A method and system for dechlorinating waste plastic oil

Abstract

The present disclosure relates to a method and system for dechlorination of waste plastic oil, the method comprising: allowing waste plastic oil and light oil to enter a first reactor respectively, and contacting with a first catalyst for dechlorination reaction to obtain a first mixed material; allowing the first mixed material and an optional heavy oil raw material to enter a second reactor, and contacting with a second catalyst for catalytic cracking reaction to obtain a second mixed material; allowing the second mixed material to enter a first separation device for first separation to obtain a catalyst to be produced and reaction oil and gas; allowing the reaction oil and gas to enter a second separation device for second separation to obtain dry gas, liquefied gas, gasoline fraction, light diesel fraction and heavy oil fraction; allowing the light diesel fraction to enter a hydrogenation device and contact with a hydrogenation catalyst for hydrogenation reaction to obtain hydrogenated light diesel; allowing the hydrogenated light diesel to return to the first reactor as light oil. Simplify the process flow, reduce capital investment and improve resource utilization effect.

Description

Technical Field

[0001] The present disclosure relates to the field of plastic dechlorination, and in particular, to a method and system for dechlorinating waste plastic oil. Background Art

[0002] Plastics come in a variety of types and shapes, which have brought great convenience to our daily lives. However, plastics have a short life cycle and poor biodegradability, and white pollution is becoming increasingly serious. my country has a large amount of waste plastic resources, and only about 9% of disposable waste plastics can be recycled. Most of them are incinerated or accumulated and landfilled, which not only pollutes the environment, but also has a low resource utilization rate. Therefore, the resource utilization technology of waste plastics to produce fuel oil has attracted much attention.

[0003] Polyvinyl chloride (PVC) is one of the general-purpose plastics, and its output exceeds 15% of the total plastic products. The chlorine content of PVC plastic is higher than 50%. When thermal cracking or catalytic cracking is used to produce fuel oil, the chlorine element in the PVC plastic is released in the form of hydrogen chloride after heating, which causes serious corrosion to the equipment; the chlorine content in waste plastic oil is high, and exists in the form of organic chlorine, which has an important impact on the subsequent secondary processing process and reduces the quality of the product. Therefore, waste plastic oil needs to be dechlorinated.

[0004] Patent CN201710675497.0 discloses a waste plastic oil refining method, which uses calcium, zinc, magnesium metal oxides, metal weak acid salts or alkaline metal complexes as dechlorinating agents, mixes the dechlorinating agent with waste plastics, adds them together into a 350°C reactor and mixes with solvent oil and stirs; introduces the molten mixture after the reaction into the next reactor for catalytic cracking reaction. The molar concentration of chlorine in the oil product of this method is less than 0.1%.

[0005] Patent US3864243 discloses a method for removing chlorides and other impurities from hydrocarbons using silicon-aluminum materials. Under normal pressure, 13X or 10X molecular sieves can be used in a fixed bed reactor to remove nitrides from hydrocarbons by adsorption. Although the adsorption method for removing chlorides is simple, the selectivity of the adsorbent is poor, the adsorption capacity is low, and the problem of regeneration and recycling is difficult to solve.

[0006] Patent CN201410770061.6 discloses a catalyst for removing organic chlorine from plastic oil and its preparation method. The dechlorination catalyst uses a composite carrier of ZSM-5 and Y molecular sieve, which is impregnated with water-soluble compounds of active components Ni and Mo, and then dried and calcined. Based on the total weight of the catalyst: NiO is 0.5% to 2%, MoO3 is 0.5% to 3%, the auxiliary agent CuO is 0.5% to 2%, the content of Re2O3 is 0.5% to 1%, and the rest is a composite carrier. The catalyst has good activity and stability, and can remove chlorides from plastic oil with a removal rate of more than 98%. The catalyst is a hydrodechlorination catalyst.

[0007] Patent CN201780045736.2 discloses a catalytic method for synchronous pyrolysis of mixed plastics and dechlorination of pyrolysis oil, in which the mixed plastics are contacted with a zeolite catalyst at a pyrolysis temperature of 300-500°C in a pyrolysis unit to produce hydrocarbon products including gas phase and liquid phase, wherein the hydrocarbon liquid stream contains one or more chlorides, and the amount of chlorides is less than about 100 mg / kg based on the total weight of the hydrocarbon liquid stream. However, in order to obtain a hydrocarbon liquid with a chlorine content of less than 10 mg / kg, a subsequent hydroprocessing method is used, resulting in an increase in equipment investment costs.

[0008] Patent CN201510122785.4 discloses a method for producing high-quality gasoline and diesel from chlorine-containing plastic oil, wherein the chlorine-containing plastic oil is injected into a high-temperature dechlorination tower equipped with activated aluminum oxide for high-temperature dechlorination, a small amount of NaOH aqueous solution is sprayed on the top of the high-temperature dechlorination tower, and the dechlorinated plastic oil enters a catalytic distillation tower equipped with a molecular sieve / alumina catalyst for reaction and distillation; after catalytic distillation, the plastic oil is hydrofined. This method is complex and the dechlorination process is long.

[0009] In order to obtain oil products with low chlorine content, the existing technology for producing fuel oil from waste plastic oil mostly uses hydrogenation treatment to dechlorinate. However, due to the high chlorine content in waste plastic oil, it is easy to cause the hydrogenation catalyst to deactivate, affecting the operation cycle of the device. In addition, the hydrogenation process is complicated and has high requirements on equipment materials, which greatly increases the investment cost. Summary of the invention

[0010] The purpose of the present invention is to provide a method and system for dechlorinating waste plastic oil, which can dechlorinate waste plastic oil under non-hydrogen conditions, avoid catalyst deactivation caused by hydrogenation dechlorination to extend the operation cycle of the device; simplify the process flow and reduce capital investment.

[0011] In order to achieve the above-mentioned purpose, the first aspect of the present disclosure provides a method for dechlorinating waste plastic oil, which comprises the following steps: S1, allowing waste plastic oil and light oil to enter a first reactor respectively, and contacting them with a first catalyst for dechlorination reaction to obtain a first mixed material; S2, allowing the first mixed material and an optional heavy oil feedstock to enter a second reactor, and contacting them with a second catalyst for catalytic cracking reaction to obtain a second mixed material; S3, allowing the second mixed material to enter a first separation device for a first separation to obtain a catalyst to be produced and reaction oil and gas; S4, allowing the reaction oil and gas to enter a second separation device for a second separation to obtain dry gas, liquefied gas, gasoline fraction, light diesel fraction and heavy oil fraction; S5, allowing the light diesel fraction to enter a hydrogenation device for contact with a hydrogenation catalyst for a hydrogenation reaction to obtain hydrogenated light diesel; and allowing the hydrogenated light diesel to return to the first reactor as the light oil.

[0012] Optionally, the method also includes: allowing the catalyst to be regenerated to enter a regenerator for regeneration treatment to obtain a regenerated catalyst; allowing a portion of the regenerated catalyst to enter the second reactor as the second catalyst; allowing another portion of the regenerated catalyst to undergo a cooling treatment and then return to the first reactor as the first catalyst; optionally, the temperature of the first catalyst is 450 to 600°C, preferably 460 to 550°C; the temperature of the second catalyst is 650 to 750°C, preferably 680 to 730°C; optionally, the weight ratio of the first catalyst to the second catalyst is 0.1 to 2:1, preferably 0.1 to 1:1.

