A method and system for treating waste oil

Abstract

This invention relates to the field of waste oil treatment technology, and discloses a method and system for treating waste oil. The waste oil treatment method provided by this invention first performs pre-hydrogenation treatment to remove chlorine, metals, sulfur, and nitrogen from the waste oil, improving the yield of clean products, avoiding contamination of the hydrorefining catalyst by impurities, and reducing corrosion of equipment and pipelines by impurities, enabling large-scale industrial application. Furthermore, hydrorefining is performed after a first separation of the first liquid phase, which reduces the reaction load of the first gas phase. The first liquid phase is high-temperature heavy oil containing solids; after the first separation, the deactivated catalyst and solid impurities in the first liquid phase are separated and discharged, reducing their contamination of the hydrorefining treatment, improving the conversion rate and quality of the target product, and increasing the oil yield by 10% compared to traditional hydrorefining technology. Moreover, the raw material pretreatment of this invention is simple, without adsorption or distillation operations, reducing process losses of raw materials and energy consumption, and enabling long-term safe and stable industrial production.

Description

Technical Field

[0001] This invention relates to the field of waste oil treatment technology, and specifically to a method and system for treating waste oil. Background Technology

[0002] Waste plastic oil and waste tire oil have high impurity content, making them major sources of harm to the social and soil environment. How to effectively dispose of waste tire oil and / or waste plastic oil has become a research hotspot in the utilization of renewable resources. Currently, pyrolysis technology is an effective means of disposing of waste tire oil and / or waste plastics, which is conducive to achieving the dual benefits of environmental protection and green energy application.

[0003] Existing technology discloses a method and system for tandem hydrotreating waste tire pyrolysis oil. Specifically, the method involves mixing pretreated waste tire pyrolysis oil with mixed hydrogen, followed by primary preheating and low-temperature hydrotreating. The low-temperature hydrotreating effluent then undergoes hydrorefining and shallow cracking reactions. The cracking products are then subjected to hot high-pressure separation, partially cold high-pressure separation, partially hot low-pressure separation, and finally cold low-pressure separation. The final mixed oil phase products are fractionated to obtain the final product. While this method achieves deep processing of waste tire pyrolysis oil and extends the continuous operation cycle of the unit, the hydrotreating process is lengthy, the unit's energy consumption is high, and the oil yield is low.

[0004] Another existing technology discloses a method for hydrotreating and desiliconizing waste plastic oil. Specifically, the waste plastic oil is treated in a slurry bed reactor with a hydrogenation catalyst and hydrogen to remove chlorine and silicon, ultimately yielding a waste plastic oil product with very low chlorine and silicon content. The hydrogenation catalyst is a composite catalyst formed by an oil-soluble catalyst and an alkali-treated powdered catalyst. The reactor is a bottom-up flowing slurry bed reactor, thus solving the problem of the impact of chlorine and silicon removal on catalytic materials, equipment, and product properties. However, this method places very high demands on equipment materials; stainless steel has a high probability of corrosion, and the powdered catalyst easily causes severe wear on pipelines and equipment, affecting the long-term operation of the equipment. Existing technologies also use chemical solvents for impurity removal, but this introduces new impurities that are difficult to separate, contaminating the reaction products and leading to substandard final product quality.

[0005] Another existing technology discloses a method for hydrogenating and purifying waste plastic pyrolysis oil, which adopts a coupled purification process of slurry bed hydrogenation pretreatment and fixed bed hydrogenation post-refining. Waste plastic pyrolysis oil, hydrogen and powdered catalyst undergo hydrogenation reaction in a slurry bed hydrogenation reactor. After gas-liquid-solid cyclone separation, the solid residue is discharged from the device, and the liquid product enters the fixed bed hydrogenation reactor for hydrogenation refining to obtain hydrogenated and purified waste plastic pyrolysis oil. This invention has a simple process flow and is not prone to coking, but the gas phase load is too large.

[0006] Therefore, how to improve the methods and systems for waste oil to reduce gas phase load, achieve qualified target product quality (fewer impurities), low energy consumption, high oil yield, and realize long-term safe and stable industrial production is a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0007] This invention provides a method for treating waste oil, which solves the problem that existing technologies cannot achieve long-term, safe, and stable industrial production.

[0008] In a first aspect, the present invention provides a method for treating waste oil, comprising the following steps: (1) Waste oil and hydrogen are mixed and then pre-hydrogenated to obtain a first liquid phase and a first gas phase; (2) After the first liquid phase is subjected to the first separation treatment, a liquid-solid phase and a second gas phase are obtained. The second gas phase and the first gas phase are mixed and then subjected to hydrogenation purification treatment to obtain the hydrogenation purified product. (3) The hydrorefined product is fractionated to obtain naphtha and diesel oil respectively.

[0009] In one optional embodiment, before the second gas phase and the first gas phase are mixed, the first gas phase is further subjected to a second separation, and the resulting gas phase is subjected to a third separation. The gas phase obtained by the third separation is purified, and the resulting gas is compressed and returned to step (1) as recycled hydrogen for pre-hydrogenation treatment. The liquids obtained by the second separation and the third separation are subjected to hydrogenation purification treatment after being pressurized and heated.

[0010] In an optional embodiment, a portion of the liquid-solid phase is returned to step (1) for pre-hydrogenation treatment, and the remaining portion is subjected to a fourth separation. The resulting liquid is then subjected to hydrogenation purification treatment after pressurization and heating.

[0011] In one alternative embodiment, prior to the hydrorefining process, the method further includes a step of cooling the second gas phase and the second separated liquid phase.

[0012] In an optional embodiment, step (1), before the pre-hydrogenation treatment after the waste oil and hydrogen are mixed, further includes pressurizing the waste oil to 1MPa-4MPa, preferably 2.5MPa-3.5MPa, and heat-exchanging it to 200℃-400℃, preferably 250℃-350℃.

[0013] In one optional embodiment, after the fractionation process, a circulating oil is further included; the circulating oil is then subjected to hydrorefining after being pressurized and heated.

[0014] In one optional embodiment, the hydrorefined product is further subjected to a fifth separation step before fractionation to obtain a second liquid phase and a third gas phase. The second liquid phase is subjected to fractionation, and the third gas phase is subjected to a sixth separation. The resulting liquid phase is naphtha, and the resulting gas phase is returned to step (2) for hydrorefining. The remaining part is compressed and returned to step (1) for pre-hydrogenation.

[0015] It should be noted that the circulating gas from the fixed-bed hydrorefining reaction is used by the upstream suspended-bed pre-hydrogenation reaction system, which can reduce the energy consumption of the entire plant, make the process more compact, and extend the operating cycle far beyond that of conventional dual fixed-bed hydrorefining technology.

