A combined method for producing industrial white oil

Abstract

A combined method for producing industrial white oil involves the following steps: Feedstock oil is reacted in a hydrocracking unit; the resulting light diesel oil fraction is solvent-extracted to obtain raffinate and extract oil; the raffinate is mixed with the heavy diesel oil fraction from the hydrocracking unit to obtain the industrial white oil product; and the extract oil undergoes an aromatics lightening reaction to obtain a C6-C8 fraction rich in BTX. The method provided by this invention utilizes relatively mild hydrocracking conditions, fully leverages aromatic resources, and produces both qualified industrial white oil and high-quality BTX feedstock, resulting in high economic efficiency.

Description

Technical Field

[0001] This invention relates to the field of hydrocarbon feedstock processing technology, and specifically to a combined method for producing industrial white oil. Background Technology

[0002] White oil is a type of colorless, odorless, and chemically stable petroleum product obtained through deep refining to remove unsaturated hydrocarbons and non-hydrocarbon impurities from lubricating oil fractions. Depending on its application and degree of refining, it can be classified into industrial grade, cosmetic grade, food grade, and pharmaceutical grade white oil. Food grade and pharmaceutical grade white oils are the most refined.

[0003] The production of white oil mainly involves removing sulfur, nitrogen, aromatics, and other impurities from base oil. Hydrogenation is a popular method for producing white oil due to its advantages, including being pollution-free, having high yields, a wide range of raw material sources, producing a complete range of products, and being able to process high-viscosity white oil. However, because white oil products have strict requirements regarding aromatic content, the hydrogenation of aromatics is limited by thermodynamic equilibrium and cannot be carried out at high temperatures. Therefore, using non-precious metal hydrorefining catalysts for white oil production requires higher pressures and also places certain demands on the raw materials. Hydrocracking processes are characterized by high pressure levels and low aromatic content in the product. Hydrocracking units with good feedstock properties and high pressure levels can generally produce industrial white oil. Medium-pressure hydrocracking units, especially those with relatively poor feedstock, generally cannot directly produce industrial white oil.

[0004] CN1362486A discloses a method for producing food-grade white oil via hydrogenation. Its key feature is the use of a layered catalyst system in the conventional hydrogenation process for producing white oil. This layered catalyst system consists of a desulfurizing agent and a reduced nickel catalyst. The process conditions are: pressure 8.0 MPa–20.0 MPa, reaction temperature 150°C–300°C, and volume hourly space velocity (VHSV) 0.1. -1 ~1.5h -1 The hydrogen-to-oil volume ratio is 100–1500. This method requires that the aromatic content in the feedstock not exceed 10% by mass, the sulfur content be less than 50 ppm, preferably less than 30 ppm, and the nitrogen content be less than 10 ppm, preferably less than 5 ppm.

[0005] CN1075547C discloses a method for producing industrial white oil, employing a single-stage high-pressure hydrogenation process, using a viscosity of 5-45 mm at 40°C. 2 Using lubricating oil base oil or distillate oil with an aromatic content of <30wt% as raw material, the mixture is processed at a temperature of 200–370℃, a pressure of 10–30MPa, and a volumetric hourly space velocity of 0.1–2.0h / s. -1 The hydrogenation catalyst used has a pore volume of 0.2–0.6 ml / g, a pore size of 1.0–10.0 nm, and a specific surface area of ​​150–200 m² / g. 2 / g. This invention specifies that the raw material is hydrotreated tail oil, lubricating oil base oil, or distillate oil, and requires the raw material viscosity range to be 5–50 mm. 2 / s (40℃), sulfur content <1000mg / kg, aromatic content <30wt%.

