Process for refining a synthetic crude oil stream

Abstract

The present invention relates to a method for refining a syncrude oil stream (1), comprising providing a syncrude oil stream (1), wherein the syncrude oil stream (1) contains diene compounds and has a diene number of 0.1 g / 100 g or greater, contacting the syncrude oil stream (1) with a sulfur stream (2) containing at least one sulfur compound to form a mixture, wherein contacting the syncrude oil stream (1) with the sulfur stream (2) converts at least a portion of the diene compounds to diene-free products, and obtaining a syncrude product stream (3) from the mixture, wherein the diene-free products are present in dissolved form in the syncrude product stream (3). The present invention also relates to a method for producing a syncrude product stream (3) from an organic material.

Description

[Technical Field]

[0001] The present invention relates to a process for refining a syncrude stream and a process for producing a syncrude product stream from organic materials. [Background technology]

[0002] Synthetic crude oil, sometimes called syncrude, can be obtained from a variety of processes. For example, synthetic crude oil can be shale oil, obtained from oil shale by pyrolysis. Another source is hydrocarbons obtained from oil sands, especially bitumen, which can be upgraded to obtain synthetic crude oil. Additionally, synthetic crude oil can also be produced from plastic materials (e.g., plastic waste) by cracking.

[0003] Synthetic crudes typically contain a variety of impurities that can adversely affect refining processes and systems or can render the crude completely unsuitable for a particular refining process. The type and content of impurities can vary widely depending on the source and method used to obtain the synthetic crude.

[0004] A particularly significant problem in the further processing of synthetic crude oil is so-called gum formation. Pyrolysis oils typically contain a variety of chemical compounds that can be prone to forming deposits. Such deposits can clog or otherwise damage subsequent refining systems, increasing cleaning efforts and shortening their lifespan. Summary of the Invention [Problem to be solved by the invention]

[0005] The gum formation problem associated with synthetic crude oils has not yet been fully resolved. There remains a need for a method for reducing the tendency of synthetic crude oils to form gums. Accordingly, it is an object of the present invention to provide a method for reducing gum formation in synthetic crude oils. [Means for solving the problem]

[0006] Accordingly, the present invention provides a method for refining a synthetic crude oil stream, comprising the steps of: providing a syncrude stream, the syncrude stream containing diene compounds and having a diene number of 0.1 g / 100 g or greater; contacting the syncrude stream with a sulfur stream containing at least one sulfur compound to form a mixture, wherein contact with the sulfur stream converts at least a portion of the diene compounds to diene-free products; - obtaining a syncrude product stream from the mixture, wherein the diene-free product is present in dissolved form in the syncrude product stream; The present invention relates to a method, including:

[0007] In a further aspect, the present invention provides a method for producing a synthetic crude product stream from organic material, preferably plastic material, comprising the steps of: providing an organic material, the organic material comprising a diene compound; - adding a sulfur-containing composition containing at least one sulfur compound to form a mixture; - feeding the mixture to a depolymerization reactor to depolymerize the organic material, wherein at least a portion of the diene compounds are reacted with the at least one sulfur compound and converted to diene-free products; - obtaining a syncrude product stream from the mixture, wherein the diene-free product is present in dissolved form in the syncrude product stream; The present invention relates to a method, including:

[0008] In a further aspect, the present invention provides a method for producing a synthetic crude product stream from organic material, preferably plastic material, comprising the steps of: providing an organic material, the organic material comprising a diene compound and at least one sulfur source; - feeding an organic material to a depolymerization reactor to depolymerize the organic material, wherein sulfur compounds are obtained from at least one sulfur source, and at least a portion of the diene compounds react with the sulfur compounds and are converted to diene-free products; - obtaining a syncrude product stream from the mixture, wherein the diene-free product is present in dissolved form in the syncrude product stream; The present invention relates to a method, including:

[0009] In the context of the present invention, it has been found that synthetic crude oils have an increased tendency to form gum, especially when the content of diene compounds is high. Therefore, reactive dienes can act as gum formers and cause harmful deposits in refinery systems. For example, dienes can undergo Diels-Alder reactions, resulting in intermolecular cross-linking and ultimately deposits. Additionally, dienes can form stable complexes with catalysts in hydroprocessing units. Therefore, within the scope of the present invention, it has been found advantageous to reduce the diene content of synthetic crude oils.

