SEBS Special Naphthenic White Oil and Its Preparation Method

Abstract

The present invention relates to the technical field of petrochemical engineering, and provides a special naphthenic white oil for SEBS and a preparation method thereof. The special naphthenic white oil for SEBS is obtained by the following method: using naphthenic fraction oil as the raw material oil, subjecting the raw material oil and the extraction solvent to centrifugal extraction together, removing aromatics and polar compounds in the raw material oil to obtain a low-aromatic oil; performing hydrotreating on the low-aromatic oil to obtain a hydrotreated product oil; performing isomerization and dewaxing on the hydrotreated product oil to obtain an isomerized dewaxed product oil; performing hydrofining on the obtained isomerized dewaxed product oil to obtain a hydrofined product oil; collecting the fraction at 300°C to 500°C, namely obtaining the special naphthenic white oil product for SEBS. The special naphthenic white oil for SEBS of the present invention has a relatively high viscosity index and a certain naphthene content, and can be used as a rubber softening filling oil for special SEBS products; its preparation method has a simple process and is suitable for large-scale industrial production.

Description

Technical Field

[0001] The present invention relates to the technical field of petrochemical industry, and is a special naphthenic base white oil for SEBS and a preparation method thereof. Background Art

[0002] The rubber industry is one of the important basic industries of the national economy in China, and plays an inestimable role in promoting economic development and improving people's living standards. Thermoplastic elastomer (TPE) is a major category of synthetic rubber, also known as thermoplastic rubber. White rubber oil is mainly used in thermoplastic elastomers. The styrenic block copolymers (SBC) have the largest oil filling amount. SBC mainly includes SBS, SEBS, SIS and SEPS. About 70% of white rubber oil (naphthenic base, paraffin base) is used in styrenic block copolymers (SBC).

[0003] Among them, SEBS is the hydrogenated product of SBS. With the increase of the hydrogenation degree, the chemical stability, heat resistance, aging resistance, weather resistance and water resistance of SEBS are improved, and the compression set is also effectively reduced, and the stability is stronger than that of SBS. At the same time, the elastomeric block of SEBS is a butene-ethylene structure, and this chain segment is softer than the butadiene chain segment of SBS. Therefore, the hand feeling of SEBS products is softer than that of SBS modified materials, and the application fields are wider than those of SBS. In China, it is mainly used in power tools, toys, stationery and the electronics industry, and the consumption is gradually increasing.

[0004] According to the principle of like dissolves like, SBS is a styrene-butadiene-styrene block copolymer with unsaturated bonds, and the main softening rubber oil filled is naphthenic base white oil; while SEBS does not contain unsaturated double bonds. Under normal circumstances, the main softening rubber oil filled is paraffin base white oil with a relatively high content of paraffinic hydrocarbons. However, special SEBS products (i.e., special SEBS thermoplastic elastomers) such as human simulation skin have different physical property requirements for the softening rubber oil filled, and it is necessary to ensure that the special SEBS products meet the requirements of (1) sufficient oil absorption and no oil leakage of the products; (2) no pungent odor; (3) good elasticity, anti-deformation, good tensile strength and easy forming of the products; (4) easy operation and high finished product rate, etc. The finished product rate of rubber products processing is directly related to the kinematic viscosity index and naphthene content of white oil. This requires that the white oil product should have a relatively high viscosity index and ensure the naphthene content of the oil product. However, the existing naphthenic base white oil has poor compatibility, and the oil-filled rubber is prone to oil leakage, and mechanical properties such as hardness, tear resistance and tensile strength are poor. The existing paraffin base white oil, industrial and cosmetic white oils of No. 10, No. 15 and No. 26 have a high viscosity index, and the content of paraffinic hydrocarbons in the oil product structure composition is higher than 50%, resulting in problems such as insufficient hydrogenation depth and too low naphthene content, resulting in poor mechanical properties or difficult processing of rubber products and low finished product rate, etc., and cannot meet the filling oil requirements of special SEBS products.

[0005] The Chinese patent document with the publication number CN101747937B discloses a method for preparing food-grade naphthenic white oil by using a noble metal aromatic saturation catalyst. Using naphthenic white oil as the raw material and adopting the method of preparing food-grade naphthenic white oil with a noble metal aromatic saturation catalyst, there are extremely stringent requirements for the raw material. The physicochemical properties of the raw material must have a carbon-type naphthene content CN distribution not greater than 35.8%, a sulfur content less than 2.0 ppm, a nitrogen content less than 1.0 ppm, an arsenic content less than 1.0 ppm, a lead content less than 1.0 ppm, a total heavy metal content less than 2.0 ppm, and an aromatic content not greater than 4.39%. Except that the easy carbon of its raw material physicochemical properties does not meet the food-grade white oil index, other indexes basically meet the requirements of food-grade white oil; however, its process has extremely stringent requirements for the raw material.

[0006] The Chinese patent document with the publication number CN1261537C discloses a method for producing high-viscosity food-grade white oil. Using a mixed oil of heavy white oil and light white oil as the raw material and adopting a hydrofining process to produce food-grade white oil, its raw material must be white oil, and there are also extremely stringent requirements for the raw material, especially the sulfur and nitrogen contents and the aromatic content.

[0007] The Chinese patent document with the publication number CN111073698B discloses a production method of a food-grade white oil with a low pour point and a low cloud point and the food-grade white oil. The Chinese patent document with the publication number CN106753550B discloses a food-grade white oil and a preparation method thereof. Both use white oil as the raw material and carry out a multi-stage hydrogenation process to produce the target product.

[0008] The Chinese patent document with the publication number CN102021032B discloses a naphthenic filling oil for soft rubber toys and a preparation method thereof. Using naphthenic fraction oil as the raw material and adopting a combination of medium-pressure hydrogenation and furfural refining to produce toy oil, the furfural refining extraction tower has poor selectivity, and the aromatic content of the refined oil after extraction is too high. The medium-pressure hydrogenation pressure is too low to saturate all the aromatics and cannot crack the naphthenes to the ideal content, so white oil cannot be produced, and the aromatics and naphthenes in the oil affect the physical and chemical properties, mechanical properties, and yellowing resistance of SEBS rubber products. Summary of the Invention

[0009] The present invention provides a naphthenic white oil special for SEBS and a preparation method thereof, overcoming the above-mentioned deficiencies of the prior art, and effectively solving the problem that the existing naphthenic white oil for SEBS cannot meet the requirements of special SEBS products in terms of viscosity index and naphthene content.

