A method for preparing aromatic rubber oil

Abstract

This invention relates to the field of petroleum and petroleum fraction refining technology, and particularly to a method for preparing aromatic rubber oil. The preparation method includes: S1: mixing a feedstock oil with a primary extractant, performing a primary extraction to obtain a primary extract and a primary raffinate; S2: mixing the primary extract with a secondary extractant, performing a secondary extraction to obtain a secondary extract and a secondary raffinate; wherein the primary extractant includes a polar aprotic solvent, and the secondary extractant includes light hydrocarbons; the feedstock oil includes one or more of paraffinic vacuum distillate oil, intermediate-based vacuum distillate oil, and naphthenic vacuum distillate oil. This invention introduces light hydrocarbons as back-extraction agents into the vacuum distillate oil system to achieve the separation of polycyclic aromatic hydrocarbons and light aromatic hydrocarbons, ultimately obtaining an extract oil with an aromatic hydrocarbon extraction rate and aromatic content as high as 80%, which is beneficial for high-carbon rubber oils. A The production of environmentally friendly aromatic oils.

Description

Technical Field

[0001] This invention relates to the field of petroleum and petroleum fraction refining technology, and in particular to a method for preparing aromatic rubber oil. Background Technology

[0002] Rubber filler oil, a crucial raw material in tire production, influences tire performance, processing technology, and production costs. To ensure compatibility between the rubber filler oil and rubber materials, rubber oils typically contain high levels of polycyclic aromatic hydrocarbons (PCA), which are highly carcinogenic. The European Union Legislative Council enacted regulations requiring that, from January 1, 2010, all rubber and its products must meet the requirements of a PCA content of less than 3% and a content of eight carcinogenic polycyclic aromatic hydrocarbons (PAHs) of less than 10 μg / g. Environmentally friendly aromatic oil (TDAE) is a high-aromatic, environmentally friendly rubber oil obtained by further removing PCA from traditional aromatic oil (DAE) through hydrogenation or solvent refining processes (generally solvent refining). TDAE not only meets environmental requirements but also has a high aromatic content and good compatibility with rubber, which is beneficial for tire processing and improving various tire performance characteristics. Therefore, it is widely used in oil-extended rubber and tire companies and is recognized worldwide as an ideal rubber processing oil.

[0003] To achieve the production of high-aromatic, environmentally friendly rubber oils, especially C... A To achieve a concentration of 20% or higher, the first step is to obtain an extract phase with high aromatic hydrocarbon (monocyclic, bicyclic, and polycyclic aromatic hydrocarbon) content through primary solvent extraction or refining. After solvent recovery, a primary extract oil is obtained. This primary extract oil is then subjected to a secondary extraction to further separate monocyclic and bicyclic aromatic hydrocarbons from polycyclic aromatic hydrocarbons. The raffinate obtained from the secondary extraction will be enriched with monocyclic and bicyclic aromatic hydrocarbons, which can be used to produce C... A High-aromatic-content environmentally friendly rubber oil with a content as high as 20%. Currently, several production patents related to environmentally friendly aromatic rubber oils have been published both domestically and internationally. Patent application number 200910088931.0 discloses an aromatic rubber oil and its production method, using furfural extraction to remove polycyclic aromatic hydrocarbons from reduced-density distillate oil. After solvent recovery, the primary extract yields primary extracted oil. The primary extracted oil is then subjected to a second extraction with furfural to obtain a second raffinate and a second extract. After solvent recovery, the second raffinate yields a second extracted oil, which is used as a rubber filler oil. Patent application number 200910088932.5 proposes to contact reduced-density distillate oil and furfural countercurrently in an extraction tower, recovering the solvent to obtain a primary refined oil, and then subjecting the primary refined oil to a second extraction. The extracted oil obtained from the second extraction is an environmentally friendly rubber oil.

[0004] In summary, the current problem is that the process of preparing high-aromatic environmentally friendly rubber oil from different raw material oils requires multiple solvent extractions. During these extractions, the extract phase and raffinate phase need to be recovered from the solvent multiple times, resulting in low oil yield, high energy consumption, large equipment investment, and low economic benefits.

