Waste lubricating oil regeneration device based on multistage catalytic pretreatment

Abstract

The utility model belongs to the technical field of waste lubricating oil regeneration, and particularly relates to a waste lubricating oil regeneration device based on multistage catalytic pretreatment. The waste lubricating oil regeneration device based on multi-stage catalytic pretreatment comprises a coalescer, the coalescer is connected with a feed port of a pre-hydrogenation reactor through a mixer, the lower portion of the pre-hydrogenation reactor is connected with a gas-liquid separation tank through a delivery pump A, the gas-liquid separation tank is connected with a hydrogenation reactor, the lower portion of the hydrogenation reactor is connected with a fractionating tower through a delivery pump B, and the fractionating tower is connected with a fractionating tower. The top of the fractionating tower is connected with a condenser which is connected with a product storage tank. According to the waste lubricating oil regeneration device based on multi-stage catalytic pretreatment, a catalyst is introduced into the pre-hydrogenation reactor stage by stage, so that refined treatment of waste lubricating oil is realized, and impurities are effectively removed by matching with the separation device; in addition, multi-raw-material composite feeding of waste lubricating oil and conventional raw materials is achieved, and the application range of the device is widened.

Description

Technical Field

[0001] The utility model belongs to the technical field of waste lubricating oil regeneration, and particularly relates to a waste lubricating oil regeneration device based on multi-stage catalytic pretreatment. Background Art

[0002] At present, the main raw materials for high-end lubricating oil base oil in China are hydrocracking tail oil, atmospheric and vacuum wax oil, etc., and the base oil of lubricating oil is produced by means of high-pressure hydrogenation for quality improvement and modification. With the rapid development of industrialization, the consumption of lubricating oil is increasing day by day, and the amount of waste lubricating oil generated is huge. If it is not properly discharged and disposed of, it will cause strong damage to the environment. In addition, in the treatment of waste lubricating oil, due to the mechanical impurities, heavy metal ions, non-metallic elements such as chlorine, silicon and phosphorus, and high-content pollutants or additives such as gum and asphaltene in the waste lubricating oil, it will seriously affect the catalytic performance and service life of conventional hydrogenation catalysts, and will also cause a series of problems such as equipment corrosion, pressure difference increase and pipeline blockage in the process.

[0003] CN212316060U discloses a waste lubricating oil regeneration device. The device first uses an oil-water separator to separate impurities from the waste lubricating oil, and then the oil liquid enters a membrane cross-flow separator for filtration. The filtered membrane permeate enters a catalytic hydrogenation reactor for hydrogenation. The reaction products are separated into hydrogenated oil and oil residue in a gas-liquid separation tank. The hydrogenated oil is obtained through a rectifier to obtain light oil and type II / III base oils with different viscosities. The oil residue is deacidified in an absorption tower. Through membrane cross-flow filtration and hydrogenation treatment, the device improves the total recovery rate of waste lubricating oil, shortens the process flow, reduces the equipment investment cost, and the membrane retentate can be sold as an asphalt product, basically realizing full recycling. However, the viscosity of the waste lubricating oil is high. After oil-water separation, it directly enters the membrane cross-flow separator, resulting in low membrane filtration flux, and there are problems of concentration polarization and membrane fouling.

[0004] CN210765213U discloses a waste oil hydrogenation regeneration device. The waste lubricating oil is preliminarily treated by a separator. The oil phase is heated by a heat exchanger and then enters the upper part of a hydrogenation reactor. Hydrogen is heated by a heat exchanger and enters from the lower part of the hydrogenation reactor. The two flow countercurrently through the catalyst layer for reaction. The reaction products respectively enter high and low pressure separators for gas-liquid separation. The separated hydrogen enters a buffer tank through a compressor and is recycled. The liquid phase enters a fractionating tower for fractionation to obtain naphtha, diesel, refined lubricating oil and heavy components. The advantages of this device are high automation, high efficiency in recovering waste lubricating oil, and the ability to recycle hydrogen in the tail gas, saving energy and being environmentally friendly. However, the waste lubricating oil in this device needs to be branched into the reactor during the hydrogenation reaction stage, which cannot guarantee the reaction efficiency of the waste lubricating oil in different branches, and thus cannot guarantee the stability during the reaction process.