[0010] One of the technical solutions of the present invention is achieved by the following measures: A naphthenic white oil special for SEBS is obtained by the following method:

[0011] First step: Using naphthenic fraction oil as the feedstock, after centrifugal extraction of the feedstock together with the extraction solvent, aromatics and polar compounds in the feedstock are removed. After the extraction is completed, the low-aromatic oil and the aromatic extraction liquid are separated to obtain the low-aromatic oil;

[0012] Second step: Using a hydrotreating catalyst to hydrotreat the low-aromatic oil obtained in the first step to obtain a hydrotreated product oil;

[0013] Third step: Using an isomerization and dewaxing catalyst to carry out isomerization and dewaxing on the hydrotreated product oil to obtain an isomerized and dewaxed product oil;

[0014] Fourth step: Using a hydrofining catalyst to hydrofine the isomerized and dewaxed product oil obtained to obtain a hydrofined product oil;

[0015] Fifth step: Carry out gas-liquid separation on the hydrofined product oil, fractionate the separated liquid phase, and collect the fraction with a distillation range of 300°C to 500°C to obtain the SEBS-special naphthenic white oil product.

[0016] The following is a further optimization or / and improvement of one of the above technical solutions of the invention:

[0017] In the above first step, the naphthenic fraction oil is a vacuum distillation fraction oil with a distillation range of 300°C to 500°C.

[0018] In the above first step, the centrifugal extraction is completed by a centrifugal extractor, and the centrifugal extractor is a multi-stage annular gap centrifugal extractor. The centrifugal extraction conditions are: the number of extraction stages is 5 to 20, the inlet oil temperature of the feedstock is 40 to 100°C, the temperature of the extractant is 60 to 120°C, the rotation speed is 2000 to 5000 rpm, and the contact time for each stage is 10 to 20 min.

[0019] In the above first step, the extraction solvent is one or more of furfural, phenol, and N-methylpyrrolidone, and the mass fraction ratio of the extraction solvent to the feedstock is 0.3:1 to 7.0:1.

[0020] In the above second step, the hydrotreating conditions are: the hydrogen partial pressure is 10.0 MPa to 22.0 MPa, the reaction temperature is 280°C to 390°C, the volume space velocity is 0.2 h -1 to 1.5 h -1 , and the hydrogen-oil volume ratio is 1000:1 to 3000:1; the carrier of the hydrotreating catalyst is alumina, and the active components of the hydrotreating catalyst are tungsten oxide, molybdenum oxide, and nickel oxide.

[0021] In the above second step, the hydrotreating conditions are: the hydrogen partial pressure is 13.0 MPa to 20.0 MPa; the reaction temperature is 300°C to 380°C; the volume space velocity is 0.3 h -1 to 0.5 h -1; The hydrogen-oil volume ratio is from 1500:1 to 2500:1.

[0022] In the above-mentioned third step, the conditions for isomerization and dewaxing are as follows: the hydrogen partial pressure is from 10.0 MPa to 22.0 MPa, the reaction temperature is from 250 °C to 400 °C, and the volume hourly space velocity is 0.3 h -1 to 2.0 h -1 , and the hydrogen-oil volume ratio is from 500:1 to 3000:1; the carrier of the isomerization and dewaxing catalyst is molecular sieve, and the active ingredient is platinum oxide or palladium oxide.

[0023] In the above-mentioned third step, the conditions for isomerization and dewaxing are as follows: the hydrogen partial pressure is from 14.0 MPa to 20.0 MPa; the reaction temperature is from 280 °C to 370 °C; the volume hourly space velocity is 0.5 h -1 to 1.0 h -1 ; and the hydrogen-oil volume ratio is from 1500:1 to 2000:1.

[0024] In the above-mentioned fourth step, the conditions for hydrofining are as follows: the hydrogen partial pressure is from 10.0 MPa to 22.0 MPa, the reaction temperature is from 200 °C to 300 °C, and the volume hourly space velocity is 1.0 h -1 to 3.0 h -1 , and the hydrogen-oil volume ratio is from 500:1 to 3000:1; the carrier of the hydrofining catalyst is molecular sieve, and the active ingredients are platinum oxide and palladium oxide.

[0025] The conditions for the above-mentioned hydrofining are as follows: the hydrogen partial pressure is from 14.0 MPa to 20.0 MPa; the reaction temperature is from 200 °C to 250 °C; the volume hourly space velocity is 2.0 h -1 to 2.5 h -1 ; and the hydrogen-oil volume ratio is from 500:1 to 1000:1.

[0026] The second technical solution of the present invention is achieved by the following measures: A method for preparing SEBS special naphthenic white oil as described in the above technical solution one is carried out according to the following steps: In the first step, using naphthenic fraction oil as the feedstock, the feedstock and the extraction solvent are centrifugally extracted together, and the aromatics and polar compounds in the feedstock are removed. After the extraction is completed, the low-aromatic oil and the aromatic extraction liquid are separated to obtain the low-aromatic oil;

[0027] In the second step, the low-aromatic oil obtained in the first step is hydrotreated using a hydrotreating catalyst to obtain a hydrotreated product oil;

[0028] In the third step, the hydrotreated product oil is isomerized and dewaxed using an isomerization and dewaxing catalyst to obtain an isomerized and dewaxed product oil;

[0029] In the fourth step, the isomerized and dewaxed product oil is hydrofined using a hydrofining catalyst to obtain a hydrofined product oil.

[0030] In the fifth step, the hydrofined product oil is subjected to gas-liquid separation. The separated liquid phase is fractionated, and the fraction with a boiling range of 300°C to 500°C is collected to obtain the SEBS-special naphthenic white oil product.

[0031] The SEBS-special naphthenic white oil of one of the present inventions has high product quality, a high viscosity index, and a certain naphthene content, and can be used as a rubber softening filler oil for special SEBS products. The preparation method of the SEBS-special naphthenic white oil provided by the second aspect of the present invention uses naphthenic fraction oil as the raw material and adopts a centrifugal extraction refining-hydrogenation combined process. The process is simple, easy to control and implement, and is suitable for large-scale industrial production. Specific embodiments

[0032] The present invention is not limited by the following embodiments, and the specific implementation manners can be determined according to the technical solutions of the present invention and the actual situation. All chemical reagents and chemical supplies mentioned in the present invention are well-known and commonly used chemical reagents and chemical supplies in the prior art unless otherwise specified; the percentages in the present invention are mass percentages unless otherwise specified; normal temperature and room temperature in the present invention generally refer to a temperature range of 15°C to 25°C, and are generally defined as 25°C.