[0010] In the method according to the present invention, this is achieved by reacting a syncrude stream with a sulfur stream containing at least one sulfur compound to convert the diene compounds into soluble, diene-free products. The diene-free products can then be dissolved in the crude stream. Therefore, the reaction products do not need to be removed prior to further processing, for example, in a hydroprocessing unit. Thus, the present invention, in simple terms, allows for the at least partial detoxification of problematic diene compounds in a single step without the need for further purification steps to remove the diene compounds or their reaction products. Instead, the diene-free products can remain in the syncrude product stream. The syncrude product stream has a lower diene content and is therefore less susceptible to gum formation. The "syncrude product stream" may also be referred to as a "refined syncrude stream."

[0011] The use of sulfur-containing compounds to remove olefins from hydrocarbon products is generally known in the prior art. For example, WO 2021 / 021449 describes a method for removing olefins from light hydrocarbon streams by mercaptanization using hydrogen sulfide in the presence of a catalyst. The olefins are converted to mercaptans, which are then oxidized and finally separated in the so-called Merox process. However, WO 2021 / 021449 does not relate to the processing of synthetic crude oils or to diene compounds, which are particularly problematic in relation to gum formation.

[0012] The present invention is also based on a completely different approach. It has been found that diene compounds contained in a syncrude stream can be directly converted into diene-free products by reaction with sulfur compounds that are soluble in and may remain in the syncrude stream. The resulting syncrude product stream can therefore even be further processed directly, for example in a hydrotreating unit, without the need for additional purification or separation steps.

[0013] Further methods relating to the treatment or refining of crude oil streams (in particular the conversion of diene compounds) or related topics are known from WO 2021 / 204818, WO 2021 / 201932, U.S. Pat. No. 4,059,504, U.S. Pat. No. 3,238,269, U.S. Pat. No. 3,595,780, U.S. Pat. No. 5,417,844, and U.S. Pat. No. 4,734,540. The hydrogenation of diene compounds is known in particular from the prior art. In this process, diene compounds are usually reduced with hydrogen (H) in the presence of a catalyst.

[0014] As noted above, the present invention takes a different approach. In connection with the present invention, contacting the syncrude stream with the sulfur stream is preferably carried out in the absence of hydrogen (H). In particular, in all aspects of the present invention, it is preferred that the sulfur compounds undergo an addition reaction with the double bonds of the diene compounds, thereby converting at least a portion of the diene compounds to diene-free products.

[0015] In the process for producing a synthetic crude product stream from an organic material according to the invention, a sulfur compound is added to the organic material even before depolymerization, or a sulfur source is already present in the organic material, which allows the diene compounds to be converted during pyrolysis into diene-free products, which are present in a dissolved state in the synthetic crude product stream obtained by this conversion. This has the advantage, among other things, that the high temperatures during depolymerization can also be used to react the diene compounds, without the need for a separate sulfur compound thereafter.

[0016] It is particularly advantageous if the sulfur source is already contained in the organic material. In this case, sulfur compounds may be released due to the high temperature during depolymerization. Therefore, if an organic material that already contains a sulfur source in addition to a diene compound is selected or formulated, there is an advantage in that there is no need to separately add a sulfur-containing composition.

[0017] The sulfur source can be any substance from which a sulfur compound, as defined herein, such as a thiol or hydrogen sulfide, can be obtained during depolymerization. In one embodiment, the sulfur source can be elemental sulfur. In a preferred embodiment, the sulfur source is a sulfur-containing polymer, preferably a vulcanized plastic. Under depolymerization conditions, hydrogen sulfide as well as mercaptans can be formed from such a sulfur source, which can then react with diene compounds contained in the organic material as described herein.

[0018] In a preferred embodiment, the concentration of the sulfur source in the organic material (preferably a sulfur-containing polymer, particularly a vulcanized plastic) is 0.05% by weight (% (w / w)) or more, more preferably 0.1% by weight or more, more preferably 0.2% by weight or more, more preferably 0.5% by weight or more, more preferably 1% by weight or more, more preferably 2% by weight or more, more preferably 5% by weight or more, and more preferably 10% by weight or more. The concentration is preferably 0.05 to 60% by weight, more preferably 0.1 to 50% by weight, more preferably 0.2 to 40% by weight, more preferably 0.5 to 35% by weight, more preferably 1 to 30% by weight, more preferably 2 to 25% by weight, more preferably 5 to 20% by weight, and more preferably 10 to 15% by weight. A higher concentration of the sulfur source has the advantage of increasing the amount of sulfur compounds obtained during depolymerization, thereby further promoting the reaction with the diene compound.

