lower limit of 15°C, 20°C, or 25°C to an upper limit of 65°C, 55°C, or 45°C.

[0056] The output 256 of the water-rich extraction column can be sent from the heat transfer unit 258 to the separator 260. The separator 260 can be used to separate hydrocarbons and water from the output 256 of the water-rich extraction column. The separator 260 may include different known configurations for various applications.

[0057] Separator 260 can provide hydrocarbon-rich separator output 120 and water-rich separator output 262. Hydrocarbon-rich separator output 120 can be removed from extraction section 105.

[0058] The output 262 of the water-rich separator can be transferred to pump 264. For example... Figure 2 As shown, the alkaline washing solution input 110 may include a first portion of the water-rich separator output 262, while a second portion of the water-rich separator output 262 may be removed from the extraction section 105 via output 266, for example, to avoid excessive accumulation of undesirable components. One or more embodiments specify that pump 264 may be used to help reduce the intake of supplemental alkaline solution via the recirculation of the water-rich separator output 262. One or more embodiments specify that the recirculation of the first portion of the water-rich separator output 262 may specify that the recirculated water to hydrocarbon mass ratio can be maintained at approximately 1:1.

[0059] like Figure 2 As shown, extraction section 105 may include extraction column residue 268. Extraction column residue 268 may be hydrogen-rich. Extraction column residue 268 can be generated by washing the depolymerization reactor effluent in the extraction column. As further discussed herein, extraction column residue 268 may be transferred to a hydrogenation reactor for hydrogenation to provide a purified hydrocarbon stream.

[0060] Extraction column residue 268 may contain hydrocarbons. Based on the total weight of hydrocarbons and water in extraction column residue 268, extraction column residue 268 may be from 60 wt% to 100 wt% hydrocarbons. This includes all individual values ​​and sub-ranges from 60 wt% to 100 wt%; for example, based on the total weight of hydrocarbons and water in extraction column residue, extraction column residue may be from a lower limit of 60 wt%, 65 wt%, or 70 wt% to an upper limit of 100 wt%, 95 wt%, or 90 wt% hydrocarbons. Water in extraction column residue 268 may be harmful to one or more downstream catalysts.

[0061] Extraction column residue 268 may have a temperature of 100 to 185°C. This includes all individual values ​​and sub-ranges from 150°C to 300°C; for example, extraction column residue 268 may have a temperature from a lower limit of 150°C, 160°C, or 170°C to an upper limit of 300°C, 280°C, or 260°C.

[0062] The extractant residue 268 can be transferred to the heat transfer unit 270. One or more embodiments specify that the extractant residue 268 entering the heat transfer unit 270 has a temperature higher than the alkaline washing liquid input 110 entering the heat transfer unit 270. In other words, heat can be transferred from the extractant residue 268 to the alkaline washing liquid input 110.

[0063] Extraction column residue 268 can be transferred from heat transfer unit 270 to heat transfer unit 272. Heat transfer unit 272 can be used to precisely control the temperature of extraction column residue 268 entering three-phase separator 274. Extraction column residue 268 entering three-phase separator 274 can have different temperatures for various applications.

[0064] The three-phase separator 274 can have a temperature range of 25°C to 100°C. This includes all individual values ​​and sub-ranges from 25°C to 100°C; for example, the three-phase separator can have a lower limit of 25°C, 30°C, or 35°C to an upper limit of 100°C, 90°C, or 80°C. The three-phase separator 274 can have a pressure that maintains 60% by weight or more of the water in the three-phase separator in a liquid state.

[0065] Three-phase separator 274 can be used to separate the extraction residue 268 from the extraction tower into a hydrogen stream 276, an aqueous stream 278, and a hydrocarbon stream 280. The aqueous stream 278 may include waste alkali.

[0066] Ideally, hydrocarbon stream 280 can provide reduced catalyst poisoning compared to hydrocarbon streams prepared by other methods. Therefore, hydrocarbon stream 280 can be advantageously used for further downstream processing.

[0067] Figure 3 This is a schematic diagram of a hydrocarbon purification system 300 utilizing an alkaline washing solution according to an embodiment of this disclosure. Figure 3 Provided Figure 1 A more detailed view of the hydrocarbon purification system 100 shown.

[0068] like Figure 1 The discussion may utilize a first input 111 containing waste plastics (e.g., unpurified hydrocarbons). The first input may include waste plastics that can be in a solid phase.

[0069] The first input 111 can be transferred to the heat transfer unit 330. The heat transfer unit 330 can specify the first input 111 to be at a temperature between 150°C and 400°C. This includes all individual values ​​and sub-ranges of 150°C to 400°C; for example, the heat transfer unit 330 can specify the first input 111 to be at a temperature from a lower limit of 150°C, 160°C, or 170°C to an upper limit of 400°C, 380°C, or 360°C.

[0070] The first input 111 can be transferred from the heat transfer unit 330 to the depolymerization reactor 332; for example, unpurified hydrocarbons can be transferred to the depolymerization reactor 332. In other words, the depolymerization reactor 332 can be in fluid communication with an upstream process (e.g., a conveyor) that supplies a stream of waste plastics to the depolymerization reactor 332. Figure 1 The discussion, for example, pertains to a portion of depolymerization section 101. The embodiment specifies that within depolymerization reactor 332, the waste plastic of the first input 111 is depolymerized, for example, the waste plastic is formed into relatively small polymer segments.