[0005] In view of this, the present invention is proposed. Summary of the Invention

[0006] To address the aforementioned problems, this invention proposes a method for preparing aromatic rubber oil, which can achieve the production of high-aromatic, environmentally friendly rubber oil while significantly reducing energy consumption and improving economic efficiency.

[0007] The specific technical solution of the present invention is as follows:

[0008] In a first aspect, the present invention provides a method for preparing aromatic rubber oil, comprising:

[0009] S1: Mix the raw oil with the primary extractant and perform a primary extraction to obtain a primary extract and a primary raffinate.

[0010] S2: Mix the primary extract with the secondary extractant, and perform a secondary extraction to obtain a secondary extract and a secondary raffinate.

[0011] The primary extractant includes a polar aprotic solvent, and the secondary extractant includes light hydrocarbons; the feedstock oil includes one or more of paraffinic vacuum distillate oil, intermediate-based vacuum distillate oil, and naphthenic vacuum distillate oil.

[0012] In this invention, the feedstock oil and primary extractant are extracted once to obtain a primary extract. The primary extract does not need to be desolventized and is directly added to the back-extraction solvent (i.e., the secondary extractant) for secondary extraction. This process can separate the monocyclic and dicyclic aromatic hydrocarbons and polycyclic aromatic hydrocarbons enriched in the primary extract. Light aromatic hydrocarbons are enriched in the secondary extract, and the secondary extract oil obtained by separating the solvent is aromatic rubber oil. The secondary raffinate retains most of the heavy components in the feedstock oil, realizing the separation and utilization of polycyclic aromatic hydrocarbons in vacuum distillate oil, and providing a new approach for the resource-based processing of heavy distillate oil.

[0013] This invention discovers and proposes for the first time the introduction of light hydrocarbons as back-extraction agents into vacuum distillation oil systems. Utilizing the differences in polarity and solubility between light hydrocarbons and polar aprotic solvents, monocyclic and dicyclic aromatic hydrocarbons (PAHs) and polycyclic aromatic hydrocarbons (PAHs) enriched in the primary extract are separated. The light hydrocarbons dissolve non-PCA (polycyclic aromatic hydrocarbon) components, allowing a greater proportion of non-PCA components to enter the extraction phase (light hydrocarbon-rich phase), thus achieving the separation of polycyclic aromatic hydrocarbons from light aromatic hydrocarbons. Ultimately, an extract oil with an aromatic hydrocarbon extraction rate and aromatic content as high as 80% can be obtained, which is beneficial for high-carbon distillation. A The production of environmentally friendly aromatic oils.

[0014] More preferably, the feedstock oil is paraffinic vacuum distillate oil and / or naphthenic vacuum distillate oil; wherein, the naphthenic vacuum distillate oil includes second-line, third-line, and fourth-line vacuum distillate fractions.

[0015] Preferably, the primary extract is desolventized to obtain the primary extract oil, wherein the aromatic hydrocarbon content in the primary extract oil is 50-90 wt%, preferably 70-90 wt%, and the saturated hydrocarbon content is less than 15 wt%, preferably less than 10 wt%.

[0016] In this invention, solvent removal is not required during the preparation of aromatic rubber oil. The primary extract and secondary extractant can be directly subjected to secondary extraction. The solvent removal of the primary extract is only used to detect the aromatic content and saturated hydrocarbon content in the primary extracted oil.

[0017] Preferably, the primary extractant includes one or more of dimethyl sulfoxide, sulfolane, acetonitrile, N-formylmorpholine, N,N-dimethylformamide, N,N-dimethylacetamide, and hexamethylphosphoric triamine.

[0018] The present invention has found that when the above-mentioned polar aprotic solvent is used as the primary extractant, the aromatic selectivity of the solvent can be better guaranteed.

