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CN-121975544-A - Method and system for preparing high-value oil product by synergistic co-hydrogenation of waste plastics and waste lubricating oil

CN121975544ACN 121975544 ACN121975544 ACN 121975544ACN-121975544-A

Abstract

A method for preparing high-value oil products by synergic co-hydrogenation of waste plastics and waste lubricating oil comprises the following steps of: the method comprises the steps of (a) preparing waste plastics, waste lubricating oil and catalyst in a raw material tank to form uniform mixed slurry, b) conveying the mixed slurry through a high-pressure feed pump and mixing with hydrogen in a pipeline, then preheating the mixed slurry in a preheater to a certain temperature, and then entering a multiphase flow reactor for carrying out a co-hydrogenation reaction, c) obtaining a gas-phase product and a heavy liquid-phase product by a reaction product output by the multiphase flow reactor through a primary separator and a secondary separator, wherein a part of the heavy liquid-phase product returns to the raw material tank for continuous reaction, and the rest part is used as a fuel oil output device, d) separating the gas-phase product through a three-stage separator, feeding top gas into a circulating hydrogen compressor, feeding bottom liquid into a fixed bed reactor for hydrofining, and separating the reaction product through a fractionating tower to obtain light white oil and lubricating oil base oil. The invention realizes the high-value utilization of waste resources.

Inventors

  • LI WEI
  • HUANG YONG
  • HUO PENGJU
  • WU SHENGXIAO
  • KANG XUWEI
  • Zhe Zhe

Assignees

  • 西北化工研究院有限公司
  • 陕西延长石油（集团）有限责任公司

Dates

Publication Date
20260505
Application Date
20260203

Claims (9)

