Method for producing a non-hazardous process oil, and use thereof

Abstract

The invention relates to a method for producing a non-hazardous aromatic process oil from a tyre pyrolysis oil. The method comprises the steps of distilling the tyre pyrolysis oil using fractional distillation, with at least one low-boiling fraction and at least one high-boiling fraction being obtained, mixing the at least one high-boiling fraction with solvent as an extractant and extracting it, an aromatic oil being obtained as the raffinate. The invention further relates to a non-hazardous aromatic process oil and to the use of the process oil in tyres or rubber mixtures.

Description

[0001] Process for producing a label-free process oil and its use

[0002] The invention relates to a process for producing a label-free aromatic process oil, the aromatic process oil and its use.

[0003] Worldwide, approximately 1.5 billion end-of-life tires are generated annually, a large portion of which are landfilled. In the European Union alone, there are approximately 3.5 million tons of end-of-life tires. A significant portion of these are incinerated, resulting in carbon dioxide emissions.

[0004] One process for the material recycling of used tires is pyrolysis, which produces recovered carbon black as its primary product. Used tires consist of several components, such as rubber, steel, soot, and additives. For processing by pyrolysis, the steel wire is extracted from the tires and can be reused as scrap metal. The remaining rubber is shredded, finely ground, and pyrolyzed in a pyrolysis reactor at high temperatures of, for example, 700°C, i.e., separated into various components, including carbon black. By-products include non-condensable gases and pyrolysis oil, which is also known as tire pyrolysis oil (TPO). Due to its low flash point and, in particular, its high content of polycyclic aromatics, this pyrolysis oil is of little value and has no established application.

[0005] WO 2019 / 067311 Ai discloses a process for processing pyrolysis oil from scrap tires. The process serves to improve the color of the pyrolysis oil and reduce the polycyclic aromatic hydrocarbon (PAH) content. The pyrolysis oil is mixed with a solvent, brought into contact with clay, and the undesirable components are bound with clay. The purified pyrolysis oil is used to clean oil drilling rigs or as fuel. The object of the invention is therefore to provide a process that allows the utilization of pyrolysis oil from scrap tires as a valuable material and, in particular, delivers a label-free product that can be reused as a raw material in industry.

[0006] The object is achieved according to the invention by a process for producing a label-free aromatic process oil according to claim 1, a process oil according to claim 9 and the use of a process oil according to claim 11.

[0007] Further embodiments are the subject of the subclaims or described below.

[0008] The process according to the invention for producing a label-free aromatic process oil comprises at least the steps of a) providing a pyrolysis oil from used tires (tire pyrolysis oil), wherein the tire pyrolysis oil has an aromatics content according to DIN 51378: 2020 of 30 wt.% to 50 wt.%, a "Bureau of Minerals Correlation Index" (BMCI for short) according to API Technical Data Book of greater than 55, a bio-based carbon content according to ASTM D6866 Method B:2022 of 40% (pme) to 55% (pme), a density at 15°C of 880-970 kg / m 3measured according to DIN 51757 Method 3 (2011), a sulfur content of 0.8-1.1 wt% measured according to DIN EN ISO 14596: 2007, a nitrogen content of 3500-6000 mg / kg measured according to DIN 51444: 2020, a benzo[a]pyrene content between 5 mg / kg and 150 mg / kg measured according to DIN EN 16143: 2023 and a PAH content determined as a sum according to Directive 2005 / 69 / EU of greater than 40 mg / kg and up to 850 mg / kg measured according to DIN EN 16143: 2023, b) distilling the pyrolysis oil from waste tires in a fractional distillation in one or more distillation steps at temperatures between 100 and 400 °C under atmospheric pressure or vacuum, whereby at least one low-boiling fraction and at least one high-boiling fraction are obtained, and in which the distillation fractions are collected, c) mixing the at least one high-boiling fraction from step b) with a solvent as extractant in a ratio of 30% by weight to 300% by weight.- % of extractant to pyrolysis oil fraction in an extraction reactor, if necessary mixing and transferring to an extraction reactor, d) extracting at temperatures of 30 to 12O°C in at least one extraction step, whereby an aromatic oil is obtained as raffinate which has a proportion of aromatic hydrocarbons CA of 15-35 wt.%, preferably 20-30 wt.%, measured according to DIN 51378: 2020, a benzo [a]pyrene content of less than 1 mg / kg measured according to DIN EN 16143: 2023 and a PAH content of less than 10 mg / kg measured according to DIN EN 16143: 2023. A PAH content of less than 10 mg / kg measured according to DIN EN 16143:2023 corresponds to a sum of polycyclic aromatics of less than 10 mg / kg measured according to Directive 2005 / 69 / EC.