[0016] In addition, if the hydrogen purity is insufficient during the pre-hydrogenation and hydrorefining processes, external supplementary hydrogen can be used to improve the hydrogen purity of the system.

[0017] In an alternative embodiment, before the hydrorefined product undergoes a fifth separation, a heat exchange step with the waste oil from step (1) is also included.

[0018] In this invention, the high-heat reaction products of hydrorefining are exchanged with waste oil, which simplifies the process and reduces the energy consumption of the equipment, thereby reducing processing costs.

[0019] In one optional embodiment, during the pre-hydrogenation treatment, the reaction residence time is 0.8h-3h, preferably 0.8h-1.5h, the liquid-gas velocity is 0.5m / s-5m / s, preferably 0.8m / s-1m / s, and the hydrogen-to-oil ratio is 200-2000:1, preferably 500-1000:1.

[0020] In one optional embodiment, the temperature of the hydrorefining treatment is 300℃-500℃, preferably 380℃-390℃, the pressure is 4MPa-20MPa, preferably 8MPa-12MPa, and the hydrogen-to-oil ratio is 300-2500:1, preferably 800-1000:1.

[0021] In one optional embodiment, the waste oil includes at least one of waste tire pyrolysis oil and waste plastic pyrolysis oil.

[0022] It should be noted that, in this invention, waste tire pyrolysis oil refers to liquid hydrocarbon material obtained by pyrolysis of various waste tires made of natural rubber and / or synthetic rubber at 300℃-800℃ under air-isolated conditions.

[0023] In one optional embodiment, the waste tire pyrolysis oil contains 1 μg / g to 10,000 μg / g of silicon, 1 μg / g to 10,000 μg / g of chlorine, 1 μg / g to 10,000 μg / g of metal, 1,000 μg / g to 10,000 μg / g of sulfur, and 1,000 μg / g to 10,000 μg / g of nitrogen.

[0024] In addition, the metals in waste tire pyrolysis oil include at least one of zinc, iron, calcium, and aluminum.

[0025] It should be noted that, in this invention, waste plastic pyrolysis oil refers to a liquid hydrocarbon material obtained by pyrolysis of at least one of polyethylene (PE), polypropylene (PP), polystyrene (PS), and polyvinyl chloride (PVC) at 300℃-800℃ under air-isolated conditions.

[0026] In one optional embodiment, the waste plastic pyrolysis oil contains 1 μg / g to 10000 μg / g of silicon, 1 μg / g to 10000 μg / g of chlorine, 1 μg / g to 10000 μg / g of metal, 1 μg / g to 5000 μg / g of sulfur, and 1 μg / g to 5000 μg / g of nitrogen.

[0027] In addition, the metals in waste plastic pyrolysis oil include at least one of iron, calcium, aluminum, and zinc.

[0028] In an alternative embodiment, step (1) further includes the addition of an oil-soluble catalyst and / or a dechlorinating agent.

[0029] It should be noted that in this invention, the oil-soluble catalyst is a metal active substance uniformly dispersed in a dispersant.

[0030] Furthermore, the metal active material includes at least one of the oxides of molybdenum, nickel, and iron.

[0031] Furthermore, the mass of the metal active material accounts for 0.1wt%-50wt% of the mass of the oil-soluble catalyst, and can be selected as 5wt%-15wt%.

[0032] Furthermore, the dispersant includes at least one of glycerol, oleic acid, fatty alcohol, and gelatin.

[0033] In one optional embodiment, the amount of oil-soluble catalyst added is 0.01wt%-3wt% of the mass of the waste oil, optionally 0.1wt%-1wt%.

[0034] In this invention, the dechlorinating agent includes at least one of calcium, sodium, potassium, zinc, and magnesium.

[0035] In one optional embodiment, the amount of the dechlorinating agent added is 0.01wt%-1wt% of the mass of the waste oil, and optionally 0.1wt%-0.5wt%.

[0036] It should be noted that, in this invention, the catalyst for the fixed-bed hydrorefining reaction includes a support and an active component. The active component includes at least one of molybdenum, nickel, tungsten, and cobalt, preferably molybdenum and tungsten or cobalt and molybdenum. The support includes at least one of molecular sieve, diatomaceous earth, and activated alumina, preferably a molecular sieve. The content of the active component accounts for 5wt%-20wt% of the total catalyst mass, preferably 12wt%-15wt%.

[0037] In a second aspect, the present invention provides a waste oil treatment system for the waste oil described in the first aspect, comprising: A pre-hydrogenation reactor, the inlet of which is connected to the outlet of a feedstock oil storage tank, the pre-hydrogenation reactor including a liquid phase outlet and a gas phase outlet; The first separation device has its inlet connected to the liquid phase outlet of the pre-hydrogenation reactor, and the first separation device includes a liquid-solid phase outlet and a gas phase outlet. The inlet of the hydrorefining unit is connected to the gas phase outlet of the first separation unit and the gas phase outlet of the pre-hydrogenation reaction unit, respectively. The fractionation unit has its inlet connected to the liquid phase outlet of the hydrorefining unit.

[0038] It should be noted that a circulating stirrer is installed at the bottom of the pre-hydrogenation reactor. A collection tank is installed above the transverse centerline of the suspended bed reactor, and the outlet of the collection tank is located higher than the downstream separator to extract heavy oil and catalyst to obtain the first liquid phase.

[0039] In an optional embodiment, a second separation device is further included, the inlet of which is connected to the gas phase outlet of the pre-hydrogenation reaction device. The second separation device includes a gas phase outlet and a liquid phase outlet, the liquid phase outlet of which is connected to the inlet of the hydrorefining device. In one alternative embodiment, a third separation device is provided, the inlet of which is connected to the gas phase outlet of the second separation device. The third separation device includes a gas phase outlet and a liquid phase outlet, the liquid phase outlet of which is connected to the inlet of the hydrorefining device.

[0040] In one alternative embodiment, the purification device has its inlet connected to the gas phase outlet of the third separation device, and the purification device includes a gas phase outlet and a liquid phase outlet.

[0041] In one alternative embodiment, a first compression device has its inlet connected to the gas phase outlet of the purification treatment device and its outlet connected to the gas phase inlet of the pre-hydrogenation reaction device.

[0042] In one optional embodiment, the liquid-solid phase outlet of the first separation device is connected to the inlet of the pre-hydrogenation reaction device and the inlet of the fourth separation device, respectively, wherein the fourth separation device includes a liquid phase outlet and a solid phase outlet.

[0043] It should be noted that the fourth separation device includes at least one of a filter, a filter press, a cyclone separator, and a centrifuge.

[0044] In one alternative embodiment, the cooling device has its inlet connected to the gas phase outlet of the first separation device and the liquid phase outlet of the second separation device, respectively.

