WASTE PLASTICS BASED PYROLYSIS FEED AND METHOD FOR UPGRADING THE SAME

Abstract

The present invention relates to a method for upgrading liquefied waste plastics, the method comprising the steps of providing a liquefied waste plastics feed, pyrolyzing the liquefied waste plastics feed in a pyrolysis reactor, and separating at least one fraction comprising ethylene from the effluent of the pyrolysis reactor, wherein the liquefied waste plastics feed has a content ratio of i-olefins to n-olefins of 3.0 or less. The present invention further provides a liquefied waste plastics feed for pyrolysis.

Description

[Technical field]

[0001] The present invention relates generally to a method for upgrading liquefied waste plastics, and in particular to a pyrolysis feed based on liquefied waste plastics, as well as to a method for pyrolyzing this feedstock and separating a fraction comprising at least ethylene from the cracking effluent, and further to the products obtained in this procedure. [Background technology]

[0002] The refining of liquefied waste plastics (LWP) to obtain more valuable (or purer) substances and the conversion of liquefied waste plastics into more valuable substances, such as light olefins that can be used as raw materials in the chemical industry, have been studied for several years.

[0003] LWPs are the depolymerization products of waste plastics and are typically produced by hydrothermal liquefaction (HTL) or pyrolysis of waste plastics. Depending on the source of the waste plastics, LWPs contain varying levels of impurities. Typical impurity elements include chlorine, nitrogen, sulfur, and oxygen. These impurities are also commonly found in post-consumer packaging waste, which is a large source of plastic waste.

[0004] Besides their use as fuel, chemical recycling of LWPs back into plastics or monomers is an interesting option that has attracted much interest in the petrochemical industry in recent years, but this requires the removal of at least some of the impurities that they contain, which may be harmful.

[0005] In addition to the impurity aspects, there are differences in the compositional characteristics of the LWP, such as the presence of olefins, aromatics, and structural isomers, which can also affect the production process, such as the performance of monomers, such as ethylene, propylene, or butylene, leading to reduced run times, variability in primary product yields, or promotion of coking tendencies.

[0006] For example, depending on the actual production method, LWPs have high or very high total olefin content. Such olefins are usually considered coke promoters in thermal conversion processes, e.g., steam cracking, and are conventionally removed, e.g., by total hydrogenation. However, this method consumes large amounts of hydrogen. Hydrogen production reduces the amount of CO2 emissions in refineries. 2 As an emitter and bulk energy production unit, avoiding the consumption of hydrogen avoids costs and is more sustainable.

[0007] Patent document 1 discloses a process for recycling plastic waste in a steam cracker, in which molten plastic waste is heated to 400-550° C. and a fraction is fed to the steam cracker.

[0008] Patent Document 2 discloses a process for producing light olefins from plastic waste, which includes a thermal pretreatment to adjust the viscosity of the waste plastic, followed by a heat treatment at 700-1100°C.

[0009] US Patent No. 5,399,633 discloses a two-stage hydrotreating process to minimize impurities such as olefins in liquefied waste plastic feed prior to steam cracking.

[0010] US Patent No. 5,399,633 discloses a process for treating mixed waste plastics, including simultaneous pyrolysis and dechlorination of the mixed waste plastics to provide a hydrocarbon gas stream and a hydrocarbon liquid stream. The hydrocarbon liquid stream may be hydrotreated to minimize its olefin content. The hydrotreated hydrocarbon liquid stream may be subjected to steam cracking.

[0011] US Patent No. 5,399,633 discloses a process for converting waste plastics into petrochemical products, comprising pyrolysis of the waste plastics to obtain a liquid stream, separating the liquid stream into an aromatics-rich stream and an aromatics-poor stream, and sending the aromatics-poor stream to a hydrocracker. [Prior art documents] [Patent documents]

[0012] [Patent Document 1] U.S. Pat. No. 5,731,483 [Patent Document 2] U.S. Pat. No. 5,639,937 [Patent Document 3] International Publication No. 2021 / 110395 [Patent Document 4] International Publication No. 2018 / 025104 [Patent Document 5] European Patent No. 3110912 Summary of the Invention

[0013] The present invention has been made in view of the above problems, and an object of the present invention is to provide an improved method for upgrading liquefied waste plastics, and a waste plastics-based pyrolysis feed for use in such a method.

[0014] This present problem of providing an improved method for upgrading liquefied waste plastics is solved by the method according to claim 1. Further advantageous developments are described in the subsequent claims.

[0015] In summary, the present invention relates to one or more of the following:

[0016] 1. A method for upgrading liquefied waste plastics, comprising: (a) providing a liquefied waste plastic feed; (b) pyrolyzing the liquefied waste plastic feed in a pyrolysis reactor; and (c) separating at least one fraction comprising ethylene from the effluent of the pyrolysis reactor. Including, The method according to claim 1, wherein the liquefied waste plastic feed has an i-olefins to n-olefins ratio of 3.0 or less.

[0017] 2. The method of claim 1, wherein the liquefied waste plastic feed has a ratio of i-olefins to n-olefins of 2.5 or less, 2.0 or less, 1.5 or less, 1.0 or less, 0.80 or less, 0.60 or less, or 0.50 or less.

[0018] 3. The method according to any one of the preceding items, wherein the liquefied waste plastic feed has a combined content of i-olefins, n-olefins, i-paraffins and n-paraffins of at least 40 wt%, preferably at least 50 wt%, at least 55 wt%, at least 60 wt%, at least 65 wt% or at least 70 wt%.

[0019] 4. The method according to any one of the preceding items, wherein the liquefied waste plastic feed is an optionally pre-treated fraction of liquefied waste plastic, or a combination of two or more optionally pre-treated fractions of liquefied waste plastic.

[0020] 5. The method according to any one of the preceding items, wherein the liquefied waste plastic feed is an optionally pretreated degassed fraction of liquefied waste plastic.

[0021] 6. The method according to any one of the preceding items, wherein the liquefied waste plastic feed is an optionally pretreated liquid or waxy fraction of liquefied waste plastic, or a combination thereof.

[0022] 7. The method according to any one of the preceding items, wherein the liquefied waste plastic feed is an optionally pretreated naphtha fraction of liquefied waste plastic, or an optionally pretreated middle distillate of liquefied waste plastic, preferably an optionally pretreated naphtha fraction of liquefied waste plastic.

[0023] 8. The method according to any one of the preceding items, wherein the liquefied waste plastic feed comprises liquefied waste plastic non-gaseous (NTP) hydrocarbons.

[0024] 9. The method according to any one of the preceding items, wherein the liquefied waste plastic feed has a total content of gaseous (NTP) components of 1.5 wt.-% or less, preferably 1.0 wt.-% or less, more preferably 0.5 wt.-% or less.

[0025] 10. The method according to any one of the preceding items, wherein the liquefied waste plastic feed has a solid content of less than 1000 wt.-ppm, preferably less than 100 wt.-ppm, more preferably less than 10 wt.-ppm.

[0026] 11. The method of any one of the preceding items, wherein the liquefied waste plastic feed has an aggregate olefin content of 10 wt.-% or more, such as 15 wt.-% or more, 20 wt.-% or more, or 30 wt.-% or more.

[0027] 12. The method according to any one of the preceding items, wherein the liquefied waste plastic feed has an aggregate olefin content of 90 wt.-% or less, preferably 80 wt.-% or less, 70 wt.-% or less, or 60 wt.-% or less.

[0028] 13. The method according to any one of the preceding items, wherein the liquefied waste plastic feed has a monoolefin to diolefin content ratio of 10 or more, preferably 12 or more, 15 or more, or 20 or more.

[0029] 14. The method according to any one of the preceding items, wherein the liquefied waste plastic feed has an i-paraffin to n-paraffin ratio of 2.0 or less, preferably 1.7 or less, 1.5 or less, 1.0 or less, or 0.90 or less.

[0030] 15. The method according to any one of the preceding items, wherein the liquefied waste plastic feed has a ratio of i-paraffins to n-paraffins of 0.80 or less, e.g., 0.70 or less, 0.60 or less, 0.50 or less, 0.40 or less, 0.30 or less, 0.20 or less, 0.15 or less, 0.10 or less, 0.09 or less, 0.08 or less, 0.07 or less, 0.06 or less, 0.05 or less, 0.04 or less.

[0031] 16. The method according to any one of the preceding items, wherein the liquefied waste plastic feed comprises optionally pretreated liquefied fractionated waste plastic or a fraction thereof.

[0032] 17. The method according to any one of the preceding items, wherein the liquefied waste plastic feed comprises optionally pretreated liquefied polyolefin-enriched waste plastic or a fraction thereof.

[0033] 18. The method according to any one of the preceding items, wherein the liquefied waste plastic feed comprises optionally pretreated liquefied polyethylene-rich waste plastic or a fraction thereof.

[0034] 19. The method according to any one of the preceding items, wherein the liquefied waste plastic feed has an aggregate paraffin content of 5 wt.-% or more, preferably 10 wt.-% or more, 12 wt.-% or more, 15 wt.-% or more, 17 wt.-% or more, 19 wt.-% or more, or 20 wt.-% or more.

[0035] 20. The method of any one of the preceding items, wherein the liquefied waste plastic feed has an aggregate monoaromatic content of 30 wt.-% or less, preferably 25 wt.-% or less, 20 wt.-% or less, or 15 wt.-% or less.

[0036] 21. The method according to any one of the preceding items, wherein the liquefied plastic feed has a combined n-paraffin and n-olefin content of at least 20 wt.-%, preferably at least 23 wt.-%, at least 25 wt.-%, at least 27 wt.-%, or at least 30 wt.-%.

[0037] 22. The method according to any one of the preceding items, wherein the liquefied waste plastic feed has a ratio of total n-paraffins and n-olefins to total i-paraffins and i-olefins ([nP]+[nO]) / ([iP]+[iO]) of 0.40 or more, preferably 0.50 or more, 0.60 or more, 0.70 or more, 0.80 or more, 0.90 or more, 1.00 or more, 1.20 or more, 1.40 or more, 1.60 or more, 1.80 or more, 2.00 or more, 2.50 or more, or 3.00 or more.

[0038] 23. The method according to any one of the preceding items, wherein the liquefied waste plastic feed has a combined content of n-olefins, i-olefins and diolefins ([nO]+[iO]+[diO]) of not more than 60 wt.-%, preferably not more than 55 wt.-%, or not more than 50 wt.-%.

[0039] 24. The method according to any one of the preceding items, wherein the liquefied waste plastic feed has a total n-olefins and i-olefins to diolefins ratio (([nO]+[iO]) / [diO]) of 5 or more, preferably 8 or more, or 10 or more.

[0040] 25. The formula: [iO]×[diO]<α Wherein, [iO] is the content of i-olefins in the liquefied waste plastic feed, and [diO] is the content of diolefins in the liquefied waste plastic feed, and α is 100, preferably 90, 80 or 75. Item 11. The method according to any one of the preceding items, wherein

[0041] 26. The formula: ([iO]+2×[iP])×[diO]<β Wherein, [iO] is the content of i-olefins in the liquefied waste plastic feed, [diO] is the content of diolefins in the liquefied waste plastic feed, [iP] is the content of i-paraffins in the liquefied waste plastic feed, and β is 150, preferably 130, 120, 100, 90, 80, or 75. Item 11. The method according to any one of the preceding items, wherein

[0042] 27. The method according to any one of the preceding items, wherein the liquefied waste plastic feed has a combined i-paraffin and i-olefin content of not more than 50 wt.-%, preferably not more than 40 wt.-%, not more than 30 wt.-%, or not more than 20 wt.-%.

[0043] 28. The method according to any one of the preceding items, wherein the liquefied waste plastic feed has a T5 temperature (5 vol-% recovery, EN ISO 3405-2019) of 20°C or higher, preferably 25°C or higher, or 30°C or higher.

[0044] 29. The method according to any one of the preceding items, wherein the liquefied waste plastic feed has a total C9 i-olefins content of not more than 10 wt.-%, preferably not more than 8 wt.-%, not more than 6 wt.-%, or not more than 5 wt.-%.