[0009] A PAH content determined as a sum according to Directive 2005 / 69 / EU includes the sum of the following eight polycyclic aromatics: Benzo(a)pyrene (CAS No. 50-32-8), Benzo(e)pyrene (CAS No. 192-97-2), Benzo(a)anthracene (CAS No. 56-55-3), Chrysene (CAS No. 218-01-9), Benzo(b)fluoranthene (CAS No. 205-99-2), Benzo(j)fluoranthene (CAS No. 205-82-3), Benzo(k)fluoranthene (CAS No. 207-08-9), Dibenz(a,h)anthracene (CAS No. 53-70-3), which according to Federal Council document 190 / 06 of 09.03.2006, Section 29 are limited in use in tires.

[0010] The aromatic oil may have a sulfur content of less than 2 wt.% measured according to DIN EN ISO 14596: 2007, preferably less than 1.5 wt.%, particularly preferably less than 1 wt.%.

[0011] In one embodiment, the raffinate obtained is an aromatic oil having a polycyclic aromatic hydrocarbon content according to IP346 of < 3 wt%.

[0012] According to the invention, pyrolysis oil from used tires is understood to mean an oil obtained as a liquid by-product during the pyrolysis of used tires or during thermal depolymerization, also known as hydrothermal liquefaction. Pyrolysis oil from used tires is thus understood according to the invention to mean a liquid, aromatic oil produced by thermal decomposition of used tires under oxygen exclusion, in particular thermal depolymerization of the rubber contained in tires, selected from natural rubber and synthetic rubber, such as styrene-butadiene rubber or other copolymers of styrene, butadiene, and / or isoprene monomers, isoprene rubber, butadiene rubber, ethylene-propylene-diene rubber, halobutyl and butyl rubber, as well as the dissolution and degradation of the various components that make up the complex structure of a tire.The thermal decomposition and depolymerization of the waste tires can be carried out by means of pyrolysis, solvolysis or hydrothermal liquefaction.

[0013] It is also known as Tire Pyrolysis Oil, or TPO for short, and has an aromatics content according to DIN 51378: 2020 of 30% to 50% by weight, as well as a Bureau of Minerals Correlation Index (BMCI) according to the API Technical Data Book of greater than 55. The untreated TPO has a low flash point of less than 50°C, measured according to DIN EN ISO 3679:2023, and in some cases even less than 21°C. The tire pyrolysis oil has a bio-based carbon content according to ASTM D6866 Method B:2022 of 40% (pme) to 55% (pme), and a density at 15°C of 880-970 kg / m 3measured according to DIN 51757 Method 3 (2011), a sulfur content of 0.8 wt.% - 1.1 wt.% measured according to DIN EN ISO 14596: 2007, a nitrogen content of 3500-6000 mg / kg measured according to DIN 51444: 2020, a benzo [a]pyrene content between 5 mg / kg and 150 mg / kg measured according to DIN EN 16143: 2023 and a PAH content determined as a sum according to Directive 2005 / 69 / EU of greater than 40 mg / kg and up to 850 mg / kg measured according to DIN EN 16143: 2023.