[0006] CN111378504A discloses a method for the harmless refining of coal-derived white oil. The method involves first subjecting crude coal-derived white oil to atmospheric and vacuum distillation, followed by catalytic hydrogenation to obtain a hydrogenated product. This hydrogenated product is then subjected to a refining reaction under the action of a catalyst after heat exchange. The reaction products are cooled and separated to recover solid waste residue, and the gaseous product is condensed to obtain refined white oil. The catalytic hydrogenation reaction temperature is 350-370℃, the pressure is 15-22 MPa, and the mass hourly space velocity (HHSV) is 0.8 h⁻¹. -1 ~2h -1 The hydrogen-to-oil ratio is 650–850; the hydrorefining reaction temperature is 160–260℃, the mass hourly space velocity is 2.5 h⁻¹–3.0 h⁻¹, the pressure is 15–22 MPa, and the hydrogen-to-oil ratio is 200–600. The product from the refining reaction is then subjected to a gasification reaction at a temperature of 1000–1800℃ and a pressure of 0.5–4 MPa to obtain gaseous products and liquid waste residue; the gaseous products are then liquefied to obtain refined white oil.

[0007] It is evident that the current production of white oil mainly relies on the hydrogenation method, which has problems such as high requirements for raw materials, and harsh processes, catalysts, and operating conditions. Moreover, when the operating conditions are harsh, most of the aromatics in the raw materials are saturated, resulting in a low utilization rate of aromatic resources while consuming a large amount of hydrogen. Summary of the Invention

[0008] The present invention aims to solve the problems in the production of industrial white oil in the prior art, such as high requirements for raw materials, stringent requirements for production processes and catalysts, and low utilization rate of aromatic resources.

[0009] This invention provides a method for producing industrial white oil, comprising:

[0010] (1) The feedstock enters the hydrocracking unit and reacts sequentially with the hydrorefining catalyst and the hydrocracking catalyst in the presence of hydrogen. The reaction effluent is separated to obtain at least naphtha fraction, kerosene fraction, light diesel oil fraction, heavy diesel oil fraction, and optional tail oil fraction.

[0011] The distillation range of the obtained light diesel fraction is 220–265℃.

[0012] The feedstock oil is selected from one or a mixture of several of atmospheric pressure wax oil, vacuum pressure wax oil, coking wax oil, deasphalted oil, catalytic diesel oil, coking diesel oil, and straight-run diesel oil;

[0013] (2) The light diesel oil fraction obtained in step (1) enters the extraction unit, comes into contact with the extraction solvent, and is separated to obtain raffinate oil and extracted oil. The extraction solvent is an alkylcyclobutane sulfone with a boiling point higher than 280°C.

[0014] (3) The raffinate obtained in step (2) is mixed with the heavy diesel fraction obtained in step (1) to obtain industrial white oil product.

[0015] (4) The extracted oil obtained in step (2) enters the aromatics lightening unit, reacts with the lightening catalyst in the presence of hydrogen, and the reaction effluent is separated to obtain C6-C8 fractions rich in BTX.

[0016] In one embodiment of the present invention, the reaction conditions of the hydrocracking unit in step (1) are: hydrogen partial pressure of 6.0 MPa to 12.0 MPa, reaction temperature of 300°C to 450°C, and hydrogen-to-oil volume ratio of 500 to 2000 Nm. 3 / m 3 The liquid hourly space velocity (LHSV) is 0.1 h⁻¹. -1 ~3.0h -1 .

[0017] In one embodiment of the present invention, the hydrocracking unit in step (1) includes one or more fixed-bed hydrocracking reactors, in which the feed oil passes sequentially through a hydrorefining catalyst and a hydrocracking catalyst in the direction of the feed stream, and the loading volume ratio of the hydrorefining catalyst and the hydrocracking catalyst is 1:5 to 5:1.

[0018] In one embodiment of the invention, based on oxides and a hydrorefining catalyst, the hydrorefining catalyst contains a support and a group VIII metal element supported on the support in an amount of 1 to 10 wt% and / or a group VIB metal element in an amount of 10 to 45 wt%, wherein the group VIII metal element is cobalt and / or nickel, and the group VIB metal element is molybdenum and / or tungsten, and the support is at least one of alumina, silicon oxide, and alumina-silicon oxide.