[0045] 30. The method according to any one of the preceding items, wherein a fraction of the liquefied waste plastic feed having a T95 temperature (95 vol-% recovery, EN ISO 3405-2019) of 180°C or less, preferably 165°C or less, has a total C9 i-olefins content of 10 wt.-% or less, preferably 8 wt.-%, 6 wt.-%, or 5 wt.-% or less.

[0046] 31. The method according to any one of the preceding items, wherein the liquefied waste plastic feed has a diolefin content of 5.0 wt.-% or less, preferably 4.0 wt.-% or less, 3.0 wt.-% or less, 2.5 wt.-% or less, 2.0 wt.-% or less, 1.5 wt.-% or less, or 1.0 wt.-% or less.

[0047] 32. The method of any one of the preceding items, wherein the liquefied waste plastic feed has a conjugated diolefin content of 5.0 wt.-% or less, more preferably 4.0 wt.-% or less, 3.0 wt.-% or less, 2.0 wt.-% or less, 1.0 wt.-% or less, 0.75 wt.-% or less, or 0.50 wt.-% or less.

[0048] 33. The method of any one of the preceding items, wherein the liquefied waste plastic feed has an acidity of 10.0 mgKOH / g or less, preferably 8.0 mgKOH / g or less, 6.0 mgKOH / g or less, 4.0 mgKOH / g or less, 2.0 mgKOH / g or less, 1.5 mgKOH / g or less, 1.0 mgKOH / g or less, 0.9 mgKOH / g or less, 0.8 mgKOH / g or less, 0.7 mgKOH / g or less, 0.6 mgKOH / g or less, or 0.5 mgKOH / g or less.

[0049] 34. The method according to any one of the preceding items, wherein the liquefied waste plastic feed has an oxygen content of 1.50 wt.-% or less, preferably 1.40 wt.-% or less, 1.30 wt.-% or less, 1.20 wt.-% or less, 1.10 wt.-% or less, 1.00 wt.-% or less, 0.90 wt.-% or less, or 0.80 wt.-% or less.

[0050] 35. The method according to any one of the preceding items, wherein the liquefied waste plastic feed is obtained by depolymerization of waste plastic, followed by gas-liquid separation and optional further fractionation and optional further pretreatment.

[0051] 36. The method according to any one of the preceding items, wherein the liquefied waste plastic feed comprises waste plastic pyrolysis oil (WPPO) or a fraction thereof.

[0052] 37. The method according to any one of the preceding items, wherein the liquefied waste plastic feed comprises waste plastic hydrothermal liquefaction (HTL) oil or a fraction thereof.

[0053] 38. The method according to any one of the preceding items, wherein the pyrolysis in step (b) comprises steam cracking.

[0054] 39. The method according to any one of the preceding items, wherein the feed to the pyrolysis reactor contains 20 to 300 ppm by weight of sulfur, preferably 20 to 250 ppm by weight, more preferably 20 to 100 ppm by weight, and even more preferably 50 to 65 ppm by weight.

[0055] 40. The method according to any one of the preceding items, wherein the pyrolysis step (b) is carried out at a coil outlet temperature (COT) selected from the range of 750°C to 920°C, preferably 750°C to 890°C, more preferably 800°C to 880°C, and even more preferably 820°C to 860°C.

[0056] 41. A method according to any one of the preceding items, wherein the pyrolysis step (b) is carried out at a coil outlet pressure (COP) in the range of 1.3 bar to 6.0 bar, preferably 1.3 bar to 3.0 bar.

[0057] 42. A method according to any one of the preceding items, wherein the pyrolysis step (b) is carried out at a flow rate ratio of cracking diluent, preferably steam, to total cracker feed (expressed as diluent flow rate [kg / h] / total cracker feed flow rate [kg / h]) in the range of 0.10 to 1.00, preferably 0.25 to 0.85.

[0058] 43. The method according to any one of the preceding items, wherein step (c) comprises recovering a recycle stream from the pyrolysis effluent and, after one or more optional hydrotreatments and / or further post-treatments, subjecting the recycle stream to pyrolysis in pyrolysis step (b) as a co-feed with the LWP feed.

[0059] 44. The method of any one of the preceding items, wherein step (c) further comprises separating at least one fraction comprising propylene from the effluent of the pyrolysis reactor.

[0060] 45. During the step (c), CO, CO 2 , MAPD, and C 2 H 2 3. The method of any one of the preceding items, comprising subjecting at least a portion of the pyrolysis effluent to a purification process to remove at least one of:

[0061] 46. ​​Providing a plurality of pyrolysis furnaces; and conducting said pyrolysis step (b) in at least one of said plurality of pyrolysis furnaces; 2. The method according to any one of the preceding items, comprising:

[0062] 47. Obtaining a pyrolysis effluent from the plurality of pyrolysis furnaces, optionally post-treating at least one of the pyrolysis effluents; and mixing the resulting pyrolysis effluents to form a composite decomposition product; and Optionally, CO, CO 2 , MAPD, and C 2 H 2 subjecting at least a portion of said complex degradation products to a purification treatment to remove at least one of The method according to the preceding paragraph, comprising:

[0063] 48. The method according to any one of the preceding items, wherein the pyrolysis in step (b) is carried out in the presence of a cofeed.

[0064] 49. The method according to any one of the preceding items, wherein the pyrolysis in step (b) is carried out in the presence of a hydrocarbon co-feed.

[0065] 50. The method according to any one of the preceding items, wherein the pyrolysis in step (b) is carried out in the presence of a fossil hydrocarbon co-feed, preferably a fossil naphtha co-feed, more preferably a fossil naphtha feed selected from full range naphtha or light naphtha.

[0066] 51. The co-feed meets the following standard specifications: The maximum specific gravity at 15°C is 0.735 g / mL. Reid vapor pressure is up to 12.5 psi. Color is at least +20 Saybolt, Initial boiling point is at least 30°C. Final boiling point is up to 180℃ A paraffin content of at least 65% by volume, an olefin content of at most 1% by volume, the remainder being naphthenes and aromatics; Sulfur content up to 500 ppm, H 2 S content is up to 10 ppm, Lead content up to 50 ppb, The organic chloride content is a maximum of 3 ppm. MTBE content is a maximum of 50 ppm; Total oxygen content is 100 ppm maximum, Mercury content up to 5ppb The method according to any one of the preceding two items, wherein the fossil naphtha feed satisfies the above.

[0067] 52. A method according to any one of the preceding items, wherein the pyrolysis in step (b) is carried out in the presence of a co-feed having a combined aromatics and naphthenes content of at most 35 wt.-%, preferably at most 30 wt.-%, at most 25 wt.-%, at most 20 wt.-%, at most 15 wt.-% or at most 10 wt.-%.

[0068] 53. A method according to any one of the preceding items, wherein the pyrolysis in step (b) is carried out in the presence of a cofeed having an aggregate olefin content of at most 3.0 wt.-%, preferably at most 1.0 wt.-%, at most 0.75 wt.-%, at most 0.50 wt.-%, at most 0.30 wt.-% or at most 0.10 wt.-%.

[0069] 54. A method according to any one of the preceding items, wherein the pyrolysis in step (b) is carried out in the presence of a co-feed having a total oxygenate content of at most 1.0 wt.-%, preferably at most 0.50 wt.-%, at most 0.30 wt.-%, at most 0.10 wt.-% or at most 0.05 wt.-%.

[0070] 55. The method according to any one of the preceding items, wherein the pyrolysis in step (b) is carried out in the presence of a renewable hydrocarbon co-feed, such as a hydrocarbon co-feed of hydrotreated vegetable oils and / or animal fats (HVO).

[0071] 56. The method according to any one of the preceding items, wherein the pyrolysis in step (b) is carried out in the presence of a Fischer-Tropsch hydrocarbon co-feed.

[0072] 57. The method according to any one of the preceding items, wherein the step of providing a liquefied waste plastic feed comprises depolymerizing solid waste plastic to provide liquefied waste plastic.

[0073] 58. The method according to item 57, wherein the step of providing a liquefied waste plastic feed further comprises a step of pretreating solid waste plastic.

[0074] 59. The method according to item 58, wherein the pretreatment of the solid waste plastic comprises separating the solid waste plastic from other waste, such as, for example, paper, metal and / or compostable waste.

[0075] 60. The method according to any one of items 58 to 59, wherein the pretreatment of the solid waste plastic comprises a step of drying the solid waste plastic.

[0076] 61. The method according to any one of items 58 to 60, wherein the pretreatment of the solid waste plastic comprises a step of reducing the size of the solid waste plastic, for example by cutting the solid waste plastic, shredding the solid waste plastic, and / or grinding the solid waste plastic.

[0077] 62. The method according to any one of items 58 to 61, wherein the pretreatment of the solid waste plastic comprises a step of melting the solid waste plastic.

[0078] 63. The method according to any one of items 57 to 62, wherein the step of depolymerizing the solid waste plastic comprises thermal depolymerization to provide a waste plastic thermally depolymerized oil.

[0079] 64. The method according to any one of items 57 to 63, wherein the step of depolymerizing the solid waste plastic comprises hydrothermal liquefaction to provide a waste plastic hydrothermal liquefaction oil.

[0080] 65. The method according to any one of items 57 to 64, wherein the step of depolymerizing the solid waste plastic comprises pyrolysis to provide waste plastic pyrolysis oil (WPPO), and the pyrolysis can be thermal non-catalytic pyrolysis or thermal catalytic pyrolysis.

[0081] 66. The method according to any one of items 57 to 65, wherein the liquefied waste plastic feed comprises at least one of depolymerized solid waste plastic, preferably waste plastic pyrolysis oil (WPPO) or hydrothermal liquefaction oil from solid waste plastic.

[0082] 67. The method according to any one of items 57 to 66, wherein the solid waste plastic comprises sorted waste plastic.

[0083] 68. The method according to any one of items 57 to 67, wherein the solid waste plastics comprises polyolefin-rich waste plastics.

[0084] 69. The method according to any one of items 57 to 68, wherein the solid waste plastic comprises polyethylene-rich waste plastic.

[0085] 70. A method according to any one of items 57 to 69, wherein the solid waste plastics has an oxygen content, determined as element O, of not more than 15 wt.-%, preferably not more than 10 wt.-%, more preferably not more than 5 wt.-%, based on the total weight of the solid waste plastics.

[0086] 71. The solid waste plastic has a ratio (E between the melting enthalpy in the temperature range of 70 to 130 ° C. and the melting enthalpy in the temperature range of 130 to 180 ° C.) of 50% or more, preferably 60% or more, or 70% or more, as measured by DSC. 70-130℃ / E 130-180℃ 71. The method according to any one of items 57 to 70, comprising the steps of:

[0087] 72. The solid waste plastic has a mean particle size of 0.3 or less, preferably 0.2 or less, 1168 cm -1 Intensity of FT-IR peaks at I 1168 and 1168cm -1 and 716 cm -1 The total intensity of the peaks in I 1168 +I 716 The intensity ratio between (I 1168 / [I 1168 +I 716 72. The method according to any one of items 57 to 71, wherein

[0088] 73. The method according to any one of the preceding items, wherein the step of providing a liquefied waste plastic feed comprises separating at least a gaseous (NTP) component from the liquefied waste plastic.

[0089] 74. A method according to any one of the preceding items, wherein the step of providing the liquefied waste plastic feed comprises separating at least a gaseous (NTP) component from the liquefied waste plastic, and recovering at least one gaseous (NTP) olefin species, preferably at least ethylene, from the gaseous (NTP) component.

[0090] 75. The method according to any preceding item, further comprising the step of combining the ethylene recovered from the gaseous (NTP) components with the fraction obtained in step (c) or with a purified ethylene fraction derived from the fraction obtained in step (c).

[0091] 76. The method according to any one of the preceding items, wherein the step (a) of providing the liquefied waste plastic feed comprises a step of fractionating the liquefied waste plastic, preferably producing a middle distillate and / or naphtha fraction, more preferably a naphtha fraction, as the liquefied waste plastic feed.