  1. 1. The method for preparing the high-value oil product by the synergistic co-hydrogenation of the waste plastics and the waste lubricating oil is characterized by comprising the following steps of; a) Waste plastics (1), waste lubricating oil (2) and a catalyst (3) are prepared in a raw material tank (4) to form uniform mixed slurry; b) The mixed slurry is conveyed by a high-pressure feed pump (5) and mixed with hydrogen (14) in a pipeline, then enters a preheater (6) for preheating to a certain temperature, and enters a multiphase flow reactor (7) for carrying out a co-hydrogenation reaction; c) The reaction product output by the multiphase flow reactor (7) passes through a first-stage separator (8) and a second-stage separator (10) to obtain a gas-phase product (9) and a heavy liquid-phase product (11), wherein part of the heavy liquid-phase product (11) returns to the raw material tank (4) to continue the reaction, and the rest is used as a fuel oil (19) output device; d) The gas phase product (9) is separated by a three-stage separator (12), the top gas enters a circulating hydrogen compressor (13), the bottom liquid enters a fixed bed reactor (15) for hydrofining, and the reaction product is separated by a fractionating tower (16) to obtain light white oil (17) and lubricating oil base oil (18).
  2. 2. The method for preparing high-value oil products by co-hydrogenation of waste plastics and waste lubricating oil according to claim 1, wherein the waste plastics 1 in the a) are one or more of PP, PE, PS, PET, PVC, are granular, and have a particle size range controlled between 5 and 150 μm.
  3. 3. The method for preparing high-value oil products by co-hydrogenation of waste plastics and waste lubricating oil according to claim 1, wherein the waste lubricating oil (2) in the step a) is at least one of waste hydraulic oil, waste gear oil, waste compressor oil, waste electrical equipment insulating oil and waste heat conducting oil, or a certain section of distillate oil obtained by distillation and cutting; The weight ratio of the waste plastics (1) to the waste lubricating oil (2) in the mixed slurry in the step a) is 1 (1-20).
  4. 4. The method for preparing high-value oil products by synergic Co-hydrogenation of waste plastics and waste lubricating oil according to claim 1, wherein the catalyst (3) in a) is in powder form, the bulk density is 0.6-0.8 g/cm 3 , the average particle size is 65-75 μm, the specific surface area is 400-600 m 2 /g, the active components are one or more of Fe, ni, co and Mo, the carrier is active carbon, coal dust and coke, and the catalyst addition amount accounts for 0.5-10.0% of the total feed mass.
  5. 5. The method for preparing high-value oil products by co-hydrogenation of waste plastics and waste lubricating oil according to claim 1, wherein the control temperature of the raw material tank (4) is 50-120 ℃, and the control temperature of the preheater (6) is 200-350 ℃.
  6. 6. The method for preparing high-value oil products by co-hydrogenation of waste plastics and waste lubricating oil according to claim 1, wherein the multiphase flow hydrogenation reaction conditions of the multiphase flow reactor (7) in b) are as follows: The reaction temperature is 370-450 ℃, the reaction pressure is 2-10 MPa, the liquid space velocity is 0.3-3.0 h -1 , and the hydrogen-oil ratio is 800-1500 NL/kg; The multiphase flow reactor (7) in the b) is one or a combination of a plurality of suspended beds, boiling beds and bubbling beds, and the operation modes can be in series connection or parallel connection.
  7. 7. The method for preparing high-value oil products by synergic co-hydrogenation of waste plastics and waste lubricating oil according to claim 1, wherein, In the d), the final distillation point of the light distillate is not higher than 520 ℃; The hydrofining reaction condition of the fixed bed reactor (15) in the d) is that the reaction temperature is 300-450 ℃, the reaction pressure is 2-10 MPa, the volume space velocity is 0.3-1.5 h -1 , and the hydrogen oil volume ratio is 500-1000 NL/kg.
  8. 8. The method for preparing high-value oil products by co-hydrogenation of waste plastics and waste lubricating oil according to claim 1, wherein the fixed bed reactor (15) in d) is filled with a hydrofining catalyst, a hydroisomerization catalyst and a hydrocracking catalyst bed, the catalyst active components are at least one or more of Co, mo, ni, W, and the content of the metal active components is 10-40% in terms of oxide based on the total weight of the catalyst.
  9. 9. A system for preparing high-value oil products by co-hydrogenation of waste plastics and heavy waste lubricating oil for realizing the method of any one of claims 1-8, which is characterized by comprising a mixed slurry preparation unit, a co-hydrogenation conversion unit and a fixed bed hydrofining unit; The mixed slurry preparation unit comprises a raw material tank (4) provided with a stirrer, and the raw material tank (4) is respectively connected with pipelines for transporting waste plastics (1), waste lubricating oil (2) and a catalyst (3); the co-hydroconversion unit comprises a high-pressure feed pump (5), a preheater (6), a multiphase flow reactor (7), a primary separator (8), a secondary separator 10, a tertiary separator (12), a recycle hydrogen compressor (13) and hydrogen (14); The mixed slurry outlet output by the raw material tank (4) is connected with the inlet of a high-pressure feed pump (5), the outlet of the high-pressure pump (5) is respectively connected with the inlet of a hydrogen (14) and the inlet of a preheater (6), the outlet of the preheater (6) is connected with the inlet of a multiphase flow reactor (7), the outlet of the multiphase flow reactor (7) is connected with the inlet of a primary separator (8), the top outlet of the primary separator (8) is connected with the inlet of a tertiary separator (12), the top outlet of the tertiary separator (12) is connected with the inlet of a circulating hydrogen compressor (13), the bottom outlet of the primary separator (8) is connected with the inlet of a secondary separator (10), the outlet of the secondary separator (10) is used for obtaining a heavy liquid phase product (11), and the heavy liquid phase product (11) is simultaneously connected with the outlet of the raw material tank (4) and the outlet of a fuel oil (19) through pipelines; the fixed bed hydrofining unit comprises a fixed bed reactor (15) and a fractionating tower (16), wherein the light distillate oil at the bottom of the three-stage separator (12) is connected with the inlet of the fixed bed reactor (15), the outlet of the fixed bed reactor (15) is connected with the inlet of the fractionating tower (16), and the outlet of the fractionating tower (16) is connected with the light white oil (17) and the lubricating oil base oil (18) through pipelines.