[0019] In one embodiment of the present invention, the hydrocracking catalyst comprises a support and a Group VIII metal element and / or a Group VIB metal element supported on the support, the support being composed of alumina and a molecular sieve, the molecular sieve being a Y-type molecular sieve and / or a β-type molecular sieve, the Group VIII metal element being cobalt and / or nickel, and the Group VIB metal element being molybdenum and / or tungsten.

[0020] Based on the overall composition of the hydrocracking catalyst, and calculated by oxides, the hydrocracking catalyst composition is as follows: 30%–72% alumina, 1%–30% molecular sieve, 15%–35% Group VIB metals, and 2%–8% Group VIII metals.

[0021] In one embodiment of the present invention, the feedstock oil undergoes hydrocracking in a hydrocracking unit. The reaction effluent is separated into a gaseous stream and a liquid stream. The resulting liquid stream is fractionated to obtain light naphtha fraction, heavy naphtha fraction, kerosene fraction, light diesel oil fraction, heavy diesel oil fraction, and optional tail oil fraction. The heavy naphtha fraction has a final boiling point of 140–175°C, the kerosene fraction has a final boiling point of 220–235°C, the light diesel oil fraction has a final boiling point of 255–265°C, the heavy diesel oil fraction has a final boiling point of 330–350°C, and the tail oil fraction is a fraction higher than heavy diesel oil.

[0022] In this invention, "optional" means selective. For example, when the feedstock is only one or more of catalytic diesel, coking diesel, and straight-run diesel, the liquid phase product may not contain tail oil fraction.

[0023] In this invention, a light diesel oil fraction is sent to an extraction unit, where it is extracted in an extraction tower by contacting an extraction solvent to obtain an aromatic-rich extracted oil and a raffinate oil. The extraction solvent used in this invention is an alkylcyclobutane sulfone with a boiling point higher than 280°C.

[0024] In a preferred embodiment, the extraction solvent is 3-methylcyclobutane sulfone and / or 2,4-dimethylcyclobutane sulfone. This invention, tailored to the characteristics of light diesel oil fractions, optimizes the extraction solvent to effectively extract aromatics from the fractions, improving extraction efficiency. This results in industrial white oil components with lower aromatic content and allows for more efficient utilization of the enriched aromatic resources.

[0025] In one embodiment of the present invention, the extraction solvent contains 0.5% to 3.0% by mass of water.

[0026] In one embodiment of the present invention, the temperature of the extraction solvent entering the extraction tower is 60°C to 180°C, preferably 90°C to 140°C; the pressure of the extraction tower is 0.2MPa to 0.8MPa absolute pressure; and the mass ratio of the extraction solvent to the extraction feed (light diesel fraction) is 3:1 to 7:1.

[0027] In one embodiment of the present invention, the light diesel oil fraction enters the extraction tower from the bottom and is extracted by countercurrent contact with the extraction solvent. Raffinate is obtained at the top of the tower and extract oil rich in extraction solvent is obtained at the bottom of the tower.

[0028] In one embodiment of the present invention, the raffinate oil is fed into a water washing tower for washing, and the resulting raffinate oil wash water is then heated and enters the lower part of a solvent recovery tower.

[0029] In one embodiment of the present invention, the extracted oil rich in extraction solvent enters a solvent recovery tower. A portion of the overhead stream from the solvent recovery tower is refluxed back to the solvent recovery tower, while the remaining portion, consisting of extracted oil, is sent to the aromatics lightening unit. The water obtained from the separation of the overhead stream from the solvent recovery tower is used as wash water and enters the upper part of the wash tower. The bottom stream from the solvent recovery tower is the recovered solvent, which is recycled back to the extraction tower.

[0030] The mass ratio of washing water to residual oil is 0.1 to 0.5, preferably 0.1 to 0.3; the pressure at the top of the washing tower is 0.4 MPa to 0.7 MPa absolute pressure; and the washing temperature is 30℃ to 50℃.