[0092] 77. A method according to any one of the preceding items, wherein the step (a) of providing a liquefied waste plastic feed comprises separating high boiling point components from the liquefied waste plastic, preferably separating components having a boiling point above 450°C.

[0093] 78. The method according to any one of the preceding items, wherein the step (a) of providing a liquefied waste plastic feed comprises at least one pretreatment step in which the liquefied waste plastic or a fraction thereof is subjected to pretreatment.

[0094] 79. The method according to item 78, wherein the pretreatment comprises a step of drying the liquefied waste plastic, for example by phase separation, evaporation and / or drying with a moisture absorbent.

[0095] 80. A method according to any one of items 78 to 79, wherein the pretreatment comprises subjecting the liquefied waste plastic to at least one treatment selected from the group consisting of desalination, reactive extraction, solvent extraction, adsorption, oxidation and reduction.

[0096] 81. The method according to any one of items 78 to 80, wherein the pretreatment comprises separation of solid particles, such as char, from the liquefied waste plastic, such as separation by sedimentation, decantation, centrifugation and / or filtration.

[0097] 82. The method according to any one of items 78 to 81, wherein the pretreatment comprises separation of gaseous (NTP) components from the liquefied waste plastic, such as gas-liquid separation and / or fractionation.

[0098] 83. The method according to any one of items 78 to 82, wherein the pretreatment comprises selective and / or mild hydrogenation of the liquefied waste plastics, for example selective and / or mild hydrogenation of dienes and / or alkynes to mono-olefins or alkanes, and / or selective and / or mild hydrogenation of MAPD to mono-olefins or alkanes.

[0099] 84. The method according to any one of the preceding items, wherein the liquefied waste plastic feed has an n-olefin content of 2 wt.-% or more, preferably 5 wt.-% or more, 10 wt.-% or more, 15 wt.-% or more, 20 wt.-% or more, or 25 wt.-% or more.

[0100] 85. The method according to any one of the preceding items, wherein the liquefied waste plastic feed has an aggregate aromatics content of 35 wt.-% or less, preferably 30 wt.-% or less, 25 wt.-% or less, 20 wt.-% or less, or 15 wt.-% or less.

[0101] Liquefied waste plastic feed for pyrolysis having an i-olefins to n-olefins ratio not greater than 86.3.0.

[0102] 87. A liquefied waste plastic feed for pyrolysis according to item 86, wherein the liquefied waste plastic feed comprises optionally pretreated liquefied waste plastic or a fraction thereof, such as optionally pretreated waste plastic thermal depolymerization oil or a fraction thereof.

[0103] 88. A liquefied waste plastic feed for pyrolysis which is an optionally pretreated liquefied waste plastic or a fraction thereof obtained from a process involving the depolymerization of polyethylene-rich waste plastic.

[0104] 89. A liquefied waste plastic feed according to any one of items 86 to 88, further having the characteristics defined for the liquefied waste plastic feed according to any one of items 1 to 85. [Brief description of the drawings]

[0105] [Figure 1] FIG. 1 is a schematic diagram showing a bench-scale pyrolysis apparatus used in the examples. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0106] The present invention relates to a method for upgrading liquefied waste plastics, which comprises the steps of providing a liquefied waste plastics feed (step a), pyrolyzing the liquefied waste plastics feed in a pyrolysis reactor (step b), and separating at least one fraction containing ethylene from the effluent of the pyrolysis reactor (step c). According to the present invention, the liquefied waste plastics feed has a content ratio of i-olefins to n-olefins of 3.0 or less.

[0107] In the present invention, liquefied waste plastics (LWP) refers to the product effluent from a liquefaction process that can be obtained by depolymerizing waste plastics. LWP usually has a high total olefin content. Olefins have traditionally been considered the main cause of coking in downstream processing. Traditionally, LWP has been subjected to severe hydrogenation of olefins to paraffins, e.g., total hydrogenation, or other workup before being further processed, in order to reduce the coking tendency.

[0108] The inventors have surprisingly found that i-olefin content correlates with ethylene and propylene yields, and that particularly high yields of ethylene can be achieved when pyrolyzing liquefied waste plastic feeds with low i-olefin content. The inventors have further found that conjugated diolefins are particularly strong coke promoters.

[0109] Based on this finding, the present invention provides an improved process which requires no or less hydrogenation yet achieves high yields of valuable products, in particular ethylene.

[0110] The liquefied waste plastic feed of the present invention is derived from liquefied waste plastic. By liquefied waste plastic is meant the product effluent from a liquefaction process which comprises at least depolymerizing waste plastic. The liquefaction process is typically carried out at high temperature and preferably under non-oxidizing conditions. The liquefaction process may be carried out at high pressure. The liquefaction process may be carried out in the presence of a catalyst. The effluent from the liquefaction process or a fraction thereof may be applied as liquefied waste plastic feed as is or, preferably, may be subjected to at least one pretreatment to provide a liquefied waste plastic feed. Suitable pretreatments are described below. In the present invention, when referring to a material constituting the liquefied waste plastic feed, this is meant to include pretreated materials. In other words, when referring to a material constituting the liquefied waste plastic feedstock, it is meant to include any pretreated material constituting the liquefied waste plastic feedstock. For example, when the LWP feed is described as a hot water liquefied oil or a fraction thereof, this includes pretreated hot water liquefied oil, pretreated fractions of hot water liquefied oil, fractions of pretreated hot water liquefied oil, and pretreated fractions of pretreated hot water liquefied oil. In other words, any pretreatment may occur before fractionation, or after fractionation, or both. Similarly, multiple fractionations may occur. In addition, two or more optionally pretreated fractions of the LWP may be combined to obtain the LWP feed. The two or more fractions may have the same or similar boiling ranges, or may have different boiling ranges.

[0111] In addition to liquid (NTP) hydrocarbons, i.e., hydrocarbons that are liquid at ambient temperature and pressure (NTP; 20° C., 101.325 kPa absolute), typical product effluents from liquefaction processes include gaseous (NTP) hydrocarbons, and hydrocarbons that are waxy or solid at NTP but become liquid upon heating, e.g., heating to 80° C.

[0112] In the context of this disclosure, depolymerization of waste plastics means breaking down or degrading the polymer backbone of the waste plastics, typically at least thermally, to an extent that results in polymer and / or oligomer species of lower molecular weight compared to the starting waste plastics, but still containing at least liquid (NTP) hydrocarbons. In other words, as used herein, liquefied waste plastics does not include liquid forms of plastics that can be obtained by simply melting or dissolving in a solvent, since these do not contain sufficient cleavage of the polymer backbone and the waste plastics are not completely depolymerized to the monomer level and therefore are not in gaseous (NTP) form. Depolymerizing waste plastics also includes cleavage of covalently bonded heteroatoms, such as O, S, N, from any heteroatom-containing compounds that are present.

[0113] Initially, the waste plastics or each waste plastic type in the mixed waste plastics subjected to liquefaction is in a solid state and typically has a melting point in the range of 100° C. or higher, as measured by DSC, as described in Larsen et al., cited below. However, the waste plastics or each waste plastic type may be melted prior to and / or during depolymerization.

[0114] The solid waste plastics may contain a variety of further components, such as, for example, additives, reinforcing materials, including, for example, fillers, pigments, printing, inks, flame retardants, stabilizers, antioxidants, plasticizers, lubricants, labels, metals, paper, board, cellulosic fibers, glass fibers, and even sand and other dirt. If desired, some of the further components may be removed from the solid waste plastics, from the molten waste plastics, and / or from the liquefied waste plastics using commonly known methods.

[0115] Preferably, the solid waste plastics subjected to depolymerization and thus serving as the base material for the LWP feed have an oxygen content of 15 wt.-% or less, preferably 10 wt.-% or less, more preferably 5 wt.-% or less, based on the weight of the total solid waste plastics. The oxygen content may be 0 wt.-% and may preferably range from 0 wt.-% to 15 wt.-% or from 0 wt.-% to 10 wt.-%. The oxygen content expressed in wt.-% may be determined by difference using the formula (100 wt.-%)-(CHN content + ash content), where the CHN content refers to the combined content of carbon, hydrogen and nitrogen, determined according to ASTM D5291, and the ash content refers to the ash content, determined according to ASTM D482 / EN15403. In this disclosure, all standards refer to the latest editions available as of December 1, 2021, unless otherwise stated.

[0116] Liquefied waste plastics obtained by depolymerizing waste plastics mainly contain hydrocarbons, typically more than 50 wt.-% based on the total weight of the LWP. Typically, the LWP contains two or more hydrocarbons selected from paraffins, olefins, naphthenes and aromatics. The composition of the LWP may vary, for example, depending on the composition of the solid waste plastics, the type and conditions of the liquefaction process, and any additional processing. Furthermore, the combination of impurities associated with various types of solid waste plastics and recovered wastes may result in the presence of various amounts of impurities in the LWP, including silicon, sulfur, nitrogen, halogens, and oxygen-related substances.

[0117] The liquefied waste plastic feed of the present invention is not particularly limited as long as it has a content ratio of i-olefins to n-olefins of 3.0 or less.

[0118] In the present invention, unless otherwise specified, the "content ratio" means the ratio of the contents of two components on a weight basis. That is, the liquefied waste plastic feed having a content ratio of i-olefins to n-olefins of 3.0 or less according to claim 1 means that the weight content of i-olefins in the liquefied waste plastic feed divided by the weight content of n-olefins in the liquefied waste plastic feed is 3.0 or less.

[0119] In the present invention, unless otherwise specified, "content" refers to the content on a weight basis and is calculated relative to the total weight of the base material, e.g., the total weight of the liquefied waste plastic feed.

[0120] In the present invention, i-olefin refers to branched non-cyclic monoolefin, and n-olefin refers to linear non-cyclic monoolefin. In this specification, i-olefin is also referred to as isoolefin, and n-olefin is also referred to as normal olefin. All non-aromatic compounds having at least one carbon-carbon double bond are collectively referred to as "total olefins" or simply "olefins". Thus, total olefin content refers to the sum of the content of all compounds having at least one carbon-carbon double bond.

[0121] The liquefied waste plastic feed preferably has a content ratio of i-olefins to n-olefins of 2.5 or less. The content ratio is more preferably 2.0 or less, 1.5 or less, 1.0 or less, 0.80 or less, 0.60 or less, or 0.50 or less. In particular, the liquefied waste plastic feed may have a content ratio of i-olefins to n-olefins of 0 to 3.0, preferably 0 to 2.0, 0 to 1.5, 0.01 to 1.0, 0.02 to 0.80, 0.03 to 0.60, or 0.05 to 0.50.

[0122] A low ratio of i-olefins to n-olefins can further improve ethylene yield and reduce coking tendency.

[0123] The liquefied waste plastic feed preferably has a total content of i-olefins, n-olefins, i-paraffins and n-paraffins of at least 40 wt.-%, more preferably at least 50 wt.-%, at least 55 wt.-%, at least 60 wt.-%, at least 65 wt.-%, or at least 70 wt.-%. For example, the liquefied waste plastic feed may have a total content of i-olefins, n-olefins, i-paraffins and n-paraffins of at least 40 wt.-%, more preferably at least 50 wt.-%, at least 55 wt.-%, at least 60 wt.-%, at least 65 wt.-%, at least 70 wt.-%, for example, 40 wt.-% to 99 wt.-%, The total content of i-olefins, n-olefins, i-paraffins and n-paraffins may be from 50 wt.-% to 99 wt.-%, 55 wt.-% to 99 wt.-%, 60 wt.-% to 99 wt.-%, 65 wt.-% to 99 wt.-%, 70 wt.-% to 99 wt.-%, or 70 wt.-% to 95 wt.-%.

[0124] In the present invention, the "total content" of a plurality of components means the sum of the contents of each component. Therefore, a liquefied waste plastic feed having a total content of i-olefins, n-olefins, i-paraffins and n-paraffins of at least 40 wt.-% means that the total content by weight of i-olefins, n-olefins, i-paraffins and n-paraffins relative to the total weight of the liquefied waste plastic feed is 40 wt.-% or more, that is, in the range of 40 wt.-% to 100 wt.-%.

