Method for producing industrial white oil by hydrocracking unit

Abstract

The invention discloses a method for producing industrial white oil by a hydrocracking unit, and relates to the technical field of petrochemical engineering. The method comprises the following steps: dearomatization and desulfurization of raw materials, preparation of mixed raw materials, pretreatment of the mixed raw materials, hydrotreatment, hydrocracking treatment, fractionation and refining, and dewaxing and dearomatization treatment. The desulfurized and dearomatized vacuum light wax oil, the catalytically cracked diesel oil, the residual oil hydrogenated diesel oil and the straight-run diesel oil are mixed and then are used for preparing the white oil, so that the raw material combination is optimized, the production cost is reduced, the quality of the white oil is improved, and the product stability and the market adaptability are enhanced. According to the method for comprehensively utilizing different raw materials, white oil production is more efficient and economical, and strict requirements of different fields on white oil can be met.

Description

Technical Field

[0001] The invention relates to the technical field of petrochemical industry, and in particular to a method for producing industrial white oil by a hydrocracking unit. Background Art

[0002] Industrial white oil, also known as mineral white oil or light mineral oil, is a highly pure mineral oil obtained through the petroleum refining process. It is usually colorless, odorless, low in viscosity, chemically stable, and does not contain harmful substances. Therefore, it is widely used in many industrial fields, such as lubrication, food processing, medicine, cosmetics, plastic processing, etc.

[0003] The existing industrial white oil is mostly prepared by using vacuum light wax oil, catalytic cracking diesel, residual oil hydrogenated diesel, straight run diesel and other raw materials in a hydrocracking unit. This preparation method still has the following shortcomings: 1. Most of the existing white oil preparations are made from a single raw material, and different raw materials have different prices. In particular, the raw materials used to produce high-quality white oil are often expensive, which makes the cost of preparing white oil from a single high-priced raw material high; 2. In the process of preparing white oil, if multiple raw materials are used for preparation, due to the different characteristics of different raw materials, it is necessary to build a white oil production line dedicated to each raw material according to its characteristics, which is very costly and often limits enterprises to the production and processing of white oil with a single raw material; Therefore, there is an urgent need for a method for producing industrial white oil using a hydrocracking unit that can overcome the above-mentioned shortcomings. Summary of the invention

[0004] In order to overcome the shortcomings of the background technology, the present invention discloses a method for producing industrial white oil by a hydrocracking unit. The present invention prepares white oil by mixing desulfurized and dearomatized vacuum light wax oil, catalytic cracking diesel, residual oil hydrogenated diesel and straight-run diesel, which helps to optimize the raw material combination, reduce production costs, improve white oil quality, and enhance product stability and market adaptability. This method of comprehensive utilization of different raw materials makes white oil production more efficient and economical, and can meet the strict requirements of white oil in different fields.

[0005] To achieve the above object, the present invention adopts the following technical solution: A method for producing industrial white oil by a hydrocracking unit comprises the following steps: S1: Dearomatization and desulfurization of raw materials; preparing vacuum light wax oil, catalytic cracking diesel, residual oil hydrogenation diesel and straight-run diesel, and performing dearomatization and desulfurization treatment on them respectively; S2: Preparation of mixed raw materials; the vacuum light wax oil, catalytic cracking diesel, residual oil hydrogenated diesel and straight-run diesel after dearomatization and desulfurization treatment in step S1 are fully stirred and mixed in a ratio of 40%-60% of vacuum light wax oil, 10%-20% of catalytic cracking diesel, 10%-20% of residual oil hydrogenated diesel and 20%-30% of straight-run diesel to obtain a mixed raw material; S3: pretreatment of the mixed raw material; the mixed raw material obtained in step S2 is sequentially subjected to impurity treatment, dehydration treatment, distillation / fractionation treatment, heavy metal treatment and dewaxing treatment; S4: Hydrogenation treatment: Hydrogenation treatment of the mixed raw material pretreated in step S3; S5: hydrocracking treatment; adding the mixed raw material after the hydrocracking treatment in step S4 to a hydrocracking reaction device for hydrocracking reaction to obtain a product; S6: fractionation and refinement: fractionating and refining the product obtained in step S5 to obtain a pre-finished white oil; S7: dewaxing and dearomatization treatment; the pre-finished white oil obtained in step S6 is dewaxed and dearomatized to obtain the finished white oil.

[0006] Furthermore, the vacuum light wax oil, catalytic cracking diesel, residual oil hydrogenated diesel and straight-run diesel after dearomatization and desulfurization treatment in step S2 are mixed under a pressure of 3-10 MPa, and the temperature should be maintained at 40-80° C. during the mixing process.