[0031] The theoretical plate number of the solvent recovery tower is 5 to 30, the reflux ratio is 0.3 to 1.0, the top pressure is 0.05 MPa to 0.15 MPa absolute pressure, and the bottom temperature is 150℃ to 200℃.

[0032] In this invention, the raffinate obtained in step (2) is mixed with the heavy diesel oil fraction obtained in step (1) to obtain an industrial white oil product. The aromatic mass fraction of the obtained industrial white oil product is less than or equal to 5%, the sulfur content is less than or equal to 10 mg / kg, and other indicators meet the requirements of the No. 5 white oil product of the Industrial White Oil (I) Class Standard (SH / T0006-2017).

[0033] In this invention, the extracted oil obtained in step (2) is sent to the aromatics lightening unit in step (4) for aromatics lightening reaction.

[0034] In one embodiment of the present invention, the reaction conditions of the aromatic hydrocarbon lightening unit are: reaction temperature of 350°C to 450°C, reaction pressure of 0.5 to 3.5 MPa, and volume hourly space velocity of 1 h⁻¹. -1 ~5h -1 The hydrogen-to-oil volume ratio is 500–1200.

[0035] In one embodiment of the present invention, the lightening catalyst is a catalyst containing ZSM-5 zeolite, alumina and a Class VIII noble metal, the catalyst having the following composition based on the support: 30% to 70% by mass of ZSM-5 zeolite and 30% to 70% by mass of γ- or η-Al2O3 as the support, and loaded with (1) 0.1% to 0.5% by mass of Re, 0.1% to 0.5% by mass of Sn and 0.05% to 0.3% by mass of Pt, or (2) 0.1% to 0.5% by mass of Re, 0.1% to 0.5% by mass of Sn and 0.2% to 0.8% by mass of Pd.

[0036] In one embodiment of the present invention, the aromatic hydrocarbon lightening reaction product is separated, and the resulting C6-C8 fraction rich in BTX is sent to the BTX extraction unit as a high-quality aromatic hydrocarbon extraction feedstock, while the remaining C9+ fraction is sent to the coking unit for utilization.

[0037] Features of this invention:

[0038] (1) The method provided by the present invention has relatively mild hydrogenation conditions, makes full use of aromatic resources, produces qualified industrial white oil products, and obtains high-quality BTX raw materials, which is highly economical.

[0039] (2) The preferred extraction solvent of the present invention has good selectivity for aromatics, is easy to recover, and has low operating costs. Attached Figure Description

[0040] Figure 1 This is a schematic diagram of one embodiment of the method for producing industrial white oil provided by the present invention. Detailed Implementation

[0041] The present invention will be further described below with reference to the accompanying drawings, but this description does not limit the scope of the invention.