[0125] In the present invention, i-paraffins and n-paraffins are collectively referred to as paraffins, so that the content of paraffins corresponds to the total content of i-paraffins and n-paraffins. In this respect, i-paraffins refer to branched acyclic alkanes, while n-paraffins refer to straight-chain acyclic alkanes. In this specification, i-paraffins are also called isoparaffins, and n-paraffins are also called normal paraffins.

[0126] It is particularly preferred that the LWP feed is rich in paraffins and olefins, as these materials are susceptible to cracking. Aromatics, on the other hand, have a very low tendency to crack and therefore do not contribute to the desired high value products, especially ethylene. Due to regulatory constraints on benzene content, especially if the non-olefinic portion is intended for fuel purposes, it may be further preferred to remove excess aromatics, especially benzene, from the LWP feed or from the cracked products. In the present invention, aromatics refers to compounds having at least one aromatic ring, including fused aromatics.

[0127] In addition, naphthenes are difficult to crack into valuable materials and furthermore exhibit a fairly high coking tendency. Thus, with higher contents of i-paraffins, n-paraffins, i-olefins and n-olefins in the LWP feed, higher yields of valuable products, such as ethylene and propylene, especially ethylene, are expected.

[0128] In the present invention, naphthenes refer to cyclic non-aromatic branched or unbranched alkanes, alkenes or alkynes containing multiple unsaturations. Paraffinic naphthenes refer to cyclic branched or unbranched alkanes. Olefinic naphthenes refer to cyclic non-aromatic branched or unbranched alkenes containing multiple unsaturations.

[0129] Liquefied waste plastic feed typically has an aggregate olefin content of 10 wt.-% or more, e.g. 15 wt.-% or more, 20 wt.-% or more, or 30 wt.-% or more. Although a high olefin content is undesirable for downstream processes, LWPs inherently contain a very high content of olefins. In fact, for the LWP production process, a high olefin content is an indicator of a more effective depolymerization process, ultimately resulting in an improved overall yield of valuable materials. Surprisingly, the method of the present invention, particularly the pyrolysis step, is capable of handling such difficult feeds. In other words, it is neither necessary nor desirable to significantly reduce the olefin content by specific means, such as, for example, hydrogenation, including saturation or total hydrogenation of the olefins. However, it is of course not excluded by the present invention, mild or selective hydrogenation. Such mild and / or selective hydrogenation may be used, for example, to convert diolefins, particularly conjugated diolefins, to monoolefins. Such mild and / or selective hydrogenation may likewise be used to convert alkynes to alkenes and / or alkanes, and / or to convert MAPD, i.e., methylacetylene and propadiene, to simple monoolefins. Mild hydrogenation is also useful for the removal of metals and halogens. Such mild and / or selective hydrogenation is particularly preferred since the aforementioned materials have been found to be strong coke promoters.

[0130] Nevertheless, it is preferred that the liquefied waste plastic feed has an aggregate olefin content of 90 wt.-% or less, preferably 80 wt.-% or less, 70 wt.-% or less, or 60 wt.-% or less. For example, the liquefied waste plastic feed may have an aggregate olefin content in the range of 10 wt.-% to 90 wt.-%, e.g., 15 wt.-% to 80 wt.-%, 20 wt.-% to 70 wt.-%, 20 wt.-% to 60 wt.-%, or 30 wt.-% to 60 wt.-%.

[0131] The liquefied waste plastic feed preferably has a content ratio of monoolefins to diolefins of 10 wt% or more, more preferably 12 wt% or more, 15 wt% or more, or 20 wt% or more. Although there is no specific upper limit, the content ratio can be, for example, 1000 or less, for example 100 or less. The inventors have surprisingly found that a high relative content of monoolefins to diolefins significantly reduces the coking tendency. Specifically, although it has been assumed in the past that olefins generally cause a high coking tendency, the inventors have found that when the proportion of diolefins is high, olefins mainly tend to produce a high amount of coke, and conjugated diolefins in particular cause a high coking tendency.

[0132] The liquefied waste plastic feed of the present invention preferably has a ratio of i-paraffins to n-paraffins of 0 to 2.0, more preferably 1.7 or less, 1.5 or less, 1.0 or less, or 0.90 or less. In addition to having the i-olefin / n-olefin ratio as defined in claim 1, applying such an LWP feed having a relatively low proportion of i-paraffins can further improve the ethylene yield of the cracking step. The ratio of i-paraffins to n-paraffins can be, in particular, 0.80 or less, for example 0.70 or less, 0.60 or less, 0.50 or less, 0.40 or less, 0.30 or less, 0.20 or less, 0.15 or less, 0.10 or less, 0.09 or less, 0.08 or less, 0.07 or less, 0.06 or less, 0.05 or less, or 0.04 or less.

[0133] The liquefied waste plastic feed preferably has a total paraffin content of 5 wt.-% or more, 10 wt.-% or more, 12 wt.-% or more, 15 wt.-% or more, 17 wt.-% or more, 19 wt.-% or more, 20 wt.-% or more. The total paraffin content can be, for example, 5 wt.-% to 100 wt.-%, for example, 5 wt.-% to 80 wt.-%, 5 wt.-% to 60 wt.-%, or 20 wt.-% to 60 wt.-%. A high content of paraffins can favorably increase the ethylene yield, while aromatics are less likely to be converted to light olefins by pyrolysis. Thus, the liquefied waste plastic feed preferably has a total aromatic content of 0 wt.-% to 35 wt.-%, more preferably 30 wt.-% or less, 25 wt.-% or less, 20 wt.-% or less, or 15 wt.-% or less. The liquefied waste plastic feed preferably has a total monoaromatic content of 0 wt.-% to 30 wt.-%, more preferably 25 wt.-% or less, 20 wt.-% or less, or 15 wt.-% or less. Monoaromatic refers to compounds having exactly one aromatic ring, i.e., no fused aromatic rings or multiple non-fused aromatic rings.

[0134] The liquefied waste plastic feed preferably has a combined n-paraffin and n-olefin content of 20 wt.-% to 100 wt.-%, more preferably 23 wt.-% or more, 25 wt.-% or more, 27 wt.-% or more, 30 wt.-% or more, for example 30 wt.-% to 100 wt.-%, or 30 wt.-% to 95 wt.-%. The liquefied waste plastic feed preferably has a weight ratio ([nP]+[nO]) / ([iP]+[iO]) of the total n-paraffins and n-olefins to the total i-paraffins and i-olefins of 0.40 or more, more preferably 0.50 or more, 0.60 or more, 0.70 or more, 0.80 or more, 0.90 or more, 1.00 or more, 1.20 or more, 1.40 or more, 1.60 or more, 1.80 or more, 2.00 or more, 2.50 or more, or 3.00 or more. The weight ratio ([nP]+[nO]) / ([iP]+[iO]) is not particularly limited, and may be, for example, 0.40 to 1000.00, for example, 0.40 to 100.00, or 0.40 to 50.00. The liquefied waste plastic feed preferably has a total content ([nO]+[iO]+[diO]) of n-olefins, i-olefins and diolefins of 60 wt.-% or less, more preferably 55 wt.-% or less, or 50 wt.-% or less, for example 0 wt.-% to 60 wt.-%, 5 wt.-% to 60 wt.-%, or 10 wt.-% to 60 wt.-%. The liquefied waste plastic feed preferably has a total content ratio (([nO]+[iO]) / [diO]) of n-olefins and i-olefins to diolefins of 5 or more, more preferably 8 or more, or 10 or more. The above ranges further improve the yield of the desired product.

[0135] For LWP feeds, the formula: [iO]×[diO]<α where [iO] is the weight content of i-olefins in the LWP feed, and [diO] is the weight content of diolefins in the LWP feed, and α is 100, preferably 90, 80, or 75. It is preferable that the following is satisfied.

[0136] For LWP feeds, the formula: ([iO]+2×[iP])×[diO]<β where [iO] is the weight content of i-olefins in the LWP feed, and [diO] is the weight content of diolefins in the LWP feed, and β is 150, preferably 130, 120, 100, 90, 80, or 75. It is preferable that the following is satisfied.

[0137] The present inventors have surprisingly found that a high content of i-olefins and / or total isomers in combination with diolefins, and particularly conjugated diolefins, results in a high coking tendency, even when the absolute amount of diolefins is relatively low.

[0138] Preferably, the liquefied waste plastic feed has a diolefin content of 0 wt.-% to 5.0 wt.-%, more preferably 4.0 wt.-% or less, 3.0 wt.-% or less, 2.5 wt.-% or less, 2.0 wt.-% or less, 1.5 wt.-% or less, or 1.0 wt.-% or less. Preferably, the liquefied waste plastic feed has a conjugated diolefin content of 0 wt.-% to 5.0 wt.-% or less, more preferably 4.0 wt.-% or less, 3.0 wt.-% or less, 2.0 wt.-% or less, 1.0 wt.-% or less, 0.75 wt.-% or less, or 0.50 wt.-% or less.

[0139] It is also preferred that the liquefied waste plastic feed has an acidity of 0 to 10.0 mgKOH / g, more preferably 8.0 mgKOH / g or less, 6.0 mgKOH / g or less, 4.0 mgKOH / g or less, 2.0 mgKOH / g or less, 1.5 mgKOH / g or less, 1.0 mgKOH / g or less, 0.9 mgKOH / g or less, 0.8 mgKOH / g or less, 0.7 mgKOH / g or less, 0.6 mgKOH / g or less, or 0.5 mgKOH / g or less. The acidity can be measured in accordance with ISO6619. The liquefied waste plastic feed may have an oxygen content of 0 wt.-% to 1.50 wt.-%, preferably 1.40 wt.-%, 1.30 wt.-%, 1.20 wt.-%, 1.10 wt.-%, 1.00 wt.-%, 0.90 wt.-%, or 0.80 wt.-% or less. The oxygen content (wt.-%) may be measured by difference using the formula (100 wt.-%)-(CHN content+ash content), where CHN content refers to the combined carbon, hydrogen and nitrogen content measured according to ASTM D5291, and ash content refers to the ash content measured according to ASTM D482 / EN15403. Isoparaffins and i-olefins are more vulnerable to oxidation reactions than unbranched hydrocarbons, and therefore it is beneficial to have as low an oxygen content as possible in the LWP feed.

[0140] The liquefied waste plastic feed preferably has a combined i-paraffin and i-olefin content of 0 wt.-% to 50 wt.-%, more preferably 40 wt.-% or less, 30 wt.-% or less, or 20 wt.-% or less.

[0141] The liquefied waste plastic feed preferably has a C9 i-olefin content of 0 wt.-% to 10 wt.-%, more preferably 8 wt.-% or less, 6 wt.-% or less, or 5 wt.-% or less. The inventors have surprisingly found that C9 i-olefins in particular tend to significantly reduce the ethylene yield in the cracking process.

[0142] The liquefied waste plastic feed preferably has an n-olefin content of at least 2 wt.-%, more preferably at least 5 wt.-%, at least 10 wt.-%, at least 15 wt.-%, at least 20 wt.-%, or at least 25 wt.-%.

[0143] The liquefied waste plastics feed preferably has a total aromatics content of 35 wt.-% or less, more preferably 30 wt.-% or less, 25 wt.-% or less, 20 wt.-% or less, or 15 wt.-% or less.

[0144] Preferably, the fraction of the liquefied waste plastic feed having a T95 temperature of 180°C or less, preferably 165°C or less, has a total C9 i-olefins content of 10 wt.-% or less, preferably 8 wt.-%, 6 wt.-%, or 5 wt.-% or less. T95 temperature (95 vol-% recovery) is measured according to EN ISO 3405-2019.

[0145] Preferably, the liquefied waste plastic feed is essentially composed of the liquid product of the waste plastic liquefaction process or a fraction thereof. In other words, the liquefied waste plastic feed (LWP feed) preferably contains only a small or negligible amount of gaseous (NTP) components and solid / non-evaporated materials such as char. Depending on the production method of the LWP feed, the effluent of the waste plastic liquefaction process may contain a large amount of gaseous (NTP) components, and in some cases, even more than 50 wt.-% of the effluent, i.e., the liquefaction product. In this specification, the term "consisting essentially of" means a content of at least 95 wt.-% and may be up to 100 wt.-%.