[0014] One variant of pyrolysis involves shredding entire tires. In this variant, the steel is separated after pyrolysis. This process also produces carbon soot, non-condensable gases, and pyrolysis oil.

[0015] A label-free aromatic process oil is understood to be a hydrocarbon mixture that has a proportion of aromatic hydrocarbons according to DIN 51378: 2020 of at least 15 wt.%, i.e. a CA content of at least 15. The aromatic process oil is considered to be label-free if it has a benzo(a)pyrene content of less than 1 mg / kg measured according to DIN EN 16143: 2023 and a sum of polycyclic aromatics of less than 10 mg / kg measured according to DIN EN 16143: 2023 according to Directive 2005 / 69 / EC, i.e. the sum of the eight polycyclic aromatics named in the Directive: Benzo(a)pyrene, Benzo(e)pyrene, Benzo(a)anthracene, Chrysene, Benzo(b)fluoranthene, Benzo(j)fluoranthene, Benzo(k)fluoranthene and Dibenz(a,h)anthracene. The pyrolysis oil from waste tires is separated into several fractions in a distillation step (step b). The first fraction is a low-boiling fraction that boils at temperatures between 40 and 300°C.This low-boiling fraction is collected separately and not further processed in the process according to the invention. Another fraction is a high-boiling fraction that boils at temperatures between 300-700°C. This high-boiling fraction is collected and further processed in the process according to the invention. The high-boiling fraction has a higher flash point and is therefore more suitable for further processing.

[0016] The distillation in step b) is carried out at atmospheric pressure or under vacuum, preferably in several distillation steps, either at the same pressure or at different pressures in the different distillation steps. For example, the distillation can be carried out in two distillation steps, with atmospheric pressure in a first distillation step and under vacuum in a second distillation step.

[0017] Distillation can be carried out in one or more distillation steps. If multiple distillation steps are involved, the high-boiling fraction from the last distillation step is used as the high-boiling fraction for the extraction step.

[0018] In a further process step, the high-boiling fraction of the pyrolysis oil is subjected to an extraction process. This reduces the concentration of polycyclic aromatics while simultaneously maintaining the proportion of non-polycyclic aromatic hydrocarbons. The extraction process is carried out under typical pressures and residence times for a liquid-liquid extraction, e.g., at atmospheric or slightly elevated pressure.

[0019] The extractant in step c) is preferably selected from furfural, n-methylpyrrolidone, n-methylpyrrolidone-water mixtures, n-pentane, isopentane, n-hexane, n-heptane, n-octane, isooctane, cyclohexane, and mixtures thereof, preferably selected from furfural, n-methylpyrrolidone, n-methylpyrrolidone-water mixtures, n-heptane, and mixtures thereof, particularly preferably a polar solvent such as furfural or n-methylpyrrolidone, assuming at least technical-grade purity of the extractants. Extractants in step c) are all solvents added to the extraction reactor. If n-methylpyrrolidone is used, it can be used mixed with 0-10% by weight of water, preferably with 0-7% by weight of water.

[0020] The ratio of extractant to pyrolysis oil fraction is from 30 wt.% to 300 wt.%, preferably from 50 wt.% to 250 wt.%, particularly preferably from 80 wt.% to 200 wt.% extractant to pyrolysis oil, wherein the ratio refers to extractant to pyrolysis oil, ie at a ratio of 80 wt.% there are 0.8 kg of extractant to 1 kg of pyrolysis oil.

[0021] The extraction process can be carried out as a single-stage or multi-stage extraction process.

[0022] In large-scale production, the product can also be processed after distillation in a first, upstream extraction step, a pre-extraction with a residence time of preferably at least 0.1 hours and a maximum of 8 hours based on the raffinate. The extract produced here represents the input to the second extraction step, the main extraction step c, in which the process oil is obtained as raffinate with a residence time of preferably at least 0.1 hours and a maximum of 8 hours based on the raffinate. For this purpose, solvent ratios in the range 150 - 800 wt.% solvent / feed are required in the first extraction step (pre-extraction), preferably 220 - 800 wt.%. The solvent ratio is adjusted depending on the respective distillation cut.