[0071] As discussed herein, the output can be transferred from depolymerization reactor 332 to extraction section 105. Embodiments of this disclosure specify, as previously mentioned, that an alkaline washing solution is used to reduce the concentration of impurities in hydrocarbons, such as the output from depolymerization reactor 332. As disclosed herein, the alkaline washing solution can reduce the concentration of one or more components from the hydrocarbon stream, such as, for example, HCl, HF, HBr, and H2S.

[0072] like Figure 2 As shown, multiple streams can be output from the extraction section 105, including a hydrogen stream 276, an aqueous stream 278, and a hydrocarbon stream 280.

[0073] like Figure 3As shown, aqueous stream 278 can be removed from hydrocarbon purification system 300. Hydrogen stream 276 can be recycled in hydrocarbon purification system 300. Hydrogen stream 280, containing hydrocarbons purified using alkaline washings from extraction section 105, can be used for further downstream hydrogenation treatment using a catalyst that deactivates more quickly in the presence of relatively high concentrations of impurities. Because hydrocarbon stream 280 contains purified hydrocarbons, i.e., contains relatively low concentrations of impurities compared to hydrocarbon streams provided by other methods, advantageously, the downstream hydrogenation catalyst remains active for a longer time than a hydrogenation catalyst exposed to a hydrocarbon stream with relatively high concentrations of impurities. One or more embodiments specify that the purified hydrocarbon stream 280 contains saturated hydrocarbons, such as alkanes. Various saturated hydrocarbons are available for different applications.

[0074] like Figure 3 As shown, the hydrocarbon stream 280 can be transferred via pump 342 to multiple heat transfer units, such as heat transfer unit 334, heat transfer unit 336, and heat transfer unit 338, in the path to... Figure 1 The hydrogenation treatment section 104 discussed is located in the hydrogenation treatment reactor 340. Although three heat transfer units 334, 336, and 338 are shown in the path to the hydrogenation treatment reactor 340, the embodiments are not limited to this. For example, various embodiments specify that there may be fewer or more than three heat transfer units in the path to the hydrogenation treatment reactor 340.

[0075] Hydrocarbons already hydrogenated in hydrogenation reactor 340 can be transferred to flash unit 344, such as a flash tank. Figure 3 As shown, the hydrocarbons hydrogenated in the hydrogenation reactor 340 may pass through multiple heat transfer units, such as heat transfer units 336 and 342, on their way to the flash unit 344. Although two heat transfer units 336 and 342 are shown on the way to the flash unit 344, the embodiments are not limited thereto. For example, various embodiments specify that there may be fewer or more than two heat transfer units on the way to the flash unit 344.

[0076] Flash evaporation unit 344 can be used to provide a gas phase stream 346 and a liquid phase stream 348. The liquid phase stream 348 can be referred to as the final product of the hydrocarbon purification system 300. The liquid phase stream 348 may contain hydrocarbons, such as C5 to C64 hydrocarbons. 12 Aromatic hydrocarbons and / or alkanes.

[0077] The gas phase stream 346 may contain hydrogen, relatively light hydrocarbons (compared to the liquid phase stream 348), and / or inorganic byproducts of hydrogenation treatment, such as H2S, NH3, and HCl.

[0078] The gas stream 346 can be transferred to a scrubber 350. The scrubber 350 can treat the gas stream 346 using an aqueous NaOH stream 352. Waste NaOH from the scrubber 350 can be recovered via the scrubber output 350. The scrubbed gas can be recycled to the hydrocarbon purification system 300 via a compressor 358 and a scrubbed gas recirculation stream 356. Figure 3 As shown, the washed gas recirculation stream 356 can be combined with the hydrogen input stream 360, for example, before the compressor 358.

[0079] A portion of the scrubbed gas from scrubber 350 can be purged from hydrocarbon purification system 300 via scrubbed gas purge stream 362. Different amounts of scrubbed gas from scrubber 350 can be used for purging in various applications.

Claims

1. A method for purifying hydrocarbons using an alkaline washing solution, the method comprising: Transfer waste plastics to a depolymerization reactor; The waste plastic is depolymerized in the depolymerization reactor to provide depolymerization reactor output; The output of the depolymerization reactor is transferred to an extraction tower with an alkaline washing liquid input. The effluent from the depolymerization reactor is washed in the extraction tower with the alkaline washing solution input to provide extraction tower residue.

2. The method according to claim 1, further comprising transferring the extraction column residue to a hydrogenation treatment reactor; The extraction column residue is hydrogenated in the hydrogenation reactor to provide a purified hydrocarbon stream.

3. The method according to claim 1, wherein the alkaline washing solution is a liquid phase composition with a pH of 8 to 14.

4. The method according to claim 1, wherein the alkaline washing solution is an aqueous solution.

5. The method according to claim 1, wherein the alkaline washing solution comprises sodium hydroxide.

6. The method of claim 1, wherein the alkaline washing solution is 20% to 150% by weight of the total weight of the depolymerized contents from the depolymerization reactor fed into the extraction tower.

7. The method of claim 1, wherein the extraction column operates at a temperature of 100°C to 300°C and a pressure of 15 bar to 200 bar.

8. A hydrocarbon purification system, said hydrocarbon purification system comprising: Depolymerization reactor; An extraction tower in fluid communication with the depolymerization reactor, wherein the extraction tower includes an alkaline washing liquid input; as well as A hydrogenation treatment reactor in fluid communication with the extraction tower.

9. The system of claim 8, wherein the depolymerization reactor is in fluid communication with an upstream process, the upstream process supplying a stream of waste plastics to the depolymerization reactor.

10. The system of claim 8, wherein the hydrogenation reactor hydrogenates the extraction column residue to provide a purified hydrocarbon stream.

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