[0045] In one alternative embodiment, the inlet of the second compression device is connected to the outlet of the cooling device, the liquid phase outlet of the third separation device, the liquid phase outlet of the fourth separation device, and the liquid phase outlet of the purification device, respectively.

[0046] In one alternative embodiment, the heating device has its inlet connected to the outlet of the second compression device, and its outlet connected to the inlet of the hydrorefining device.

[0047] In one alternative embodiment, a third compression unit has its inlet connected to the outlet of the feedstock oil storage tank, its outlet connected to the process inlet of the heat exchange unit, and the process outlet of the heat exchange unit connected to the inlet of the pre-hydrogenation reactor.

[0048] In one alternative embodiment, the outlet of the hydrorefining unit is connected to the working fluid inlet of the heat exchanger, the working fluid outlet of the heat exchanger is connected to the inlet of the fifth separation unit, the fifth separation unit includes a liquid phase outlet and a gas phase outlet, and the liquid phase outlet of the fifth separation unit is connected to the inlet of the fractionation unit.

[0049] In one alternative embodiment, the circulating oil outlet of the fractionation unit is connected to the inlet of the second compression unit.

[0050] In one alternative embodiment, a sixth separation device is provided, the inlet of which is connected to the gas phase outlet of the fifth separation device. The sixth separation device includes a gas phase outlet and a liquid phase outlet. The gas phase outlet of the sixth separation device is connected to the inlet of the hydrorefining device and the inlet of the first compression device, respectively.

[0051] The technical solution of this invention has the following advantages: 1. The waste oil treatment method provided by the present invention includes the following steps: (1) waste oil and hydrogen are mixed and pre-hydrogenated to obtain a first liquid phase and a first gas phase; (2) the first liquid phase is separated to obtain a liquid-solid phase and a second gas phase, the second gas phase and the first gas phase are mixed and hydrorefined to obtain a hydrorefined product; (3) the hydrorefined product is fractionated to obtain naphtha and diesel oil respectively. This invention first performs pre-hydrogenation treatment to remove chlorine, metals, sulfur, and nitrogen from waste oil, improving the yield of clean products, avoiding contamination of the hydrorefining catalyst by impurities, and reducing the corrosion of equipment and pipelines by impurities, enabling large-scale industrial application. Furthermore, the first liquid phase undergoes a first separation before hydrorefining, which reduces the reaction load on the first gas phase. The first liquid phase is high-temperature, heavy oil containing solids; after the first separation, the deactivated catalyst and solid impurities in the first liquid phase are separated and discharged, reducing their contamination of the hydrorefining process and improving the conversion rate and quality of the target product. This results in a 10% increase in oil yield compared to traditional hydrorefining technologies. Moreover, the raw material pretreatment of this invention is simple, without adsorption or distillation operations, reducing process losses and energy consumption, and enabling long-term, safe, and stable industrial production. Attached Figure Description

[0052] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0053] Figure 1 This is the system for preparing clean diesel fuel by hydrogenating waste oil in Embodiment 1 of the present invention.

[0054] Explanation of reference numerals in the attached figures: 1. First raw material storage tank; 2. First booster pump; 3. Heat exchanger; 4. Suspended bed pre-hydrogenation reactor; 5. Hot high-pressure separator; 6. Solid-liquid separator; 7. First circulating pump; 8. First gas separator; 9. Purification device; 10. Solid-liquid separation tank; 11. Mixed hydrogen compressor; 12. Cooling device; 13. Second raw material storage tank; 14. Second booster pump; 15. Heating furnace; 16. Fixed bed hydrorefining reactor; 17. Cold high-pressure separator; 18. Fractionating tower; 19. Second gas separator; 20. Second circulating pump. Detailed Implementation

[0055] The following embodiments are provided to better understand the present invention, but the following embodiments do not constitute a limitation on the content and scope of protection of the present invention. Any product that is the same as or similar to the present invention, derived by any person under the guidance of the present invention or by combining the features of the present invention with other prior art, falls within the scope of protection of the present invention.

[0056] Unless otherwise specified, the experimental steps or conditions in the examples were performed in accordance with conventional experimental procedures and conditions in the art. Reagents or instruments whose manufacturers are not specified are all commercially available products.

[0057] Example 1 like Figure 1 As shown, this embodiment provides a waste oil treatment system, including a first raw material storage tank 1, a first booster pump 2, a heat exchanger 3, a suspended bed pre-hydrogenation reactor 4, a hot high-pressure separator 5, a solid-liquid-gas separator 6, a first circulating pump 7, a first gas separator 8, a purification device 9, a solid-liquid separation device 10, a mixed hydrogen compressor 11, a cooling device 12, a second raw material storage tank 13, a second booster pump 14, a heating furnace 15, a fixed bed hydrorefining reactor 16, a cold high-pressure separator 17, a fractionation tower 18, a second gas separator 19, and a second circulating pump 20; specifically: First raw material storage tank 1: used to store pre-hydrogenation catalyst, dechlorination agent and waste oil; The inlet of the first booster pump 2 is connected to the outlet of the first raw material storage tank 1; Heat exchanger 3, whose process inlet is connected to the outlet of the first booster pump 2; The suspended bed pre-hydrogenation reactor 4 has its inlet connected to the process outlet of the heat exchanger 3. The suspended bed pre-hydrogenation reactor 4 includes a gas phase outlet and a liquid phase outlet. The hot high-pressure separator 5 has its inlet connected to the gas phase outlet of the suspended bed pre-hydrogenation reactor 4. The hot high-pressure separator 5 includes a gas phase outlet and a liquid phase outlet. The first gas separator 8 has its inlet connected to the gas phase outlet of the hot high-pressure separator 5. The first gas separator 8 includes a gas phase outlet and a liquid phase outlet. The purification device 9 has its inlet connected to the gas phase outlet of the first gas separator 8. The purification device 9 includes a gas phase outlet and a liquid phase outlet. The inlet of the mixed hydrogen compressor 11 is connected to the gas phase outlet of the purification device 9, and its outlet is connected to the gas phase inlet of the suspended bed pre-hydrogenation reactor 4. The solid-liquid-gas separator 6 has its inlet connected to the liquid phase outlet of the suspended bed pre-hydrogenation reactor 4. The solid-liquid-gas separator 6 includes a gas phase outlet and a solid-liquid phase outlet. The first circulating pump 7 has its inlet connected to the solid-liquid phase outlet of the solid-liquid separation tank 6, and its outlet connected to the liquid phase inlet of the suspended bed pre-hydrogenation reactor 4. The inlet of the cooling device 12 is connected to the gas phase outlet of the solid-liquid-gas separator 6 and the liquid phase outlet of the thermal high-pressure separator 5, respectively. The solid-liquid separation device 10 has its inlet connected to the solid-liquid phase outlet of the solid-liquid-gas separator 6. The solid-liquid separation device 10 includes a liquid phase outlet and a solid phase outlet. The inlet of the second raw material storage tank 13 is connected to the liquid phase outlet of the first gas separator 8, the outlet of the cooling device 12, and the liquid phase outlet of the solid-liquid separation device 10, respectively. The inlet of the second booster pump 14 is connected to the outlet of the second raw material storage tank 13; The heating furnace 15 has its inlet connected to the outlet of the second booster pump 14; The fixed-bed hydrorefining reactor 16 has its inlet connected to the outlet of the heater 15 and its outlet connected to the working fluid inlet of the heat exchanger 3. The cold high-pressure separator 17 has its inlet connected to the working fluid outlet of the heat exchanger 3. The cold high-pressure separator 17 includes a liquid phase outlet and a gas phase outlet. The second gas separator 19 has its inlet connected to the gas phase outlet of the cold high-pressure separator 17. The second gas separator 19 includes a liquid phase outlet and a gas phase outlet. Its gas phase outlet is connected to the gas phase inlet of the fixed bed hydrorefining reactor 16 and the inlet of the mixed hydrogen compressor 11, respectively. Its liquid phase outlet produces clean and renewable naphtha. The fractionation tower 18 has its inlet connected to the liquid phase outlet of the cold high-pressure separator 17. The fractionation tower 18 includes a light fraction outlet that yields clean and renewable naphtha, a middle fraction outlet that yields clean and renewable diesel, and a heavy fraction outlet. The heavy fraction outlet is connected to the inlet of the second circulation pump 20, and the outlet of the second circulation pump 20 is connected to the inlet of the second raw material storage tank 13.