[0023] During extraction, the pyrolysis oil from waste tires can be mixed with a mineral oil-based process oil, preferably selected from distilled aromatic extract (DAE), residual aromatic extract (RAE), and mixtures thereof, and then transferred to extraction with an extraction agent. Preferably, a homogeneous mixture of pyrolysis oil and mineral oil-based process oil is first prepared, and this mixture is then mixed with an extraction agent. The ratio of mineral oil-based process oil to pyrolysis oil in the mixture is preferably between 99-70 wt.% mineral oil-based to 1-30 wt.% pyrolysis oil-based. This mixture is mixed in the same ratio of extraction agent to extracting mixture as the pure pyrolysis oil.

[0024] The extraction process can be carried out on an industrial scale in an extraction column. Suitable extraction columns are designed, for example, as: a. packed column b. packed column c. tray column or d. rotating disc extractor (RDC).

[0025] Both the distillation step and the extraction step can be carried out either with the pure pyrolysis oil or in a mixture with mineral oil-based products, such as DAE or RAE, whereby the extraction step is carried out starting from the heavy fraction of the pure pyrolysis oil or the mixture of the heavy fraction of the pyrolysis oil with a mineral oil-based product.

[0026] Solvent extraction with a polar solvent such as furfural or N-methyl-2-pyrrolidone at the temperatures and solvent ratios preferentially extracts the polycyclic aromatics. The resulting process oil is still aromatic, allowing it to be used in tire compounds, for example, while also being label-free.

[0027] In one embodiment of the process, the pyrolysis oil from waste tires is hydrogenated in an additional step a2), wherein the hydrogenation of the entire pyrolysis oil can take place before the distillation or of the heavy fraction after the distillation of step b).

[0028] The hydrogenation is preferably carried out using a metal catalyst at temperatures between 200°C and 400°C, preferably between 220°C and 300°C, particularly preferably at temperatures between 280°C and 340°C, and a pressure between 30 bar and 200 bar, preferably between 50 bar and 150 bar. The metal catalyst is, for example, a cobalt-molybdenum catalyst, a nickel-cobalt-molybdenum catalyst, a nickel-molybdenum catalyst, a mixture of a nickel-molybdenum catalyst with zeolites, or a nickel-tungsten catalyst.

[0029] Mild hydrogenation is preferably used to saturate diolefins and olefins to stabilize the product. Selective hydrogenation also achieves saturation of polycyclic aromatics while preserving the alkylated monoaromatics.

[0030] The invention further relates to a label-free aromatic process oil produced from pyrolysis oil from used tires, characterized in that the process oil has a proportion of aromatic hydrocarbons CA of 15-35, preferably 20-30, measured according to DIN 51378: 2020, a concentration of benzo(a)pyrene <1 mg / kg measured according to DIN EN 16143: 2023, a PAH content determined as a sum according to Directive 2005 / 69 / EU of less than 10 mg / kg measured according to DIN EN 16143: 2023, and that the process oil is a hydrocarbon mixture, wherein the carbons originate from fossil sources to a maximum of 99% by weight and at least 1% by weight from bio-based sources which have a bio-based carbon content measured according to ASTM D6866 Method B: 2022 greater than 1% (pMC), preferably greater than 10% (pMC), particularly preferably greater 40% (pMC) or even greater than 50% (pMC).The bio-based carbon content preferably originates from natural rubber and other bio-based components of the tire, such as bio-based synthetic rubbers, bio-based fillers, bio-based plasticizers, bio-based resins, bio-based waxes, bio-based anti-aging agents or vulcanization chemicals, as well as bio-based reinforcements. The carbon contained in the process oil preferably originates from up to a maximum of 95% fossil sources and at least 5% (pMC) bio-based sources, particularly preferably from a maximum of 90% fossil sources and at least 10% (pMC) bio-based sources, and further preferably from a maximum of 85% fossil sources and at least 15% (pMC) bio-based sources.