[0019] Preferred embodiments of the process for refining a syncrude stream according to the present invention and the process for producing a syncrude product stream from an organic material according to the present invention are described together below, and thus preferred embodiments described for a process, e.g., with respect to diene content or sulfur compounds, are also preferred for the other processes.

[0020] The diene compounds contained in the synthetic crude oil stream or organic material preferably have conjugated or cumulative carbon-carbon double bonds, especially compounds containing conjugated carbon-carbon double bonds. Such compounds are particularly prone to gum formation, for example by the Diels-Alder reaction, and are particularly susceptible to removal by the method according to the invention.

[0021] Those skilled in the art are familiar with methods for determining the diene number. Preferably, the diene number is determined according to the ASTM UOP326-07 standard.

[0022] The synthetic crude stream has a densitometric value of at least 0.1 g / 100 g, preferably at least 0.2 g / 100 g, more preferably at least 0.3 g / 100 g, more preferably at least 0.4 g / 100 g, more preferably at least 0.5 g / 100 g, more preferably at least 0.6 g / 100 g, more preferably at least 0.7 g / 100 g, more preferably at least 0.8 g / 100 g, more preferably at least 0.9 g / 100 g, more preferably at least 1.0 g / 100 g, and more preferably at least 1.5 g / 100 g. The synthetic crude stream or organic material preferably has a diene number in the range of from 0.1 g / 100g to 15 g / 100g, more preferably from 1.0 g / 100g to 12 g / 100g, especially from 1.5 g / 100g to 10 g / 100g. For processes for producing a synthetic crude product stream from an organic material according to the invention, it is preferred that the organic material has a diene number of from 0.1 g / 100g to 15 g / 100g, more preferably from 1.0 g / 100g to 12 g / 100g, especially from 1.5 g / 100g to 10 g / 100g. It is particularly preferred if the organic material has a diene value as described herein for the syncrude stream, i.e., the preferred diene value values ​​described for the syncrude stream are also preferred for the organic material.

[0023] The syncrude product stream preferably has a lower diene number than the syncrude stream or the organic material. The syncrude product stream preferably has a diene number of less than 5g / 100g, more preferably less than 4g / 100g, more preferably less than 3g / 100g, more preferably less than 2g / 100g, more preferably less than 1.5g / 100g, more preferably less than 1g / 100g, more preferably less than 0.9g / 100g, more preferably less than 0.8g / 100g, more preferably less than 0.7g / 100g, more preferably less than 0.6g / 100g, more preferably less than 0.5g / 100g. The syncrude product stream preferably has a diene number in the range of 0.01g / 100g to 5g / 100g, more preferably 0.1g / 100g to 2g / 100g, especially 0.2g / 100g to 1g / 100g.

[0024] The at least one sulfur compound is preferably selected from the group consisting of thiols, thioketones, thioethers, thiocarboxylic acids, mercaptocarboxylic acids, and hydrogen sulfide. Thiols are particularly preferred. Thiols can react with dienes via an addition reaction to form thioethers, which can remain dissolved in the synthetic crude oil stream. The dienes are thus removed and can no longer undergo Diels-Alder reactions, which can result in gum formation, for example. Similarly, the other sulfur compounds mentioned above can react with dienes to form soluble, diene-free, less reactive products. Hydrogen sulfide is also suitable as a sulfur compound in the context of the method according to the present invention. However, hydrogen sulfide has the disadvantage that it generates free thiols by addition reaction with dienes, which can continue to react and thus contribute to some degree to molecular crosslinking and deposit formation. Therefore, thiols, thioketones, thioethers, thiocarboxylic acids, and mercaptocarboxylic acids have proven particularly advantageous.

[0025] It is particularly preferred that the at least one sulfur compound is selected from the group consisting of methyl mercaptan, ethyl mercaptan, n-propyl mercaptan, isopropyl mercaptan, phenyl mercaptan, ethanedithiol, propanedithiol, mercaptoethanol, mercaptopropanol, thioacetic acid, mercaptoacetic acid, cysteine, methionine, thiourea, and hydrogen sulfide. For the reasons mentioned above, hydrogen sulfide is less preferred among the exemplified compounds. On the other hand, all of the exemplified compounds have the advantage that no free thiol is formed during the reaction with the diene, which may not cause undesirable secondary reactions. Therefore, in the context of the present invention, it is particularly preferred that the at least one sulfur compound is selected from the group consisting of methyl mercaptan, ethyl mercaptan, n-propyl mercaptan, isopropyl mercaptan, phenyl mercaptan, ethanedithiol, propanedithiol, mercaptoethanol, mercaptopropanol, thioacetic acid, mercaptoacetic acid, cysteine, methionine, and thiourea.