[0058] Example 2 This embodiment provides a method for treating waste oil, including the following steps: (1) Waste tire pyrolysis oil (containing 1252 μg / g silicon, 339 μg / g iron, 243 μg / g calcium, 196 μg / g aluminum, 12 μg / g zinc, 323 μg / g chlorine, 5347 μg / g sulfur, and 4582 μg / g nitrogen), oil-soluble catalyst (containing glycerol and molybdenum oxide, with molybdenum oxide content of 12 wt%), and dechlorination agent (calcium oxide) are transported to raw material storage tank 1. The oil-soluble catalyst and dechlorinating agent account for 0.8 wt% and 0.3 wt% of the waste tire pyrolysis oil, respectively, and are thoroughly mixed using a stirrer. The mixed feedstock oil is then pressurized to 2.5 MPa by a booster pump 2 and sent to a heat exchanger 3 to be heated to 300°C. The heat source is the downstream fixed-bed hydrorefining reaction product. The product is then mixed with hydrogen and enters a suspended-bed pre-hydrogenation reactor 4 for impurity removal. The reaction residence time is 1.5 h, the liquid-phase gas velocity is 0.9 m / s, and the hydrogen-to-oil ratio is 800:1. (2) The gaseous product of the suspended bed pre-hydrogenation reaction in step (1) flows out from the top and is sent to the hot high-pressure separator 5 for gas-liquid separation to obtain the first liquid phase and the first gas phase; the first liquid phase is cooled to 50°C and stored in the second raw material storage tank 13; the first gas phase enters the oil-gas separator 8 to obtain the second liquid phase and the second gas phase; the second liquid phase is stored in the second raw material storage tank 13; the second gas phase is sent to the purification device 9, and after the hydrogen sulfide is removed by the amine liquid, the gas is compressed by the mixed hydrogen compressor 11 and circulated as circulating hydrogen to the inlet of the suspended bed pre-hydrogenation reactor 4; (3) The liquid phase product of the suspension bed pre-hydrogenation reaction in step (1) flows out from the middle and upper part and is sent to the solid-liquid-gas separator 6 for solid-liquid-gas three-phase separation. The third gas phase separated from the top is cooled to 50°C and stored in the second raw material storage tank 13. The solid and liquid phases separated from the bottom are divided into two parts. One part is returned to the suspension bed pre-hydrogenation reactor 4 via the first circulation pump 7. The other part is separated from the solid containing impurities by the solid-liquid separation device 10 and stored in the second raw material storage tank 13. (4) The mixed oil in the second raw material storage tank 13 is mixed with hydrogen after passing through the second booster pump 14 and the heater 15, and then transported to the fixed bed hydrorefining reactor 16 to undergo hydrodesulfurization and denitrification refining reaction. The refining reaction temperature is 385℃, the pressure is 10.0MPa, and the hydrogen-to-oil ratio is 900:1. After the fixed bed hydrorefining reaction product is cooled to 45℃ by heat exchanger 3, it is transported to the cold high-pressure separator 17 for oil-gas separation to obtain the third liquid phase and the fourth gas phase. The fourth gas phase is sent to the second gas separator 19, and the mixed hydrogen produced at the top is mixed with the external supplemented hydrogen. One part is injected into the inlet of the fixed-bed hydrorefining reactor as hydrogen required for the refining reaction, and the other part is mixed with the purified gas and then compressed by the mixed hydrogen compressor 11 and injected into the inlet of the suspended bed reactor; the liquid produced at the bottom of the second gas separator 19 is used as clean renewable naphtha product; the third liquid phase is sent to the fractionation tower 18, the top produces light oil as clean renewable naphtha product and is sent out; the middle produces clean renewable diesel; the bottom produces heavy oil as circulating oil, which is mixed with the liquid phase separated by the solid-liquid separation device 10 in step (3) and stored in the second raw material storage tank 13.