[0005] Therefore, it is necessary to reasonably design the waste lubricating oil regeneration and reuse device, improve the removal rate of impurities in the waste lubricating oil, ensure the quality of the treated oil product, and achieve the effective substitution of conventional raw materials. Summary of the Invention

[0006] The purpose of the present invention is to overcome the above-mentioned defects existing in the prior art, and provide a waste lubricating oil regeneration device based on multi-stage catalytic pretreatment. By introducing multi-stage catalysts in a hierarchical manner in the pre-hydrogenation reactor, fine treatment of waste lubricating oil is achieved. In combination with the front and rear separation devices, effective removal of impurities is realized. At the same time, the combination of the pre-hydrogenation device and the conventional hydrogenation device realizes the substitution of conventional raw materials. In addition, this device realizes the multi-raw material composite feeding of waste lubricating oil and conventional raw materials, broadening the application range of the device.

[0007] The waste lubricating oil regeneration device based on multi-stage catalytic pretreatment described in the present invention includes a coalescer, a pre-hydrogenation reactor, a gas-liquid separation tank, a hydrogenation reactor, and a fractionating tower. The coalescer is connected to the feed inlet of the pre-hydrogenation reactor through a mixer. The feed inlet of the mixer is connected to a hydrogen gas pipeline, and the hydrogen gas pipeline is provided with branches directly connected to the pre-hydrogenation reactor and the hydrogenation reactor respectively. The lower part of the pre-hydrogenation reactor is connected to the gas-liquid separation tank through a transfer pump A. The gas-liquid separation tank is connected to the hydrogenation reactor. The lower part of the hydrogenation reactor is connected to the fractionating tower through a transfer pump B. The top of the fractionating tower is connected to a condenser, and the condenser is connected to a product storage tank.

[0008] Preferably, the coalescer is sequentially provided with a screen, a coalescing filter element, and a filler from top to bottom. The screen is composed of an upper coarse screen and a lower fine screen, and is used for filtering particulate impurities in the waste lubricating oil. Further, the coalescing filter element is made of a hydrophilic material, and moisture will be adsorbed by the filter element material and form a water film on its surface, while the oil phase cannot adhere to the surface of the filter element and cannot pass through the coalescing filter element. The filler is a mixture of hydrophilic polypropylene fiber material and activated carbon fiber.

[0009] Preferably, the pre-hydrogenation reactor is sequentially provided with an adsorption zone, a demetallization zone, a denonmetalization zone, a heavy aromatic hydrocarbon cracking zone, and a filtration zone from top to bottom. Inside the adsorption zone, the demetallization zone, the denonmetalization zone, and the heavy aromatic hydrocarbon cracking zone, serrated baffle plates, hydrogen gas distribution rings, and catalyst layers are sequentially provided from top to bottom. The filtration zone is composed of 3-5 layers of filter meshes.

[0010] Preferably, a waste lubricating oil feed inlet is provided at the upper part of the coalescer. The feed inlet is connected to a waste lubricating oil transfer pipeline, and the feed inlet is located above the screen.

[0011] Preferably, a pipeline connected to the buffer tank is provided at the bottom of the coalescer. A reflux pipeline is provided at the upper part of the buffer tank and is connected to the waste lubricating oil conveying pipeline for refluxing the waste lubricating oil in the buffer tank to the coalescer. The bottom of the buffer tank is connected to the sewage pipeline.

[0012] Preferably, a feed tray is provided at the feed inlet of the pre-hydrogenation reactor. The feed tray is composed of a conveying pipe and a tray body. A plurality of liquid outlet holes are provided at the bottom of the tray body. A sewage pipeline is provided at the bottom of the pre-hydrogenation reactor.

[0013] Preferably, the branch of the hydrogen pipeline connected to the pre-hydrogenation reactor is divided into four paths before entering the pre-hydrogenation reactor and is respectively connected to the hydrogen distribution ring.

[0014] Preferably, the hydrogen distribution ring is of a circular ring structure and is located on the inner side wall of the pre-hydrogenation reactor. A plurality of openings are provided on the hydrogen distribution ring.

[0015] Preferably, a layer of filter screen is provided in front of the adsorption zone for further filtering the waste lubricating oil-hydrogen mixture.

[0016] Preferably, a pipeline connected to the hydrogen recovery and treatment device is provided at the top of the gas-liquid separation tank. A pipeline for refluxing to the feed inlet of the mixer is provided at the output end of the hydrogen recovery and treatment device.

[0017] Preferably, the hydrogenation reactor is filled with a hydrofining catalyst and an isomerization catalyst. The top of the hydrogenation reactor is connected to the conventional raw material pipeline, and a sewage pipeline is provided at the bottom.