Description

Method and system for preparing high-value oil product by synergistic co-hydrogenation of waste plastics and waste lubricating oil Technical Field The invention belongs to the technical field of waste recycling, and particularly relates to a method and a system for preparing high-value oil products by co-hydrogenation of waste plastics and waste lubricating oil. Background In reality, the recycling rate of waste plastics is less than 10%, and a large amount of plastic garbage is treated in a landfill mode, an incineration mode or a pyrolysis mode and the like, so that heavy environmental pollution and resource waste are caused. The publication CN 120020227a discloses a method and apparatus for treating inferior oil and waste plastics by a slurry bed. The method comprises the steps of firstly, carrying out hydrogenation reaction on inferior oil in a slurry bed reactor, separating a product by a thermal high-pressure separator to obtain a gas phase component and a liquid phase component, mixing the liquid phase component with waste plastics, feeding the mixture into a cracking furnace for thermal cracking, fractionating the product to obtain a light fraction and a heavy fraction, separating the heavy fraction by a centrifugal separation device to obtain the heavy fraction and the light fraction, and carrying out reaction on the heavy fraction and the light fraction in the slurry bed reactor in a circulating manner to obtain the final product. The method has the following defects that the direct mixing of waste plastics and hydrogenated liquid phase components with higher temperature easily causes softening and adhesion of plastics, causes blockage of a conveying pipeline, influences long-period stable operation of a device, and has the problems of low liquid yield, poor product quality and the like in the high-temperature pyrolysis reaction. Disclosure of Invention The invention aims to overcome the defects of difficult conveying, easy coking, low added value of products and the like of waste plastics in the prior art, and aims to provide a method and a system for preparing high-value oil products by synergic co-hydrogenation of waste plastics and waste lubricating oil. The method not only fundamentally solves the problems of conveying blockage and coking in the waste plastic processing process, but also can flexibly adjust the product structure according to market demands, directionally produce light white oil and lubricating oil base oil with high added value, and realize the high-value utilization of waste resources. In order to achieve the above purpose, the technical scheme adopted by the invention is as follows: a method for preparing high-value oil products by synergic co-hydrogenation of waste plastics and waste lubricating oil comprises the following steps of; a) Preparing waste plastic 1, waste lubricating oil 2 and catalyst 3 in a raw material tank 4 to form uniform mixed slurry; b) The mixed slurry is conveyed by a high-pressure feed pump 5 and mixed with hydrogen in a pipeline, then enters a preheater 6 to be preheated to a certain temperature, and enters a multiphase flow reactor 7 to carry out a co-hydrogenation reaction; c) The reaction product output by the multiphase flow reactor 7 passes through a first-stage separator 8 and a second-stage separator 10 to obtain a gas-phase product 9 and a heavy liquid-phase product 11, wherein part of the heavy liquid-phase product returns to the raw material tank 4 to continue the reaction, and the rest is taken as a fuel oil 19 output device. D) The gas phase product is separated by a three-stage separator 12, the top gas enters a circulating hydrogen compressor 13, the bottom liquid enters a fixed bed reactor 15 for hydrofining, and the reaction product is separated by a fractionating tower 16 to obtain light white oil 17 and lubricating oil base oil 18. The waste plastic 1 in the a) is one or more of PP, PE, PS, PET, PVC, is granular and has the particle size range controlled between 5 and 150 mu m. The maximum particle size is limited to prevent clogging of machine pumps and piping. The waste lubricating oil 2 in the step a) is at least one of waste hydraulic oil, waste gear oil, waste compressor oil, waste electrical equipment insulating oil and waste heat conducting oil, or a certain section of distillate oil obtained by distillation and cutting. The weight ratio of the waste plastics 1 to the waste lubricating oil 2 in the mixed slurry in the step a) is 1 (1-20). The proportion ensures good pulping performance of the waste plastic particles and the waste lubricating oil, and the liquefied waste plastic component contains a large amount of alkane or isoparaffin, so that the liquefied waste plastic component can be better complemented with the hydrocarbon component of the waste lubricating oil, and the product quality is improved. The catalyst 3 in the a) is in a powder shape, the bulk density is 0.6-0.8 g/cm 3, the average particle size is 65-75 mu