[0059] Example 3 This embodiment provides a method for treating waste oil, including the following steps: (1) Waste plastic pyrolysis oil (containing 1089 μg / g silicon, 157 μg / g calcium, 85 μg / g aluminum, 63 μg / g zinc, 21 μg / g iron, 453 μg / g chlorine, 2010 μg / g sulfur, and 1221 μg / g nitrogen), oil-soluble catalyst (containing oleic acid and molybdenum oxide, with molybdenum oxide content of 8 wt%), and dechlorination agent (magnesium oxide) are transported to raw material storage tank 1. The oil-soluble catalyst and dechlorinating agent account for 0.1 wt% and 0.5 wt% of the waste plastic pyrolysis oil, respectively, and are thoroughly stirred using a stirrer. The mixed feedstock oil is then pressurized to 3.0 MPa by a booster pump 2 and sent to a heat exchanger 3 to be heated to 350°C. The heat source is the downstream fixed-bed hydrorefining reaction product. The product is then mixed with hydrogen and enters a suspended-bed pre-hydrogenation reactor 4 for impurity removal. The reaction residence time is 0.8 h, the liquid-phase gas velocity is 0.8 m / s, and the hydrogen-to-oil ratio is 1000:1. (2) The gaseous product of the suspended bed pre-hydrogenation reaction in step (1) flows out from the top and is sent to the hot high-pressure separator 5 for gas-liquid separation to obtain the first liquid phase and the first gas phase; the first liquid phase is cooled to 50°C and stored in the second raw material storage tank 13; the first gas phase enters the oil-gas separator 8 to obtain the second liquid phase and the second gas phase; the second liquid phase is stored in the second raw material storage tank 13; the second gas phase is sent to the purification device 9, and after the hydrogen sulfide is removed by the amine liquid, the gas is compressed by the mixed hydrogen compressor 11 and circulated as circulating hydrogen to the inlet of the suspended bed pre-hydrogenation reactor 4; a small amount of liquid phase is sent to the downstream fixed bed hydrogenation refining raw material tank 13. (3) The liquid phase product of the suspension bed pre-hydrogenation reaction in step (1) flows out from the middle and upper part and is sent to the solid-liquid-gas separator 6 for solid-liquid-gas three-phase separation. The third gas phase separated from the top is cooled to 50°C and stored in the second raw material storage tank 13. The solid and liquid phases separated from the bottom are divided into two parts. One part is returned to the suspension bed pre-hydrogenation reactor 4 via the first circulation pump 7. The other part is separated from the solid containing impurities by the solid-liquid separation device 10 and stored in the second raw material storage tank 13. (4) The mixed oil in the second raw material storage tank 13 is mixed with hydrogen after passing through the second booster pump 14 and the heater 15, and then transported to the fixed bed hydrorefining reactor 16 to undergo hydrodesulfurization and denitrification refining reactions. The refining reaction temperature is 380℃, the pressure is 8.0MPa, and the hydrogen-to-oil ratio is 800:1. After the fixed bed hydrorefining reaction product is cooled to 45℃ by heat exchanger 3, it is transported to the cold high-pressure separator 17 for oil-gas separation to obtain the third liquid phase and the fourth gas phase. The fourth gas phase is sent to the second gas separator 19, and the mixed hydrogen produced at the top is mixed with the external supplementary hydrogen. A portion of the hydrogen is injected into the inlet of the fixed-bed hydrorefining reactor as the hydrogen required for the refining reaction, and another portion is mixed with the purified gas and then compressed by the mixed hydrogen compressor 11 and injected into the inlet of the suspended-bed reactor. The liquid produced at the bottom of the second gas separator 19 is used as a clean and renewable naphtha product. The third liquid phase is sent to the fractionation tower 18, where light oil is produced at the top and sent out as a clean and renewable naphtha product. Clean and renewable diesel is produced in the middle section. Heavy oil is produced at the bottom as circulating oil and mixed with the liquid separated by the solid-liquid separation device 10 in step (3) and stored in the second raw material storage tank 13.

[0060] Example 4 This embodiment provides a method for treating waste oil, including the following steps: (1) Waste tire pyrolysis oil (silicon content 6089 μg / g, iron content 1677 μg / g, calcium content 878 μg / g, aluminum content 532 μg / g, zinc content 161 μg / g, chlorine content 465 μg / g, sulfur content 4796 μg / g, nitrogen content 5002 μg / g), oil-soluble catalyst (catalyst is fatty alcohol and nickel oxide, nickel oxide content is 15 wt%), and dechlorination agent (sodium hydroxide) are transported to Raw material storage tank 1; wherein, the oil-soluble catalyst and dechlorinating agent account for 1wt% and 0.1wt% of the mass of waste tire pyrolysis oil, respectively, and are thoroughly stirred evenly using a stirrer; then the mixed raw material oil is pressurized to 3.5MPa by booster pump 2 and then sent to heat exchanger 3 to be heated to 250℃. The heat source is the downstream fixed bed hydrorefining reaction product, which is then mixed with hydrogen and enters the suspended bed pre-hydrogenation reactor 4 for impurity removal reaction. The reaction residence time is 1h, the liquid phase gas velocity is 1.0m / s, and the hydrogen-to-oil ratio is 500:1; (2) The gaseous product of the suspended bed pre-hydrogenation reaction in step (1) flows out from the top and is sent to the hot high-pressure separator 5 for gas-liquid separation to obtain the first liquid phase and the first gas phase; the first liquid phase is cooled to 50°C and stored in the second raw material storage tank 13; the first gas phase enters the oil-gas separator 8 to obtain the second liquid phase and the second gas phase; the second liquid phase is stored in the second raw material storage tank 13; the second gas phase is sent to the purification device 9, and after the hydrogen sulfide is removed by the amine liquid, the gas is compressed by the mixed hydrogen compressor 11 and circulated to the inlet of the suspended bed pre-hydrogenation reactor as circulating hydrogen, and a small amount of liquid phase is sent to the downstream fixed bed hydrogenation refining raw material tank 13; (3) The liquid phase product of the suspension bed pre-hydrogenation reaction in step (1) flows out from the middle and upper part and is sent to the solid-liquid-gas separator 6 for solid-liquid-gas three-phase separation. The third gas phase separated from the top is cooled to 50°C and stored in the second raw material storage tank 13. The solid and liquid phases separated from the bottom are divided into two parts. One part is returned to the suspension bed pre-hydrogenation reactor 4 via the first circulation pump 7. The other part is separated from the solid containing impurities by the solid-liquid separation device 10 and stored in the second raw material storage tank 13. (4) The mixed oil in the second raw material storage tank 13 is mixed with hydrogen after passing through the second booster pump 14 and the heater 15, and then transported to the fixed bed hydrorefining reactor 16 to undergo hydrodesulfurization and denitrification refining reaction. The refining reaction temperature is 390℃, the pressure is 12.0MPa, and the hydrogen-to-oil ratio is 1000:1. After the fixed bed hydrorefining reaction product is cooled to 45℃ by heat exchanger 3, it is transported to the cold high-pressure separator 17 for oil-gas separation to obtain the third liquid phase and the fourth gas phase. The fourth gas phase is sent to the second gas separator 19, and the mixed hydrogen produced at the top is mixed with the external supplemented hydrogen. One part is injected into the inlet of the fixed-bed hydrorefining reactor as hydrogen required for the refining reaction, and the other part is mixed with the purified gas and then compressed by the mixed hydrogen compressor 11 and injected into the inlet of the suspended bed reactor; the liquid produced at the bottom of the second gas separator 19 is used as clean renewable naphtha product; the third liquid phase is sent to the fractionation tower 18, the top produces light oil as clean renewable naphtha product for external delivery; the middle produces clean renewable diesel; the bottom produces heavy oil as circulating oil, which is mixed with the liquid separated by the solid-liquid separation device 10 in step (3) and stored in the second raw material storage tank 13.