[0033] The present invention will be further described below in conjunction with embodiments:

[0034] Example 1: The SEBS-special naphthenic white oil is obtained by the following method:

[0035] In the first step, using naphthenic fraction oil as the feedstock, the feedstock and the extraction solvent are centrifugally extracted together to remove aromatics and polar compounds from the feedstock. After the extraction is completed, the low-aromatic oil and the aromatic extraction liquid are separated to obtain the low-aromatic oil;

[0036] In the second step, the low-aromatic oil obtained in the first step is subjected to hydrogenation treatment using a hydrotreating catalyst to obtain a hydrotreated product oil;

[0037] In the third step, the hydrotreated product oil is subjected to isomerization and dewaxing using an isomerization dewaxing catalyst to obtain an isomerization dewaxed product oil;

[0038] In the fourth step, the isomerization dewaxed product oil is subjected to hydrorefining using a hydrorefining catalyst to obtain a hydrorefined product oil;

[0039] In the fifth step, the hydrorefined product oil is subjected to gas-liquid separation. The separated liquid phase is fractionated, and the fraction with a boiling range of 300°C to 500°C is collected to obtain the SEBS-special naphthenic white oil product.

[0040] Example 2: As an optimization of the above example, in the first step, the naphthenic fraction oil is a vacuum distillation fraction oil with a distillation range of 300°C to 500°C.

[0041] Example 3: As an optimization of the above example, in the first step, the centrifugal extraction is completed by a centrifugal extractor, which is a multi-stage annular gap centrifugal extractor. The centrifugal extraction conditions are as follows: the number of extraction stages is 5 to 20, the inlet temperature of the feed oil is 40 to 100 °C, the temperature of the extractant is 60 to 120 °C, the rotational speed is 2000 to 5000 rpm, and the contact time for each stage is 10 to 20 min.

[0042] In the present invention, one complete centrifugal extraction from oil inlet to oil outlet is one stage of the centrifugal extraction stage number.

[0043] Example 4: As an optimization of the above example, in the first step, the extraction solvent is one or more of furfural, phenol, and N-methylpyrrolidone, and the mass fraction ratio of the extraction solvent to the feed oil is 0.3:1 to 7.0:1.

[0044] Example 5: As an optimization of the above example, in the second step, the hydrotreating conditions are as follows: the hydrogen partial pressure is 10.0 MPa to 22.0 MPa, the reaction temperature is 280 °C to 390 °C, the volume space velocity is 0.2 h -1 to 1.5 h -1 , and the hydrogen-oil volume ratio is 1000:1 to 3000:1; the carrier of the hydrotreating catalyst is alumina, and the active components of the hydrotreating catalyst are tungsten oxide, molybdenum oxide, and nickel oxide.

[0045] In the second step of the present invention, the purpose of hydrotreating is to cause a series of chemical upgrading reactions such as deep desulfurization, deoxygenation, denitrification, hydrogenation saturation of polycyclic aromatic hydrocarbons, and ring-opening cracking of the naphthenic fraction oil, so as to generate more alkanes and naphthenes and remove non-hydrocarbon compounds such as sulfur, nitrogen, oxygen, gum, and asphaltene. In the hydrotreating catalyst, the mass content of tungsten oxide (WO3) and molybdenum oxide Mo2O3 is 4.0 wt% to 30.0 wt%, and the mass content of nickel oxide (NiO) is 1.0 wt% to 6.0 wt%. The hydrotreating catalyst also contains promoters, and the promoters are tungsten, phosphorus, and fluoride ions, and the mass content of the promoters in the hydrotreating catalyst is 2.0 wt% to 4.0 wt%. The specific surface area of the hydrotreating catalyst is 80 m 2 / g to 180 m 2 / g, the pore volume is 0.20 ml / g to 0.35 ml / g, the radial strength can be 16 N / mm to 20 N / mm, the appearance shape is butterfly-shaped, and the diameter is 1.5 mm to 2.6 mm. In addition, before use, the hydrotreating catalyst can be pretreated according to the conventional method; in the presence of hydrogen, at a temperature of 140 °C to 370 °C, the hydrotreating catalyst is pre-sulfurized with sulfur, hydrogen sulfide, or a sulfur-containing raw material, so as to convert it into a sulfide type.

[0046] Example 6: As an optimization of the above example, in the second step, the conditions for hydrotreating are as follows: hydrogen partial pressure is 13.0 MPa to 20.0 MPa; reaction temperature is 300 °C to 380 °C; volumetric space velocity is 0.3 h -1 to 0.5 h -1 ; hydrogen-to-oil volume ratio is 1500:1 to 2500:1.

[0047] Example 7: As an optimization of the above example, in the third step, the conditions for isomerization and dewaxing are as follows: hydrogen partial pressure is 10.0 MPa to 22.0 MPa, reaction temperature is 250 °C to 400 °C, volumetric space velocity is 0.3 h -1 to 2.0 h -1 , hydrogen-to-oil volume ratio is 500:1 to 3000:1; the carrier of the isomerization and dewaxing catalyst is molecular sieve, and the active ingredient is platinum oxide or palladium oxide.

[0048] In the third step of the present invention, the purpose of isomerization and dewaxing is to selectively isomerize the high pour point normal paraffins in the product oil into low pour point branched paraffins. At the same time, it also has a deep refining effect and a certain aromatics saturation effect. The mass content of the active ingredient in the isomerization and dewaxing catalyst is 0.1 wt% to 1.0 wt%. The specific surface area of the isomerization and dewaxing catalyst is 150 m 2 / g to 300 m 2 / g, the pore diameter is 7 Å to 22 Å, the radial strength is 10 N / mm to 16 N / mm, the appearance shape is cylindrical, and the diameter is 1.0 mm to 2.6 mm. Before use, the isomerization and dewaxing catalyst can be pretreated according to the conventional method, and heated at a temperature of 150 °C to 500 °C in the presence of hydrogen to convert it into the reduced state.

[0049] Example 8: As an optimization of the above example, in the third step, the conditions for isomerization and dewaxing are as follows: hydrogen partial pressure is 14.0 MPa to 20.0 MPa; reaction temperature is 280 °C to 370 °C; volumetric space velocity is 0.5 h -1 to 1.0 h -1 ; hydrogen-to-oil volume ratio is 1500:1 to 2000:1.