[0026] It has been found advantageous for the contacting of the synthetic crude oil stream with the sulfur stream to be carried out at a temperature of at least 80° C., preferably at least 100° C., more preferably at least 120° C., more preferably at least 140° C., more preferably at least 160° C., more preferably at least 180° C., more preferably at least 200° C., more preferably at least 220° C., more preferably at least 240° C. In particular, it is preferred if the contacting of the synthetic crude oil stream with the sulfur stream is carried out at a temperature in the range of 80 to 450° C., preferably 100 to 400° C., more preferably 120 to 350° C., more preferably 140 to 300° C., more preferably 160 to 260° C., more preferably 180 to 220° C. Higher temperatures can promote the reaction between diene compounds and sulfur compounds, and therefore the diene content can be reduced even more significantly.

[0027] Preferably, the contact between the syncrude oil stream and the sulfur stream is carried out at the specified temperature for a time of at least 0.5 minutes, preferably at least 1 minute, more preferably at least 2 minutes, even more preferably at least 5 minutes, and most preferably at least 12 minutes. Providing a longer contact time allows for a more complete reaction between the diene compound and the sulfur compound, thereby further reducing the diene content. Therefore, particularly preferred contact times are from 0.5 to 180 minutes, preferably from 1 to 120 minutes, more preferably from 2 to 60 minutes, even more preferably from 5 to 30 minutes, and most preferably from 12 to 20 minutes.

[0028] In a preferred embodiment, the contacting is carried out in the presence of at least one radical initiator and / or catalyst. The presence of the radical initiator and / or catalyst can promote the addition of sulfur compounds to double bonds, thus resulting in more complete removal of diene compounds. In particular, the use of a free radical initiator and / or catalyst has the advantage that the required activation energy can be reduced, resulting in rapid reaction of diene compounds even when the contacting of the syncrude oil stream with the sulfur stream is carried out at a lower temperature. Preferably, the at least one radical initiator and / or catalyst is selected from the group consisting of ultraviolet light, azobis(isobutyronitrile), dibenzoyl peroxide, amine compounds, and heavy metal salts.

[0029] The concentration of the sulfur compounds in the sulfur stream is preferably 0.01 wt% or more, more preferably 0.5 wt% or more, more preferably 2 wt% or more, more preferably 10 wt% or more. The higher the concentration of the sulfur compounds, the more likely they are to react with the diene compounds.

[0030] More preferably, the concentration of sulfur compounds in the mixture formed from the synthetic crude oil stream and the sulfur stream is at least 0.05 wt%, preferably at least 0.1 wt%, more preferably at least 1 wt%. Particularly preferably, the concentration of sulfur compounds in the mixture formed from the synthetic crude oil stream and the sulfur stream is in the range of 0.05 to 10 wt%, preferably 0.1 to 5 wt%, more preferably 0.2 to 2 wt%.

[0031] In a preferred embodiment, the volumetric blend ratio of the syncrude oil stream to the sulfur stream is between 1000:1 and 10:1, preferably between 200:1 and 50:1. Blend ratios within this range have been found to be particularly well suited as they ensure a sufficient concentration of sulfur compounds without excessively diluting the syncrude oil stream.

[0032] In a preferred embodiment of the method for refining a syncrude stream according to the invention or the method for producing a syncrude stream from an organic material according to the invention, the syncrude product stream is fed to a gas-liquid separator. Preferably, at least a portion of the unused sulfur compounds is separated via the gas phase. This has the advantage that the sulfur content in the syncrude product stream is reduced, especially when large amounts of sulfur compounds are used. It is particularly advantageous if at least a portion of the sulfur compounds separated via the gas phase are recycled to the sulfur stream. This allows for efficient utilization of the sulfur compounds. In addition, this allows for a higher concentration of sulfur compounds in the mixture of the syncrude stream and the sulfur stream, which promotes the reaction of diene compounds.