[0061] Example 5 This embodiment provides a method for treating waste oil, including the following steps: (1) Waste plastic pyrolysis oil (silicon content 4967μg / g, calcium content 1855μg / g, aluminum content 106μg / g, zinc content 98μg / g, iron content 56μg / g, chlorine content 409μg / g, sulfur content 1893μg / g, nitrogen content 1342μg / g), oil-soluble catalyst (catalyst is gelatin, molybdenum oxide and nickel oxide, molybdenum oxide content is 20wt%, nickel oxide content is 15wt%), dechlorination agent ( Zinc oxide is transported to raw material storage tank 1; wherein, the oil-soluble catalyst and dechlorinating agent account for 0.01wt% and 1wt% of the mass of waste plastic pyrolysis oil, respectively, and are thoroughly stirred evenly using a stirrer; then the mixed raw material oil is pressurized to 4MPa by booster pump 2 and then transported to heat exchanger 3 to be heated to 200℃, the heat source being the downstream fixed bed hydrorefining reaction product, and then mixed with hydrogen and entered the suspended bed pre-hydrogenation reactor 4 for impurity removal reaction, the reaction residence time is 3h, the liquid phase gas velocity is 0.5m / s, and the hydrogen-to-oil ratio is 2000:1; (2) The gaseous product of the suspended bed pre-hydrogenation reaction in step (1) flows out from the top and is sent to the hot high-pressure separator 5 for gas-liquid separation to obtain the first liquid phase and the first gas phase; the first liquid phase is cooled to 50°C and stored in the second raw material storage tank 13; the first gas phase enters the oil-gas separator 8 to obtain the second liquid phase and the second gas phase; the second liquid phase is stored in the second raw material storage tank 13; the second gas phase is sent to the purification device 9, and after the hydrogen sulfide is removed by the amine liquid, the gas is compressed by the mixed hydrogen compressor 11 and circulated as circulating hydrogen to the inlet of the suspended bed pre-hydrogenation reactor 4; a small amount of liquid phase is sent to the downstream fixed bed hydrogenation refining raw material tank 13. (3) The liquid phase product of the suspension bed pre-hydrogenation reaction in step (1) flows out from the middle and upper part and is sent to the solid-liquid-gas separator 6 for solid-liquid-gas three-phase separation. The third gas phase separated from the top is cooled to 50°C and stored in the second raw material storage tank 13. The solid and liquid phases separated from the bottom are divided into two parts. One part is returned to the suspension bed pre-hydrogenation reactor 4 via the first circulation pump 7. The other part is separated from the solid containing impurities by the solid-liquid separation device 10 and stored in the second raw material storage tank 13. (4) The mixed oil in the second raw material storage tank 13 is mixed with hydrogen after passing through the second booster pump 14 and the heater 15, and then transported to the fixed bed hydrorefining reactor 16 to undergo hydrodesulfurization and denitrification refining reaction. The refining reaction temperature is 300℃, the pressure is 4.0MPa, and the hydrogen-to-oil ratio is 2500:1. After the fixed bed hydrorefining reaction product is cooled to 45℃ by heat exchanger 3, it is transported to the cold high-pressure separator 17 for oil-gas separation to obtain the third liquid phase and the fourth gas phase. The fourth gas phase is sent to the second gas separator 19, and the mixed hydrogen produced at the top is mixed with the external supplemented hydrogen. One part is injected into the inlet of the fixed-bed hydrorefining reactor as hydrogen required for the refining reaction, and the other part is mixed with the purified gas and then compressed by the mixed hydrogen compressor 11 and injected into the inlet of the suspended bed reactor; the liquid produced at the bottom of the second gas separator 19 is used as clean renewable naphtha product; the third liquid phase is sent to the fractionation tower 18, the top produces light oil as clean renewable naphtha product and is sent out; the middle produces clean renewable diesel; the bottom produces heavy oil as circulating oil, which is mixed with the liquid phase separated by the solid-liquid separation device 10 in step (3) and stored in the second raw material storage tank 13.

[0062] Example 6 This embodiment provides a method for treating waste oil, including the following steps: (1) Waste tire pyrolysis oil (silicon content 4669 μg / g, iron content 1078 μg / g, calcium content 478 μg / g, aluminum content 389 μg / g, zinc content 32 μg / g, chlorine content 408 μg / g, sulfur content 6102 μg / g, nitrogen content 4988 μg / g), oil-soluble catalyst (catalyst is glycerol and iron oxide, iron oxide content is 0.1 wt%), and dechlorination agent (potassium hydroxide) are transported to Raw material storage tank 1; wherein, the oil-soluble catalyst and dechlorinating agent account for 3wt% and 0.01wt% of the mass of waste plastic pyrolysis oil, respectively, and are thoroughly stirred evenly using a stirrer; then the mixed raw material oil is pressurized to 1MPa by booster pump 2 and then sent to heat exchanger 3 to be heated to 400℃, the heat source being the downstream fixed bed hydrorefining reaction product, and then mixed with hydrogen and entered the suspended bed pre-hydrogenation reactor 4 for impurity removal reaction, the reaction residence time is 2.5h, the liquid phase gas velocity is 5m / s, and the hydrogen-oil ratio is 200:1; (2) The gaseous product of the suspended bed pre-hydrogenation reaction in step (1) flows out from the top and is sent to the hot high-pressure separator 5 for gas-liquid separation to obtain the first liquid phase and the first gas phase; the first liquid phase is cooled to 50°C and stored in the second raw material storage tank 13; the first gas phase enters the oil-gas separator 8 to obtain the second liquid phase and the second gas phase; the second liquid phase is stored in the second raw material storage tank 13; the second gas phase is sent to the purification device 9, and after the hydrogen sulfide is removed by the amine liquid, the gas is compressed by the mixed hydrogen compressor 11 and circulated as circulating hydrogen to the inlet of the suspended bed pre-hydrogenation reactor 4; a small amount of liquid phase is sent to the downstream fixed bed hydrogenation refining raw material tank 13. (3) The liquid phase product of the suspension bed pre-hydrogenation reaction in step (1) flows out from the middle and upper part and is sent to the solid-liquid-gas separator 6 for solid-liquid-gas three-phase separation. The third gas phase separated from the top is cooled to 50°C and stored in the second raw material storage tank 13. The solid and liquid phases separated from the bottom are divided into two parts. One part is returned to the suspension bed pre-hydrogenation reactor 4 via the first circulation pump 7. The other part is separated from the solid containing impurities by the solid-liquid separation device 10 and stored in the second raw material storage tank 13. (4) The mixed oil in the second raw material storage tank 13 is mixed with hydrogen after passing through the second booster pump 14 and the heater 15, and then transported to the fixed bed hydrorefining reactor 16 to undergo hydrodesulfurization and denitrification refining reaction. The refining reaction temperature is 450℃, the pressure is 18.0MPa, and the hydrogen-to-oil ratio is 300:1. After the fixed bed hydrorefining reaction product is cooled to 45℃ by heat exchanger 3, it is transported to the cold high-pressure separator 17 for oil-gas separation to obtain the third liquid phase and the fourth gas phase. The fourth gas phase is sent to the second gas separator 19, and the mixed hydrogen produced at the top is mixed with the external supplemented hydrogen. One part is injected into the inlet of the fixed-bed hydrorefining reactor as hydrogen required for the refining reaction, and the other part is mixed with the purified gas and then compressed by the mixed hydrogen compressor 11 and injected into the inlet of the suspended bed reactor; the liquid produced at the bottom of the second gas separator 19 is used as clean renewable naphtha product; the third liquid phase is sent to the fractionation tower 18, the top produces light oil as clean renewable naphtha product and is sent out; the middle produces clean renewable diesel; the bottom produces heavy oil as circulating oil, which is mixed with the liquid phase separated by the solid-liquid separation device 10 in step (3) and stored in the second raw material storage tank 13.