[0146] In particular, the liquefied waste plastic feed preferably has a gaseous (NTP) component content of 1.5 wt.-% or less, preferably 1.0 wt.-% or less, more preferably 0.5 wt.-% or less. The content of the gaseous (NTP) component may be, for example, 0 wt.-% to 1.5 wt.-%. Here, the gaseous (NTP) component refers to a component that is gaseous at normal pressure of 101.325 kPa and absolute temperature of 20°C (NTP). Such gaseous (NTP) components typically contain a high proportion of light olefins, especially ethylene, propylene, butene and butadiene, which can be better utilized / separated before decomposition. Furthermore, the hydrocarbons in the gaseous (NTP) component tend to have significantly different optimal pyrolysis conditions compared to the non-gaseous (NTP) component, and therefore it is not preferred to decompose the gaseous (NTP) component together with the non-gaseous (NTP) component.

[0147] Similarly, the liquefied waste plastic feed preferably has a solid content of 1000 wt.-ppm or less, preferably 100 wt.-ppm or less, more preferably 10 wt.-ppm or less, since such components may cause problems in the decomposition stage. It is not necessary to have any solid components (0 wt.-ppm content). In the present invention, solid components refer to components that are insoluble in the LWP feed. Their content can therefore be determined according to ISO 663. Examples of solid components in the LWP feed include coke particles from the heating tubes, iron scale from corrosion, soluble impurities such as compounds containing iron, arsenic, calcium, sodium chloride, silicon contained in upstream additives, and other impurities from upstream processes.

[0148] Solid components may be prevalent in liquefied waste plastics. Therefore, it is preferred that the LWP or a fraction thereof is pretreated to provide the LWP feed, where pretreatment at least includes removal of the solid components. Conventional techniques and equipment can be applied to remove the solid components. Such equipment includes, for example, demineralizers, filters, coalescers, etc. Such equipment can be provided, for example, in the feed train of the pyrolyzer. Thus, a low solid content in the feed entering the pyrolyzer can be ensured.

[0149] The liquefied waste plastic feed can be optionally pretreated waste plastic pyrolysis oil (WPPO) or an optionally pretreated fraction thereof, or optionally pretreated waste plastic-based hydrothermal liquefaction oil (HTL oil) or an optionally pretreated fraction thereof. The term waste plastic-based HTL oil refers to oil produced by hydrothermal liquefaction of waste plastic.

[0150] The liquefied waste plastic feed preferably comprises an optionally pretreated fraction of the product of waste plastic liquefaction, preferably the product of polyolefin-rich waste plastic liquefaction, more preferably the product of polyethylene-rich waste plastic liquefaction. In the context of the present invention, the term "polyolefin-rich" means a polyolefin content relative to the total waste plastics subjected to liquefaction, which is between 50 wt.-% and 100 wt.-%, preferably at least 60 wt.-% or at least 70 wt.-%. Similarly, the term "polyethylene-rich" means a polyethylene content relative to the total waste plastics subjected to liquefaction, which is between 50 wt.-% and 100 wt.-%, preferably at least 60 wt.-% or at least 70 wt.-%. The polyolefin and / or polyethylene content can be determined using commonly known methods, such as, for example, DSC, enthalpy of fusion, FT-IR, NMR, in particular solid-state NMR.

[0151] More specifically, the DSC fusion enthalpy E 70-130℃ , and the DSC fusion enthalpy E from 130 to 180 °C 130-180℃ can be used to measure and distinguish between polypropylene and polyethylene. DSC or Dynamic Scanning Calorimetry can be performed under heating conditions of 5°C per minute and is preferably measured on homogenized samples of solid waste plastics that are subjected to depolymerization. In this regard, DSC melting enthalpies of 70-130°C correspond to polyethylene materials in the waste plastics and DSC melting enthalpies of 130-180°C correspond to polypropylene materials in the waste plastics.

[0152] 1168cm -1 and 716 cm -1 FT-IR peaks at can also be used to measure the relative content of polyethylene-based materials.

[0153] However, in the context of the present invention, the determination of the content as commonly applied in industrial waste plastic sorting plants, i.e. based on near infrared (NIR) analysis, is entirely sufficient and is preferably applied in the present invention. The application of a high proportion of polyolefins, especially polyethylene, favorably influences the composition of the LWP feed and in particular increases the ethylene yield in the pyrolysis process.

[0154] The liquefied waste plastic feed preferably comprises or is composed of a naphtha fraction of liquefied waste plastic or a middle fraction of liquefied waste plastic. Particularly preferably, it comprises or is composed of a naphtha fraction of liquefied waste plastic. The inventors have surprisingly found that the naphtha fraction of the LWP causes less coking.

[0155] The process of providing a liquefied waste plastic feed may include a step of separating at least the gaseous (NTP) components from the liquefied waste plastic, i.e., at least the components that are gaseous at normal pressure and temperature ("NTP"). The step of separating at least the gaseous (NTP) components may simply be referred to as degassing. The result of degassing may be referred to as degassed liquefied waste plastic. Thus, preferably, a low content of the gaseous (NTP) components as described above may be achieved. The process of providing a liquefied waste plastic feed may in particular include a step of separating at least the gaseous (NTP) components from the liquefied waste plastic and a step of recovering at least olefins from the gaseous (NTP) components. Thus, light olefins in the gaseous (NTP) components, which are high-value materials, may be added to the value chain rather than being subjected to a pyrolysis step, thus improving the overall process yield, in particular the ethylene yield.

[0156] The step of providing a liquefied waste plastic feed may include a step of fractionating the liquefied waste plastic, for example the crude LWP, i.e. the optionally degassed effluent of the liquefaction process, to provide fractions of the LWP. The fractionation step preferably results in a middle distillate and / or naphtha fraction, more preferably a naphtha fraction. Each of these fractions may then, after optional pretreatment, be provided as the liquefied waste plastic feed of the present invention and may be subjected to a cracking step.

[0157] The step of providing a liquefied waste plastic feed preferably includes pre-treating the liquefied waste plastic or a fraction of the liquefied waste plastic. Suitable pre-treatment may be carried out before and / or after fractionation. For ease of reference, the optionally pre-treated liquefied waste plastic may be simply referred to as the liquefied waste plastic, and the optionally pre-treated fraction of the liquefied waste plastic may be simply referred to as the fraction of the liquefied waste plastic.

[0158] The process of providing a liquefied waste plastic feed may include separating high boiling components from the liquefied waste plastic. "High-boiling" components, or simply "heavies", are preferably those components that boil at temperatures above 450°C at atmospheric pressure. Depending on the liquefaction conversion technology used, the LWP may or may not contain heavy components. If substantial amounts are present, such as in the crude LWP, the heavy components are preferably removed prior to the pyrolysis step, since they do not readily convert to ethylene and / or propylene. Alternatively, the liquefaction conversion technology may be selected such that potential heavy components are processed and thus do not end up in the liquefaction conversion effluent, i.e., in the crude LWP.

[0159] The process of providing a liquefied waste plastic feed can include thermally depolymerizing the waste plastic, i.e., thermal depolymerization is a standard method for producing LWP. Among the thermal polymerization methods, hydrothermal liquefaction (HTL) and pyrolysis, e.g. fast pyrolysis, can be mentioned.

[0160] The liquefied waste plastic feed may be based on sorted waste plastics. In other words, the solid waste plastics, i.e. waste plastics before being subjected to liquefaction, may comprise, consist essentially of, or consist of sorted waste plastics. In particular, in post-consumer plastic recycling, sorted grades of waste plastics are readily available. Thus, the composition of the solid waste plastics, and thus the composition and / or properties of the LWP feed, may be tailored not only by using different liquefaction conditions, but also by using different grades of solid waste plastics, e.g. different grades of sorted waste plastics.

[0161] The solid waste plastics may also include a mixture of different types of sorted waste plastics. Similarly, the liquefied waste plastics may include different types of optionally pretreated liquefied sorted waste plastics. The liquefied waste plastic feed may include, consist essentially of, or consist of a mixture of different fractions of optionally pretreated liquefied waste plastics and / or a mixture of different fractions of optionally pretreated liquefied sorted waste plastics.

[0162] The solid waste plastics particularly preferably comprise polyolefin-enriched waste plastics, more preferably polyethylene-enriched waste plastics. The polyethylene (PE) can be any type of polyethylene, such as, for example, LLDPE (linear low density PE), LDPE (low density PE) or HDPE (high density PE). Polyolefin-enriched waste plastics are preferred as solid waste plastics from which LWP feeds can be derived, since they can be more easily converted into LWP feeds having the preferred total i-olefin, n-olefin, i-paraffin and n-paraffin contents and ratios of i-olefins to n-olefins. Furthermore, such materials tend to have low contents of diolefins. Furthermore, a high polyolefin content in the solid waste plastics tends to result in a lower oxygen content in the LWP feed, which contributes in particular to low carbon monoxide production during pyrolysis, thus favoring the particularly desirable ethylene production and reducing downtime by reducing impurity species known to be harmful to polymerization catalysts. Polyethylene-enriched solid waste plastics are more preferred, since they allow even lower i-olefin to n-olefin ratios. In addition, the total isomer content, i.e., the sum of i-olefins and i-paraffins, can be adjusted lower, which contributes to reducing coke formation during pyrolysis, which is presumably related to reduced MAPD formation. In particular, a high MAPD content in the product is likely due to the formation of the unstable intermediate cyclopropyne (C 3 H 2 ) or cyclopropene (C 3 H4 These intermediates are particularly potent coke promoters and contribute rapidly to the formation of polyaromatics.

[0163] Providing liquefied waste plastics may include depolymerizing solid waste plastics to provide liquefied waste plastics.

[0164] The process of providing a liquefied waste plastic feed may further include a step of pretreating the solid waste plastic. The pretreatment step may include separating the solid waste plastic from other waste, such as paper, metal and / or compostable waste. The pretreatment step may include washing the solid waste plastic with water. The pretreatment step may include drying the solid waste plastic. The pretreatment step may include reducing the size of the solid waste plastic, such as, for example, cutting the solid waste plastic, shredding the solid waste plastic, and / or grinding the solid waste plastic. The pretreatment step may include melting the solid waste plastic. In this regard, melting means converting the solid waste plastic into a melt, essentially without decomposing the polymer backbone.

[0165] The depolymerization of the solid waste plastic may include thermal depolymerization to provide liquefied waste plastic. The depolymerization of the solid waste plastic may include hydrothermal liquefaction to provide waste plastic hot water liquefaction oil (HTL oil). The depolymerization of the solid waste plastic may include pyrolysis to provide waste plastic pyrolysis oil (WPPO), where the pyrolysis may be thermal non-catalytic pyrolysis or thermal catalytic pyrolysis. In the present specification, both waste plastic hot water liquefaction oil and waste plastic pyrolysis oil are embodiments of fractions of liquefied waste plastic, more particularly the liquid (NTP) fraction thereof.

[0166] Specific conditions for the depolymerization process that can be used in the present invention are shown below.

[0167] In general, both hydrothermal liquefaction and pyrolysis are thermal liquefaction processes.

[0168] In hydrothermal liquefaction (HTL) of waste plastics, the waste plastics are contacted with supercritical water or subcritical or near-critical water, typically at a temperature of 250°C to 550°C, preferably 280°C to 400°C; at an absolute pressure of typically 5MPa to 50MPa, preferably 7MPa to 30MPa; and for a contact time that is typically 0.1h to 10h, preferably 0.5h to 6h. Hydrothermal liquefaction is typically carried out under non-oxidizing conditions. Non-oxidizing conditions can be achieved, for example, by purging the liquefaction equipment with an inert gas, such as nitrogen. By lowering the temperature and contact time, less gaseous (NTP) products and more liquid (NTP) products can be obtained.