[0019] Preferably, when the secondary extractant includes one or more of n-hexane, n-heptane, n-pentane, and petroleum ether, it is more beneficial to change the distribution of different components of the feedstock oil in the extract phase and the raffinate phase, thereby effectively separating polycyclic aromatic hydrocarbons and light aromatic hydrocarbons.

[0020] Preferably, the temperature of the secondary extraction is 30–50°C.

[0021] Preferably, the temperature of the first extraction is 60–100°C.

[0022] Preferably, in the secondary extraction, the mass ratio of the primary extract to the secondary extractant is (0.5-2):1; more preferably, the mass ratio of the primary extract to the secondary extractant is (0.5-1.5):1; even more preferably, the mass ratio of the primary extract to the secondary extractant is 1:1.

[0023] Preferably, in the primary extraction, the mass ratio of the raw oil to the primary extractant is (3-8):1; more preferably, the mass ratio of the raw oil to the primary extractant is (3-6):1.

[0024] Preferably, the primary and secondary extractions are independent, identical, or different, with an extraction time of 50–80 min; and the extraction pressure is atmospheric pressure.

[0025] Preferably, the method for preparing aromatic rubber oil further includes S3: desolventizing the secondary extract and the secondary raffinate to obtain secondary extract oil and secondary raffinate oil, wherein the secondary extract oil is aromatic rubber oil.

[0026] In this invention, the solvent is removed from the secondary extract and the secondary raffinate to obtain secondary raffinate oil and secondary extract oil. This method eliminates the solvent recovery step in the primary extraction process, greatly reducing energy consumption.

[0027] Preferably, during the recovery of the secondary raffinate and the solvent from the secondary extract, the temperature is controlled at approximately 110°C, and the pressure is controlled at approximately 0.09 MPa (vacuum).

[0028] In the specific implementation process, those skilled in the art can also desolventize and recover the solvent from the primary raffinate to obtain primary raffinate oil; preferably, the temperature is controlled at about 90°C and the pressure is controlled at a vacuum degree of about 3 kPa.

[0029] The primary raffinate oil is rich in saturated hydrocarbons and can be used as feedstock for catalytic cracking or for hydrogenation to produce lubricating oil.

[0030] Based on the above technical solution, the beneficial effects of the present invention are as follows:

[0031] (1) This invention introduces light hydrocarbons as back-extraction agents into the vacuum distillation oil system. Utilizing the differences in polarity and solubility between light hydrocarbons and aprotic solvents, it separates monocyclic and dicyclic aromatic hydrocarbons and polycyclic aromatic hydrocarbons enriched in the primary extract. The light hydrocarbons dissolve non-PCA components, allowing more non-PCA components to enter the extraction phase (light hydrocarbon-rich phase), thus achieving the separation of polycyclic aromatic hydrocarbons from light aromatic hydrocarbons. Ultimately, an extract oil with an aromatic hydrocarbon extraction rate and aromatic content as high as 80% can be obtained, which is beneficial for high-carbon distillation. A The production of environmentally friendly aromatic oils.

[0032] (2) The preparation method described in this invention is simple, does not require other high-energy-consuming processes, requires low temperature and pressure, has fewer solvent recovery times, and existing refineries do not need to carry out large-scale technical or equipment transformation, thereby significantly reducing investment and operating costs. Attached Figure Description

[0033] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0034] Figure 1 This is a schematic diagram of the preparation process of aromatic rubber oil provided in Example 1 of the present invention. Detailed Implementation

[0035] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0036] Unless otherwise specified, all raw materials used in the examples are commercially available conventional raw materials, and the techniques used are conventional methods well known to those skilled in the art. In the following examples, conventional extraction devices in the art can be used, and no further limitations are made here.

[0037] Example 1

[0038] This embodiment first provides an aromatic rubber oil, the process diagram of which is shown below. Figure 1 Its preparation method includes the following steps:

[0039] (1) Naphthenic vacuum distillate oil (oil properties are shown in Table 1, C of the feed oil) A The feed oil (value 9.5%) was used as raw material for solvent extraction, with dimethyl sulfoxide (DMSO) as the solvent. Extraction was carried out in an extraction apparatus, yielding primary raffinate and primary extract from the upper and lower portions, respectively. The extraction conditions were: extraction temperature 80℃, solvent to feed oil mass ratio 5:1, extraction time 60 min, and extraction pressure at atmospheric pressure.