[0018] Specifically, the working process of the waste lubricating oil regeneration device based on multi-stage catalytic pretreatment is as follows: The waste lubricating oil enters the feed inlet at the upper part of the coalescer through the waste lubricating oil conveying pipeline, first passes through the coarse screen (30 - 50 meshes) on the upper layer and the fine screen (100 - 200 meshes) on the lower layer in the coalescer to remove particulate impurities, and then passes through the coalescing filter element. Due to the difference in the affinity of the coalescing filter element material for water and oil, the water in the waste lubricating oil will be adsorbed by the filter element material and form a water film on its surface. As the waste lubricating oil continuously passes through, the water film thickens continuously, and the tiny water droplets gradually coalesce into larger water beads. And because the pressure difference inside and outside the coalescing filter element gradually increases, the water beads will pass through the coalescing filter element and enter the lower part of the coalescer. While the oil phase, due to its hydrophobic interaction with the filter element material, cannot adhere to the surface of the filter element and cannot pass through the coalescing filter element. As the oil phase increases, the oil phase that realizes water-oil separation overflows into the mixer. The treated wastewater and a small amount of waste lubricating oil enter the buffer tank under the action of the hydrophilic polypropylene fiber material and the activated carbon fiber mixed filler. The water and oil in the buffer tank are further settled and separated. The sewage is discharged through the sewage pipeline, and the oil phase can be refluxed to the coalescer through the pipeline at the upper part of the buffer tank;

[0019] The waste lubricating oil coming out of the buffer tank is mixed with hydrogen from the hydrogen pipeline in a mixer. After heating up, the viscosity of the waste lubricating oil decreases, and under the action of hydrogen, it enters the inside of the pre-hydrogenation reactor through the feed tray to participate in the reaction. It sequentially passes through the adsorption zone, demetallization zone, denonmetal zone, and heavy aromatic hydrocarbon cracking zone in the pre-hydrogenation reactor, and finally completes the pre-hydrogenation reaction through a filtration zone composed of 3 - 5 layers of filter screens. Among them, a hydrogenation protective agent is filled in the adsorption zone, which can adsorb components such as asphalt in the waste lubricating oil, and its filling amount is 15% of the reactor volume; a catalyst with a corrugated hole structure is filled in the demetallization zone, and its main chemical composition is alumina - Mo - Ni, and its filling amount is 25% of the reactor volume; a catalyst with a main chemical composition of alumina - Mo - Ni - W is filled in the denonmetal zone, and its filling amount is 35% of the reactor volume. The waste lubricating oil removes non-metal elements such as chlorine, silicon, and phosphorus in this area; in the heavy aromatic hydrocarbon cracking zone, the waste lubricating oil cracks heavy aromatic hydrocarbons into small molecule hydrocarbons under the action of a catalyst (alumina - Ni - Mo - W) and hydrogen. Finally, after filtration in the filtration zone, a pre-hydrogenation product is obtained.

[0020] The product after the pre-hydrogenation reaction is transported from the lower part of the pre-hydrogenation reactor to a gas-liquid separation tank through a transfer pump A for gas-liquid separation. The top of the gas-liquid separation tank is connected to a hydrogen recovery and treatment device, and the recovered hydrogen is refluxed to the feed inlet of the mixer through a pipeline; the liquid after gas-liquid separation enters the hydrogenation reactor. A hydrogenation refining catalyst and an isomerization catalyst are filled in the hydrogenation reactor, and the top is connected to a conventional raw material pipeline to achieve the composite feeding of multiple raw materials. The conventional raw materials are hydrocracking tail oil, atmospheric and vacuum wax oil, etc. produced by other production devices; the product after the hydrogenation reaction is transported from the lower part of the hydrogenation reactor to a fractionating tower through a transfer pump B for fractionation. The steam at the top of the fractionating tower enters a condenser for condensation and then enters a product storage tank to obtain a regenerated lubricating oil product.

[0021] Compared with the prior art, the beneficial effects of the present utility model are as follows: The waste lubricating oil regeneration device based on multi-stage catalytic pretreatment of the present utility model can effectively remove particulate impurities and moisture in the waste lubricating oil through preliminary separation by a coalescer. By introducing multi-stage catalysts in a graded manner in the pre-hydrogenation reactor, cooperating with the feed tray, zigzag baffle plate, and hydrogen distribution ring, it realizes the refined treatment of the waste lubricating oil, improves the oil product quality and conversion efficiency; in addition, this device can meet the composite feeding of multiple raw materials of waste lubricating oil and conventional raw materials, expanding the application range of the device. Description of the Drawings

[0022] Figure 1 It is a structural schematic diagram of the waste lubricating oil regeneration device based on multi-stage catalytic pretreatment in the present utility model;

[0023] Figure 2 It is a structural schematic diagram of the coalescer device in the present utility model;

[0024] Figure 3 It is a schematic structural diagram of the pre-hydrogenation reactor in the present utility model;

[0025] Figure 4 It is a schematic structural diagram of the feed tray in the present utility model.