[0169] Typically, hydrothermal liquefaction is more tolerant of moisture in waste plastics than other liquefaction methods. Thus, waste plastics for HTL will require less effort for drying than in the case of pyrolysis. Overall, HTL can achieve liquefaction with less energy consumption. Furthermore, in HTL, hydrogen ions that are easily released during the process can promote the cleavage of heteroatoms and stabilize coke-forming radicals. Thus, HTL can provide liquefied waste plastics with fewer heteroatoms. Furthermore, the LWP obtained from the HTL process has such qualities that there can be less coking in downstream processing, such as pyrolysis and especially steam cracking.

[0170] Thermal non-catalytic pyrolysis typically employs temperatures in the range of 300° C. to 850° C., preferably 400° C. to 800° C. The process is typically carried out at atmospheric pressure, usually under non-oxidizing conditions, particularly in the absence of air. Non-oxidizing conditions may be achieved, for example, by purging the liquefaction apparatus with an inert gas, such as nitrogen.

[0171] Thermal catalytic pyrolysis typically uses temperatures ranging from 250°C to 500°C, preferably 300°C to 450°C. The process is typically carried out at atmospheric pressure and usually under non-oxidizing conditions, especially in the absence of air. The process typically uses a solid catalyst, preferably an acidic solid catalyst, such as an acidic FCC catalyst, an acidic zeolite catalyst, or an acidic silica-alumina catalyst, such as ZSM-5 or H-ultra stable Y-type zeolite, to name a few. Non-oxidizing conditions can be achieved, for example, by purging the liquefaction unit with an inert gas, such as nitrogen.

[0172] The liquefied waste plastic feed preferably comprises optionally pretreated depolymerized solid waste plastics or fractions thereof, preferably optionally pretreated thermally depolymerized waste plastics or fractions thereof. The solid waste plastics preferably comprise sorted waste plastics. The solid waste plastics may comprise polyolefin-enriched waste plastics. The solid waste plastics may in particular comprise polyethylene-enriched waste plastics.

[0173] It is preferred that the solid waste plastics have an oxygen content relative to the total weight of the solid waste plastics of 15 wt.-% or less, preferably 10 wt.-% or less, more preferably 5 wt.-% or less. The oxygen content (wt.-%) can be determined by difference using the formula (100 wt.-%)-(CHN content+ash content), where CHN content refers to the combined carbon, hydrogen and nitrogen content as determined according to ASTM D5291, and ash content refers to the ash content as determined according to ASTM D482 / EN15403.

[0174] The solid waste plastic preferably comprises waste plastic, wherein the ratio between the melting enthalpy in the temperature range of 70 to 130 ° C. and the melting enthalpy in the temperature range of 130 to 180 ° C., E 70-130℃ / E 130-180℃ is 50% to 100%, preferably 60% or more, or 70% or more.

[0175] Similarly, the solid waste plastic preferably comprises waste plastic, wherein 1168 cm -1 Intensity of FT-IR peaks at I 1168 and 1168cm -1 and 716 cm -1 The total intensity of the peaks in I 1168 +I 716 The intensity ratio between 1168 / [I 1168 +I 716 ] is 0 to 0.3, preferably 0.2 or less.

[0176] intensity ratio I 1168 / [I 1168 +I 716 ] has been found to be particularly useful in measuring the polyethylene content in waste plastic materials (see Larsen et al., "Determining the PE fraction in recycled PP," Polymer testing, Vol. 96, April 2021, 107058), and a ratio of 0.3 or less is considered preferred in the present invention. The Larsen et al. paper further describes an FT-IR method that can be used in the present invention, and a DSC method for measuring the enthalpy of fusion in the present invention.

[0177] The liquefied waste plastic feed preferably has an initial boiling point of 150°C or less, preferably 120°C or less, or 100°C or less.

[0178] Preferably, the liquefied waste plastic feed is obtained by liquefaction of solid waste plastic, followed by gas-liquid separation and optional fractionation, and optional further pretreatment. The liquefied waste plastic feed may comprise or consist of any fraction of liquefied waste plastic (LWP), preferably the degassed fraction of the liquefaction process effluent, or the liquid fraction and / or waxy fraction of liquefied waste plastic, or a mixture of two or more thereof. The waxy fraction of LWP is also often referred to as the tetrahydrofuran extractable LWP fraction. In particular, the LWP feed may comprise or consist of the naphtha fraction and / or the middle distillate (MD) fraction of LWP. As mentioned above, any fraction mentioned herein may be pretreated before fractionation, or after fractionation, or before and after fractionation.

[0179] In the present invention, the naphtha fraction of the LWP is preferably a fraction having a T5 temperature of 20°C or more, preferably 25°C or more, or 30°C or more, and a T95 temperature of 180°C or less, more preferably a T5-T95 boiling point range of 30-180°C, 40-180°C, or 40-165°C. The difference between the T5 temperature and the T95 temperature (T95-T5) can be at least 20°C, for example, in the range of 20°C to 150°C, 20°C to 120°C, or 30°C to 80°C. The MD fraction of the LWP is a fraction having a T5 temperature of 160°C or more and a T95 temperature of 360°C or less, more preferably a T5-T95 boiling point range of 160-360°C, 160-330°C, or 165-300°C. The difference between the T5 and T95 temperatures can be at least 40°C, for example, in the range of 40°C to 200°C, 40°C to 150°C, or 50°C to 100°C. Boiling points and boiling ranges are based on atmospheric pressure, i.e., normal pressure of 101.325 kPa, unless otherwise specified. The T5 temperature (5 vol recovery) and T95 temperature (95 vol% recovery) as well as other temperatures can be measured according to EN ISO 3405-2019.

[0180] The pyrolysis in step (b) may include steam cracking, which is generally preferred in the present invention since steam cracking is more tolerant of various impurities, especially compared to catalytic processes.

[0181] The feed to the pyrolysis reactor (also referred to as total cracker feed) may contain 20-300 ppm by weight of sulfur, preferably 20-250 ppm by weight, more preferably 20-100 ppm by weight, and even more preferably 50-65 ppm by weight. The feed to the pyrolysis reactor refers to the liquefied waste plastic feed, any co-feed, and any additives.

[0182] Any conventional pyrolysis additive may be added to the decomposition step (b). Examples of such conventional pyrolysis additives include, for example, dimethyl disulfide (DMDS) or carbon disulfide (CS 2 ), and other sulfur-containing species (sulfur additives). DMDS is a particularly preferred sulfur additive. The sulfur additive may be mixed with the LWP feed, any co-feed, or both, prior to feeding the LWP feed and any co-feed to pyrolysis. Alternatively or additionally, the sulfur additive may be added by injecting a diluent, preferably steam, containing the sulfur additive into the pyrolysis furnace.

[0183] The pyrolysis step (b) may be carried out at a coil outlet temperature (COT) selected from the range of 750°C to 920°C, preferably 750°C to 890°C, more preferably 800°C to 880°C, and even more preferably 820°C to 860°C.

[0184] When conventional feeds are subjected to thermal cracking, high cracking temperatures tend to favor ethylene production. However, when applying the cracker feed containing the LWP feed of the present invention, it has been surprisingly found that the same ethylene yield can be achieved at a lower COT. It is assumed that this effect is at least partially related to the high olefin content typically present in LWPs.

[0185] The pyrolysis step (b) may be carried out under conventional conditions, for example with a coil outlet pressure (COP) selected in the range of from 1.3 bar to 6.0 bar, preferably from 1.3 bar to 3.0 bar. Unless otherwise specified, the pressure refers to absolute pressure.

[0186] When applying a pyrolysis diluent, such as for example steam in steam cracking, the pyrolysis step (b) is preferably carried out with a flow rate ratio between the pyrolysis diluent, preferably steam, and the LWP feed and any co-feeds (flow rate of diluent [kg / h] / flow rate of LWP feed and any co-feeds [kg / h]) being in the range of 0.10 to 1.00, preferably 0.25 to 0.85.

[0187] Step (c) may include recovering a recycle stream from the pyrolysis effluent and subjecting the recycle stream to pyrolysis in pyrolysis step (b) as a co-feed with the LWP feed after one or more optional hydrotreating and / or further post-treatments. Recycling unconverted reactants improves the overall profitability and overall yield of the pyrolysis process and / or the overall yield of desired products, particularly ethylene, such as ethylene and propylene. The one or more optional hydrotreating processes may include, in particular, mild or selective hydrogenation of diolefins, optionally followed by complete hydrogenation to alkanes.

[0188] Step (c) may further comprise separating other fractions from the pyrolysis reactor effluent. Preferably, step (c) comprises separating at least one fraction comprising propylene from the pyrolysis reactor effluent. Other fractions may also be separated, such as a fraction comprising at least butenes, a fraction comprising at least ethane, a fraction comprising at least propane, a fraction comprising at least butanes, a fraction comprising at least hydrogen, etc. These fractions may be product fractions of the process. These fractions may be separated in a single stage or in multiple subsequent stages. Preferably, a fraction rich in C2 hydrocarbons is separated, and this fraction is then further separated into at least an ethene-containing fraction and an ethane-containing fraction. Such separation of the C2 hydrocarbon-rich fraction, such as a fraction comprising 30 wt.-% to 100 wt.-%, preferably at least 40 wt.-%, of C2 hydrocarbons, may be sent to a C2 splitter to provide an ethene-containing fraction and an ethane-containing fraction. Similarly, a fraction rich in C3 hydrocarbons may be separated, and this fraction is then further separated into at least a propene-containing fraction and a propane-containing fraction. Such a separation of the C3 hydrocarbon-rich fraction, e.g., a fraction containing 30 wt.-% to 100 wt.-%, preferably at least 40 wt.-%, C3 hydrocarbons, may be sent to a C3 splitter to provide a propene-containing fraction and a propane-containing fraction. The C3 hydrocarbon-rich fraction may be separated after the C2 hydrocarbon-rich fraction has been separated, or may be separated at the same stage. Each of these fractions may be recovered as a product fraction of the process, or may be further refined or post-processed to provide a product fraction of the process.

[0189] The step (a) of providing a liquefied waste plastic feed may include one or more optional pretreatment steps, in which the liquefied waste plastic or a fraction thereof is subjected to pretreatment.

[0190] Pretreatment may include drying the liquefied waste plastic. Drying may be accomplished by conventional means such as, for example, phase separation, evaporation, and / or moisture absorbents.

[0191] Pretreatment may include separation of solid particles from the liquefied waste plastic feed. Such solid particles may include char or other solids. Separation of solid particles may be accomplished by conventional means such as, for example, settling, centrifugation, decantation and / or filtration. Settling may include gravitational settling and / or induced settling.

[0192] Pretreatment may include separation of gaseous (NTP) components from the liquefied waste plastic feed. Such separation may be accomplished by known means, such as, for example, gas-liquid separation and / or fractionation.

[0193] Pretreatment may include selective and / or mild hydrogenation of the liquefied waste plastic feed. Selective and / or mild hydrogenation may include selective hydrogenation of dienes and / or alkynes to mono-olefins or alkanes, but mild hydrogenation essentially converts dienes and / or alkynes to mono-olefins or alkanes, but preferably essentially does not convert mono-olefins to alkanes. Preferably, pretreatment does not essentially convert mono-olefins to alkanes, and particularly preferably does not include complete hydrogenation of mono-olefins to alkanes. Selective and / or mild hydrogenation may include, in particular, selective hydrogenation of MAPD to mono-olefins or alkanes, but mild hydrogenation essentially converts MAPD to mono-olefins or alkanes, but preferably essentially does not convert mono-olefins to alkanes.

[0194] The method may include providing a plurality of pyrolysis furnaces and carrying out the pyrolysis step (b) in at least one of the plurality of pyrolysis furnaces. In particular, the method may include obtaining pyrolysis products from the plurality of pyrolysis furnaces, mixing the obtained pyrolysis effluents to form a composite pyrolysis product, and optionally, mixing CO, CO 2 , MAPD, and C 2 H 2At least a portion of the complex decomposition products can be subjected to a purification process to remove at least one of the following: MAPD and acetylene, which can then be converted into valuable products, such as ethylene and propylene.