[0031] Bio-based sources can be of plant or animal origin. A plant source of hydrocarbons can be natural rubber, which is found in used tires. An animal source can be stearic acid, which is also found in used tires.

[0032] The label-free aromatic process oil, for example, has a density of 890 to 990 g / cm 3 , preferably from 940 - 965 g / cm 3 at 15°C according to DIN 51757 Method 3: 2011, a kinematic viscosity of 17.5 - 37mm 2 / s at 100°C measured according to DIN EN ISO 3104: 2024, an aniline point of 68 - 79 °C measured according to DIN ISO 2977: 2020.

[0033] The label-free aromatic process oil can have a sulfur content of less than 2 wt.% measured according to DIN EN ISO 14596: 2007, preferably less than 1.5 wt.%, particularly preferably less than 1 wt.%.

[0034] In one embodiment, the label-free aromatic process oil has a polycyclic aromatic hydrocarbon content of less than 3 wt.% measured according to IP346.

[0035] The aromatic process oil according to the invention is preferably produced by a process according to one of claims 1 to 8.

[0036] Furthermore, the invention relates to the use of a label-free aromatic process oil produced by a process according to one of claims 1 to 8 or a process oil according to one of claims 9 or 10 as a plasticizer in tires or rubber mixtures or as an extender oil, ie extender oil in polymers.

[0037] The process oil is preferably present in the rubber compound, tire, or polymer in an amount of up to 60 phr, more preferably up to 40 phr. When used as an extender oil, the process oil is preferably used in an amount of up to 37.5 phr. In addition to the process oil, other plasticizers can be added. When using rubbers that have already been extended with oil, these are in the low range, e.g., 10 - 20 phr. When using non-oil-extended rubbers (so-called dry grades), correspondingly high amounts of plasticizer can be used, e.g., up to 50-60 phr. For the production of tire and rubber compounds, an extracted aromatic oil, treated distillated aromatic extract (TDAE), or naphthenic base oils are typically used as a plasticizer, i.e. as a process oil. These conventional products are 100% mineral oil-based.The present invention replaces mineral oil-based process oils with a product from the chemical recycling of used tires, which is obtained from pyrolysis oil (tire pyrolysis oil, TPO for short). The treated oil has a reduced concentration of polycyclic aromatics compared to TPO, with values ​​of (benzo(a)pyrene <1 mg / kg according to DIN EN 16143:2023, Directive 2005 / 69 / EC total <10 mg / kg according to DIN EN 16143:2023, and PCA according to IP346 <3 wt.%). This allows the aromatic process oil to be used in tire and rubber compounds and replace conventional process oils such as TDAE.

[0038] The method according to the invention is explained by way of example with reference to the drawings.

[0039] Figure 1 shows a first embodiment of the process. First, a pyrolysis oil (TPO) 10 is provided. The pyrolysis oil is separated in a distillation step 20, producing a low-boiling fraction 21 and a high-boiling fraction 22. The high-boiling fraction is transferred to an extraction reactor 30, where it is extracted with solvent. A label-free aromatic process oil 40 and an extract 41 are obtained.

[0040] Figure 2 shows another embodiment of the process. The pyrolysis oil (TPO) 10 is again provided. It is hydrogenated 15 in a hydrogenation reactor in a first process step. The hydrogenated pyrolysis oil is then separated again in a distillation step 20, producing a low-boiling fraction 21 and a high-boiling fraction 22. The high-boiling fraction is transferred to an extraction reactor 30 and extracted there with solvent. The result of the process is a label-free aromatic process oil 40 and an extract 41.