[0013] Optionally, the first reactor is a fluidized bed reactor, the second reactor is a riser reactor, and the first mixed material of the fluidized bed reactor is connected to the second mixed material inlet of the riser reactor; the method also includes the following steps: allowing the first catalyst to enter the fluidized bed reactor and move upward in a fluidized state under the lifting action of the pre-lifting medium; allowing the waste plastic oil to be mixed with the light oil and then enter the fluidized bed reactor, contact with the first catalyst for dechlorination reaction and move upward; allowing the second catalyst to enter through the lower part of the riser reactor, mix with the first mixed material from the fluidized bed reactor, perform catalytic cracking reaction and continue to move upward; optionally, allowing the heavy oil feedstock to enter the riser reactor, contact with the existing material in the riser reactor for catalytic cracking reaction, and continue to move upward; wherein along the material flow direction in the riser reactor, the introduction position of the heavy oil feedstock is located downstream of the introduction position of the second catalyst.

[0014] Optionally, the waste plastic oil is an oil product obtained by thermal cracking or catalytic cracking of plastic products; the plastic products include one or more of polyethylene, polypropylene, polystyrene and polyvinyl chloride; the content of polyvinyl chloride in the plastic products is 0.1 to 50% by weight, preferably 1 to 20% by weight; the chlorine content of the waste plastic oil is 50 to 500 mg / kg.

[0015] Optionally, the light oil comprises one or more selected from straight-run light diesel, hydrogenated heavy gasoline and hydrogenated light diesel; optionally, the total content of cycloalkyl aromatics and cycloalkanes in the light oil is 30 to 60% by weight.

[0016] Optionally, in step S1, the conditions for the dechlorination reaction include: a reaction temperature of 400 to 550°C, preferably 450 to 520°C; an oil and gas residence time of 1 to 4 seconds, preferably 1.1 to 3.2 seconds, an oil and gas linear velocity of 0.6 to 2 m / s, preferably 0.7 to 1.5 m / s; a reaction pressure of 0.1 to 0.4 MPa, preferably 0.12 to 0.30 MPa; a catalyst-oil weight ratio of 5 to 50:1, preferably 6 to 40:1; a weight ratio of the light oil to the waste plastic oil of 0.01 to 5:1, preferably 0.05 to 0.5:1.

[0017] Optionally, in step S2, the conditions of the catalytic cracking reaction include: a reaction temperature of 450 to 700°C, preferably 500 to 650°C; an oil and gas residence time of 0.5 to 10 seconds, preferably 1 to 5 seconds; a reaction pressure of 0.1 to 1 MPa, preferably 0.1 to 0.4 MPa; a catalyst-oil weight ratio of 4 to 60:1, preferably 6 to 30:1; a weight ratio of waste plastic oil to heavy oil raw material of 0.01 to 1:1, preferably 0.02 to 0.6:1; optionally, the temperature of the heavy oil raw material is 180 to 360°C, preferably 200 to 320°C.

[0018] Optionally, based on the total weight of the catalyst, the first catalyst and the second catalyst each independently include: 15 to 65 weight % of natural minerals, 10 to 30 weight % of oxides and 25 to 75 weight % of zeolite; Optionally, the zeolite includes a medium-pore zeolite and an optional large-pore zeolite, the medium-pore zeolite accounts for 30 to 80 weight % of the total weight of the zeolite, and the large-pore zeolite accounts for 20 to 70 weight % of the total weight of the zeolite; wherein the medium-pore zeolite includes a ZSM series zeolite and / or a ZRP zeolite; the large-pore zeolite includes a Y-type zeolite or a Beta zeolite; the Y-type zeolite is selected from REY zeolite, REHY zeolite, USY zeolite One or more; preferably, the zeolite is selected from one or more of Y-type molecular sieve containing or not containing rare earth, HY-type molecular sieve containing or not containing rare earth, ultra-stable Y-type molecular sieve containing or not containing rare earth, ZSM-5-type molecular sieve containing or not containing rare earth, high-silicon molecular sieve with a five-membered ring structure containing or not containing rare earth, and Beta molecular sieve containing or not containing rare earth; the natural minerals include one or more of kaolin, halloysite, montmorillonite, diatomaceous earth, attapulgite, sepiolite, halloysite, hydrotalcite, bentonite and rectorite; the oxides include one or more of silicon oxide, aluminum oxide, zirconium oxide, titanium oxide and amorphous silicon aluminum.

[0019] Optionally, in step S2, the heavy oil feedstock is selected from one or more of vacuum gas oil, vacuum residue oil, atmospheric residue oil, coker gas oil, deasphalted oil, hydrogenated heavy oil, hydrocracking tail oil, crude oil and coal liquefaction oil.

[0020] Optionally, in step S5, the conditions of the hydrogenation reaction include: hydrogen partial pressure of 4.0 to 15.0 MPa, preferably 6.0 to 12.0 MPa; reaction temperature of 300 to 420°C, preferably 330 to 380°C; volume space velocity of 2.0 to 10.0 h -1 , preferably 2.5 to 6.0 hours -1 ; Hydrogen oil volume ratio 200~1000Nm 3 / m 3 , preferably 300~800Nm 3 / m 3 ; Optionally, the initial distillation point of the light diesel oil distillation range is any temperature within the range of 160-220°C, and the final distillation point is any temperature within the range of 250-320°C; preferably, the initial distillation point of the light diesel oil distillation range is any temperature within the range of 180-210°C, and the final distillation point is any temperature within the range of 260-300°C.

[0021] Optionally, the hydrogenation catalyst includes a carrier and an active metal component supported on the carrier; the carrier includes one or more selected from alumina, silica and amorphous silica-alumina; the active metal component includes a VIB group metal and / or a VIII group non-precious metal; the VIB group metal includes molybdenum and / or tungsten, and the VIII group non-precious metal includes nickel and / or cobalt; preferably, the active metal component includes one or more of nickel-tungsten, nickel-tungsten-cobalt, nickel-molybdenum or cobalt-molybdenum.

[0022] According to a second aspect of the present disclosure, there is provided a system for dechlorinating waste plastic oil, the system comprising: a first reactor, a second reactor, a first separation device, a second separation device and a hydrogenation device; the first reactor comprises a waste plastic oil inlet, a light oil inlet, a first catalyst inlet, a pre-lifting medium inlet and a first mixed material outlet; the second reactor comprises a first mixed material inlet, a second catalyst inlet, an optional heavy oil feedstock inlet and a second mixed material outlet, wherein the first mixed material inlet is connected to the first mixed material outlet of the first reactor; the first separation device comprises a first separation inlet, a spent catalyst outlet and a reaction oil and gas outlet; wherein the first separation inlet is connected to the second mixed material outlet of the second reactor; the second separation device comprises a second separation inlet, a dry gas outlet, a liquefied gas outlet, a gasoline outlet, a light diesel outlet and a heavy oil outlet; wherein the second separation inlet is connected to the reaction oil and gas outlet of the first separation device; the hydrogenation device comprises a hydrogenation catalyst filler, a hydrogenation feedstock inlet and a hydrogenation reactant outlet; wherein the hydrogenation feedstock inlet is connected to the light diesel outlet of the second separation device, and the hydrogenation reactant outlet is connected to the light oil inlet of the first reactor.