[0033] In a preferred embodiment of the method for refining a syncrude stream or the method for producing a syncrude stream from an organic material according to the present invention, the syncrude product stream is fed to a hydrotreating unit. It has been found that reducing the diene content in the syncrude stream is particularly advantageous, especially during the hydrogenation process in the hydrotreating unit, since dienes can form stable complexes with the catalyst in such systems. Thus, the use of the method according to the present invention in combination with hydrotreating can significantly improve the service life of the hydrotreating unit, and in particular the catalysts used.

[0034] In the context of the present invention, "syncrude oil stream" is preferably understood to mean a material stream containing a synthetic crude oil or a fraction thereof. Preferably, the synthetic crude oil stream consists of a synthetic crude oil or a fraction thereof. Within the scope of the present invention, it is particularly preferred if the synthetic crude oil stream comprises, and in particular consists of, a pyrolysis oil or a fraction thereof. The pyrolysis oil is preferably a pyrolysis oil obtained from biomass (especially wood) and / or plastic. The process according to the present invention has proven particularly suitable when the synthetic crude oil stream is a hydrocarbon mixture obtained from the depolymerization of biomass or plastic materials, in particular plastic materials. Thus, the synthetic crude oil stream is preferably a plastic pyrolysis product or a fraction thereof, or a biomass pyrolysis product (especially wood pyrolysis product) or a fraction thereof. However, the process according to the present invention is also well suited to other synthetic crude oils and fractions thereof. Therefore, in a further preferred embodiment, the synthetic crude oil stream comprises, and preferably consists of, shale oil or upgraded bitumen.

[0035] Thus, in a particularly preferred embodiment of the method for refining a synthetic crude stream, the synthetic crude stream is produced by depolymerization of plastic material, in particular plastic waste. Those skilled in the art are familiar with the production of synthetic crude streams by depolymerization of plastic material. Such methods are known, for example, from WO 2012 / 149590 and U.S. Pat. No. 6,060,631. Similarly, for the method for producing a synthetic crude product stream from organic material, it is preferred if the organic material is plastic material, in particular plastic waste.

[0036] Preferably, the plastic material comprises polyethylene (PE), polypropylene (PP), polystyrene (PS), polyvinyl chloride (PVC), polyethylene terephthalate (PET), polyamide (PA), styrene-acrylonitrile (SAN), and / or acrylonitrile-butadiene-styrene (ABS). The method according to the invention has been found to be particularly suitable for purifying pyrolysis oil from the exemplified plastic materials.

[0037] In a preferred embodiment of the process for producing a synthetic crude product stream from organic material, the organic material is depolymerized at a temperature of at least 250° C., preferably at least 300° C., more preferably at least 350° C. The organic material is preferably depolymerized at a temperature in the range of 250-550° C., preferably 300-500° C., more preferably 350-450° C., more preferably 400-440° C. Both of these temperatures are well suited for the depolymerization of organic materials, particularly plastic materials, while also being shown to promote the reaction of sulfur compounds with dienes.

[0038] All parameters mentioned herein refer to SATP (Standard Ambient Temperature and Pressure) conditions according to IUPAC, in particular a temperature of 25° C. and a pressure of 101,300 Pa, unless otherwise stated.

[0039] Unless otherwise specified, all percentages (%) herein refer to weight percent.

[0040] Unless otherwise stated, all mix ratios specified herein relate to volume mix ratios, i.e., volume:volume ratios.

[0041] The invention is illustrated by the following figures, but it will be appreciated that the invention is not limited thereto. [Brief explanation of the drawings]

[0042] [Figure 1] FIG. 1 is a process flow diagram of a preferred embodiment of a method for refining a synthetic crude stream in accordance with the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0043] In the embodiment shown in FIG. 1, a synthetic crude oil stream 1 is obtained by depolymerization of a plastic material. The plastic material is compressed, degassed, and melted in an extruder 12. The plastic melt obtained from the extruder 12 is mixed in a static mixer 13 with an external solvent 14 (preferably heavy oil) and / or previously cracked plastic material, which is recycled as a recycle stream 15, in order to reduce the viscosity of the plastic melt. The resulting mixture is introduced into a depolymerization reactor 16, where the plastic material is depolymerized at a temperature preferably between 400°C and 440°C. The cracked plastic material is obtained as the overhead product of a column 17. After separation of a gas stream 18 in a further column 19, a synthetic crude oil stream 1 having a diene number of at least 0.1 g / 100 g is obtained. The synthetic crude oil stream 1 is then contacted with a sulfur stream 2 containing at least one sulfur compound, preferably a thiol. At least a portion of the diene compounds present in syncrude stream 1 are reacted with sulfur compounds and converted to diene-free products, resulting in syncrude product stream 3, in which the diene-free products are present in solution.