[0042] Figure 1 This is a schematic diagram of one embodiment of the method for producing industrial white oil provided by the present invention. Figure 1As shown, in the hydrocracking unit, the feedstock oil is mixed with hydrogen-rich gas from pipeline 2 via pipeline 1 and then enters the hydrorefining reactor 101 to react with the hydrorefining catalyst. The resulting hydrorefining effluent enters the hydrocracking reactor 102 via pipeline 3 to react with the hydrocracking catalyst. The hydrocracking reactor effluent enters the separator 103 via pipeline 4 for gas-liquid separation. The resulting gas phase enters the compressor 104 via pipeline 6 for pressurization and is mixed with supplemental hydrogen to form a hydrogen-rich gas. The resulting oil phase enters the fractionation tower 105 via pipeline 5 for fractionation, obtaining light naphtha fraction, heavy naphtha fraction, kerosene fraction, light diesel fraction, heavy diesel fraction, and tail oil fraction, which are extracted via pipelines 7, 8, 9, 10, 11, and 12, respectively. The light diesel oil fraction enters the lower part of the extraction tower 106 in the extraction unit via pipeline 10, while the lean solvent (recovered solvent) enters the upper part of the extraction tower 106 via pipeline 13. The two solvents are in countercurrent contact for extraction. The extracted oil (rich solvent) obtained at the bottom of the extraction tower 106, rich in extraction solvent, enters the middle part of the recovery tower 107 via pipeline 14. The extracted oil obtained at the top of the recovery tower 107 is condensed via pipeline 15 and enters the reflux tank. After water separation in the reflux tank, part of the extracted oil is returned to the recovery tower 107 via pipeline 16, and the remainder enters the aromatics lightening unit 109 via pipeline 17. The water separated from the water tank in the reflux tank is used as washing water and enters the upper part of the washing tower 108 via pipeline 18. The recovered solvent (lean solvent) obtained at the bottom of the recovery tower 107 is returned to the upper part of the extraction tower 106 via pipeline 13 after heat exchange. The raffinate from the top of extraction tower 106 enters the lower part of water washing tower 108 via pipeline 19. After washing, the raffinate (low-aromatic light diesel fraction) is mixed with the heavy diesel fraction from pipeline 11 via pipeline 20 to obtain industrial white oil product, which is then discharged from the unit via pipeline 23. The washing water at the bottom of water washing tower 108, after heat exchange, enters the lower part of recovery tower 107 via pipeline 21. The extracted oil from pipeline 17 enters the aromatics lightening unit 109 for aromatics lightening reaction. The BTX-rich C6-C8 fraction obtained from the reaction product is sent to the BTX extraction unit via pipeline 22.

[0043] The present invention will be further described below with reference to embodiments, but this does not limit the present invention in any way.

[0044] The commercially available hydrorefining catalysts used in the examples and comparative examples are RN-410 and RN-32V, and the commercially available hydrocracking catalysts are RHC-131 and RHC-220, both produced by Changling Catalyst Plant of Sinopec Catalyst Branch.

[0045] The raw materials used in the examples and comparative examples are shown in Table 1, wherein raw material A is catalytic diesel oil, raw material B is straight-run wax oil, raw material C is coking wax oil, and raw material D is straight-run diesel oil.

[0046] In this invention, the relevant calculation formulas in the embodiments and comparative examples are as follows:

[0047]

[0048]

[0049]

[0050] Example 1

[0051] This embodiment uses raw material oil B, according to... Figure 1 The process flow is as follows:

[0052] (1) The feedstock enters the hydrocracking unit, where it reacts sequentially with the hydrorefining catalyst and the hydrocracking catalyst in the presence of hydrogen. The reaction effluents are separated to obtain light naphtha fraction, heavy naphtha fraction, kerosene fraction, light diesel oil fraction, heavy diesel oil fraction, and tail oil fraction.

[0053] (2) The light diesel oil fraction obtained in step (1) enters the extraction unit and comes into countercurrent contact with the extraction solvent to obtain raffinate oil and extract oil rich in extraction solvent. The raffinate oil is washed in a water washing tower. The water obtained after washing the raffinate oil enters the lower part of the solvent recovery tower after heat exchange. The extract oil rich in extraction solvent enters the solvent recovery tower. Part of the top stream of the solvent recovery tower is returned to the solvent recovery tower, and the remaining part is the extract oil sent to the aromatics lightening unit. The water obtained from the separation of the top stream of the solvent recovery tower enters the upper part of the water washing tower as washing water. The bottom stream of the solvent recovery tower is the recovered solvent, which is recycled to the extraction tower.

[0054] (3) The raffinate obtained in step (2) is mixed with the heavy diesel fraction obtained in step (1) to obtain industrial white oil product.

[0055] (4) The extracted oil obtained in step (2) enters the aromatics lightening unit, reacts with the lightening catalyst in the presence of hydrogen, and the reaction effluent is separated to obtain C6-C8 fractions rich in BTX.