[0063] Comparative Example 1 This comparative study provides a method for preparing clean diesel fuel by hydrogenation of waste oil, comprising the following steps: (1) Waste plastic oil (containing 1089 μg / g silicon, 157 μg / g calcium, 85 μg / g aluminum, 63 μg / g zinc, 21 μg / g iron, 453 μg / g chlorine, 2010 μg / g sulfur, and 1221 μg / g nitrogen) was pressurized to 2.5 MPa by a booster pump and then transported to a heat exchanger to be heated to 300°C. It was mixed with hydrogen and then entered a fixed-bed pretreatment reactor to undergo a de-impurification reaction. The reaction residence time was 1.5 h, the liquid phase gas velocity was controlled at 0.9 m / s, the reaction temperature was 385°C, the pressure was 10.0 MPa, and the hydrogen-to-oil ratio was 900:1. (2) After oil-gas separation, the gas phase of the fixed-bed pretreatment reactor is returned to the inlet of the fixed-bed pretreatment reactor as circulating hydrogen, and the liquid phase is transported to the fixed-bed hydrotreating reactor to undergo hydrorefining reaction. The refining reaction temperature is 385℃, the pressure is 10.0MPa, and the hydrogen-to-oil ratio is 900:1. The refining reaction product undergoes two-step oil-gas separation in a high-pressure separator and a low-pressure separator. The gas phase of the high-pressure separator is returned to the inlet of the fixed-bed hydrotreating reactor as circulating hydrogen, and the liquid phase produced by the high-pressure separator is depressurized and used as clean renewable naphtha product. The liquid phase of the low-pressure separator is depressurized and sent to the fractionation tower. The light oil product produced at the top of the fractionation tower is sent out as clean renewable naphtha product. The clean renewable diesel product is produced in the middle section. The heavy oil product produced at the bottom is returned to the inlet of the fixed-bed hydrorefining reactor as circulating oil.

[0064] Comparative Example 2 This comparison provides a method for preparing clean diesel by hydrogenating waste oil, which is basically the same as the steps in Example 2, except that step (3) is omitted, that is, all the suspended bed pre-hydrogenated products are directly sent to a hot high-pressure separator for gas-liquid separation.

[0065] Experimental Example The clean renewable diesel oil obtained in Examples 2-6 and Comparative Examples 1-2 was tested for sulfur content according to SH / T 0689 (ultraviolet fluorescence method), nitrogen content according to GB / T 17674 (chemiluminescence method), and total metal content according to GB / T37160 (inductively coupled plasma atomic emission spectrometry). The total yield of liquid products was calculated, and the results are shown in Table 1. The liquid products include clean renewable naphtha and clean renewable diesel oil. The total yield of liquid products = (amount of clean renewable diesel oil + amount of clean renewable naphtha) / amount of raw materials added.

[0066] The sulfur and nitrogen content of the clean renewable naphtha obtained in Examples 2-6 and Comparative Examples 1-2 were tested using the same methods as those used for determining the physical properties of clean renewable diesel oil. The results are shown in Table 2.

[0067] Table 1. Total liquid yield and physical properties of clean renewable diesel oil for each example and comparative example.

[0068] Table 2 Physical properties of clean renewable naphtha from each embodiment and comparative example

[0069] As can be seen from Tables 1 and 2, the waste oil treatment method of this invention has a high total yield of liquid products and good product quality, making it suitable for large-scale production and enabling continuous mass production. In contrast, the total liquid yield of Comparative Example 1 is only 80%, and the oil quality is poor. This is because the catalyst in the fixed-bed pre-hydrogenation treatment is easily deactivated by high-content metals in the feedstock clogging the pores and by sulfur and nitrogen compounds, making it unable to effectively remove impurities from the feedstock. The total liquid yield of Comparative Example 2 is only 85%, and the oil quality is also poor. This is because some of the deactivated catalyst is not discharged from the system in time, which easily reduces the reaction conversion rate of the feedstock, resulting in a decrease in oil yield and poor impurity removal effect.

[0070] Experimental Example 2 The consumption per ton of waste oil for each of the above embodiments and comparative examples was tested, including hydrogen consumption, catalyst life, and power consumption. The results are shown in Table 3.

[0071] Table 3. Waste oil treatment consumption per ton

[0072] As can be seen from Table 3, the waste oil treatment method of the present invention has low energy consumption, can achieve continuous large-scale production, and saves production costs. In contrast, Comparative Example 1 has a rapid catalyst failure, and the raw materials need to consume a lot of energy during the reaction process to ensure the normal progress of the catalytic reaction, which ultimately leads to a large consumption of hydrogen and electricity. The catalyst life is also reduced due to the easy acceleration of deactivation caused by catalyst contamination in the bed. In the comparative example of Comparative Example 2, the oil-soluble catalyst circulation process in the suspended bed hydrogenation section is too long, and the catalyst concentration in the reactor is insufficient, resulting in a large consumption of hydrogen and electricity during the reaction process. The catalyst cannot be discharged from the system in time, causing poisoning and deactivation.

[0073] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A method for treating waste oil, characterized in that, Includes the following steps: (1) Waste oil and hydrogen are mixed and then pre-hydrogenated to obtain a first liquid phase and a first gas phase; (2) After the first liquid phase is subjected to the first separation treatment, a liquid-solid phase and a second gas phase are obtained. The second gas phase and the first gas phase are mixed and then subjected to hydrogenation purification treatment to obtain the hydrogenation purified product. (3) The hydrorefined product is fractionated to obtain naphtha and diesel oil respectively.