[0040] The present invention further evaporates the solvent from the primary raffinate and the primary extract to obtain primary raffinate oil and primary extract oil, respectively, and their properties are shown in Table 1. As can be seen from Table 1, after primary solvent extraction, the aromatic content in the primary extract oil is as high as 80% or more, of which the saturated hydrocarbon content is only about 8%, indicating that the aromatics are fully enriched in the extract phase, which is more conducive to the preparation of high-aromatic environmentally friendly rubber oil.

[0041] Table 1. Properties of naphthenic vacuum distillate oil, primary raffinate oil, and primary extract oil.

[0042]

[0043] (2) The primary extract (without solvent removal) from step (1) was subjected to a secondary extraction in an extraction apparatus. Petroleum ether (60–90°C) was selected as the solvent. The upper and lower portions yielded a secondary extract and a secondary raffinate, respectively. The extraction conditions were: extraction temperature 40°C, solvent to feed oil mass ratio 1:1, extraction time 60 min, and extraction pressure at atmospheric pressure. After evaporating the solvent from the secondary extract and the secondary raffinate, the secondary extract oil and secondary raffinate oil were obtained, respectively. Their properties are shown in Table 2. The aromatic hydrocarbon extraction rate of the extract oil was 80.18%, the extract phase recovery rate was 72.74%, and the C0.05... A The value is 23.86%, and the PCA content is less than 3%, which meets the quality requirements for environmentally friendly rubber oil.

[0044] Table 2. Property Analysis of Secondary Extraction Oil and Secondary Rake Residue Oil

[0045] Testing items Secondary extraction residue oil Secondary extraction oil Yield, % 27.60 72.74 <![CDATA[Density (20 °C), g / cm 3 > 1.2123 0.99970 Refractive index (20℃) 1.4976 1.5308 Saturation fraction (wt,%) 0.00 7.75 Aromatic components (wt, %) 80.24 80.46 Polar components (wt,%) 19.76 11.79 Aromatic extraction rate, % / 80.18 <![CDATA[C A ,%]]> 20.23 23.86 Polycyclic aromatic hydrocarbon (PCA) content, % 15.3 2.4

[0046] Example 2

[0047] This embodiment first provides an aromatic rubber oil, the preparation method of which includes the following steps:

[0048] (1) Naphthenic vacuum distillate oil (oil properties are shown in Table 3, C of the feed oil) A The feed oil (with a purity of 11.3%) was used as raw material for solvent extraction. N-methylpyrrolidone (NMP) was selected as the solvent. The extraction was carried out in an extraction apparatus, and the upper and lower portions yielded primary raffinate and primary extract, respectively. The extraction conditions were: extraction temperature 80℃, solvent to feed oil mass ratio of 4:1, extraction time 60 min, and extraction pressure at atmospheric pressure.

[0049] The present invention further evaporates the solvent from the first raffinate and the first extract to obtain first raffinate oil and first extract oil, respectively, and their properties are shown in Table 3. As can be seen from Table 3, after first solvent extraction, the aromatic content of the first extract oil is as high as 80% or more, of which the saturated hydrocarbon content is only about 7%, indicating that the aromatics are fully enriched in the extract phase, which is more conducive to the preparation of high aromatic environmentally friendly rubber oil.

[0050] Table 3. Properties of naphthenic vacuum distillate oil, primary raffinate oil, and primary extract oil.

[0051]

[0052]

[0053] (2) The primary extract (without solvent removal) from step (1) was subjected to a secondary extraction in an extraction apparatus. The solvent used was n-heptane. The upper and lower portions yielded a secondary extract and a secondary raffinate, respectively. The extraction conditions were: extraction temperature 40℃, solvent to feed oil mass ratio 1:1, extraction time 60 min, and extraction pressure at atmospheric pressure. After evaporating the solvent from the secondary extract and secondary raffinate, the secondary extract oil and secondary raffinate oil were obtained, respectively. Their properties are shown in Table 4. The aromatic hydrocarbon extraction rate of the extract oil was 81.78%, the extract phase recovery rate was 74.75%, and the C0.05... A The value is 21.10%, and the PCA content is less than 3%, which meets the quality requirements for environmentally friendly rubber oil.