[0007] Furthermore, in step S4, the mixed raw material should be pressurized and heated before being hydrogenated, the pressurization pressure is 10-15 MPa, and the heating temperature is 340-380°C.

[0008] Furthermore, in step S6, fractionation and refinement of the product are carried out sequentially through a hot high-pressure separator, a hot low-pressure separator, a cold low-pressure separator, a hydrogen sulfide stripping tower, a flash tank, a fractionation tower and a stripping tower.

[0009] Compared with the prior art, the beneficial effects of the present invention are as follows: the present invention prepares white oil by mixing desulfurized and dearomatized vacuum light wax oil, catalytic cracking diesel, residual oil hydrogenation diesel and straight-run diesel in a certain proportion and then preparing white oil by hydrocracking, which can not only obtain the comprehensive advantages of various raw materials and improve the quality of white oil, but also reduce the investment in preparation equipment and the cost of traditional single high-priced raw material preparation; the present invention prepares white oil by mixing desulfurized and dearomatized vacuum light wax oil, catalytic cracking diesel, residual oil hydrogenation diesel and straight-run diesel, which helps to optimize the raw material combination, reduce production costs, improve the quality of white oil, and enhance product stability and market adaptability. This method of comprehensive utilization of different raw materials makes white oil production more efficient and economical, and can meet the strict requirements of different fields for white oil. DETAILED DESCRIPTION

[0010] The technical solution of the present invention will be described below in conjunction with the embodiments of the present invention.

[0011] The present invention provides a technical solution: Embodiment 1, a method for producing industrial white oil by a hydrocracking unit, comprising the following steps: S1: Dearomatization and desulfurization of raw materials; preparing vacuum light wax oil, catalytic cracking diesel, residual oil hydrogenation diesel and straight-run diesel, and performing dearomatization and desulfurization treatment on them respectively; Among them, the dearomatization and desulfurization of vacuum light wax oil adopts hydroprocessing technology, the temperature is controlled at 320°C - 380°C, the pressure is controlled at 45 bar - 70 bar, the hydrogen volume is controlled at 5-12 L / L of raw oil, and the catalyst type is molybdenum / tungsten-based catalyst, cobalt / nickel-based catalyst; The dearomatization and desulfurization of catalytic cracking diesel adopts hydrofining technology, with the temperature controlled at 300C -400C, the pressure controlled at 4 - 10 MPa, the ratio of hydrogen to oil is usually between 500-1000 Nm³ / m³, and the catalyst is a metal-based catalyst such as molybdenum, tungsten, cobalt, and nickel; Dearomatization and desulfurization of residual oil hydrodiesel adopts hydroprocessing technology, with temperature controlled at 320°C - 380°C, pressure controlled at 6 - 12 MPa, hydrogen to oil ratio usually between 500-1000 Nm³ / m³, and catalyst types such as Ni-Mo, Co-Mo, Ni-W, etc.; Dearomatization and desulfurization of straight-run diesel oil adopts hydroprocessing technology, with temperature controlled at 300°C - 380°C and pressure controlled at 30 - 100MPa. The ratio of hydrogen to oil is usually between 0.5-2.5 Nm³ / m³. The catalyst types are molybdenum (Mo) based, cobalt molybdenum (CoMo) based, and nickel molybdenum (NiMo); S2: Preparation of mixed raw materials: vacuum light wax oil, catalytic cracking diesel, residual oil hydrogenated diesel and straight-run diesel after dearomatization and desulfurization treatment in step S1 are mixed at a ratio of 40%-60% vacuum light wax oil, 10%-20% catalytic cracking diesel, 10%-20% residual oil hydrogenated diesel and 20%-30% straight-run diesel under a pressure condition of 3-10 MPa and a temperature controlled between 40-80° C., and stirred to obtain a mixed raw material; S3: pretreatment of the mixed raw material; the mixed raw material obtained in step S2 is sequentially subjected to impurity treatment, dehydration treatment, distillation / fractionation treatment, heavy metal treatment and dewaxing treatment, specifically, impurities are removed by filtration, sedimentation or centrifugation, water is removed by heating or vacuum dehydration, low molecular weight impurities are removed by a distillation tower, heavy metals are removed by chemical adsorbent or ion exchange method, and solid wax is removed by freeze dewaxing or solvent dewaxing; S4: Hydrogenation treatment; the mixed raw material pretreated in step S3 is subjected to pressurization and heating treatment, the pressurization pressure is 10-15MPa, the heating temperature is 340-380°C, and then the pressurization and heating treatment is subjected to hydrogenation treatment; S5: hydrocracking treatment; adding the mixed raw material after the hydrocracking treatment in step S4 to a hydrocracking reaction device for hydrocracking reaction to obtain a product; S6: fractionation and refinement; the product obtained in step S5 is fractionated and refined to obtain pre-finished white oil, and the fractionation and refinement of the product are sequentially carried out through a hot high-pressure separator, a hot low-pressure separator, a cold low-pressure separator, a hydrogen sulfide stripping tower, a flash tank, a fractionation tower and a stripping tower. Specifically, the cracking reaction product first enters the hot high-pressure separator, the hot high-pressure separator separates the liquid phase and enters the hot low-pressure separator, the hot high-pressure separator gas phase enters the cold high-pressure separator, the hot low-pressure separator separates the gas phase and enters the cold low-pressure separator, the cold high-pressure separator separates the gas phase and supplies it to the hydrogenation refining reactor as circulating hydrogen, and the cold high-pressure separator separates the liquid phase and enters the cold low-pressure separator. The hot low-pressure separator is used to separate the gas phase into low-pressure gas, and the hot low-pressure separator and the cold low-pressure separator are used to separate the liquid phase into the reaction oil. The reaction oil is then sent to a hydrogen sulfide stripping tower to remove the hydrogen sulfide and then sent to a flash tank for fractionation. The reaction oil is obtained at the bottom of the flash tank. The reaction oil obtained at the bottom of the flash tank is heated to and then enters the fractionation tower. The top of the flash tank is connected to the fractionation tower through a pipeline to realize gas phase feeding. The oil separated in the fractionation tower is pumped out to the stripping tower. The oil at the bottom of the stripping tower is pumped out by a centrifugal pump, and the heat is recovered by a heat exchanger and an air cooler for heat exchange and cooling. The industrial white oil is then obtained after coalescing and dehydrating in a coalescer and a salt drying tank. S7: dewaxing and dearomatization treatment; the pre-finished white oil obtained in step S6 is dewaxed and dearomatized to obtain the finished white oil.