[0056] The grades or compositions of the hydrorefining catalyst, hydrocracking catalyst, and lightening catalyst are shown in Table 2. The operating conditions of each tower in the hydrorefining reactor, hydrocracking reactor, lightening reactor, and extraction unit are shown in Table 3. The extraction solvent used is 3-methylcyclobutanesulfone, and the mass fraction of water in the extraction solvent is 0.9%. The properties of the products from the hydrocracking unit are shown in Table 4. The properties of the raffinate oil and the industrial white oil obtained by mixing the raffinate oil with the hydrocracking heavy diesel oil fraction are shown in Table 5. The properties of the extracted oil and the lightening product oil obtained by the lightening reaction of the extracted oil are shown in Table 6.

[0057] Example 2

[0058] This embodiment uses a mixture of raw material A (20% by mass) and raw material B (80% by mass), according to... Figure 1 The process flow is used for processing.

[0059] The grades or compositions of the hydrorefining catalyst, hydrocracking catalyst, and lightening catalyst are shown in Table 2. The operating conditions of each tower in the hydrorefining reactor, hydrocracking reactor, lightening reactor, and extraction unit are shown in Table 3. The extraction solvent used is 2,4-dimethylcyclobutanesulfone, and the mass fraction of water in the extraction solvent is 0.9%. The properties of the products from the hydrocracking unit are shown in Table 4. The properties of the raffinate oil and the industrial white oil obtained by mixing the raffinate oil with the hydrocracking heavy diesel oil fraction are shown in Table 5. The properties of the extracted oil and the lightening product oil obtained by the lightening reaction of the extracted oil are shown in Table 6.

[0060] Example 3

[0061] This embodiment uses a mixture of raw material oil B (85% by mass) and raw material oil C (15% by mass), according to... Figure 1 The process flow is used for processing.

[0062] The grades or compositions of the hydrorefining catalyst, hydrocracking catalyst, and lightening catalyst are shown in Table 2. The operating conditions of each tower in the hydrorefining reactor, hydrocracking reactor, lightening reactor, and extraction unit are shown in Table 3. The extraction solvent used is 3-methylcyclobutanesulfone, and the mass fraction of water in the extraction solvent is 1.5%. The properties of the products from the hydrocracking unit are shown in Table 4. The properties of the raffinate oil and the industrial white oil obtained by mixing the raffinate oil with the hydrocracking heavy diesel oil fraction are shown in Table 5. The properties of the extracted oil and the lightening product oil obtained by the lightening reaction of the extracted oil are shown in Table 6.

[0063] Example 4

[0064] This embodiment uses a mixture of raw material A (70% by mass) and raw material D (30% by mass), according to... Figure 1 The process flow is used for processing.

[0065] The grades or compositions of the hydrorefining catalyst, hydrocracking catalyst, and lightening catalyst are shown in Table 2. The operating conditions of each tower in the hydrorefining reactor, hydrocracking reactor, lightening reactor, and extraction unit are shown in Table 3. The extraction solvent used is 3-methylcyclobutanesulfone, and the mass fraction of water in the extraction solvent is 1.5%. The properties of the products from the hydrocracking unit are shown in Table 4. The properties of the raffinate oil and the industrial white oil obtained by mixing the raffinate oil with the hydrocracking heavy diesel oil fraction are shown in Table 5. The properties of the extracted oil and the lightening product oil obtained by the lightening reaction of the extracted oil are shown in Table 6.

[0066] Comparative Example 1

[0067] Using the same feedstock as in Example 1, the feedstock entered the hydrocracking unit and, in the presence of hydrogen, reacted sequentially with the hydrorefining catalyst and the hydrocracking catalyst. The reaction effluent was separated to obtain light naphtha fraction, heavy naphtha fraction, kerosene fraction, light diesel fraction, heavy diesel fraction, and tail oil fraction. The hydrocracking unit used the same catalyst and process parameters as the hydrocracking unit in Example 1, as detailed in Table 7. In this comparative example, the light diesel fraction and the heavy diesel fraction were directly mixed, and the properties of the resulting mixed diesel product are shown in Table 7.