[0023] Optionally, the system also includes a regenerator and a heat exchanger; the regenerator includes an inlet for the catalyst to be regenerated, a first catalyst outlet and a second catalyst outlet; the heat exchanger includes a high-temperature catalyst inlet and a low-temperature catalyst outlet; the inlet for the catalyst to be regenerated is connected to the outlet of the catalyst to be regenerated of the first separation device, the first catalyst outlet is connected to the high-temperature catalyst inlet of the heat exchanger, and the low-temperature catalyst outlet of the heat exchanger is connected to the first catalyst inlet of the first reactor; the second catalyst outlet is connected to the second catalyst inlet of the second reactor; optionally, the first reactor is a fluidized bed reactor, and the second reactor is a riser reaction; wherein the first catalyst inlet of the fluidized bed reactor is located below the waste plastic oil inlet and the light oil inlet; the pre-lifting medium inlet is located at the bottom of the fluidized bed reactor; the second catalyst inlet is located below the riser reactor, and the heavy oil feedstock inlet is located above the second catalyst inlet; optionally, the fluidized bed reactor is a turbulent bed or a fast bed reactor.

[0024] Through the above technical scheme, the present disclosure provides a method and system for dechlorination of waste plastic oil. The present disclosure introduces hydrogenated light diesel oil with high content of cycloalkyl aromatics and cycloalkanes into the first reactor, and performs dechlorination reaction together with the waste plastic oil, which can effectively promote the hydrogen transfer reaction in the first reactor and improve the dechlorination performance; the light diesel oil fraction obtained by the system itself can also realize the effective utilization of inferior catalytic cracking light diesel oil at the same time; compared with the traditional waste plastic hydrogenation dechlorination process, the present disclosure also avoids the problem of affecting the operation cycle of the device due to the deactivation of the hydrogenation catalyst; the present disclosure can also choose to introduce heavy oil raw materials into the second reactor for catalytic cracking reaction, so as to improve the processing capacity and operation flexibility of the device. The dechlorination method disclosed in the present disclosure is simple and easy to operate, with a high chlorine removal rate, and the chlorine-containing waste plastic oil is converted into propylene and high-octane gasoline, with significant economic benefits.

[0025] Other features and advantages of the present disclosure will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The accompanying drawings are used to provide a further understanding of the present disclosure and constitute a part of the specification. Together with the following specific embodiments, they are used to explain the present disclosure but do not constitute a limitation of the present disclosure. In the accompanying drawings:

[0027] Figure 1 It is a schematic flow diagram of the method for dechlorinating waste plastic oil provided by the present invention.

[0028] Description of Reference Numerals

[0029] 1- Fluidized bed reactor 2- Riser reactor 3- Settler

[0030] 4-Regenerator 5-External heat exchanger 6-Separation system

[0031] 7-Hydroprocessing reactor 8-Pipeline 9-Pipeline

[0032] 10-Pipeline 11-Pipeline 12-Pipeline

[0033] 13- cyclone separator 14- gas collecting chamber 15- settling device stripping section

[0034] 16- inclined tube for catalyst to be produced 17- pipeline 18- cyclone separator

[0035] 19- pipeline 20- low temperature catalyst regeneration inclined tube 21- regeneration catalyst inclined tube

[0036] 22-Large oil and gas pipeline 23-Pipeline DETAILED DESCRIPTION

[0037] The specific implementation of the present disclosure is described in detail below in conjunction with the accompanying drawings. It should be understood that the specific implementation described herein is only used to illustrate and explain the present disclosure, and is not used to limit the present disclosure.

[0038] The first aspect of the present disclosure provides a method for dechlorinating waste plastic oil, the method comprising the following steps:

[0039] S1, allowing the waste plastic oil and the light oil to enter the first reactor respectively, and contact with the first catalyst to perform a dechlorination reaction to obtain a first mixed material;

[0040] S2, allowing the first mixed material and the optional heavy oil feedstock to enter a second reactor, and contacting them with a second catalyst to perform a catalytic cracking reaction to obtain a second mixed material;

[0041] S3, allowing the second mixed material to enter a first separation device for first separation to obtain a catalyst to be produced and reaction oil and gas;

[0042] S4, allowing the reaction oil and gas to enter a second separation device for second separation to obtain dry gas, liquefied gas, gasoline fraction, light diesel fraction and heavy oil fraction;

[0043] S5, allowing the light diesel oil fraction to enter a hydrogenation device to contact with a hydrogenation catalyst for a hydrogenation reaction to obtain hydrogenated light diesel oil; and allowing the hydrogenated light diesel oil to return to the first reactor as the light oil.

[0044] The inventors of the present disclosure have found in experiments that hydrogen transfer reaction can promote the removal of chlorine element, transfer chlorides in waste plastic oil to gas or stripping water, thereby achieving the removal of chlorine in waste plastic oil; and in the catalytic cracking reaction process, cycloalkyl aromatics and cycloalkanes are prone to hydrogen transfer reaction.

[0045] The present disclosure provides a method and system for dechlorinating waste plastic oil. Hydrogenated light diesel oil with high content of cycloalkyl aromatics and cycloalkanes is introduced into the first reactor to carry out dechlorination reaction together with the waste plastic oil, which can effectively promote the hydrogen transfer reaction in the first reactor and improve the dechlorination performance; and by using the light diesel oil fraction obtained by the system itself, the effective utilization of inferior catalytic cracking light diesel oil can also be achieved at the same time; compared with the traditional waste plastic hydrogenation dechlorination process, the present disclosure also avoids the problem of affecting the operation cycle of the device due to the deactivation of the hydrogenation catalyst; the present disclosure can also choose to introduce heavy oil raw materials into the second reactor for catalytic cracking reaction, thereby improving the processing capacity and operational flexibility of the device. The dechlorination method disclosed in the present disclosure is simple and easy to operate, with a high chlorine removal rate, and converts chlorine-containing waste plastic oil into propylene and high-octane gasoline, with significant economic benefits.

[0046] In one embodiment, the waste plastic oil is an oil product obtained by thermal cracking or catalytic cracking of plastic products; the plastic products include one or more of polyethylene, polypropylene, polystyrene and polyvinyl chloride;

[0047] The content of polyvinyl chloride in the plastic product is 0.1 to 50% by weight, preferably 1 to 20% by weight;

[0048] The chlorine content of the waste plastic oil is 50-500 mg / kg.

[0049] According to the present disclosure, since waste plastics have various shapes and are often mixed with water, sand, metal, etc., plastic products need to be sorted, cleaned, washed, and crushed into materials less than 300 mm before thermal cracking or catalytic cracking.

[0050] According to the present disclosure, plastic products may be subjected to thermal cracking treatment or catalytic cracking treatment using a process method conventionally selected in the art.

[0051] In a specific embodiment, the reactor used in the thermal cracking or catalytic cracking process of plastic products is selected from a constant temperature stirring reactor, a tank rotary cracking reactor, and a slurry bed reactor, and the reaction temperature is 200-360°C, preferably 260-320°C; at this reaction temperature, polyvinyl chloride begins to decompose and generate HCl, thereby achieving the initial dechlorination process of waste plastics. In a preferred embodiment, before the waste plastic oil contacts the catalyst, the waste plastic oil is preheated to 150-300°C, more preferably 160-240°C.

[0052] In one embodiment, the light oil includes one or more selected from straight-run light diesel, hydrogenated heavy gasoline, and hydrogenated light diesel;

[0053] Optionally, the total content of cycloalkyl aromatics and cycloalkanes in the light oil is 30 to 60% by weight.

[0054] In one embodiment, the heavy oil feedstock is selected from one or more of vacuum gas oil, vacuum residue oil, atmospheric residue oil, coker gas oil, deasphalted oil, hydrogenated heavy oil, hydrocracking tail oil, crude oil and coal liquefaction oil.