[0012] The parts of the present invention that are not described in detail are prior art. It is obvious to those skilled in the art that the present invention is not limited to the details of the above exemplary embodiments and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention.

Claims

1. A method for producing industrial white oil by a hydrocracking unit, characterized in that: The following steps are involved: S1: Dearomatization and desulfurization of raw materials; preparing vacuum light wax oil, catalytic cracking diesel, residual oil hydrogenation diesel and straight-run diesel, and performing dearomatization and desulfurization treatment on them respectively; S2: Preparation of mixed raw materials; the vacuum light wax oil, catalytic cracking diesel, residual oil hydrogenated diesel and straight-run diesel after dearomatization and desulfurization treatment in step S1 are fully stirred and mixed in a ratio of 40%-60% of vacuum light wax oil, 10%-20% of catalytic cracking diesel, 10%-20% of residual oil hydrogenated diesel and 20%-30% of straight-run diesel to obtain a mixed raw material; S3: pretreatment of the mixed raw material; the mixed raw material obtained in step S2 is sequentially subjected to impurity treatment, dehydration treatment, distillation / fractionation treatment, heavy metal treatment and dewaxing treatment; S4: Hydrogenation treatment: Hydrogenation treatment of the mixed raw material pretreated in step S3; S5: hydrocracking treatment; adding the mixed raw material after the hydrocracking treatment in step S4 to a hydrocracking reaction device for hydrocracking reaction to obtain a product; S6: fractionation and refinement: fractionating and refining the product obtained in step S5 to obtain a pre-finished white oil; S7: dewaxing and dearomatization treatment; the pre-finished white oil obtained in step S6 is dewaxed and dearomatized to obtain the finished white oil.

2. The method for producing industrial white oil by a hydrocracking unit according to claim 1, characterized in that: In step S2, the vacuum light wax oil, catalytic cracking diesel, residual oil hydrogenated diesel and straight-run diesel after dearomatization and desulfurization treatment are mixed under a pressure of 3-10 MPa, and the temperature should be maintained at 40-80° C. during the mixing process.

3. The method for producing industrial white oil by a hydrocracking unit according to claim 1, characterized in that: In step S4, the mixed raw material should be pressurized and heated before the mixed raw material is subjected to hydrogenation treatment, the pressurization pressure is 10-15 MPa, and the heating temperature is 340-380°C.

4. The method for producing industrial white oil by a hydrocracking unit according to claim 1, characterized in that: In step S6, the fractionation and refinement of the product are carried out in sequence through a hot high-pressure separator, a hot low-pressure separator, a cold low-pressure separator, a hydrogen sulfide stripping tower, a flash tank, a fractionation tower and a stripping tower.