[0050] Example 9: As an optimization of the above example, in the fourth step, the conditions for hydrofining are as follows: hydrogen partial pressure is 10.0 MPa to 22.0 MPa, reaction temperature is 200 °C to 300 °C, volumetric space velocity is 1.0 h -1 to 3.0 h -1 , hydrogen-to-oil volume ratio is 500:1 to 3000:1; the carrier of the hydrofining catalyst is molecular sieve, and the active ingredients are platinum oxide and palladium oxide.

[0051] In the fourth step of the present invention, the purpose of hydrofining is to further hydrogenate and saturate the olefins and trace amounts of unsaturated aromatics generated from the oil produced by isomerization and dewaxing to form stable saturated alkanes and cycloalkanes, and further improve the stability of the oil product. In the fourth step, the mass content of platinum oxide PtO2 in the hydrofining catalyst is 0.2 wt% to 1.0 wt%, and the mass content of palladium oxide PdO in the hydrofining catalyst is 0.1 wt% to 0.5 wt%; the specific surface area of the hydrofining catalyst is 100 m 2 / g to 300m 2 / g; the pore diameter is 7 Å to 34 Å, the radial strength is 16 N / mm to 20 N / mm; the appearance shape is cylindrical; the diameter is 1.0 mm to 2.6 mm. In addition, before use, the hydrofining catalyst is pretreated according to the conventional method; for example, in the presence of hydrogen, at a temperature of 150 °C to 500 °C, it is converted into a reduced state.

[0052] Example 10: As an optimization of the above example, the conditions for hydrofining are: hydrogen partial pressure 14.0 MPa to 20.0 MPa; reaction temperature 200 °C to 250 °C; volume space velocity 2.0 h -1 to 2.5h -1 ; hydrogen-oil volume ratio 500:1 to 1000:1.

[0053] The naphthenic base white oil special for SEBS prepared by the preparation method of the present invention has a viscosity index of not less than 70, a pour point of not more than -30 °C, a carbon type structure C A value (measured according to ASTM D2140) of 0%, a C N value (measured according to ASTM D2140) between 30% and 35%, the hydrocarbon composition of the heavy oil fraction (measured by mass spectrometry ASTM D2786, 3239) has an alkane content between 30% and 40% and a cycloalkane content between 60% and 70%, and the easily carbonizable substances pass.

[0054] Example 11:

[0055] In this example, the fractionated oil with a boiling range of 320 °C to 500 °C from naphthenic base crude oil is used as the feedstock oil, and the specific composition is: the content of total aromatics is 29.7%, the content of polar compounds is 7.8%, and the content of saturated hydrocarbons is 62.5% (measured according to the SH / T 0753 method). The properties of this feedstock oil are shown in Table 1, and the physical properties of the hydrotreating catalyst, isomerization and dewaxing catalyst, and hydrofining catalyst used in this example are shown in Table 2.

[0056] The naphthenic base white oil special for SEBS is prepared by the following steps:

[0057] The first step is to remove aromatics by multi-stage annular gap centrifugation

[0058] The raw material oil, naphthenic fraction oil, and the extractant are fed into a centrifugal extractor simultaneously. The extractant is furfural, and the mass ratio of furfural to the raw material oil is 0.5:1. The mixed liquid is passed through the centrifugal extractor. The centrifugal extraction conditions are as follows: the number of extraction stages is 7; the inlet temperature of the raw material oil is 70 °C, and the inlet temperature of the extractant into the centrifuge is 90 °C; the rotational speed is 3000 rpm; the contact time for each stage is 10 min. After the two-phase separation, low-aromatic oil and aromatic extract are obtained. The low-aromatic oil is used as the feedstock for hydrotreating, and the properties of the low-aromatic oil are shown in Table 3.

[0059] Second step, hydrotreating

[0060] The low-aromatic oil is hydrotreated using a hydrotreating catalyst to obtain hydrotreated product oil. The hydrotreating conditions are as follows: hydrogen partial pressure is 10.0 MPa; reaction temperature is 380 °C; volume space velocity is 0.6 h -1 ; the hydrogen-oil volume ratio is 1000:1.

[0061] Third step, isomerization and dewaxing

[0062] The hydrotreated product oil is subjected to isomerization and dewaxing refining using an isomerization and dewaxing catalyst to obtain isomerized and dewaxed product oil. The isomerization and dewaxing conditions are as follows: hydrogen partial pressure is 10.0 MPa; reaction temperature is 400 °C; volume space velocity is 0.6 h -1 ; the hydrogen-oil volume ratio is 3000:1.

[0063] Fourth step, hydrorefining

[0064] The isomerized and dewaxed product oil is hydrorefined using a hydrorefining catalyst to obtain hydrorefined product oil. The hydrorefining conditions are as follows: hydrogen partial pressure is 10.0 MPa; reaction temperature is 300 °C; volume space velocity is 1.0 h -1 ; the hydrogen-oil volume ratio is 3000:1.

[0065] Fifth step, gas-liquid separation and fractionation

[0066] The hydrorefined product oil enters a gas-liquid separator for gas-liquid separation. The separated liquid phase enters a fractionating column for fractionation, and the fraction at 300 °C to 380 °C is collected to obtain SEBS-special naphthenic white oil, and its properties are shown in Table 4-1.

[0067] Example 12:

[0068] The naphthenic fraction oil, hydrotreating catalyst, isomerization and dewaxing catalyst, and hydrorefining catalyst in this example are the same as those in Example 11. The SEBS-special naphthenic white oil is prepared by the following steps:

[0069] First step, multi-stage annular gap centrifugal removal of aromatics

[0070] The raw material oil, naphthenic fraction oil, and the extractant are fed into a centrifugal extractor simultaneously. The extractant is N-methylpyrrolidone, and the mass ratio of N-methylpyrrolidone to the raw material oil is 1.5:1. The mixed liquid is passed through the centrifugal extractor. The centrifugal extraction conditions are as follows: the number of extraction stages is 17; the inlet temperature of the raw material oil is 60 °C, and the inlet temperature of the extractant into the centrifuge is 100 °C; the rotational speed is 2500 rpm; the contact time for each stage is 16 min. After the two-phase separation, low-aromatic oil and aromatic extract are obtained. The low-aromatic oil is used as the feedstock for hydrotreating, and the properties of this low-aromatic oil are shown in Table 3.

[0071] Step 2, hydrotreating

[0072] The low-aromatic oil is hydrotreated using a hydrotreating catalyst to obtain hydrotreated product oil. The hydrotreating conditions are as follows: hydrogen partial pressure is 17.0 MPa; reaction temperature is 280 °C; volumetric space velocity is 1.5 h -1 ; the hydrogen-oil volume ratio is 3000:1.