[0055] In one embodiment, the first reactor is a fluidized bed reactor, the second reactor is a riser reactor, and the first mixed material of the fluidized bed reactor is connected to the second mixed material inlet of the riser reactor; the method further comprises the following steps:

[0056] The first catalyst is allowed to enter the fluidized bed reactor and move upward in a fluidized state under the lifting action of the pre-lifting medium;

[0057] The waste plastic oil is mixed with the light oil and then enters the fluidized bed reactor, contacts with the first catalyst to undergo a dechlorination reaction and moves upward;

[0058] Allowing the second catalyst to enter through the lower portion of the riser reactor, mix with the first mixed material from the fluidized bed reactor, undergo catalytic cracking reaction and continue to move upward;

[0059] Optionally, the heavy oil feedstock is allowed to enter the riser reactor, contact with the existing material in the riser reactor to carry out catalytic cracking reaction, and continue to move upward; wherein along the material flow direction in the riser reactor, the introduction position of the heavy oil feedstock is located downstream of the introduction position of the second catalyst.

[0060] According to the present disclosure, the introduction method of the heavy oil feedstock includes: introducing all the heavy oil feedstock into the reactor at one feeding position of the riser reactor, or introducing the heavy oil feedstock into the reactor at the same or different proportions at at least two different feeding positions. In the above two introduction methods, it is preferred that all the feeding positions of the heavy oil feedstock are located at the lower part of the riser reactor, that is, downstream of the second catalyst introduction position.

[0061] According to the present disclosure, the dechlorination reaction in step S1 may further include: the pre-lifting medium introduced into the first reactor may be selected from one or more of water vapor, dry gas or nitrogen, and the weight ratio of the pre-lifting medium to the heavy oil feedstock may be 0.01 to 2, preferably 0.05 to 1; and water vapor is injected at the bottom of the riser reactor; the water vapor is preferably injected in the form of atomized steam. The weight ratio of the injected water vapor to the heavy oil feedstock may be 0.01 to 1, preferably 0.05 to 0.3.

[0062] In one embodiment, in step S1, the conditions of the dechlorination reaction include: a reaction temperature of 400 to 550° C., preferably 450 to 520° C.; an oil and gas residence time of 1 to 4 seconds, preferably 1.1 to 3.2 seconds, an oil and gas linear velocity of 0.6 to 2 m / s, preferably 0.7 to 1.5 m / s; a reaction pressure of 0.1 to 0.4 MPa, preferably 0.12 to 0.30 MPa; a catalyst-oil weight ratio of 5 to 50:1, preferably 6 to 40:1; and a weight ratio of the light oil to the waste plastic oil of 0.01 to 5:1, preferably 0.05 to 0.5:1.

[0063] In one embodiment, in step S2, the conditions of the catalytic cracking reaction include: a reaction temperature of 450 to 700°C, preferably 500 to 650°C; an oil and gas residence time of 0.5 to 10 seconds, preferably 1 to 5 seconds; a reaction pressure of 0.1 to 1 MPa, preferably 0.1 to 0.4 MPa; a catalyst-oil weight ratio of 4 to 60:1, preferably 6 to 30:1; a weight ratio of waste plastic oil to heavy oil raw material of 0.01 to 1:1, preferably 0.02 to 0.6:1. Optionally, the temperature of the heavy oil raw material is 180 to 360°C, preferably 200 to 320°C.

[0064] In the present disclosure, the reaction temperature refers to the outlet temperature of the fluidized bed or riser reactor; the reaction pressure refers to the gauge pressure.

[0065] In a specific embodiment, based on the total weight of the catalyst, the first catalyst and the second catalyst each independently include: 15-65 weight % of natural minerals, 10-30 weight % of oxides and 25-75 weight % of zeolite; wherein zeolite is used as an active component, oxides are used as binders, and natural minerals are used as a matrix (i.e., a carrier).

[0066] Optionally, the zeolite comprises a medium-pore zeolite and an optional large-pore zeolite, wherein the medium-pore zeolite accounts for 30 to 80% by weight of the total weight of the zeolite, and the large-pore zeolite accounts for 20 to 70% by weight of the total weight of the zeolite; wherein the medium-pore zeolite comprises a ZSM series zeolite and / or a ZRP zeolite;

[0067] The large-pore zeolite includes Y-type zeolite or Beta zeolite; the Y-type zeolite is selected from one or more of REY zeolite, REHY zeolite and USY zeolite;

[0068] Preferably, the zeolite is selected from one or more of a Y-type molecular sieve containing or not containing rare earth, a HY-type molecular sieve containing or not containing rare earth, an ultra-stable Y-type molecular sieve containing or not containing rare earth, a ZSM-5-type molecular sieve containing or not containing rare earth, a high-silicon molecular sieve with a five-membered ring structure containing or not containing rare earth, and a Beta molecular sieve containing or not containing rare earth;

[0069] The natural minerals include one or more of kaolin, halloysite, montmorillonite, diatomaceous earth, attapulgite, sepiolite, halloysite, hydrotalcite, bentonite and rectorite;

[0070] The oxide includes one or more of silicon oxide, aluminum oxide, zirconium oxide, titanium oxide and amorphous silicon aluminum.

[0071] According to the present disclosure, the first catalyst and the second catalyst can be prepared by methods known in the art.

[0072] In one embodiment, the method further comprises:

[0073] The catalyst to be regenerated is allowed to enter a regenerator for regeneration treatment to obtain a regenerated catalyst;

[0074] allowing a portion of the regenerated catalyst to enter the second reactor as the second catalyst;

[0075] Another portion of the regenerated catalyst is subjected to a temperature reduction treatment and then returned to the first reactor as the first catalyst.

[0076] The present invention uses the low-temperature regenerated catalyst after cooling as the first catalyst and the regenerated high-temperature catalyst as the second catalyst, which is more compatible with the different reactions occurring in the first reactor and the second reactor, thereby simplifying the process and improving efficiency.

[0077] In a preferred embodiment, the temperature of the first catalyst is 450-600°C, preferably 460-550°C; the temperature of the second catalyst is 650-750°C, preferably 680-730°C.

[0078] Optionally, the weight ratio of the first catalyst to the second catalyst is 0.1 to 2:1, preferably 0.1 to 1:1.

[0079] According to the present disclosure, the regeneration process of the catalyst to be regenerated can be implemented according to the conventional catalyst regeneration method in the art, for example: introducing oxygen-containing gas (such as air) from the bottom of the regenerator, the catalyst to be regenerated is contacted with oxygen and charred and regenerated, and the generated flue gas is separated from the gas and solid by the cyclone separator of the regenerator and enters the subsequent energy recovery system. The regeneration conditions of the catalyst to be regenerated are: the regeneration temperature is 600-750°C, preferably 650-700°C; the gas superficial linear velocity is 0.2-3 m / s, preferably 0.5-2 m / s; the average residence time of the catalyst to be regenerated is 0.5-3 minutes, preferably 0.8-2 minutes.

[0080] In a specific implementation, in step S3, the first separation device may be a cyclone separator for separating the reaction oil gas and the catalyst to be generated.

[0081] In a specific embodiment, the method of performing the second separation in step S4 to obtain dry gas, liquefied gas, gasoline fraction, light diesel fraction and heavy oil fraction is well known to those skilled in the art.

[0082] In a preferred embodiment, the initial distillation point of the light diesel oil distillation range obtained by the second separation is any temperature within the range of 160 to 220°C, and the final distillation point is any temperature within the range of 250 to 320°C; preferably, the initial distillation point of the light diesel oil distillation range is any temperature within the range of 180 to 210°C, and the final distillation point is any temperature within the range of 260 to 300°C.