[0054] Table 4. Property Analysis of Secondary Raffinate Oil and Secondary Extract Oil

[0055] Testing items Secondary extraction residue oil Secondary extraction oil Yield, % 25.25 74.75 <![CDATA[Density (20 °C), g / cm 3 > 1.2851 1.0129 Refractive index (20℃) 1.4896 1.5371 Saturation fraction (wt,%) 0.00 6.32 Aromatic components (wt, %) 84.18 79.85 Polar components (wt,%) 15.82 13.83 Aromatic extraction rate, % / 81.78 <![CDATA[C A ,%]]> 20.21 21.10 Polycyclic aromatic hydrocarbon (PCA) content, % 14.1 2.6

[0056] Example 3

[0057] This embodiment first provides an aromatic rubber oil, the preparation method of which includes the following steps:

[0058] (1) Paraffin-based vacuum distillate oil (oil properties are shown in Table 5, C of the feed oil) A The feedstock was solvent-extracted using N,N-dimethylacetamide (DMA) as the solvent. Extraction was carried out in an extraction apparatus, yielding a primary raffinate and a primary extract from the upper and lower portions, respectively. The extraction conditions were: extraction temperature 80℃, solvent to feedstock oil mass ratio 5:1, extraction time 60 min, and extraction pressure at atmospheric pressure.

[0059] The present invention further evaporates the solvent from the primary raffinate and the primary extract to obtain primary raffinate oil and primary extract oil, respectively, and their properties are shown in Table 5. As can be seen from Table 5, after primary solvent extraction, the aromatic content of the primary extract oil can reach more than 74%, of which the saturated hydrocarbon content is about 13%, indicating that the aromatics are fully enriched in the extract phase, which is more conducive to the preparation of high-aromatic environmentally friendly rubber oil.

[0060] Table 5. Property Analysis of Paraffinic Vacuum Distillate Oil, Primary Razor Residue Oil, and Primary Extract Oil

[0061]

[0062] (2) The primary extract (without solvent removal) from step (1) was subjected to a secondary extraction in an extraction apparatus. Hexane was selected as the solvent. The upper and lower portions yielded a secondary extract and a secondary raffinate, respectively. The extraction conditions were: extraction temperature 40℃, solvent to feed oil mass ratio 1:1, extraction time 60 min, and extraction pressure at atmospheric pressure. After evaporation to remove the solvent, the secondary extract and secondary raffinate were respectively obtained as secondary extract oil and secondary raffinate oil. Their properties are shown in Table 6. The aromatic hydrocarbon extraction rate of the extract oil was 79.81%, the extract phase recovery rate was 72.40%, and the C2... A The value is 21.75%, PC A With a content of less than 3%, it meets the quality requirements for environmentally friendly rubber oils.

[0063] Table 6. Property Analysis of Secondary Extraction Oil and Secondary Rake Oil

[0064]

[0065]

[0066] Example 4

[0067] This embodiment first provides an aromatic rubber oil, the preparation method of which differs from that of Example 1 only in that the secondary extraction temperature in step (2) is 60°C.

[0068] After evaporation to remove the solvent, the secondary extract and secondary raffinate were respectively treated as secondary extract oil and secondary raffinate oil, and their properties are shown in Table 7. The aromatic extraction rate of the extract oil was 84.50%, and the oil yield was 75.32%. C A The value was 24.52%, and the PCA content was 4.1%. Compared with Example 1, the extracted oil had a higher content of polar components and a higher PCA content, failing to meet the quality requirements for environmentally friendly rubber oil. Experimental results indicate that excessively high extraction temperatures increase the polycyclic aromatic hydrocarbon (PAH) content in the extracted oil obtained from the back-extraction of light hydrocarbons, which is detrimental to the production of aromatic environmentally friendly rubber oil.