2. The waste oil treatment method according to claim 1, characterized in that, Before the second gas phase and the first gas phase are mixed, the process further includes a second separation of the first gas phase and a third separation of the resulting gas phase. The gas phase obtained from the third separation is purified and then compressed and returned to step (1) for pre-hydrogenation treatment as circulating hydrogen. The liquids obtained from the second separation and the third separation are pressurized and heated before undergoing the hydrogenation purification treatment.

3. The waste oil treatment method according to claim 1, characterized in that, It also includes returning a portion of the liquid-solid phase to step (1) for pre-hydrogenation treatment, and after the remaining portion undergoes a fourth separation, the resulting liquid is subjected to hydrogenation purification treatment after pressurization and heating. And / or, prior to the hydrorefining process, the method further includes a step of cooling the second gas phase and the second separated liquid phase.

4. The waste oil treatment method according to claim 1, characterized in that, In step (1), before the pre-hydrogenation treatment is performed after the waste oil and hydrogen are mixed, the waste oil is pressurized to 1MPa-4MPa and heated to 200℃-400℃.

5. The waste oil treatment method according to claim 1, characterized in that, The fractionation process also includes circulating oil; the circulating oil is then subjected to hydrorefining after being pressurized and heated. And / or, before fractionation, the hydrorefined product further includes a fifth separation step to obtain a second liquid phase and a third gas phase. The second liquid phase is fractionated, and the third gas phase is separated in a sixth step. The resulting liquid phase is naphtha, and the resulting gas phase is returned to step (2) for hydrorefining. The remaining part is compressed and returned to step (1) for pre-hydrogenation. And / or, prior to the fifth separation of the hydrorefined product, a heat exchange step with the waste oil from step (1) is also included.

6. The method for treating waste oil according to claim 1, characterized in that, In the pre-hydrogenation treatment, the reaction residence time is 0.8h-3h, the liquid phase gas velocity is 0.5m / s-5m / s, and the hydrogen-to-oil ratio is 200-2000:1; And / or, the hydrorefining treatment is carried out at a temperature of 300℃-500℃, a pressure of 4.0MPa-20MPa, and a hydrogen-to-oil ratio of 300-2500:

1.

7. The method for treating waste oil according to claim 1, characterized in that, The waste oil includes at least one of waste tire pyrolysis oil and waste plastic pyrolysis oil. Optionally, in the waste tire pyrolysis oil, the silicon content is 1μg / g-10000μg / g, the chlorine content is 1μg / g-10000μg / g, the metal content is 1μg / g-10000μg / g, the sulfur content is 1000μg / g-10000μg / g, and the nitrogen content is 1000μg / g-10000μg / g; Optionally, the waste plastic pyrolysis oil contains 1 μg / g-10000 μg / g of silicon, 1 μg / g-10000 μg / g of chlorine, 1 μg / g-10000 μg / g of metal, 1 μg / g-5000 μg / g of sulfur, and 1 μg / g-5000 μg / g of nitrogen.

8. The method for treating waste oil according to claim 1, characterized in that, Step (1) also includes the addition of an oil-soluble catalyst and / or a dechlorinating agent; Optionally, the amount of the oil-soluble catalyst added is 0.01wt%-3wt% of the mass of the waste oil; Optionally, the amount of the dechlorinating agent added is 0.01wt%-1wt% of the mass of the waste oil.

9. A waste oil treatment system according to any one of claims 1-8, characterized in that, include: A pre-hydrogenation reactor, the inlet of which is connected to the outlet of a feedstock oil storage tank, the pre-hydrogenation reactor including a liquid phase outlet and a gas phase outlet; The first separation device has its inlet connected to the liquid phase outlet of the pre-hydrogenation reactor, and the first separation device includes a liquid-solid phase outlet and a gas phase outlet. The inlet of the hydrorefining unit is connected to the gas phase outlet of the first separation unit and the gas phase outlet of the pre-hydrogenation reaction unit, respectively. The fractionation unit has its inlet connected to the liquid phase outlet of the hydrorefining unit.

10. The waste oil treatment system according to claim 9, characterized in that, It also includes a second separation device, the inlet of which is connected to the gas phase outlet of the pre-hydrogenation reaction device. The second separation device includes a gas phase outlet and a liquid phase outlet, the liquid phase outlet of which is connected to the inlet of the hydrorefining device. And / or, a third separation unit, the inlet of which is connected to the gas phase outlet of the second separation unit, the third separation unit including a gas phase outlet and a liquid phase outlet, the liquid phase outlet of which is connected to the inlet of the hydrorefining unit; And / or, a purification treatment device, the inlet of which is connected to the gas phase outlet of the third separation device, the purification treatment device including a gas phase outlet and a liquid phase outlet; And / or, a first compression device, the inlet of which is connected to the gas phase outlet of the purification treatment device, and the outlet of which is connected to the gas phase inlet of the pre-hydrogenation reaction device; And / or, the liquid-solid phase outlet of the first separation device is connected to the inlet of the pre-hydrogenation reaction device and the inlet of the fourth separation device, respectively, the fourth separation device including a liquid phase outlet and a solid phase outlet; And / or, a cooling device, the inlet of which is connected to the gas phase outlet of the first separation device and the liquid phase outlet of the second separation device, respectively; And / or, the inlet of the second compression device is connected to the outlet of the cooling device, the liquid phase outlet of the third separation device, and the liquid phase outlet of the fourth separation device, respectively; And / or, a heating device, the inlet of which is connected to the outlet of the second compression device, and the outlet of which is connected to the inlet of the hydrorefining device; And / or, a third compression unit, the inlet of which is connected to the outlet of the feedstock oil storage tank, the outlet of which is connected to the process inlet of the heat exchange unit, and the process outlet of the heat exchange unit is connected to the inlet of the pre-hydrogenation reaction unit; And / or, the outlet of the hydrorefining unit is connected to the working fluid inlet of the heat exchanger, the working fluid outlet of the heat exchanger is connected to the inlet of the fifth separation unit, the fifth separation unit includes a liquid phase outlet and a gas phase outlet, and the liquid phase outlet of the fifth separation unit is connected to the inlet of the fractionation unit; And / or, the circulating oil outlet of the fractionation unit is connected to the inlet of the second compression unit; And / or, a sixth separation device, the inlet of which is connected to the gas phase outlet of the fifth separation device, the sixth separation device including a gas phase outlet and a liquid phase outlet, the gas phase outlet of the sixth separation device being connected to the inlet of the hydrorefining device and the inlet of the first compression device, respectively.

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