[0083] In one embodiment, in step S5, the conditions of the hydrogenation reaction include: hydrogen partial pressure of 4.0 to 15.0 MPa, preferably 6.0 to 12.0 MPa; reaction temperature of 300 to 420°C, preferably 330 to 380°C; volume space velocity of 2.0 to 10.0 hours -1 , preferably 2.5 to 6.0 hours -1 ; Hydrogen oil volume ratio 200~1000Nm 3 / m 3 , preferably 300~800Nm 3 / m 3 .

[0084] According to the present disclosure, the hydrogenation catalyst may be a conventionally purchased hydrogenation catalyst, or a hydrogenation catalyst prepared by a known preparation method.

[0085] In a specific embodiment, the hydrogenation catalyst comprises a carrier and an active metal component supported on the carrier; the carrier comprises one or more selected from alumina, silica and amorphous silica-alumina;

[0086] The active metal component includes a VIB group metal and / or a VIII group non-precious metal; the VIB group metal includes molybdenum and / or tungsten, and the VIII group non-precious metal includes nickel and / or cobalt; preferably, the active metal component includes one or more of nickel-tungsten, nickel-tungsten-cobalt, nickel-molybdenum or cobalt-molybdenum.

[0087] Any device used in the present disclosure is a device conventionally used in the art.

[0088] A second aspect of the present disclosure provides a system for dechlorinating waste plastic oil, the system comprising: a first reactor, a second reactor, a first separation device, a second separation device, and a hydrogenation device;

[0089] The first reactor comprises a waste plastic oil inlet, a light oil inlet, a first catalyst inlet, a pre-lifting medium inlet and a first mixed material outlet;

[0090] The second reactor comprises a first mixed material inlet, a second catalyst inlet, an optional heavy oil feed inlet and a second mixed material outlet, wherein the first mixed material inlet is in communication with the first mixed material outlet of the first reactor;

[0091] The first separation device comprises a first separation inlet, a catalyst outlet to be produced and a reaction oil and gas outlet; wherein the first separation inlet is connected to the second mixed material outlet of the second reactor;

[0092] The second separation device comprises a second separation inlet, a dry gas outlet, a liquefied gas outlet, a gasoline outlet, a light diesel outlet and a heavy oil outlet; wherein the second separation inlet is connected to the reaction oil and gas outlet of the first separation device;

[0093] The hydrogenation device comprises a hydrogenation catalyst packing, a hydrogenation feedstock inlet and a hydrogenation reactant outlet; wherein the hydrogenation feedstock inlet is connected to the light diesel outlet of the second separation device, and the hydrogenation reactant outlet is connected to the light oil inlet of the first reactor.

[0094] In one embodiment, the system further comprises a regenerator and a heat exchanger; the regenerator comprises an inlet for a catalyst to be regenerated, a first catalyst outlet and a second catalyst outlet; the heat exchanger comprises an inlet for a high-temperature catalyst and an outlet for a low-temperature catalyst;

[0095] The inlet of the catalyst to be regenerated is communicated with the outlet of the catalyst to be regenerated of the first separation device, the first outlet of the catalyst is communicated with the high-temperature catalyst inlet of the heat exchanger, and the low-temperature catalyst outlet of the heat exchanger is communicated with the first catalyst inlet of the first reactor;

[0096] The second catalyst outlet is in communication with the second catalyst inlet of the second reactor;

[0097] Optionally, the first reactor is a fluidized bed reactor, and the second reactor is a riser reactor; wherein the first catalyst inlet of the fluidized bed reactor is located below the waste plastic oil inlet and the light oil inlet; and the pre-lifting medium inlet is located at the bottom of the fluidized bed reactor;

[0098] The second catalyst inlet is located below the riser reactor, and the heavy oil feedstock inlet is located above the second catalyst inlet;

[0099] Optionally, the fluidized bed reactor is a turbulent bed or a fast bed reactor.

[0100] In a specific implementation, see Figure 1 The specific process of the method for dechlorination of waste plastic oil provided by the present disclosure includes:

[0101] The pre-lifting medium enters from the bottom of the fluidized bed reactor 1 (the first reactor) through pipeline 9, and the low-temperature regenerated catalyst (the first catalyst) from pipeline 20 is accelerated upward under the lifting effect of the pre-lifting medium. The waste plastic oil is mixed with the hydrogenated light diesel oil introduced from pipeline 8 (the distillation range of the light diesel oil fraction before hydrogenation treatment is 200-260°C) through pipeline 10 and introduced into the fluidized bed reactor (the first reactor), and dechlorinated by hydrogen transfer reaction at low temperature and long residence time; the high-temperature regenerated catalyst (the second catalyst) enters the lower part of the riser reactor 2 (the second reactor) through pipeline 21, and the optional heavy oil feedstock is injected into the bottom of the riser reactor 2 (the second reactor) together with the atomized medium from pipeline 12 through pipeline 11, and mixed with the existing logistics of the riser reactor 2 (the second reactor), and the heavy oil feedstock undergoes catalytic cracking reaction (mainly cracking reaction) on the hot catalyst. The generated reaction products and the catalyst to be regenerated with carbon enter the cyclone separator 13 (first separation device) in the settler 3, and the catalyst to be regenerated is separated from the reaction products. The reaction products (reaction oil and gas) enter the gas collecting chamber 14, and then enter the subsequent separation system through the large oil and gas pipeline 22. The catalyst fine powder returns to the settler 3 from the cyclone separator 13 feed leg. The catalyst to be regenerated flows to the stripping section 15 and contacts with the stripping steam in countercurrent. The stripped catalyst to be regenerated enters the regenerator 4 through the catalyst to be regenerated conveying inclined pipe 16, and the air from the pipeline 17 burns off the coke on the catalyst to be regenerated in the dense phase bed, so that the deactivated catalyst to be regenerated is regenerated, and the flue gas enters the subsequent energy recovery system through the cyclone separator 18. A part of the regenerated high-temperature catalyst (as the second catalyst) returns to the riser reactor 2 (the second reactor) through the regenerated catalyst conveying inclined pipe 21, and a part of it is cooled by the external heat exchanger 5 (as the first catalyst) and returns to the fluidized bed reactor 1 (the first reactor) through the regenerated catalyst conveying inclined pipe 20.

[0102] The reaction oil and gas enter the fractionation tower 6 (second separation device) through the large oil and gas pipeline 22, and after separation by the separation system, dry gas, liquefied gas, gasoline, light diesel oil and heavy oil are obtained. Light diesel oil with a distillation range of 200-260°C enters the hydroprocessing reactor 7 through pipeline 23, and aromatics saturation reaction occurs under the action of hydrogen and hydrogenation catalyst. The light diesel oil fraction after hydroprocessing returns to the fluidized bed reactor 1 (first reactor) through pipeline 8.

[0103] The present invention will be further described in the following examples, but the present invention is not limited thereto.

[0104] The properties of the waste plastic oil used in the examples and comparative examples are listed in Table 1, and the properties of the heavy oil raw materials are listed in Table 2; the brand name of the hydrogenation catalyst is RS-2000, purchased from the Changling Branch of Sinopec Catalyst Co., Ltd.

[0105] The chlorine content of liquid oil is determined by single wavelength dispersive X-ray fluorescence spectrometry. The test method is based on the standard ASTM D7536-09.