[0026] In the figure: 1. Coalescer; 101. Coarse screen; 102. Fine screen; 103. Coalescing filter element; 104. Filler; 2. Pre-hydrogenation reactor; 201. Feed tray; 202. Filter screen; 203. Catalyst layer; 204. Zigzag baffle; 205. Hydrogen distribution ring; 206. Tray body; 207. Delivery pipe; 208. Liquid outlet hole; 3. Gas-liquid separation tank; 4. Hydrogenation reactor; 5. Fractionating tower; 6. Product storage tank; 7. Buffer tank; 8. Mixer; 9. Delivery pump A; 10. Delivery pump B; 11. Condenser; 12. Waste lubricating oil delivery pipeline; 13. Sewage pipeline; 14. Hydrogen pipeline; 15. Hydrogen recovery and treatment device; 16. Conventional raw material pipeline; 17. Drainage pipeline. Specific embodiments

[0027] The technical solution of the present utility model will be further described below with reference to the accompanying drawings.

[0028] As Figures 1-4 shown, the waste lubricating oil regeneration device based on multi-stage catalytic pretreatment includes a coalescer 1, a pre-hydrogenation reactor 2, a gas-liquid separation tank 3, a hydrogenation reactor 4, and a fractionating tower 5. The coalescer 1 is connected to the feed inlet of the pre-hydrogenation reactor 2 through a mixer 8. The feed inlet of the mixer 8 is connected to the hydrogen pipeline 14. The hydrogen pipeline 14 is provided with branches directly connected to the pre-hydrogenation reactor 2 and the hydrogenation reactor 4 respectively. The lower part of the pre-hydrogenation reactor 2 is connected to the gas-liquid separation tank 3 through a delivery pump A 9. The gas-liquid separation tank 3 is connected to the hydrogenation reactor 4. The lower part of the hydrogenation reactor 4 is connected to the fractionating tower 5 through a delivery pump B 10. The top of the fractionating tower 5 is connected to a condenser 11, and the condenser 11 is connected to a product storage tank 6.

[0029] The coalescer 1 is sequentially provided with a screen, a coalescing filter element 103, and a filler 104 from top to bottom. The screen is composed of an upper-layer coarse screen 101 and a lower-layer fine screen 102.

[0030] In the pre-hydrogenation reactor 2, an adsorption zone, a demetallization zone, a de-nonmetal zone, a heavy aromatic hydrocarbon cracking zone, and a filtration zone are sequentially arranged from top to bottom. In the adsorption zone, the demetallization zone, the de-nonmetal zone, and the heavy aromatic hydrocarbon cracking zone, a zigzag baffle 204, a hydrogen distribution ring 205, and a catalyst layer 203 are sequentially arranged from top to bottom. The filtration zone is composed of 3-5 layers of filter screens 202.

[0031] The upper part of the coalescer 1 is provided with a waste lubricating oil inlet, which is connected to the waste lubricating oil pipeline 12 and is located above the screen.

[0032] The bottom of the coalescer 1 is provided with a pipeline connected to the buffer tank 7. The upper part of the buffer tank 7 is provided with a reflux pipeline connected to the waste lubricating oil pipeline 12 for refluxing the waste lubricating oil in the buffer tank 7 to the coalescer 1, and the bottom of the buffer tank 7 is connected to the sewage pipeline 13.

[0033] At the inlet of the pre-hydrogenation reactor 2, there is a feed tray 201, which is composed of a delivery pipe 207 and a tray body 206. The bottom of the tray body 206 is provided with a plurality of liquid outlet holes 208, and the bottom of the pre-hydrogenation reactor 2 is provided with a blowdown pipeline 17.

[0034] The branch of the hydrogen pipeline 14 connected to the pre-hydrogenation reactor 2 is divided into four paths before entering the pre-hydrogenation reactor 2 and is respectively connected to the hydrogen distribution ring 205.

[0035] The hydrogen distribution ring 205 is of a circular ring structure and is located on the inner side wall of the pre-hydrogenation reactor 2. The hydrogen distribution ring 205 is provided with a plurality of openings.