[0195] The pyrolysis in step (b) can be carried out in the presence of a co-feed. The presence of a co-feed can be used to reduce the diolefin content of the total cracker feed. A co-feed can also be used to reduce the halogen content of the steam cracker feed (total cracker feed) when the LWP feed has a high halogen content, which is typical for post-consumer waste plastics. Finally, adding a co-feed, such as a conventional steam cracker feed (such as a conventional naphtha feed), can reduce the coking tendency while still maintaining the advantages of the present invention. In this regard, total cracker feed means the material fed to the pyrolysis step (b) excluding the cracking diluent, and thus the total cracker feed includes at least the LWP feed and may further include at least one co-feed and / or at least one additive. However, if the diolefin content is low in the LWP feed, less co-feed is needed to "diluting" the LWP feed before cracking. The co-feed is preferably such that the properties of the aggregate cracker feed are shifted by the addition of the co-feed towards the more favorable values ​​of the above-mentioned properties of the LWP feed.

[0196] The co-feed may be a hydrocarbon feed, particularly a fossil hydrocarbon feed. The term fossil may also refer to crude oil origin. The co-feed is preferably a fossil naphtha feed. The fossil naphtha feed may be, for example, a full-range naphtha or a light naphtha. In the present invention, the naphtha preferably has an initial boiling point of at least 30°C, for example, in the range of 30°C to 80°C, and a final boiling point of at most 200°C, for example, in the range of 100°C to 200°C. The full-range naphtha has an initial boiling point of at least 35°C and a final boiling point of at most 180°C. The light naphtha has an initial boiling point of at least 30°C and a final boiling point of at most 120°C.

[0197] The at least one co-feed may in particular be a fossil naphtha feed that meets the following open naphtha specification “Platts specification guide to refined oil products” (September 2021 edition thereof), available at https: / / www.spglobal.com / platts / PlattsContent / _assets / _files / en / our-methodology / methodology-specifications / europe-africa-refined-products-methodology.pdf. The maximum specific gravity at 15°C is 0.735 g / mL. Reid vapor pressure is up to 12.5 psi. Color is at least +20 Saybolt, Initial boiling point is at least 30°C. Final boiling point is up to 180℃ A paraffin content of at least 65% by volume, an olefin content of at most 1% by volume, the remainder being naphthenes and aromatics; Sulfur content up to 500 ppm, H 2 S content is up to 10 ppm, Lead content up to 50 ppb, The organic chloride content is a maximum of 3 ppm. MTBE content is a maximum of 50 ppm; Total oxygen content is 100 ppm maximum, Mercury content up to 5 ppb.

[0198] The content of the LWP feed in the total cracker feed is preferably at least 2 wt.-%, more preferably at least 5 wt.-%, at least 10 wt.-%, at least 15 wt.-%, at least 20 wt.-%, at least 25 wt.-%, at least 30 wt.-%, at least 35 wt.-%, at least 40 wt.-%, at least 45 wt.-%, at least 50 wt.-%, at least 55 wt.-%, or at least 60 wt.-%. The content of the LWP feed in the total cracker feed can be, for example, in the range of 2 wt.-% to 100 wt.-%, 5 wt.-% to 80 wt.-%, or 10 wt.-% to 70 wt.-%.

[0199] The pyrolysis in step (b) may preferably be carried out in the presence of a co-feed having a combined aromatics and naphthenes content of 0 wt.-% to 35 wt.-%, preferably at most 30 wt.-%, at most 25 wt.-%, at most 20 wt.-%, at most 15 wt.-%, or at most 10 wt.-%.

[0200] Furthermore, the pyrolysis in step (b) may be carried out in the presence of a co-feed having a total olefin content of 0 wt.-% to 3.0 wt.-%, preferably at most 1.0 wt.-%, preferably at most 0.75 wt.-%, preferably at most 0.50 wt.-%, at most 0.30 wt.-% or at most 0.10 wt.-% and / or having a total oxygenate content of 0 wt.-% to 1.0 wt.-%, preferably at most 0.50 wt.-%, at most 0.30 wt.-%, at most 0.10 wt.-% or at most 0.05 wt.-%.

[0201] The pyrolysis in step (b) may be carried out in the presence of a renewable hydrocarbon co-feed, such as a HVO hydrocarbon co-feed. In the present invention, the HVO hydrocarbons may be obtained by catalytic hydroprocessing of vegetable oils and / or animal fats to produce mainly paraffins.

[0202] The pyrolysis in step (b) may be carried out in the presence of Fischer-Tropsch hydrocarbons. Fischer-Tropsch based hydrocarbons are particularly preferred since they usually contain low amounts of aromatics, olefins, naphthenes and heteroatoms. Fischer-Tropsch based hydrocarbons are obtained by catalytic conversion of synthesis gas containing carbon monoxide and hydrogen, typically resulting in a substantial Gaussian distribution of hydrocarbon chains, mainly n-paraffins. Fischer-Tropsch based hydrocarbons may be of fossil origin, renewable origin or both. The distinction between fossil and renewable may be made based on the content of biogenic carbon. In particular, the renewable or fossil origin of any organic compound, including hydrocarbons, may be measured by suitable methods for analyzing the carbon content from renewable sources, such as, for example, DIN 51637 (2014), ASTM D6866 (2020) and EN 16640 (2017). These methods are based on the fact that renewable or biogenic carbon atoms contain a large number of labile radiocarbons ( 14 C) It is based on the fact that it contains atoms. Therefore, 12 C and 14By analyzing the isotope ratio of C, it is possible to distinguish carbon compounds from renewable or biological sources or raw materials from carbon compounds from fossil sources or raw materials. Thus, the specific ratio of the isotopes can be used as a "tag" to identify and distinguish renewable carbon compounds from non-renewable carbon compounds. The isotope ratio does not change during the course of a chemical reaction. Thus, the isotope ratio can be used to identify renewable compounds, components, and compositions and to distinguish them from non-renewable fossil materials in reactor feeds, reactor effluents, separated product fractions, and their various blends. As used herein, the content of carbon from biological or renewable sources is expressed as biogenic carbon content, which means the amount of biogenic carbon in a material as a weight percent of the total carbon (TC) in the material, according to ASTM D6866 (2020) or EN 16640 (2017).

[0203] Within step (c), the method of the present invention comprises the steps of: 2 , MAPD, and C 2 H 2 The pyrolysis effluent may include a step of subjecting at least a portion of the pyrolysis effluent to a post-treatment (or purification treatment) to remove at least one of the following: Other post-treatments, such as, for example, further fractionation of one or more of the effluent fractions, may be performed as well.

[0204] The present invention further provides an LWP feed for pyrolysis having a content ratio of i-olefins to n-olefins of 3.0 or less. The LWP feed preferably comprises optionally pretreated liquefied waste plastics or fractions thereof, such as optionally pretreated waste plastic pyrolysis oil or fractions thereof. In addition, the present invention provides an LWP feed for pyrolysis which is optionally pretreated liquefied waste plastics or fractions thereof obtained from the depolymerization of polyethylene-rich waste plastics.

[0205] The LWP feed of the present invention preferably has one, more than one, or all of the properties described for the LWP feed subjected to pyrolysis in step (b) of the process of the present invention. EXAMPLES

[0206] The present invention is illustrated below by non-limiting examples, however, the examples are intended to illustrate preferred embodiments of the invention, and it is to be understood that in particular the numerical values ​​and ranges set forth in the examples may be combined with other ranges and values ​​disclosed herein to provide new ranges embodying the invention.

[0207] In the following examples and comparative examples, various LWP feeds were subjected to steam cracking as an embodiment of thermal cracking. The LWP feeds were analyzed prior to cracking to measure the relative content of n-paraffins, i-paraffins, n-olefins, i-olefins, di-olefins, naphthenes and aromatics using the PIONA method, which may be used in the present invention generally to determine the composition of materials such as LWP feeds.

[0208] The PIONA method is described in Pyl et al, Journal of Chromatography A, 1218 (2011) 3217-3223.

[0209] A depolymerized sorted polyethylene-based waste plastic derived feed was degassed and fractionated into a middle distillate (PE_MD; boiling point range, IBP-FBP, ca. 160-350°C) and naphtha range fraction (PE_N; boiling point range ca. 35-190°C). The naphtha fraction and the middle distillate were analyzed by PIONA to give the content of n-paraffins (nP), i-paraffins (iP), n-olefins (nO), i-olefins (iO), diolefins (diO), paraffinic naphthenes (pN), olefinic naphthenes (oN) and aromatics (A) per carbon number. The results (numbers rounded) were as follows:

[0210] [Table 1]

[0211] Similarly, feeds with high isoparaffin contents were provided. These feeds were naphtha fractions (PP_N; boiling range about 35-190°C) and middle fractions (PP_MD; boiling range about 160-350°C) of depolymerized graded polypropylene feedstock. The PIONA analysis of these fractions is shown below (numbers have been rounded):

[0212] [Table 2]

[0213] The key characteristics of each sample are summarized in the table below, where n_tot means total n-paraffins and n-olefins, and i_tot means total i-paraffins and i-olefins:

[0214] [Table 3]

[0215] Additionally, a fossil naphtha (FN) co-feed was provided with the following PIONA analysis results:

[0216] [Table 4]

[0217] Examples and 2 and Comparative Examples 1 and 2 The LWP-based feeds PE_N, PE_MD, PP_N and PP_MD were blended with fossil naphtha feed to give feedstocks containing 20 wt.-% waste plastic-derived feed and 80 wt.-% fossil naphtha feed, respectively (total cracker feed).

[0218] Steam cracking experiments illustrating certain embodiments of the present invention were carried out on bench-scale equipment. The main parts of the steam cracking unit, the analytical equipment and the calibration procedures used in these examples and comparative examples are described in detail in the following publications: KM Van Geem, SP Pyl, MF Reyniers, J. Vercammen, J. Beens, GB Marin, On-line analysis of complex hydrocarbon mixtures using comprehensive two-dimensional gas chromatography, Journal of Chromatography A. 1217 (2010) 6623-6633 and JB Beens, UAT Comprehensive two-dimensional gas chromatography - a powerful and versatile technique. Analyst. 130 (2005) 123-127.

[0219] The bench-scale apparatus is described with reference to FIG. 1. The feed section controls the supply of steam cracking feedstock and water from reservoirs 1 and 2, respectively, to the reactor coil 3. The liquid flow was controlled by a coriolis flowmeter-controlled pump 4 (Bronkhorst, The Netherlands) equipped with a Bronkhorst™ CORI-FLOW™ series mass flowmeter to provide high accuracy: ±0.2% of reading. The CORI-FLOW™ mass flowmeter employs an advanced Coriolis mass flow sensor to achieve reliable performance even under changing operating conditions, e.g. pressure, temperature, density, conductivity and viscosity. The pumping frequency was automatically adjusted by the CORI-FLOW™ mass flowmeter controller. In contrast to volumetric flow rates, mass flow rates are not affected by changes in temperature or pressure and all streams were measured every second, i.e. essentially continuously. Steam was used as the diluent and was heated to the same temperature as the vaporized feedstock. Both the feedstock and the steam were heated in electrically heated ovens 5 and 6, respectively. Downstream from ovens 5 and 6, the feedstock and the steam were mixed in an electrically heated oven 7 filled with quartz beads, which allowed for efficient and uniform mixing of the feedstock and diluent streams before entering the reactor coil 3. The mixture of the feedstock and the diluent streams entered the reactor coil 3, which was vertically placed in a rectangular electrically heated furnace 8. Eight thermocouples T, placed along the axial reactor coordinate, measured the process gas temperature at various positions. The rectangular furnace 8 was divided into eight separate sections that could be independently controlled to set a specific temperature profile. The pressure in the reactor coil 3 was controlled by a back pressure regulator (not shown) placed downstream from the outlet of the reactor coil 3. Two pressure transducers (not shown), placed at the inlet and outlet of the reactor, indicated the coil inlet pressure (CIP) and the coil outlet pressure (COP), respectively. At the reactor outlet, nitrogen was injected into the reactor effluent both as an internal standard for analytical measurements and to contribute to some degree to the quenching of the reactor effluent.The reactor effluent was sampled online, i.e., during the operation of the steam cracking setup, at high temperature (350 °C). That is, via a valve-based sampling system and a uniformly heated transfer line, a gaseous sample of the reactor effluent was injected into a comprehensive two-dimensional gas chromatograph (GC × GC) 9 coupled to a flame ionization detector (FID) and a mass spectrometer (MS). The high-temperature 6-port 2-way sampling valve of the valved sampling system was placed in an oven, where the temperature was kept above the dew point of the effluent sample. Further downstream, the reactor effluent was cooled to about 80 °C. Water and condensed heavier products (pyrolysis gasoline (PyGas) and pyrolysis fuel oil (PFO)) were removed by a knockout vessel and a cyclone 10, while the remainder of the effluent stream was sent directly to a vent. Before reaching the vent, a portion of the effluent was taken for analysis in a refinery gas analyzer (RGA) 11. After removal of all remaining water using a water-cooled heat exchanger and a dehydrator, this effluent fraction was automatically injected into a so-called refinery gas analyzer (RGA) 11 using a built-in gas sampling valve system (80 °C).