[0073] Step 3, isomerization and dewaxing

[0074] The hydrotreated product oil is subjected to isomerization and dewaxing refining using an isomerization and dewaxing catalyst to obtain isomerized and dewaxed product oil. The isomerization and dewaxing conditions are as follows: hydrogen partial pressure is 17.0 MPa; reaction temperature is 250 °C; volumetric space velocity is 1.0 h -1 ; the hydrogen-oil volume ratio is 3000:1.

[0075] Step 4, hydrofining

[0076] The isomerized and dewaxed product oil is hydrofined using a hydrofining catalyst to obtain hydrofined product oil. The hydrofining conditions are as follows: hydrogen partial pressure is 17.0 MPa; reaction temperature is 200 °C; volumetric space velocity is 2.0 h -1 ; the hydrogen-oil volume ratio is 2000:1.

[0077] Step 5, gas-liquid separation and fractionation

[0078] The hydrofined product oil enters a gas-liquid separator for gas-liquid separation. The separated liquid phase enters a fractionating column for fractionation, and the fraction at 300 °C to 380 °C is collected to obtain SEBS-special naphthenic white oil, and its properties are shown in Table 4-1.

[0079] Example 13:

[0080] The naphthenic fraction oil, hydrotreating catalyst, isomerization and dewaxing catalyst, and hydrofining catalyst in this example are the same as those in Example 11. The SEBS-special naphthenic white oil is prepared by the following steps:

[0081] Step 1, multi-stage annular gap centrifugal removal of aromatics

[0082] The raw material oil, naphthenic fraction oil, and the extractant are fed into a centrifugal extractor simultaneously. The extractant is furfural, and the mass ratio of furfural to the raw material oil is 1.2:1. The mixture is passed through the centrifugal extractor. The centrifugal extraction conditions are as follows: the number of extraction stages is 12; the raw material oil inlet temperature is 80°C, and the extractant inlet temperature to the centrifuge is 100°C; the rotational speed is 3000 rpm; the contact time for each stage is 10 min. After the two-phase separation, low-aromatic oil and aromatic extract are obtained. The low-aromatic oil is used as the feedstock for hydrotreating, and the properties of the low-aromatic oil are shown in Table 3.

[0083] Second step, hydrotreating

[0084] The low-aromatic oil is hydrotreated using a hydrotreating catalyst to obtain hydrotreated product oil. The hydrotreating conditions are as follows: hydrogen partial pressure is 17.0 MPa; reaction temperature is 375°C; volume hourly space velocity is 0.5 h -1 ; the hydrogen-oil volume ratio is 1500:1.

[0085] Third step, isomerization and dewaxing

[0086] The hydrotreated product oil is subjected to isomerization and dewaxing refining using an isomerization and dewaxing catalyst to obtain isomerized and dewaxed product oil. The isomerization and dewaxing conditions are as follows: hydrogen partial pressure is 17.0 MPa; reaction temperature is 33°C; volume hourly space velocity is 2.0 h -1 ; the hydrogen-oil volume ratio is 1500:1.

[0087] Fourth step, hydrorefining

[0088] The isomerized and dewaxed product oil is hydrorefined using a hydrorefining catalyst to obtain hydrorefined product oil. The hydrorefining conditions are as follows: hydrogen partial pressure is 17.0 MPa; reaction temperature is 250°C; volume hourly space velocity is 3.0 h -1 ; the hydrogen-oil volume ratio is 1000:1.

[0089] Fifth step, gas-liquid separation and fractionation

[0090] The hydrorefined product oil enters a gas-liquid separator for gas-liquid separation. The separated liquid phase enters a fractionating column for fractionation, and the fraction at 380°C to 480°C is collected to obtain SEBS-special naphthenic white oil, and its properties are shown in Table 4-1.

[0091] Example 14:

[0092] The naphthenic fraction oil, hydrotreating catalyst, isomerization and dewaxing catalyst, and hydrorefining catalyst in this example are the same as those in Example 11. The SEBS-special naphthenic white oil is prepared by the following steps:

[0093] First step, multi-stage annular gap centrifugal removal of aromatics

[0094] The raw material oil, naphthenic fraction oil, and the extractant are fed into a centrifugal extractor simultaneously. The extractant is furfural, and the mass ratio of furfural to the raw material oil is 1.5:1. The mixed liquid is passed through the centrifugal extractor. The centrifugal extraction conditions are as follows: the number of extraction stages is 18; the inlet temperature of the raw material oil is 90 °C, and the inlet temperature of the extractant into the centrifuge is 110 °C; the rotational speed is 3500 rpm; the contact time for each stage is 12 min. After the two-phase separation, low-aromatic oil and aromatic extract are obtained. The low-aromatic oil is used as the feedstock for hydrotreating, and the properties of the low-aromatic oil are shown in Table 3.

[0095] The second step, hydrotreating

[0096] The low-aromatic oil is hydrotreated using a hydrotreating catalyst to obtain hydrotreated product oil. The hydrotreating conditions are as follows: hydrogen partial pressure is 17.0 MPa; reaction temperature is 380 °C; volume hourly space velocity is 0.3 h -1 ; the hydrogen-oil volume ratio is 2500:1.

[0097] The third step, isomerization and dewaxing

[0098] The hydrotreated product oil is subjected to isomerization and dewaxing refining using an isomerization and dewaxing catalyst to obtain isomerized and dewaxed product oil. The isomerization and dewaxing conditions are as follows: hydrogen partial pressure is 17.0 MPa; reaction temperature is 300 °C; volume hourly space velocity is 2.0 h -1 ; the hydrogen-oil volume ratio is 2000:1.

[0099] The fourth step, hydrorefining

[0100] The isomerized and dewaxed product oil is hydrorefined using a hydrorefining catalyst to obtain hydrorefined product oil. The hydrorefining conditions are as follows: hydrogen partial pressure is 17.0 MPa; reaction temperature is 270 °C; volume hourly space velocity is 2.0 h -1 ; the hydrogen-oil volume ratio is 500:1.

[0101] The fifth step, gas-liquid separation and fractionation

[0102] The hydrorefined product oil enters a gas-liquid separator for gas-liquid separation. The separated liquid phase enters a fractionating column for fractionation, and the fraction at 380 °C to 480 °C is collected to obtain SEBS-special naphthenic white oil, and its properties are shown in Table 4-1.