[0036] A layer of filter screen 202 is provided in front of the adsorption zone.

[0037] The top of the gas-liquid separation tank 3 is provided with a pipeline connected to the hydrogen recovery and treatment device 15, and the output end of the hydrogen recovery and treatment device 15 is provided with a pipeline refluxing to the inlet of the mixer 8.

[0038] The hydrogenation reactor 4 is filled with a hydrofining catalyst and an isomerization catalyst. The top of the hydrogenation reactor 4 is connected to the conventional raw material pipeline 16, and the bottom is provided with a blowdown pipeline 17.

[0039] The described waste lubricating oil regeneration device based on multi-stage catalytic pretreatment has the following working process: Waste lubricating oil enters the feed port at the upper part of the coalescer 1 through the waste lubricating oil delivery pipeline 12. First, it passes through the coarse screen 101 (30 - 50 meshes) on the upper layer and the fine screen 102 (100 - 200 meshes) on the lower layer inside the coalescer 1 to remove particulate impurities. Then, it passes through the coalescing filter element 103. Due to the difference in the affinity of the coalescing filter element 103 material for water and oil, the moisture in the waste lubricating oil will be adsorbed by the filter element material and form a water film on its surface. As the waste lubricating oil continuously passes through, the water film thickens continuously, and tiny water droplets gradually coalesce into larger water beads. And because the pressure difference inside and outside the coalescing filter element 103 gradually increases, the water beads will enter the lower part of the coalescer 1 through the coalescing filter element 103. While the oil phase, due to its hydrophobic interaction with the filter element material, cannot adhere to the filter element surface and cannot pass through the coalescing filter element 103. As the oil phase increases, the oil phase that realizes water-oil separation overflows into the mixer 8. The treated wastewater and a small amount of waste lubricating oil enter the buffer tank 7 under the action of the hydrophilic polypropylene fiber material and the activated carbon fiber mixed filler 104. In the buffer tank 7, the water and oil are further settled and separated, and the sewage is discharged through the sewage pipeline 13. The oil phase can flow back to the coalescer 1 through the pipeline at the upper part of the buffer tank 7;

[0040] The waste lubricating oil coming out of the buffer tank 7 is mixed with hydrogen from the hydrogen pipeline 14 in the mixer 8. After heating up, the viscosity of the waste lubricating oil decreases, and under the action of hydrogen, it enters the inside of the pre-hydrogenation reactor 2 through the feed tray 201 to participate in the reaction; it successively passes through the adsorption zone, the demetallization zone, the denonmetalization zone, and the heavy aromatic hydrocarbon cracking zone in the pre-hydrogenation reactor 2, and finally completes the pre-hydrogenation reaction through the filtration zone composed of 3 - 5 layers of filter screens 202; among them, a hydrogenation protective agent is loaded in the adsorption zone, which can adsorb components such as asphalt in the waste lubricating oil, and its loading amount is 15% of the reactor volume; a catalyst with a corrugated hole structure is loaded in the demetallization zone, and its main chemical composition is alumina - Mo - Ni, and its loading amount is 25% of the reactor volume; a catalyst with a main chemical composition of alumina - Mo - Ni - W is loaded in the denonmetalization zone, and its loading amount is 35% of the reactor volume. The waste lubricating oil removes non-metal elements such as chlorine, silicon, and phosphorus in this area; in the heavy aromatic hydrocarbon cracking zone, the waste lubricating oil cracks heavy aromatic hydrocarbons into small molecule hydrocarbons under the action of a catalyst (alumina - Ni - Mo - W) and hydrogen, and finally after being filtered by the filtration zone, a pre-hydrogenation product is obtained;

[0041] The product after the pre-hydrogenation reaction is transported from the lower part of the pre-hydrogenation reactor 2 to the gas-liquid separation tank 3 through the transfer pump A9 for gas-liquid separation. The top of the gas-liquid separation tank 3 is connected to the hydrogen recovery and treatment device 15, and the recovered hydrogen is refluxed to the inlet of the mixer 8 through a pipeline; the liquid after gas-liquid separation enters the hydrogenation reactor 4. The hydrogenation reactor 4 is filled with a hydrofining catalyst and an isomerization catalyst, and the top is connected to the conventional raw material pipeline 16 to achieve the composite feeding of various raw materials. The conventional raw materials are hydrocracked tail oil, atmospheric and vacuum gas oil, etc. produced by other production units; the product after the hydrogenation reaction is transported from the lower part of the hydrogenation reactor 4 to the fractionating tower 5 through the transfer pump B10 for fractionation. The steam at the top of the fractionating tower 5 enters the condenser 11 for condensation and then enters the product storage tank 6 to obtain the regenerated lubricating oil product.