[0106] Preparation Example

[0107] This preparation example is used to prepare the first catalyst and the second catalyst, and specifically includes the following steps:

[0108] (1) adding ZSM-5 molecular sieve to a NaOH solution, heating to 80° C., reacting for 30 minutes, cooling, filtering, washing until the filtrate is neutral, and then performing ion exchange to obtain a molecular sieve filter cake; taking the molecular sieve filter cake and adding water to prepare a molecular sieve slurry, adding oxalic acid, hydrochloric acid and fluorosilicic acid during stirring, filtering and washing with water until the filtrate is neutral; adding water to the filter cake and then adding phosphoric acid, uniformly mixing, impregnating, drying, and calcining to obtain a phosphorus-modified ZSM-5 molecular sieve.

[0109] (2) Aluminum sol and kaolin are mixed and prepared into a slurry with a solid content of 40 wt% with decationized water, stirred evenly, and the pH of the slurry is adjusted to 3 with hydrochloric acid, and the pH value is maintained. After standing and aging for 1 hour at 40°C, aluminum sol is added, stirred for 1 hour to form a colloid, phosphorus-modified ZSM-5 molecular sieve and USY molecular sieve are added to form a catalyst slurry (solid content of 35 wt%), wherein ZSM-5 molecular sieve: USY molecular sieve: kaolin: aluminum sol = 15:25:40:20, continued stirring and spray dried to form a microsphere catalyst. The microsphere catalyst is then calcined at 500°C for 1 hour, washed with ammonium sulfate at 60°C until the sodium oxide content is less than 0.25 wt%, then rinsed with deionized water and filtered, and then dried at 110°C, i.e., the catalyst provided by the present invention.

[0110] The main physicochemical properties of the prepared catalyst product are listed in Table 3.

[0111] The regenerated catalyst is divided into two parts. The catalyst introduced into the fluidized bed reactor is denoted as catalyst A, and the catalyst introduced into the riser reactor is denoted as catalyst B.

[0112] Example 1

[0113] This example is used to illustrate the dechlorination effect of the method provided by the present disclosure on waste plastic oil.

[0114] according to Figure 1 The process shown was tested on a pilot plant of a riser reactor.

[0115] Waste plastic oil is mixed with hydrogenated light diesel oil with a distillation range of 200-260°C and injected into a fluidized bed reactor together with atomized steam. The weight ratio of hydrogenated light diesel oil to waste plastic oil is 0.1:1. Under the action of low-temperature regeneration catalyst A (first catalyst, temperature is 520°C), dechlorination is carried out through hydrogen transfer reaction. Then it enters the riser reactor, and hot regeneration catalyst B (second catalyst temperature is 710°C) is introduced into the riser reactor for cracking reaction. The generated reaction products and the catalyst to be regenerated with carbon enter the settler, and the separation of the catalyst to be regenerated and the reaction products is achieved through a cyclone separator. The reaction products enter the subsequent separation system through a large oil and gas pipeline. The catalyst to be regenerated flows to the stripping section and contacts with the stripping steam in countercurrent. The stripped catalyst to be regenerated enters the regenerator through a conveying inclined tube, and air is introduced to burn off the coke on the catalyst to be regenerated to complete the regeneration of the catalyst. The flue gas enters the subsequent energy recovery system through a cyclone separator. Part of the regenerated high-temperature catalyst returns to the riser reactor through the regenerated catalyst conveying inclined pipe, and part of it returns to the fluidized bed reactor through the regenerated catalyst conveying inclined pipe after being cooled by the external heat exchanger, wherein the mass ratio of the low-temperature catalyst to the high-temperature catalyst is 0.2:1.

[0116] The reaction oil and gas enter the fractionation tower through the large oil and gas pipeline, and after further separation, dry gas, liquefied gas, gasoline, light diesel oil and heavy oil are obtained. The light diesel oil with a distillation range of 200-260°C enters the hydroprocessing reactor, and under the action of hydrogen and hydrogenation catalyst (RS-2000, purchased from Changling Branch of Sinopec Catalyst Co., Ltd.), aromatic saturation reaction occurs. The light diesel oil after hydrogenation is returned to the riser reactor. The total content of cycloalkyl aromatics and cycloalkanes in the hydrogenated light diesel oil is 45.7% by weight, wherein the hydroprocessing conditions are: reaction temperature 340°C, hydrogen partial pressure 8.0 MPa, volume space velocity 4.0 h -1 , hydrogen-to-oil volume ratio 600 standard cubic meters / cubic meters. The operating conditions and reaction results are listed in Table 4.

[0117] Example 2

[0118] This example is used to illustrate the dechlorination effect of the method provided by the present invention on waste plastic oil when the heavy oil feedstock is introduced into the riser reactor.

[0119] The experiment was conducted according to the method and process of Example 1, except that the heavy oil feedstock (the properties of the heavy oil feedstock are listed in Table 2) preheated to 240°C was introduced into the riser reactor, the feed position of the heavy oil feedstock was located downstream of the riser reactor along the material flow direction, the weight ratio of the waste plastic oil to the heavy oil feedstock was 0.12:1, and the total content of cycloalkyl aromatics and cycloalkanes in the hydrogenated light diesel oil was 48.5% by weight. The operating conditions and reaction results are listed in Table 4.

[0120] Example 3

[0121] This example is used to illustrate the dechlorination effect of the method provided by the present invention on waste plastic oil at a high reaction temperature.

[0122] The experiment was conducted according to the method and process of Example 1, except that the reaction temperature of the riser reactor was 600° C. and the total content of cycloalkyl aromatics and cycloalkane in the hydrogenated light diesel oil was 44.2% by weight. The operating conditions and reaction results are listed in Table 4.

[0123] Example 4

[0124] This embodiment adopts the method and apparatus of embodiment 2, and the difference from embodiment 2 is that the temperature of low-temperature regeneration catalyst A is 610°C, the mass ratio of low-temperature catalyst to high-temperature catalyst is 1.2:1, the weight ratio of light oil to waste plastic oil is 0.03:1, the weight ratio of waste plastic oil to heavy oil raw material is 0.8:1, and the total content of cycloalkyl aromatics and cycloalkanes in hydrogenated light diesel is 42.1% by weight. The operating conditions and reaction results are listed in Table 4.

[0125] Example 5

[0126] This embodiment adopts the method and apparatus of embodiment 1 to carry out the test. The difference from embodiment 1 is that the light diesel oil with a distillation range of 270-330° C. is hydrotreated according to the following reaction conditions:

[0127] Reaction temperature 420°C, hydrogen partial pressure 4.0 MPa, volume space velocity 10.0 h -1 , hydrogen to oil volume ratio 200 standard cubic meters / cubic meters. The total content of cycloalkyl aromatics and cycloalkanes in hydrogenated light diesel oil is 22.1% by weight. The operating conditions and reaction results are listed in Table 4.

[0128] Comparative Example 1

[0129] This comparative example adopts the method and apparatus of Example 1 to conduct the test, and the difference from Example 1 is that: no fluidized bed reactor is set, and the waste plastic oil is directly injected into the lower part of the riser reactor, first contacts with the low-temperature regeneration catalyst, and then contacts with the high-temperature regeneration catalyst for reaction, wherein the hydrogenated light diesel oil with a distillation range of 200-260°C is not returned to the catalytic cracking reactor, and the mass ratio of the low-temperature catalyst to the high-temperature catalyst is 0.2:1. The operating conditions and reaction results are listed in Table 4.

[0130] Comparative Example 2

[0131] This comparative example adopts the method and apparatus of Example 3 to conduct the test (at a high reaction temperature of 600°C), which is different from Example 3 in that: no fluidized bed reactor is provided, waste plastic oil is mixed with hydrogenated light diesel oil having a distillation range of 200-260°C and then injected into the lower part of the riser reactor, the weight ratio of hydrogenated light diesel oil to waste plastic oil is 0.1:1, the reaction temperature of the riser reactor is 600°C, and the total content of cycloalkyl aromatics and cycloalkanes in the hydrogenated light diesel oil is 40.8% by weight. The operating conditions and reaction results are listed in Table 4.