[0103] Example 15:

[0104] The naphthenic fraction oil, hydrotreating catalyst, isomerization and dewaxing catalyst, and hydrorefining catalyst in this example are the same as those in Example 11. The SEBS-special naphthenic white oil is prepared by the following steps:

[0105] The first step, multi-stage annular gap centrifugal removal of aromatics

[0106] The cycloalkane fraction of the feedstock oil and the extractant were simultaneously fed into a centrifugal extractor. The extractant was N-methylpyrrolidone (NMP) at a mass ratio of 2.0:1 to the feedstock oil. The mixed liquid was then passed through the centrifugal extractor. The centrifugal extraction conditions were: 18 extraction stages; feedstock inlet temperature of 80°C; extractant inlet temperature of 120°C; centrifuge speed of 3500 rpm; and contact time per stage of 20 minutes. After phase separation, a low-aromatic oil and an aromatic extract were obtained. The low-aromatic oil was used as the feedstock for hydrotreating. The properties of this low-aromatic oil are shown in Table 3.

[0107] The second step is hydrotreatment

[0108] The low aromatic oil is hydrotreated using a hydrotreating catalyst to obtain a hydrotreated product oil. The hydrotreating conditions are: hydrogen partial pressure 22.0 MPa; reaction temperature 300°C; volume space velocity 1.0 h -1 ; Hydrogen to oil volume ratio 1500:1.

[0109] The third step is isomerization degassing

[0110] The isomerization depressant catalyst is used to perform isomerization depressant refining on the hydrotreated product oil to obtain isomerization depressant product oil. The isomerization depressant conditions are: hydrogen partial pressure 22.0MPa; reaction temperature 350℃; volume space velocity 0.5h -1 ; Hydrogen to oil volume ratio 1500:1.

[0111] The fourth step is hydrotreating

[0112] The isomerized decondensate product oil is hydrotreated using a hydrotreating catalyst to obtain a hydrotreated product oil. The hydrotreating conditions are: hydrogen partial pressure 22.0 MPa; reaction temperature 250°C; volume space velocity 2.5 h -1 ; Hydrogen to oil volume ratio 1000:1.

[0113] Step 5: Gas-liquid separation and fractionation

[0114] The oil generated by hydrorefining enters the gas-liquid separator for gas-liquid separation, and the separated liquid phase enters the distillation tower for fractionation. The fractions between 380℃ and 480℃ are collected to obtain SEBS-specific cycloalkyl white oil, the properties of which are shown in Table 4-1.

[0115] Comparative Example 1:

[0116] The cycloalkyl distillate oil, hydrotreating catalyst, isomerization pour point depressant catalyst, and hydrotreating catalyst of this comparative example are the same as those of Example 11. The cycloalkyl white oil is prepared by the following steps:

[0117] The first step is to refine furfural to remove aromatics

[0118] After heating the raw material oil, naphthenic fraction oil is fed from the bottom of the extraction column using a furfural refining unit and contacts the solvent countercurrently from bottom to top. The solvent is furfural, and the mass ratio of furfural to raw material oil is 2.5:1. The furfural refining conditions are as follows: the raw material inlet temperature is 60 °C, the temperature at the top of the extraction column is 85 °C, and the temperature at the bottom of the column is 65 °C. After two-phase separation, low-aromatic oil and aromatic extraction liquid are obtained. The low-aromatic oil is used as the raw material for hydrotreating, and the properties of the low-aromatic oil are shown in Table 3.

[0119] The second step, hydrotreating

[0120] The low-aromatic oil is hydrotreated using a hydrotreating catalyst to obtain hydrotreated product oil. The hydrotreating conditions are as follows: hydrogen partial pressure 16.0 MPa; reaction temperature 370 °C; space velocity 0.3 h -1 ; hydrogen-oil volume ratio 1500:1.

[0121] The third step, isomerization and dewaxing

[0122] The hydrotreated product oil is subjected to isomerization and dewaxing refining using an isomerization and dewaxing catalyst to obtain isomerized and dewaxed product oil. The isomerization and dewaxing conditions are as follows: hydrogen partial pressure 16.0 MPa; reaction temperature 300 °C; space velocity 2.0 h -1 ; hydrogen-oil volume ratio 1000:1.

[0123] The fourth step, hydrofining

[0124] The isomerized and dewaxed product oil is hydrofined using a hydrofining catalyst to obtain hydrofined product oil. The hydrofining conditions are as follows: hydrogen partial pressure 16.0 MPa; reaction temperature 270 °C; space velocity 2.0 h -1 ; hydrogen-oil volume ratio 900:1.

[0125] The fifth step, gas-liquid separation and fractionation

[0126] The hydrofined product oil enters a gas-liquid separator for gas-liquid separation. The separated liquid phase enters a fractionating column for fractionation, and the fraction at 290 °C to 360 °C is collected to obtain naphthenic white oil, and its properties are shown in Table 4-2.

[0127] Comparative Example 2

[0128] The naphthenic fraction oil, hydrotreating catalyst, isomerization and dewaxing catalyst, and hydrofining catalyst in this comparative example are the same as those in Example 11. The naphthenic white oil is prepared by the following steps:

[0129] The first step, hydrotreating

[0130] The raw material oil, naphthenic fraction oil, is hydrotreated using a hydrotreating catalyst to obtain hydrotreated product oil. The hydrotreating conditions are as follows: hydrogen partial pressure 17.0 MPa; reaction temperature 400 °C; space velocity 0.3 h-1 ; The hydrogen-oil volume ratio is 2500:1.

[0131] The second step is isomerization and dewaxing

[0132] The hydrotreated product oil is subjected to isomerization and dewaxing refining using an isomerization and dewaxing catalyst to obtain an isomerization and dewaxing product oil. The isomerization and dewaxing conditions are as follows: hydrogen partial pressure is 17.0 MPa; reaction temperature is 370 °C; volumetric space velocity is 2.0 h -1 ; The hydrogen-oil volume ratio is 2000:1.

[0133] The third step is hydrorefining

[0134] The isomerization and dewaxing product oil is subjected to hydrorefining using a hydrorefining catalyst to obtain a hydrorefined product oil. The hydrorefining conditions are as follows: hydrogen partial pressure is 17.0 MPa; reaction temperature is 270 °C; volumetric space velocity is 2.0 h -1 ; The hydrogen-oil volume ratio is 1000:1.

[0135] The fourth step is gas-liquid separation and fractionation

[0136] The hydrorefined product oil enters a gas-liquid separator for gas-liquid separation, and the separated liquid phase enters a fractionating column for fractionation. The fraction at 290 °C to 380 °C is collected to obtain naphthenic base white oil, and its properties are shown in Table 4-2.