[0069] Table 7. Property Analysis of Secondary Extraction Oil and Secondary Rake Oil

[0070] Testing items Secondary extraction residue oil Secondary extraction oil Yield, % 24.68 75.32 <![CDATA[Density (20 °C), g / cm 3 > 1.1219 1.0075 Refractive index (20℃) 1.5115 1.5346 Saturation fraction (wt,%) 0.33 4.88 Aromatic components (wt, %) 78.25 81.89 Polar components (wt,%) 21.42 13.23 Aromatic extraction rate, % / 84.50 <![CDATA[C A ,%]]> 21.40 24.52 Polycyclic aromatic hydrocarbon (PCA) content, % 16.7 4.1

[0071] Example 5

[0072] This embodiment first provides an aromatic rubber oil, the preparation method of which differs from that of Example 1 only in that the extractant in the secondary extraction in step (2) is isoheptane.

[0073] After evaporation to remove the solvent, the secondary extract and secondary raffinate were respectively divided into secondary extract oil and secondary raffinate oil, and their properties are shown in Table 8. The aromatic extraction rate of the extract oil was 79.26%, the extract phase yield was 70.68%, and C0.05... AThe value is 20.45%, and the PCA content is 3.5%, which exceeds the product requirement that the PCA content of high aromatic environmentally friendly rubber oil should not exceed 3wt%.

[0074] Table 8. Property Analysis of Secondary Extraction Oil and Secondary Raster Oil

[0075] Testing items Secondary extraction residue oil Secondary extraction oil Yield, % 29.32 70.68 Density (20℃), g / cm3 1.2963 1.0112 Refractive index (20℃) 1.5021 1.5542 Saturation fraction (wt,%) 0.00 5.74 Aromatic components (wt, %) 85.63 74.28 Polar components (wt,%) 14.37 19.98 Aromatic extraction rate, % / 79.26 <![CDATA[C A ,%]]> 22.36 20.45 Polycyclic aromatic hydrocarbon (PCA) content, % 17.8 3.5

[0076] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing an aromatic rubber oil, characterized in that, include: S1: Mix the raw oil with the primary extractant and perform a primary extraction to obtain a primary extract and a primary raffinate. S2: The primary extract is directly mixed with the secondary extractant without desolventizing, and the secondary extract and secondary raffinate are obtained by secondary extraction. S3: Desolventize the secondary extract to obtain secondary extract oil, which is aromatic rubber oil; Wherein, the primary extractant is a polar aprotic solvent, and the secondary extractant is a light hydrocarbon; the feed oil is selected from one or more of paraffinic vacuum distillate oil, intermediate-based vacuum distillate oil, and naphthenic vacuum distillate oil. The primary extract oil obtained by desolventizing the primary extract contains 70-90 wt% aromatic hydrocarbons and less than 10 wt% saturated hydrocarbons. The polar aprotic solvent is selected from one or more of dimethyl sulfoxide, sulfolane, acetonitrile, N-formylmorpholine, N,N-dimethylformamide, N,N-dimethylacetamide and hexamethylphosphoric triamine; The light hydrocarbon is selected from one or more of n-hexane, n-heptane, n-pentane, and petroleum ether at 60-90℃; The temperature for the secondary extraction is 30~50℃; The temperature of the first extraction is 60~100℃.

2. The method for preparing aromatic rubber oil according to claim 1, characterized in that, In the secondary extraction, the mass ratio of the primary extract to the secondary extractant is (0.5~2):

1.

3. The method for preparing aromatic rubber oil according to claim 1, characterized in that, In the primary extraction, the mass ratio of the raw oil to the primary extractant is (3~8):

1.

4. The method for preparing aromatic rubber oil according to any one of claims 1 to 3, characterized in that, The primary and secondary extraction pressures are at atmospheric pressure, and the extraction times are each independently selected from 50 to 80 minutes.

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