[0132] Table 1 Properties of waste plastic oil

[0133] project data <![CDATA[Density (20 °C), kg / m 3 > 801.1 <![CDATA[Kinematic viscosity (20 °C), mm 2 / s]]> 2.726 Freezing point, ℃ 7 Elemental composition, weight % C 86.10 H 13.90 Sulfur content, mg / kg 395 Nitrogen content, mg / kg 360 Chlorine content, mg / kg 120.6 Distillation range, ℃ Initial distillation point 39 5% by volume 96 10% by volume 127 30% by volume 188 50% by volume 254 80% by volume 348 95% by volume 415

[0134] Table 2 Properties of heavy oil feedstock

[0135]

[0136]

[0137] Table 3 Main physicochemical properties of the catalyst

[0138] project data Main chemical composition, weight % <![CDATA[Al2O3]]> 54.7 <![CDATA[SiO2]]> 40.9 <![CDATA[RE2O3]]> 2.1 <![CDATA[Na2O]]> 0.15 Physical properties <![CDATA[Specific surface area, (m 2 / g)]]> 153 <![CDATA[Total pore volume, (cm 3 / g)]]> 0.192 Micro-reaction (800℃, 17h), % 64

[0139] Table 4 Operating conditions and reaction results

[0140]

[0141]

[0142]

[0143] In Table 4, chlorine removal rate = [1-C1×(m1+m2+m3) / (100×C0)]×100%; wherein C1 represents the chlorine content of the liquid product in Table 4, (m1+m2+m3) represents the total content of gasoline, diesel and heavy oil liquid products in the product distribution of Table 4, and C0 represents the chlorine content of the waste plastic oil in Table 1.

[0144] It can be seen from the data in the above table that the dechlorination rate of the method provided in this application can reach 84.5-98.7% by weight, and the dechlorination rate is high.

[0145] Comparing Comparative Example 1 with Example 1, it can be seen that the gasoline octane number, dechlorination rate and propylene yield of Example 1 are higher.

[0146] Comparing Comparative Example 2 with Example 3, it can be seen that the gasoline octane number, dechlorination rate and propylene yield of Example 3 are higher.

[0147] Further comparing Example 2 with Example 4, it can be seen that Example 2 satisfies the weight ratio of light oil to waste plastic oil of 0.05-0.5:1, the temperature of the first catalyst is 460-550°C, the weight ratio of the first catalyst to the second catalyst is 0.1-1:1, the weight ratio of waste plastic oil to heavy oil feedstock is 0.02-0.6:1, and the catalytic cracking reaction temperature is 500-650°C. The gasoline octane number, dechlorination rate and propylene yield of Example 2 are higher.

[0148] Comparing Example 1 with Example 5, it can be seen that the initial distillation point that satisfies the distillation range of light diesel in Example 1 is any temperature within the range of 180 to 210°C, the final distillation point is any temperature within the range of 260 to 300°C, the total content of cycloalkyl aromatics and cycloalkanes in the light oil is 30 to 60% by weight, and the gasoline octane number, dechlorination rate and propylene yield of Example 1 are higher.

[0149] The preferred embodiments of the present disclosure are described in detail above in conjunction with the accompanying drawings; however, the present disclosure is not limited to the specific details in the above embodiments. Within the technical concept of the present disclosure, a variety of simple modifications can be made to the technical solution of the present disclosure, and these simple modifications all fall within the protection scope of the present disclosure.

[0150] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present disclosure will not further describe various possible combinations.

[0151] In addition, various embodiments of the present disclosure may be arbitrarily combined, and as long as they do not violate the concept of the present disclosure, they should also be regarded as the contents disclosed by the present disclosure.

Claims

1. A method for dechlorinating waste plastic oil, characterized in that: The method comprises the following steps: S1, allowing waste plastic oil and light oil to enter the first reactor respectively, and contact with the first catalyst to perform dechlorination reaction to obtain a first mixed material; wherein the total content of cycloalkyl aromatics and cycloalkanes in the light oil is 30-60% by weight; S2, allowing the first mixed material and the optional heavy oil feedstock to enter a second reactor, and contacting with a second catalyst to perform a catalytic cracking reaction to obtain a second mixed material; S3, allowing the second mixed material to enter a first separation device for first separation to obtain a catalyst to be produced and reaction oil and gas; S4, allowing the reaction oil and gas to enter a second separation device for second separation to obtain dry gas, liquefied gas, gasoline fraction, light diesel fraction and heavy oil fraction; S5, allowing the light diesel oil fraction to enter a hydrogenation unit to contact with a hydrogenation catalyst for a hydrogenation reaction to obtain hydrogenated light diesel oil; and allowing the hydrogenated light diesel oil to return to the first reactor as at least part of the light oil.

2. The method according to claim 1, characterized in that The method further includes: The catalyst to be regenerated is allowed to enter a regenerator for regeneration treatment to obtain a regenerated catalyst; allowing a portion of the regenerated catalyst to enter the second reactor as the second catalyst; Another portion of the regenerated catalyst is subjected to a temperature reduction treatment and then returned to the first reactor as the first catalyst.

3. The method according to claim 2, characterized in that The temperature of the first catalyst is 450-600°C; the temperature of the second catalyst is 650-750°C; The weight ratio of the first catalyst to the second catalyst is 0.1-2:1:

1.

4. The method according to claim 3, characterized in that The temperature of the first catalyst is 460-550° C.; the temperature of the second catalyst is 680-730° C.; and the weight ratio of the first catalyst to the second catalyst is 0.1-1:

1.

5. The method according to claim 1, characterized in that The first reactor is a fluidized bed reactor, the second reactor is a riser reactor, and the first mixed material of the fluidized bed reactor is connected to the second mixed material inlet of the riser reactor; The method further comprises the following steps: The first catalyst is allowed to enter the fluidized bed reactor and move upward in a fluidized state under the lifting action of the pre-lifting medium; The waste plastic oil is mixed with the light oil and then enters the fluidized bed reactor, contacts with the first catalyst to undergo a dechlorination reaction and moves upward; The second catalyst is introduced into the lower part of the riser reactor, mixed with the first mixed material from the fluidized bed reactor, undergoes catalytic cracking reaction and continues to move upward.

6. The method according to claim 5, characterized in that The heavy oil feedstock is allowed to enter the riser reactor, contact with the existing material in the riser reactor to perform catalytic cracking reaction, and continue to move upward; wherein along the material flow direction in the riser reactor, the introduction position of the heavy oil feedstock is located downstream of the introduction position of the second catalyst.

7. The method according to claim 1, characterized in that The waste plastic oil is an oil product obtained by thermal cracking or catalytic cracking of plastic products; the plastic products include one or more of polyethylene, polypropylene, polystyrene and polyvinyl chloride; The content of polyvinyl chloride in plastic products is 0.1~50% by weight; The chlorine content of the waste plastic oil is 50-500 mg / kg.

8. The method according to claim 7, characterized in that The content of polyvinyl chloride in plastic products is 1~20% by weight.

9. The method according to claim 1, characterized in that: The light oil includes one or more selected from straight-run light diesel, hydrogenated heavy gasoline and hydrogenated light diesel.