[0068] Comparative Example 2

[0069] Using the same feedstock as in Example 2, the fuel oil was fed into the hydrocracking unit for hydrocracking. The reaction effluent was separated to obtain light naphtha fraction, heavy naphtha fraction, kerosene fraction, light diesel oil fraction, heavy diesel oil fraction, and tail oil fraction. The hydrocracking unit used the same catalyst and process parameters as the hydrocracking unit in Example 2, as detailed in Table 7. In this comparative example, the light diesel oil fraction and the heavy diesel oil fraction were directly mixed, and the properties of the resulting mixed diesel product are shown in Table 7.

[0070] As can be seen from the examples and comparative examples, processing inferior feedstocks under medium-pressure hydrocracking conditions cannot directly yield industrial white oil products with an aromatic hydrocarbon content of less than 5% by mass.

[0071] Comparative Example 3

[0072] The same feedstock, process flow, catalyst, and hydrocracking and lightening reaction conditions as in Example 1 were used. The difference was that sulfolane with a water content of 1% by mass was selected as the extraction solvent. The properties of the obtained raffinate oil and the mixed diesel product obtained by mixing the raffinate oil with the hydrocracking heavy diesel fraction are shown in Table 5. The properties of the obtained extract oil and the lightening product oil obtained by the lightening reaction of the extract oil are shown in Table 6.

[0073] As can be seen from Table 5, the aromatic content in the raffinate of this comparative example is as high as 7.8% by mass, and the aromatic content of the mixed diesel product obtained after mixing with the hydrocracking heavy diesel fraction is 6.7% by mass, which cannot meet the quality requirements of industrial white oil products.

[0074] Table 1

[0075]

[0076]

[0077] Table 2

[0078]

[0079]

[0080] Table 3

[0081]

[0082]

[0083] Table 4

[0084]

[0085]

[0086] Table 5

[0087]

[0088] Table 6

[0089]

[0090]

[0091] Table 7

[0092] project Comparative Example 1 Comparative Example 2 Blended diesel products Aromatic hydrocarbon content, mass % 8.3 11.4 <![CDATA[Kinematic viscosity (40 °C) / (mm 2 / s)]]> 4.58 4.22 Sulfur, μg / g <1 <1 Open flash point / °C 128 132 Distillation range / ℃ 223～349 229～353 Blended diesel product quality yield, % 27.5 28.5

Claims

1. A method for producing industrial white oil, comprising: (1) The feedstock enters the hydrocracking unit, where it reacts sequentially with the hydrorefining catalyst and the hydrocracking catalyst in the presence of hydrogen. The reaction effluent is separated to obtain at least naphtha fraction, kerosene fraction, light diesel oil fraction, heavy diesel oil fraction, and tail oil fraction. The distillation range of the obtained light diesel fraction is 220–265℃. The feedstock oil is selected from one or a mixture of several of atmospheric pressure wax oil, vacuum pressure wax oil, coking wax oil, deasphalted oil, catalytic diesel oil, coking diesel oil, and straight-run diesel oil; (2) The light diesel oil fraction obtained in step (1) enters the extraction unit, contacts the extraction solvent, and is separated to obtain raffinate oil and extracted oil. The main solvent of the extraction solvent is 3-methylcyclobutane sulfone and / or 2,4-dimethylcyclobutane sulfone, and the extraction solvent contains 0.5% to 3.0% by mass of water. (3) The raffinate obtained in step (2) is mixed with the heavy diesel fraction obtained in step (1) to obtain industrial white oil product. (4) The extracted oil obtained in step (2) enters the aromatics lightening unit and reacts with the lightening catalyst in the presence of hydrogen. The reaction effluent is separated to obtain C6-C8 fractions rich in BTX. The reaction conditions of the aromatics lightening unit are: reaction temperature of 350℃-450℃, reaction pressure of 0.5-3.5MPa, and volume hourly space velocity of 1h. -1 ~5h -1 The hydrogen-to-oil volume ratio is 500–1200; The lightening catalyst is a catalyst containing ZSM-5 zeolite, alumina and a Group VIII noble metal, and has the following composition based on the support: 30% to 70% by mass of ZSM-5 zeolite and 30% to 70% by mass of γ- or η-Al2O3 as the support, and loaded with (1) 0.1% to 0.5% by mass of Re, 0.1% to 0.5% by mass of Sn and 0.05% to 0.3% by mass of Pt, or (2) 0.1% to 0.5% by mass of Re, 0.1% to 0.5% by mass of Sn and 0.2% to 0.8% by mass of Pd.