[0137] Comparative Example 3

[0138] The naphthenic base fraction oil, hydrotreating catalyst, isomerization and dewaxing catalyst, and hydrorefining catalyst in this comparative example are the same as those in Example 1. This naphthenic base white oil is prepared by the following steps:

[0139] The first step is furfural refining to remove aromatics

[0140] After heating the raw material oil, naphthenic base fraction oil, it is pumped into the extraction column from the bottom and contacts the solvent countercurrently from bottom to top. The solvent is furfural, and the mass ratio of furfural to the raw material oil is 2.0:1. The furfural refining conditions are as follows: the raw material inlet oil temperature is 60 °C, the extraction tower top temperature is 85 °C, and the tower bottom temperature is 65 °C. After two-phase separation, low-aromatic oil and aromatic extraction liquid are obtained. The low-aromatic oil is used as the hydrotreating raw material, and its properties are shown in Table 3.

[0141] The second step is hydrotreating

[0142] The low-aromatic oil is subjected to hydrotreating using a hydrotreating catalyst to obtain a hydrotreated product oil. The hydrotreating conditions are as follows: hydrogen partial pressure is 14.0 MPa; reaction temperature is 380 °C; volumetric space velocity is 0.7 h -1 ; The hydrogen-oil volume ratio is 1500:1.

[0143] The third step is isomerization and dewaxing

[0144] The hydrotreated product oil is subjected to isomerization dewaxing refining using an isomerization dewaxing catalyst to obtain an isomerization dewaxing product oil. The isomerization dewaxing conditions are as follows: hydrogen partial pressure of 14.0 MPa; reaction temperature of 350 °C; volumetric space velocity of 1.50 h -1 ; hydrogen-to-oil volume ratio of 1000:1.

[0145] Step 4, hydrofining

[0146] The isomerization dewaxing product oil is subjected to hydrofining using a hydrofining catalyst to obtain a hydrofined product oil. The hydrofining conditions are as follows: hydrogen partial pressure of 14.0 MPa; reaction temperature of 230 °C; volumetric space velocity of 1.5 h -1 ; hydrogen-to-oil volume ratio of 1000:1.

[0147] Step 5, gas-liquid separation and fractionation

[0148] The hydrofined product oil enters a gas-liquid separator for gas-liquid separation. The separated liquid phase enters a fractionating column for fractionation, and the fraction at 350 °C to 460 °C is collected to obtain naphthenic base white oil, and its properties are shown in Table 4-2.

[0149] Comparative Example 4

[0150] The naphthenic base fraction oil, hydrotreating catalyst, isomerization dewaxing catalyst, and hydrofining catalyst in this comparative example are the same as those in Example 11. This naphthenic base white oil is prepared by the following steps:

[0151] Step 1, hydrotreating

[0152] The raw material oil, naphthenic base fraction oil, is subjected to hydrotreating using a hydrotreating catalyst to obtain a hydrotreated product oil. The hydrotreating conditions are as follows: hydrogen partial pressure of 17.0 MPa; reaction temperature of 410 °C; volumetric space velocity of 0.4 h -1 ; hydrogen-to-oil volume ratio of 2500:1.

[0153] Step 2, isomerization dewaxing

[0154] The hydrotreated product oil is subjected to isomerization dewaxing refining using an isomerization dewaxing catalyst to obtain an isomerization dewaxing product oil. The isomerization dewaxing conditions are as follows: hydrogen partial pressure of 17.0 MPa; reaction temperature of 360 °C; volumetric space velocity of 1.0 h -1 ; hydrogen-to-oil volume ratio of 2000:1.

[0155] Step 3, hydrofining

[0156] The isomerization dewaxing product oil is subjected to hydrofining using a hydrofining catalyst to obtain a hydrofined product oil. The hydrofining conditions are as follows: hydrogen partial pressure of 17.0 MPa; reaction temperature of 280 °C; volumetric space velocity of 1.0 h -1 ; hydrogen-to-oil volume ratio of 1000:1.

[0157] Step 4: Gas-liquid separation and fractionation

[0158] The hydrogenated refined product oil enters a gas-liquid separator for gas-liquid separation. The separated liquid phase enters a fractionating column for fractionation, and the fraction at 350°C to 460°C is collected to obtain naphthenic base white oil, and its properties are shown in Table 4-2.

[0159] Comparative Example 5: Domestic paraffin base white oil 1, and its properties are shown in Table 4-2.

[0160] Comparative Example 6: Domestic paraffin base white oil 2, and its properties are shown in Table 4-2.

[0161] In the present invention, the property tests of the naphthenic base white oil for SEBS obtained in Examples 11 to 15 and the naphthenic base white oils in Comparative Examples 1 to 6 are carried out with reference to the ASTM series standards of the American Society for Testing and Materials.

[0162] The naphthenic base white oil for SEBS prepared in Examples 11 and 13 and the white oils in Comparative Examples 1 to 6 are respectively used to fill SEBS rubber, and the properties of the obtained SEBS oil-extended rubber such as yellowing resistance, processing yield, elasticity, resistance to deformation, oil leakage rate, etc. are evaluated. The evaluation results are shown in Table 5. It can be seen from Tables 4-1, 4-2 and Table 5 that for the domestic paraffin base white oil 1 in Comparative Example 5 and the domestic paraffin base white oil 2 in Comparative Example 6, the oil-extended rubber filled with them has excellent structural elasticity and excellent resistance to deformation. However, due to its too low naphthene content and poor fluidity, the oil-extended rubber filled with it is prone to generate more bubbles in the mold, forming defective products, and the processing yield is relatively low. For the naphthenic base white oils obtained in Comparative Examples 1 to 4, due to their too high naphthene content (greater than 70%), the structural support force of the oil-extended rubber filled with them is poor, the resistance to deformation is poor, and the product is not easy to be formed. The naphthenic base white oil for SEBS obtained in Examples 11 and 13 of the present invention has appropriate kinematic viscosity, viscosity index greater than 70, and naphthene content between 60% and 70%. The oil-extended rubber filled with it has the characteristics of sufficient oil absorption, no oil leakage, yellowing resistance, good elasticity of the oil-extended rubber products, strong anti-deformation ability, good tensile strength, easy to be formed, high yield, etc.

[0163] In summary, the present invention provides a naphthenic base white oil for SEBS, which has high product quality, high viscosity index, and a certain naphthene content, and can be used as a rubber softening filling oil for special SEBS products. The present invention uses naphthenic fraction oil as the raw material and adopts a centrifugal extraction refining - hydrogenation combined process to prepare the naphthenic base white oil for SEBS. The preparation method has a simple process, is easy to control and implement, and is suitable for large-scale industrial production.