[0041] Figure 3 shows a further embodiment of the process with a hydrogenation step. The pyrolysis oil (TPO) 10 is again provided. The pyrolysis oil is first separated in a distillation step 20, producing a low-boiling fraction 21 and a high-boiling fraction 22. The high-boiling fraction is transferred to a hydrogenation reactor and hydrogenated there 15. The hydrogenated fraction is then transferred to an extraction reactor 30 and extracted there with solvent. Alternatively, a co-extraction 31 can be carried out with a mineral oil-based process oil, such as DAE. The result of the process is a label-free aromatic process oil 40 and an extract 41.

[0042] Examples

[0043] Label-free aromatic process oils were produced from pyrolysis oil. For this purpose, pyrolysis oil TPOs were converted with the parameters listed in Table 1 as follows:

[0044] Example 1

[0045] 1. Distillation

[0046] In a first step, 40 l of pyrolysis oil were prepared according to Table 1 and fed into a distillation column (batch column). The batch column was initially operated at atmospheric pressure up to 170°C. To prevent cracking of the pyrolysis oil during the further course of distillation, the pressure was reduced to 30 mbar as the temperature increased. A residue fraction with an initial boiling point greater than 350°C was obtained.

[0047] In a second distillation step, the residue fraction was distilled again using a D1160 apparatus to further remove low-boiling components. The D1160 was operated at a pressure of 13.33 mbar up to an AET temperature of 424°C.

[0048] 2. Extraction

[0049] In the next step, the high-boiling fraction obtained from the second distillation stage was subjected to a three-stage laboratory extraction. This was operated at a temperature of 55°C. Furfural was used as the solvent. This produced a label-free raffinate and an extract in which the polycyclic aromatics were preferentially found.

[0050] A furfural ratio of 110 wt.% was used. A process oil with the parameters listed in Table 1 was obtained. The results are listed in Table 1 as L-Ex-3 raffinate. The process oil has a low content of polycyclic aromatic hydrocarbons, and the relevant compounds such as benzo[a]pyrene and PAH are below the required limits. Despite a high sulfur content in the tire, which is caused by the vulcanization process, sulfur contents in the process oil can be reliably achieved in the same order of magnitude as in a mineral oil-based process oil.

[0051] The bio-based carbon content according to ASTM D6866 Method B: 2022 was 39% (pMC). The process thus transforms a waste product (tires) into a high-quality raw material with a reduced fossil carbon content and a high bio-based carbon content.

[0052] Example 2 - Co-extraction

[0053] 1. Distillation

[0054] For this example, the pyrolysis oil from Example 1 was used proportionally, so that the same distillation product (residue) was used for the subsequent steps.

[0055] 2. DAE sample + preparation of the mixture

[0056] For co-extraction, a DAE sample was taken from a large-scale production facility. This was mixed in a ratio of 80% DAE to 20% TPO distillation residue from step 1 (Example 1).

[0057] 3. Extraction

[0058] In the next step, the mixture was subjected to a three-stage laboratory extraction. This was carried out at a temperature of 55°C. Furfural was used as the solvent. A label-free raffinate and an extract containing the polycyclic aromatics were produced. A furfural ratio of 90% was used.

[0059] A process oil with the parameters listed in Table 1 was obtained. The results are listed in Table 1 as L-Ex-5 raffinate. Example 2 - Pure DAE extraction / scale-up (comparison)

[0060] 1. Distillation

[0061] Distillation took place in large-scale production.

[0062] 2. DAE sample

[0063] A DAE sample was taken from an ongoing production at the point of use of the extraction.

[0064] 3. Extraction

[0065] The pure DAE was subjected to a three-stage laboratory extraction. This was carried out at a temperature of 55°C. Furfural was used as the solvent. A label-free raffinate and an extract in which the polycyclic aromatics were preferentially found were produced. A furfural ratio of 80% was used. The results are listed in Table 2 as L-Ex-6 raffinate.