Claims

1. 1. A process for refining a synthetic crude oil stream (1), comprising: providing said synthetic crude stream (1), wherein said synthetic crude stream (1) contains diene compounds and has a diene number of 0.1 g / 100 g or greater; contacting said synthetic crude oil stream (1) with a sulfur stream (2) containing at least one sulfur compound to form a mixture, wherein contact with said sulfur stream (2) converts at least a portion of said diene compounds into diene-free products; - obtaining a syncrude product stream (3) from said mixture, wherein said diene-free products are present in dissolved form in said syncrude product stream (3); A method comprising:

2. 2. The process of claim 1, wherein the contacting of the syncrude oil stream (1) with the sulfur stream (2) is carried out at a temperature of 80°C or greater.

3. 3. The method of claim 1 or claim 2, wherein the contacting is carried out in the presence of at least one radical initiator and / or catalyst, preferably the at least one radical initiator and / or catalyst is selected from the group consisting of ultraviolet light, azobis(isobutyronitrile), dibenzoyl peroxide, an amine compound, and a heavy metal salt.

4. 4. The method according to any one of claims 1 to 3, wherein the concentration of the sulfur compounds in the mixture formed from the syncrude oil stream (1) and the sulfur stream (2) is at least 0.05 wt%.

5. 5. The method according to any one of claims 1 to 4, wherein the concentration of the sulfur compounds in the mixture formed from the syncrude oil stream (1) and the sulfur stream (2) is in the range of 0.05 to 10 wt.%.

6. The process according to any one of claims 1 to 5, wherein the volumetric mixing ratio of the synthetic crude oil stream (1) to the sulfur stream (2) is between 1000:1 and 10:

1.

7. The method according to any one of claims 1 to 6, wherein said synthetic crude stream (1) is produced by depolymerization of plastic material, in particular plastic waste.

8. 1. A process for producing a synthetic crude product stream (3) from organic material, preferably plastic material, comprising: - providing an organic material, wherein the organic material comprises a diene compound; - adding a sulfur-containing composition containing at least one sulfur compound to form a mixture; - feeding said mixture to a depolymerization reactor (16) to depolymerize said organic material, wherein at least a portion of said diene compounds react with said at least one sulfur compound and are converted to diene-free products; - obtaining a syncrude product stream (3) from said mixture, wherein said diene-free products are present in dissolved form in said syncrude product stream (3); A method comprising:

9. 1. A process for producing a synthetic crude product stream (3) from organic material, preferably plastic material, comprising: providing an organic material, wherein the organic material comprises a diene compound and at least one sulfur source; - feeding said organic material to a depolymerization reactor (16) to depolymerize said organic material, wherein sulfur compounds are obtained from at least one sulfur source, and at least a portion of said diene compounds react with said sulfur compounds and are converted to diene-free products; - obtaining a syncrude product stream (3) from said mixture, wherein said diene-free products are present in dissolved form in said syncrude product stream (3); A method comprising:

10. 10. The method of any one of claims 1 to 9, wherein the at least one sulfur compound is selected from the group consisting of thiols, thioketones, thioethers, thiocarboxylic acids, mercaptocarboxylic acids, and hydrogen sulfide.

11. 11. The method of any one of claims 1 to 10, wherein the at least one sulfur compound is selected from the group consisting of methyl mercaptan, ethyl mercaptan, n-propyl mercaptan, isopropyl mercaptan, phenyl mercaptan, ethanedithiol, propanedithiol, mercaptoethanol, mercaptopropanol, thioacetic acid, mercaptoacetic acid, cysteine, methionine, and thiourea.

12. 12. The method of any one of claims 1 to 11, wherein the plastic material comprises polyethylene (PE), polypropylene (PP), polystyrene (PS), polyvinyl chloride (PVC), polyethylene terephthalate (PET), polyamide (PA), styrene-acrylonitrile (SAN), and / or acrylonitrile-butadiene-styrene (ABS).

13. A method according to any one of claims 8 to 12, wherein the depolymerisation of the organic material is carried out at a temperature of 250°C or higher.

14. A method according to any one of claims 8 to 13, wherein the depolymerisation of the organic material is carried out at a temperature in the range of 250 to 550°C.

15. The method of any one of claims 1 to 14, wherein the syncrude product stream (3) containing the diene-free product is fed to a hydroprocessing unit.

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