[0220] The steam cracking experiment was carried out at a dilution of 0.5 (H 2 O diluent supply rate [kg / h] / feed and cofeed supply rate [kg / h] (H 2 The steam cracking effluent was analyzed and the product yields of the main products, and the main by-products and wastes were as follows (values ​​are given in wt.-%):

[0221] [Table 5]

[0222] As can be seen from the above data, aggregate cracker feeds containing LWP-based feeds (PE_N and PE_MD) with low (or even very low) i-olefin to n-olefin ratios tend to increase ethylene yields, while aggregate cracker feeds containing LWP-based feeds with i-olefin to n-olefin ratios above 3.0 (PP_N) or even as high as 4.6 (PP_D) tend to decrease ethylene yields while showing increased isobutene yields. In addition, propylene yields are generally favored by LWP-based feeds with high i-olefin content, but this effect can be compensated for by varying the COT so that the LWP feed and aggregate pyrolysis feed of the present invention can be optimized towards high ethylene and propylene yields. Ethylene is converted to isobutene (iC 4 H 8 ), the LWP feed according to the present invention is clearly more preferable in this regard in terms of the value of the resulting decomposition products.

[0223] Similarly, the undesired product, i.e. acetylene (C 2 H 2 ), propadiene (PD) and methylacetylene (MeAc; propyne) are less prevalent when using the feed of the present invention. In particular, feeds with a high content of i-olefins, namely PP_N and PP_MD, are found to be especially prone to the formation of MeAc following the propylene product stream. This product, if untreated, can cause fouling of the product stream, oligomerization / polymerization, and can also act as a polymerization catalyst poison.

[0224] The results also show that CO (carbon monoxide) production is increased in i-olefin-rich feeds, while CO 2The results show that the production of CO is little affected by the feed. CO is a serious poison for polymerization catalysts and requires removal from the ethylene and propylene streams. The comparative examples show poorer performance in that they have higher CO production compared to the inventive examples.

[0225] Furthermore, it can be seen from the table below that the coking tendency is much lower for naphtha range fractions with low i-olefin content, while it is further increased for naphtha fractions based on i-olefin rich feeds, as measured in a separate coking experiment in which the amount of coking accumulated during successive cracking at 650° C. for 6 hours was quantified. The quantification was carried out to determine the amount of CO and CO produced upon decoking the reactor coil using the following decoking procedure. 2 This was done using an infrared meter to measure the volumetric concentration of: Temperature in all heating zones: 850℃ Water vapor flow: 0.05kg / h Air flow: 0.05kg / h CO 2 After the value of falls below 1 vol.%, the water flow is stopped and the reactor temperature is increased to 900° C. in all zones in order to completely decoke the reactor.

[0226] CO and CO in the effluent 2 Decoking was stopped when the vol% of the mixture reached zero.

[0227] [Table 6]

[0228] Reference examples 1~5 Model feeds containing primarily n-decane (nC10) were produced according to the following table to illustrate the effect of embodiments of the present invention. Although these model feeds are not based on liquefied waste plastics, they do show the impact of certain types of components, namely monoolefins, non-conjugated diolefins, and conjugated diolefins.

[0229] [Table 7]

[0230] These model feeds were then run at 0.5 H at a coil outlet pressure of 1.7 bar. 2 Decomposition occurred at 750°C, 800°C, and 880°C with O:HC ratios.

[0231] The steam cracking effluent was analyzed and the product and by-product yields are shown in the table below. In addition, after cracking at three temperatures (low to high), the reactor was decoked and the amounts were recorded in grams.

[0232] [Table 8]

[0233] The nO model feed is a model of a degassed naphtha range LWP feed with a total olefin content of 40 wt.-%, while the iO model feed is a model of a degassed naphtha range LWP feed with a total olefin content of 40 wt.-% and a high (infinite) i-olefin / n-olefin ratio. It can be clearly seen that a high content of i-olefins leads to a significant decrease in ethylene yield and in addition causes more coking and a significantly higher propadiene yield. A comparison of n-diO (non-conjugated) and i-diO (conjugated) shows that the model feed containing conjugated diolefins clearly has the highest coking tendency.

Claims

1. 1. A method for upgrading liquefied waste plastics, comprising: (a) providing a liquefied waste plastic feed; (b) pyrolyzing the liquefied waste plastic feed in a pyrolysis reactor; and (c) separating at least one fraction comprising ethylene from the effluent of the pyrolysis reactor. Including, The method according to claim 1, wherein the liquefied waste plastic feed has an i-olefins to n-olefins ratio of 3.0 or less.

2. 2. The method of claim 1, wherein the liquefied waste plastic feed has an i-olefins to n-olefins ratio of 2.5 or less, 2.0 or less, 1.5 or less, 1.0 or less, 0.80 or less, 0.60 or less, or 0.50 or less.

3. 3. The method of claim 1 or 2, wherein the liquefied waste plastic feed has a total content of i-olefins, n-olefins, i-paraffins and n-paraffins of at least 40 wt%, preferably at least 50 wt%, at least 55 wt%, at least 60 wt%, at least 65 wt% or at least 70 wt%.

4. The method according to any one of claims 1 to 3, wherein the liquefied waste plastic feed has a total content of gaseous (NTP) components of less than or equal to 1.5 wt.-%, preferably less than or equal to 1.0 wt.-%, more preferably less than or equal to 0.5 wt.-%.

5. The method according to any one of claims 1 to 4, wherein the liquefied waste plastics feed has an aggregate olefins content of 10 wt.-% or more, such as 15 wt.-% or more, 20 wt.-% or more, or 30 wt.-% or more, and preferably has an aggregate olefins content of 90 wt.-% or less, more preferably 80 wt.-% or less, 70 wt.-% or less, or 60 wt.-% or less.

6. The method according to any one of claims 1 to 5, wherein the liquefied waste plastic feed has a monoolefins to diolefins ratio of 10 or more, preferably 12 or more, 15 or more, or 20 or more.

7. 7. The method of any one of claims 1 to 6, wherein the liquefied waste plastic feed has an i-paraffins to n-paraffins ratio of 2.0 or less, preferably 1.7 or less, 1.5 or less, 1.0 or less, 0.90 or less, 0.80 or less, 0.70 or less, 0.60 or less, 0.50 or less, 0.40 or less, 0.30 or less, 0.20 or less, 0.15 or less, 0.10 or less, 0.09 or less, 0.08 or less, 0.07 or less, 0.06 or less, 0.05 or less, or 0.04 or less.

8. The method according to any one of claims 1 to 7, wherein the liquefied waste plastic feed has an aggregate paraffin content of at least 5 wt.-%, preferably at least 10 wt.-%, at least 12 wt.-%, at least 15 wt.-%, at least 17 wt.-%, at least 19 wt.-%, or at least 20 wt.-%.

9. The liquefied plastic feed has a combined n-paraffin and n-olefin content of 20 wt.-% or more, preferably 23 wt.-% or more, 25 wt.-% or more, 27 wt.-% or more, or 30 wt.-% or more; and / or and / or the liquefied waste plastic feed has a ratio of total n-paraffins and n-olefins to total i-paraffins and i-olefins ([nP]+[nO]) / ([iP]+[iO]) of 0.40 or more, preferably 0.50 or more, 0.60 or more, 0.70 or more, 0.80 or more, 0.90 or more, 1.00 or more, 1.20 or more, 1.40 or more, 1.60 or more, 1.80 or more, 2.00 or more, 2.50 or more, or 3.00 or more; and / or The liquefied waste plastic feed has a combined n-olefin, i-olefin and diolefin content ([nO] + [iO] + [diO]) of 60 wt.-% or less, preferably 55 wt.-% or less, or 50 wt.-% or less; and / or the liquefied waste plastic feed has a total n-olefins and i-olefins to diolefins ratio (([nO]+[iO]) / [diO]) of 5 or more, preferably 8 or more, or 10 or more; and / or The liquefied waste plastic feed has a total i-paraffin and i-olefin content of 50 wt.-% or less, preferably 40 wt.-% or less, 30 wt.-% or less, or 20 wt.-% or less. The method according to any one of claims 1 to 8.

10. The liquefied waste plastic feed has a total C9 i-olefins content of 10 wt.-% or less, preferably 8 wt.-% or less, 6 wt.-% or less, or 5 wt.-% or less; and / or The liquefied waste plastic feed has a diolefin content of 5.0 wt.-% or less, preferably 4.0 wt.-% or less, 3.0 wt.-% or less, 2.5 wt.-% or less, 2.0 wt.-% or less, 1.5 wt.-% or less, or 1.0 wt.-% or less; and / or The liquefied waste plastic feed has a conjugated diolefin content of 5.0 wt.-% or less, more preferably 4.0 wt.-% or less, 3.0 wt.-% or less, 2.0 wt.-% or less, 1.0 wt.-% or less, 0.75 wt.-% or less, or 0.50 wt.-% or less. The method according to any one of claims 1 to 9.

11. The method according to any one of claims 1 to 10, wherein the liquefied waste plastic feed has a content of n-olefins of 2 wt.-% or more, preferably 5 wt.-% or more, 10 wt.-% or more, 15 wt.-% or more, 20 wt.-% or more, or 25 wt.-% or more.

12. The method according to any one of claims 1 to 11, wherein the pyrolysis in step (b) comprises steam cracking.

13. The process according to any one of claims 1 to 12, wherein the pyrolysis in step (b) is carried out in the presence of a co-feed, preferably a hydrocarbon co-feed, more preferably a fossil naphtha co-feed, such as a fossil naphtha feed selected from full range naphtha or light naphtha.

14. The method according to any one of claims 1 to 13, wherein the step (a) of providing the liquefied waste plastic feed comprises at least one pretreatment stage in which the liquefied waste plastic or a fraction thereof is subjected to pretreatment, and the pretreatment preferably comprises subjecting the liquefied waste plastic or a fraction thereof to at least one treatment selected from the group consisting of drying, desalting, reactive extraction, solvent extraction, adsorption, oxidation, reduction, separation of solid particles from the liquefied waste plastic, separation of gaseous (NTP) components from the liquefied waste plastic, and selective and / or mild hydrogenation of the liquefied waste plastic.

15. 15. The method according to any one of claims 1 to 14, wherein the liquefied waste plastic feed has a total content of i-olefins, n-olefins, i-paraffins and n-paraffins ranging from 40 wt.-% to 100 wt.-%, e.g., 50 wt.-% to 100 wt.-%, 55 wt.-% to 100 wt.-%, 60 wt.-% to 100 wt.-%, 65 wt.-% to 100 wt.-%, 70 wt.-% to 100 wt.-%.

16. A liquefied waste plastic feed for pyrolysis having a content ratio of i-olefins to n-olefins of not more than 3.

0.

17. The liquefied waste plastic feed of claim 16, wherein the liquefied waste plastic feed is further defined in any one of claims 2 to 11 or 15.

18. A liquefied waste plastic feed for pyrolysis which is an optionally pretreated liquefied waste plastic or a fraction thereof obtained from a process involving the depolymerization of polyethylene-rich waste plastic.

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