[0066] During production, an average solvent ratio of 154% was used and an average temperature of 50°C was measured.

[0067] Process oils were produced as raffinate, which have properties according to Table 2 (TDAE, L-Ex 6 raffinate).

[0068] Example 4 (L-Ex 7 Raffinate)

[0069] 1. Distillation

[0070] Another batch of pyrolysis oil was investigated. For this, 40 l of pyrolysis oil were again fed into a distillation column (batch column). The batch column was initially operated at atmospheric pressure to separate an initial low-boiling fraction. A maximum head temperature of 170°C was selected for the first fraction. For the subsequent fractions, the pressure was reduced to 30 mbar to prevent cracking of the pyrolysis oil. Distillation was stopped at a head temperature of 220°C. This corresponds to an AET temperature of 348°C.

[0071] The resulting residue fraction was further narrowed in another batch vacuum distillation column at a pressure of 0.1 mbar and an AET of up to 484°C. 2. Extraction

[0072] In the next step, the obtained high-boiling fraction was subjected to a three-stage laboratory extraction. This was carried out at a temperature of 55°C. Furfural was used as the solvent. A label-free raffinate and an extract in which the polycyclic aromatics were preferentially found were produced. A furfural ratio of 80% was used for this purpose.

[0073] In this way, a process oil was produced as a raffinate (L-Ex 7 raffinate), which exhibits the properties shown in Table 3. The biobased carbon content was comparatively high at 41% (pMC). The process thus transforms a waste product (tires) into a high-quality raw material with a reduced fossil carbon content.

[0074] Table i: Parameters of the starting materials and obtained process oils according to examples i and 2

[0075] Table 2: Parameters of the starting materials and obtained process oils according to Example 3

[0076] Table 3: Parameters of the starting materials and obtained process oils according to Example 4

[0077] Table 4: Composition of the rubber mixtures with process oils according to the invention: solution-polymerized styrene-butadiene copolymer, Sprintan SLR 4602, Synthos Nd-catalyzed butadiene polymer, Buna CB 24, Arlanxeo Ultrasil 7000 GR, Evonik

[0078] d TESPT, 3,3'-bis(triethoxysilylpropyl)tetrasulfide e TMQ, 2,2,4-trimethyl-i,2-dihydroquinoline, polymerized f 6PPD, N-(i,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine

[0079] § CBS, N-Cyclohexylbenzothiazole-2-sulfenamide h DPG, N,N'-diphenylguanidine

[0080] Use as process oil

[0081] The process oils prepared according to the above examples were tested in a rubber compound. The compositions are shown in Table 4. The compounds were vulcanized, and the properties of the resulting vulcanizates were measured. These are shown in Table 5.

[0082] Table 5: Properties of rubber compounds

[0083] The invention is not limited to one of the embodiments described above, but can be modified in many ways.

[0084] All features and advantages arising from the claims, the description, and the drawings, including structural details, spatial arrangements, and method steps, may be essential to the invention both individually and in a wide variety of combinations.

[0085] Pyrolysis oil (TPO) 10

[0086] Hydrogenation 15 Distillation 20 Low-boiling fraction 21 High-boiling fraction 22