[0164] The above technical features constitute the embodiments of the present invention, which have strong adaptability and implementation effects. Non-essential technical features can be increased or decreased according to actual needs to meet the requirements of different situations.

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Claims

1. A naphthenic white oil special for SEBS, characterized in that Obtained by the following method: First step: Using naphthenic fraction oil as the feedstock, after centrifugal extraction of the feedstock together with the extraction solvent, aromatics and polar compounds in the feedstock are removed. After the extraction is completed, the low-aromatic oil and the aromatic extraction liquid are separated to obtain the low-aromatic oil; Second step: Using a hydrotreating catalyst to hydrotreat the low-aromatic oil obtained in the first step to obtain a hydrotreated product oil; Third step: Using an isomerization and dewaxing catalyst to carry out isomerization and dewaxing on the hydrotreated product oil to obtain an isomerized and dewaxed product oil; Fourth step: Using a hydrofining catalyst to hydrofine the isomerized and dewaxed product oil to obtain a hydrofined product oil; Fifth step: Carry out gas-liquid separation on the hydrofined product oil, fractionate the separated liquid phase, and collect the fraction with a distillation range of 300°C to 500°C to obtain the SEBS-special naphthenic white oil product; In the first step, the naphthenic fraction oil is a vacuum distillation fraction oil with a distillation range of 300°C to 500°C; the centrifugal extraction is completed by a centrifugal extractor, and the centrifugal extractor is a multi-stage annular-gap centrifugal extractor. The centrifugal extraction conditions are: the number of extraction stages is 5 to 20, the inlet temperature of the feedstock oil is 40 to 100°C, the temperature of the extraction solvent is 60 to 120°C, the rotation speed is 2000 to 5000 rpm, and the contact time for each stage is 10 to 20 min.

2. The SEBS special naphthenic white oil according to claim 1, wherein In the first step, the extraction solvent is one or more of furfural, phenol, and N-methylpyrrolidone, and the mass ratio of the extraction solvent to the feedstock oil is 0.3:1 to 7.0:

1.

3. The SEBS-special naphthenic white oil according to claim 1 or 2, characterized in that In the second step, the hydrotreating conditions are as follows: hydrogen partial pressure is from 10.0 MPa to 22.0 MPa, reaction temperature is from 280 °C to 390 °C, volumetric space velocity is from 0.2 h -1 to 1.5 h -1 , hydrogen-oil volume ratio is from 1000:1 to 3000:1; the carrier of the hydrotreating catalyst is alumina, and the active components of the hydrotreating catalyst are tungsten oxide, molybdenum oxide and nickel oxide.

4. The SEBS special naphthenic white oil according to claim 3, characterized in that In the second step, the hydrotreating conditions are as follows: hydrogen partial pressure is 13.0 MPa to 20.0 MPa; reaction temperature is 300 °C to 380 °C; volumetric space velocity is 0.3 h -1 to 0.5 h -1 ; hydrogen-to-oil volume ratio is 1500:1 to 2500:

1.

5. The SEBS special naphthenic white oil according to claim 1 or 2, characterized in that In the third step, the conditions for isomerization and dewaxing are as follows: hydrogen partial pressure is 10.0 MPa to 22.0 MPa, reaction temperature is 250 °C to 400 °C, volumetric space velocity is 0.3 h -1 to 2.0 h -1 , hydrogen-oil volume ratio is 500:1 to 3000:1; the carrier of the isomerization and dewaxing catalyst is molecular sieve, and the active ingredient is platinum oxide or palladium oxide.

6. The SEBS-special naphthenic white oil according to claim 5, characterized in that In the third step, the conditions for isomerization and dewaxing are as follows: hydrogen partial pressure is 14.0 MPa to 20.0 MPa; reaction temperature is 280 °C to 370 °C; volumetric space velocity is 0.5 h -1 to 1.0 h -1 ; hydrogen-to-oil volume ratio is 1500:1 to 2000:

1.

7. The special naphthenic white oil for SEBS according to claim 1 or 2, characterized in that In the fourth step, the conditions for hydrofining are as follows: hydrogen partial pressure is 10.0 MPa to 22.0 MPa, reaction temperature is 200 °C to 300 °C, volumetric space velocity is 1.0 h -1 to 3.0 h -1 , hydrogen-oil volume ratio is 500:1 to 3000:1; the carrier of the hydrofining catalyst is molecular sieve, and the active components are platinum oxide and palladium oxide.

8. The SEBS special naphthenic white oil according to claim 7, wherein The conditions for hydrofining are as follows: hydrogen partial pressure is from 14.0 MPa to 20.0 MPa; reaction temperature is from 200 °C to 250 °C; volume space velocity is from 2.0 h -1 to 2.5 h -1 ; hydrogen-to-oil volume ratio is from 500:1 to 1000:

1.

9. A method for preparing the SEBS-special naphthenic white oil according to any one of claims 2 to 8, characterized in that Carried out according to the following steps: First step: Using naphthenic fraction oil as the feedstock, after centrifugal extraction of the feedstock together with the extraction solvent, aromatics and polar compounds in the feedstock are removed. After the extraction is completed, the low-aromatic oil and the aromatic extraction liquid are separated to obtain the low-aromatic oil; Second step: Using a hydrotreating catalyst to hydrotreat the low-aromatic oil obtained in the first step to obtain a hydrotreated product oil; Third step: Using an isomerization and dewaxing catalyst to carry out isomerization and dewaxing on the hydrotreated product oil to obtain an isomerized and dewaxed product oil; Fourth step: Using a hydrofining catalyst to hydrofine the isomerized and dewaxed product oil to obtain a hydrofined product oil; Fifth step: Carry out gas-liquid separation on the hydrofined product oil, fractionate the separated liquid phase, and collect the fraction with a distillation range of 300°C to 500°C to obtain the SEBS-special naphthenic white oil product; In the first step, the naphthenic fraction oil is a vacuum distillation fraction oil with a distillation range of 300°C to 500°C; the centrifugal extraction is completed by a centrifugal extractor, and the centrifugal extractor is a multi-stage annular-gap centrifugal extractor. The centrifugal extraction conditions are: the number of extraction stages is 5 to 20, the inlet temperature of the feedstock oil is 40 to 100°C, the temperature of the extraction solvent is 60 to 120°C, the rotation speed is 2000 to 5000 rpm, and the contact time for each stage is 10 to 20 min.

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