2. The method according to claim 1, characterized in that, The reaction conditions for the hydrocracking unit in step (1) are: hydrogen partial pressure of 6.0 MPa to 12.0 MPa, reaction temperature of 300℃ to 450℃, and hydrogen-to-oil volume ratio of 500 to 2000 Nm. 3 / m 3 The liquid hourly space velocity (LHSV) is 0.1 h⁻¹. -1 ~3.0h -1 .

3. The method according to claim 1, characterized in that, In the hydrocracking unit of step (1), the loading volume ratio of the hydrorefining catalyst and the hydrocracking catalyst is 1:5 to 5:

1.

4. The method according to claim 1, characterized in that, Based on oxides and a hydrorefining catalyst, the hydrorefining catalyst contains a support and a group VIII metal element supported on the support in an amount of 1 to 10 wt% and / or a group VIB metal element in an amount of 10 to 45 wt%, wherein the group VIII metal element is cobalt and / or nickel, and the group VIB metal element is molybdenum and / or tungsten, and the support is at least one of alumina, silicon oxide, and alumina-silicon oxide.

5. The method according to claim 1, characterized in that, The hydrocracking catalyst comprises a support and a Group VIII metal element and a Group VIB metal element supported on the support. The support is composed of alumina and a molecular sieve, wherein the molecular sieve is a Y-type molecular sieve and / or a β-type molecular sieve, the Group VIII metal element is cobalt and / or nickel, and the Group VIB metal element is molybdenum and / or tungsten. Based on the overall hydrocracking catalyst, the composition of the hydrocracking catalyst, calculated by oxides, is as follows: 30% to 72% alumina, 1% to 30% molecular sieve, 15% to 35% Group VIB metals, and 2% to 8% Group VIII metals.

6. The method according to claim 1, characterized in that, The temperature of the extraction solvent entering the extraction tower is 60℃~180℃; the pressure of the extraction tower is 0.2MPa~0.8MPa absolute pressure; and the mass ratio of the extraction solvent to the extraction feed is 3:1~7:

1.

7. The method according to claim 6, characterized in that, The temperature of the extraction solvent entering the extraction tower is 90–140°C.

8. The method according to claim 1, characterized in that, The residual oil is fed into a water washing tower for washing. The resulting residual oil, after washing, is heated and then enters the lower part of the solvent recovery tower. The mass ratio of washing water to residual oil is 0.1 to 0.5, the pressure at the top of the washing tower is 0.4 MPa to 0.7 MPa absolute pressure, and the washing temperature is 30℃ to 50℃. The theoretical plate number of the solvent recovery tower is 5 to 30, the reflux ratio is 0.3 to 1.0, the top pressure is 0.05 MPa to 0.15 MPa absolute pressure, and the bottom temperature is 150℃ to 200℃.

9. The method according to claim 8, characterized in that, The mass ratio of washing water to residual oil is 0.1 to 0.

3.

10. The method according to claim 1, characterized in that, The aromatic hydrocarbon mass fraction of the industrial white oil product obtained in step (3) is less than or equal to 5%, and the sulfur content is less than or equal to 10 mg / kg.

11. The method according to claim 1, characterized in that, The aromatic hydrocarbon lightening reaction products are separated, and the C6-C8 fraction rich in BTX is sent to the BTX extraction unit, while the C9+ fraction is sent to the coking unit.

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