[0087] Extraction reaction 30 Label-free aromatic process oil 40 Extract 41

Claims

Patent claims 1. A process for producing a label-free aromatic process oil comprising the steps of a) providing a pyrolysis oil from waste tires, wherein the tire pyrolysis oil has an aromatic content according to DIN 51378: 2020 of 30 wt.% to 50 wt.%, a BMCI according to API Technical Data Book of greater than 55, a bio-based carbon content according to ASTM D6866 Method B:2022 of 40% (pme) to 55% (pme), a density at 15°C of 880-970 kg / m 3measured according to DIN 51757 Method 3 (2011), a sulphur content of 0.8-1.1 wt% measured according to DIN EN ISO 14596: 2007, a nitrogen content of 3500-6000 mg / kg measured according to DIN 51444: 2020, a benzo[a]pyrene content between 5 mg / kg and 150 mg / kg measured according to DIN EN 16143: 2023 and a PAH content determined as a sum according to Directive 2005 / 69 / EU of greater than 40 mg / kg and up to 850 mg / kg measured according to DIN EN 16143: 2023, b) distilling the pyrolysis oil from waste tyres in a fractional distillation at temperatures between 00 and 400 °C under atmospheric pressure or vacuum, whereby at least one low-boiling fraction and at least one high-boiling fraction is obtained, c) mixing the at least one high-boiling fraction from step b with a solvent as extractant in a ratio of 30 wt.% to 300 wt.-% of extractant to pyrolysis oil fraction in an extraction reactor, d) extracting at temperatures of 30 to 12O°C in at least one extraction step, whereby an aromatic oil is obtained as raffinate which has a proportion of aromatic hydrocarbons CA of 15-35 wt.%, preferably 20-30 wt.%, measured according to DIN 51378: 2020, a benzo [a]pyrene content of less than 1 mg / kg measured according to DIN EN 16143: 2023 and a PAH content as a sum according to Directive. 2005 / 69 / EU of less than 10 mg / kg measured according to DIN EN 16143:2020.

2. Process according to claim 1, characterized in that the extractant in step c) is selected from furfural, n-methylpyrrolidone, n-methylpyrrolidone-water mixtures, n-heptane and mixtures thereof, preferably selected from furfural and n-methylpyrrolidone.

3. Process according to claim 1 or 2, characterized in that the heavy fraction of the pyrolysis oil from waste tires after step b) is mixed with a mineral oil-based raw material selected from DAE, RAE, naphthenic HVGOs and mixtures thereof and the mixture of pyrolysis oil and mineral oil-based process oil is transferred for extraction.

4. Process according to one of the preceding claims, characterized in that the extraction reactor is an extraction column.

5. Process according to one of the preceding claims, characterized in that the pyrolysis oil from waste tires is hydrogenated in an additional step a2, wherein the hydrogenation of the entire pyrolysis oil can take place before distillation or the hydrogenation of the heavy fraction can take place after distillation.

6. Process according to claim 5, characterized in that the hydrogenation is carried out with a metal catalyst at temperatures between 200°C and 400°C and a pressure between 30 bar and 200 bar.

7. Process according to one of the preceding claims, characterized in that the raffinate obtained is an aromatic oil having a polycyclic aromatic hydrocarbon content according to IP346 of < 3% by weight.

8. Process according to one of the preceding claims, characterized in that the distillation is carried out in several distillation steps and the high-boiling fraction of the last distillation step is used as the high-boiling fraction for the extraction step.

9. Label-free aromatic process oil produced from pyrolysis oil from used tires, characterized in that the process oil has a proportion of aromatic hydrocarbons CA of 15-35 wt.%, preferably 20-30 wt.- %, measured according to DIN 51378 : 2020, a concentration of benzo(a)pyrene <1 mg / kg measured according to DIN EN 16143 : 2023, a PAH content (sum according to Directive 2005 / 69 / EU) of less than 10 mg / kg measured according to DIN EN 16143 : 2023, and that process oil is a hydrocarbon mixture which has a bio-based carbon content measured according to ASTM D6866-22 greater than 1% pMC, preferably greater than 10% (pMC), particularly preferably greater than 40% (pMC), further preferably greater than 50% (pMC).

10. Aromatic process oil according to claim 9, characterized in that the process oil has been produced by a process according to one of claims 1 to 8.

11. Use of a label-free aromatic process oil produced by a process according to one of claims 1 to 8 or of a process oil according to one of claims 9 or 10 as a plasticizer in tires or rubber compounds or as an extender oil in polymers.

12. Use according to claim 11, wherein the process oil is present in the rubber mixture in an amount of up to 60 phr, preferably up to 35 phr.

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