10. The method according to claim 1, characterized in that In step S1, the conditions of the dechlorination reaction include: reaction temperature of 400-550°C; oil and gas residence time of 1-4 seconds; oil and gas linear velocity of 0.6-2 m / s; reaction pressure of 0.1-0.4 MPa; agent-oil weight ratio of 5-50:1; and the weight ratio of the light oil to the waste plastic oil of 0.01-5:

1.

11. The method according to claim 10, characterized in that In step S1, the conditions of the dechlorination reaction include: reaction temperature of 450-520°C; oil-gas residence time of 1.1-3.2 seconds; oil-gas linear velocity of 0.7-1.5 m / s; reaction pressure of 0.12-0.30 MPa; agent-oil weight ratio of 6-40:1; The weight ratio of the light oil to the waste plastic oil is 0.05-0.5:

1.

12. The method according to claim 1, characterized in that In step S2, the conditions of the catalytic cracking reaction include: reaction temperature of 450-700°C; oil and gas residence time of 0.5-10 seconds; reaction pressure of 0.1-1 MPa; catalyst-oil weight ratio of 4-60:1; weight ratio of waste plastic oil to heavy oil raw material of 0.01-1:1; and temperature of the heavy oil raw material of 180-360°C.

13. The method according to claim 12, characterized in that In step S2, the conditions of the catalytic cracking reaction include: reaction temperature of 500-650°C; oil and gas residence time of 1-5 seconds; reaction pressure of 0.1-0.4 MPa; catalyst-oil weight ratio of 6-30:1; weight ratio of waste plastic oil to heavy oil raw material of 0.02-0.6:1; and temperature of the heavy oil raw material of 200-320°C.

14. The method according to claim 1, characterized in that Based on the total weight of the catalyst, the first catalyst and the second catalyst each independently include: 15 to 65 weight % of natural minerals, 10 to 30 weight % of oxides and 25 to 75 weight % of zeolite.

15. The method according to claim 14, characterized in that The zeolite comprises a medium-pore zeolite and an optional large-pore zeolite, wherein the medium-pore zeolite accounts for 30-80% by weight of the total weight of the zeolite, and the large-pore zeolite accounts for 20-70% by weight of the total weight of the zeolite; wherein the medium-pore zeolite comprises a ZSM series zeolite and / or a ZRP zeolite; The large-pore zeolite includes Y-type zeolite or Beta zeolite; the Y-type zeolite is selected from one or more of REY zeolite, REHY zeolite and USY zeolite; The natural minerals include one or more of kaolin, montmorillonite, diatomaceous earth, attapulgite, sepiolite, halloysite, hydrotalcite, bentonite and rectorite; The oxide includes one or more of silicon oxide, aluminum oxide, zirconium oxide, titanium oxide and amorphous silicon aluminum.

16. The method according to claim 15, characterized in that The zeolite is selected from one or more of a Y-type molecular sieve containing or not containing rare earth, a HY-type molecular sieve containing or not containing rare earth, an ultra-stable Y-type molecular sieve containing or not containing rare earth, a ZSM-5 type molecular sieve containing or not containing rare earth, a high-silicon molecular sieve with a five-membered ring structure containing or not containing rare earth, and a Beta molecular sieve containing or not containing rare earth.

17. The method according to claim 1, characterized in that In step S2, the heavy oil raw material is selected from one or more of vacuum gas oil, vacuum residue oil, atmospheric residue oil, coker gas oil, deasphalted oil, hydrogenated heavy oil, crude oil and coal liquefaction oil.

18. The method according to claim 1, characterized in that In step S5, the conditions of the hydrogenation reaction include: hydrogen partial pressure of 4.0-15.0 MPa; reaction temperature of 300-420°C; volume space velocity of 2.0-10.0 h -1 ; Hydrogen oil volume ratio is 200~1000Nm 3 / m 3 .

19. The method according to claim 18, characterized in that In step S5, the conditions of the hydrogenation reaction include: hydrogen partial pressure of 6.0-12.0 MPa; reaction temperature of 330-380°C; volume emptying time of 2.5-6.0 hours; -1 ; Hydrogen oil volume ratio is 300~800Nm 3 / m 3 .

20. The method according to claim 1, characterized in that The initial distillation point of the light diesel oil distillation range is any temperature within the range of 160-220°C, and the final distillation point is any temperature within the range of 250-320°C.

21. The method according to claim 20, characterized in that The initial distillation point of the light diesel distillation range is any temperature within the range of 180-210°C, and the final distillation point is any temperature within the range of 260-300°C.

22. The method according to claim 1, characterized in that The hydrogenation catalyst comprises a carrier and an active metal component supported on the carrier; the carrier comprises one or more selected from alumina, silicon dioxide and amorphous silicon aluminum; The active metal component includes a metal of Group VIB and / or a non-noble metal of Group VIII; the metal of Group VIB includes molybdenum and / or tungsten, and the non-noble metal of Group VIII includes nickel and / or cobalt.

23. The method according to claim 22, characterized in that The active metal component includes one or more of nickel-tungsten, nickel-tungsten-cobalt, nickel-molybdenum or cobalt-molybdenum.

24. A system for dechlorinating waste plastic oil according to the method of claim 1, characterized in that: The system comprises: a first reactor, a second reactor, a first separation device, a second separation device and a hydrogenation device; The first reactor comprises a waste plastic oil inlet, a light oil inlet, a first catalyst inlet, a pre-lifting medium inlet and a first mixed material outlet; The second reactor comprises a first mixed feed inlet, a second catalyst inlet, an optional heavy oil feed inlet and a second mixed feed outlet, wherein the first mixed feed inlet is in communication with the first mixed feed outlet of the first reactor; The first separation device comprises a first separation inlet, a catalyst outlet to be produced and a reaction oil and gas outlet; wherein the first separation inlet is connected to the second mixed material outlet of the second reactor; The second separation device comprises a second separation inlet, a dry gas outlet, a liquefied gas outlet, a gasoline outlet, a light diesel outlet and a heavy oil outlet; wherein the second separation inlet is connected to the reaction oil and gas outlet of the first separation device; The hydrogenation device comprises a hydrogenation catalyst packing, a hydrogenation feedstock inlet and a hydrogenation reactant outlet; wherein the hydrogenation feedstock inlet is connected to the light diesel outlet of the second separation device, and the hydrogenation reactant outlet is connected to the light oil inlet of the first reactor.

25. The system according to claim 24, characterized in that The system also includes a regenerator and a heat exchanger; the regenerator includes an inlet for a catalyst to be regenerated, a first catalyst outlet, and a second catalyst outlet; the heat exchanger includes an inlet for a high-temperature catalyst and an outlet for a low-temperature catalyst; The inlet of the catalyst to be regenerated is communicated with the outlet of the catalyst to be regenerated of the first separation device, the first outlet of the catalyst is communicated with the high-temperature catalyst inlet of the heat exchanger, and the low-temperature catalyst outlet of the heat exchanger is communicated with the first catalyst inlet of the first reactor; The second catalyst outlet is in communication with the second catalyst inlet of the second reactor.

26. The system according to claim 25, characterized in that The first reactor is a fluidized bed reactor, and the second reactor is a riser reactor; wherein the first catalyst inlet of the fluidized bed reactor is located below the waste plastic oil inlet and the light oil inlet; and the pre-lifting medium inlet is located at the bottom of the fluidized bed reactor; The second catalyst inlet is located below the riser reactor, and the heavy oil feedstock inlet is located above the second catalyst inlet.

27. The system according to claim 26, characterized in that The fluidized bed reactor is a turbulent bed or a fast bed reactor.

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