Claims

1. A waste lubricating oil regeneration device based on multi-stage catalytic pretreatment, characterized in that, It includes a coalescer (1), a pre-hydrogenation reactor (2), a gas-liquid separation tank (3), a hydrogenation reactor (4) and a fractionating tower (5). The coalescer (1) is connected to the feed inlet of the pre-hydrogenation reactor (2) through a mixer (8). The feed inlet of the mixer (8) is connected to a hydrogen pipeline (14), and the hydrogen pipeline (14) is provided with branches directly connected to the pre-hydrogenation reactor (2) and the hydrogenation reactor (4) respectively; the lower part of the pre-hydrogenation reactor (2) is connected to the gas-liquid separation tank (3) through a transfer pump A (9). The gas-liquid separation tank (3) is connected to the hydrogenation reactor (4). The lower part of the hydrogenation reactor (4) is connected to the fractionating tower (5) through a transfer pump B (10). The top of the fractionating tower (5) is connected to a condenser (11), and the condenser (11) is connected to a product storage tank (6); The coalescer (1) is sequentially provided with a screen, a coalescing filter element (103) and a filler (104) from top to bottom. The screen is composed of an upper coarse screen (101) and a lower fine screen (102); In the pre-hydrogenation reactor (2), an adsorption zone, a demetallization zone, a non-metal removal zone, a heavy aromatic hydrocarbon cracking zone and a filtration zone are sequentially arranged from top to bottom. In the adsorption zone, the demetallization zone and the non-metal removal zone, zigzag guide plates (204), hydrogen distribution rings (205) and catalyst layers (203) are sequentially arranged from top to bottom. The filtration zone is composed of 3-5 layers of filter meshes (202).

2. The waste lubricating oil regeneration device based on multi-stage catalytic pretreatment according to claim 1, wherein, The upper part of the coalescer (1) is provided with a waste lubricating oil feed inlet, and the feed inlet is connected to a waste lubricating oil transfer pipeline (12). The feed inlet is located above the screen.

3. The waste lubricating oil regeneration device based on multi-stage catalytic pretreatment according to claim 2, wherein, The bottom of the coalescer (1) is provided with a pipeline connected to a buffer tank (7). The upper part of the buffer tank (7) is provided with a reflux pipeline connected to the waste lubricating oil transfer pipeline (12), and the bottom of the buffer tank (7) is connected to a sewage pipeline (13).

4. The waste lubricating oil regeneration device based on multi-stage catalytic pretreatment according to claim 1, wherein A feed tray (201) is arranged at the feed inlet of the pre-hydrogenation reactor (2). The feed tray (201) is composed of a transfer pipe (207) and a tray body (206). A plurality of liquid outlet holes (208) are arranged at the bottom of the tray body (206). A sewage pipeline (17) is arranged at the bottom of the pre-hydrogenation reactor (2).

5. The waste lubricating oil regeneration device based on multi-stage catalytic pretreatment according to claim 1, characterized in that, The branch of the hydrogen pipeline (14) connected to the pre-hydrogenation reactor (2) is divided into four paths before entering the pre-hydrogenation reactor (2) and is respectively connected to the hydrogen distribution ring (205).

6. The waste lubricating oil regeneration device based on multi-stage catalytic pretreatment according to claim 5, characterized in that, The hydrogen distribution ring (205) is of a circular ring structure and is located on the inner side wall of the pre-hydrogenation reactor (2). A plurality of openings are arranged on the hydrogen distribution ring (205).

7. The waste lubricating oil regeneration device based on multi-stage catalytic pretreatment according to claim 1, wherein, A layer of filter mesh (202) is arranged in front of the adsorption zone.

8. The waste lubricating oil regeneration device based on multi-stage catalytic pretreatment according to claim 1, wherein The top of the gas-liquid separation tank (3) is provided with a pipeline connected to a hydrogen recovery and treatment device (15). The output end of the hydrogen recovery and treatment device (15) is provided with a pipeline that returns to the feed inlet of the mixer (8).

9. The waste lubricating oil regeneration device based on multi-stage catalytic pretreatment according to claim 1, characterized in that, The top of the hydrogenation reactor (4) is connected to a conventional raw material pipeline (16), and a sewage pipeline (17) is arranged at the bottom.

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