A method and system for treating chlorine-containing waste plastics using a delayed coking device

Abstract

The present disclosure relates to a method and system for treating chlorine-containing waste plastics using a delayed coking device, the method comprising heating, mixing and melting the chlorine-containing waste plastic raw materials to be treated in a raw material mixing and melting device to obtain a waste plastic mixture material; mixing the waste plastic mixture material with a high-temperature solvent and entering a liquefaction dechlorination reactor for dechlorination treatment under stripping conditions to obtain a gas phase material containing hydrogen chloride and a dechlorinated waste plastic liquid phase material; mixing the dechlorinated waste plastic liquid phase material with a first portion of delayed coking raw materials and entering a coking tower for coking reaction to obtain a coking product; and allowing the coking product to enter a fractionation tower for separation treatment to obtain a first dry gas, liquefied gas, gasoline fraction, diesel fraction and wax oil fraction. Dechlorination of waste plastics is achieved, and the utilization rate of waste plastic resources and the yield of delayed coking reaction are improved.

Description

Technical Field

[0001] The present disclosure relates to the field of waste plastic resource recycling and processing, and in particular, to a method and system for processing chlorine-containing waste plastic using a delayed coking device. Background Art

[0002] With the advancement of science and technology and industrial development, plastics are widely used as packaging materials in people's daily lives. Used waste plastics cannot be decomposed by themselves in nature. Only a few types of waste plastics can be reprocessed and reused through specific recycling channels. A large amount of waste plastics enters landfills in the form of domestic garbage. Since waste plastics are not easy to decompose, they occupy a lot of space. In recent years, the amount of waste plastics has increased rapidly. It has become an urgent task to recycle waste plastics quickly and greenly.

[0003] The simplest chemical method to deal with waste plastics is direct incineration, but direct incineration will produce toxic gases that are harmful to the human body and cause secondary environmental pollution. Waste plastic oil technology is to crack waste plastics under anaerobic or anoxic conditions by heating or catalyst conditions to crack polymers into low molecular weight substances to obtain gasoline, kerosene, diesel fractions and some pyrolysis gases. On the one hand, waste plastic oil technology alleviates the pollution problem caused by waste plastics, and on the other hand, it realizes the recycling of waste plastics, which is an important direction for the resource treatment of waste plastics.

[0004] At present, waste plastic oil recovery technology mainly includes waste plastic thermal cracking, catalytic thermal cracking and thermal cracking catalytic modification technology. The thermal cracking method has the advantages of simple process, relatively less equipment investment, no catalyst required, and short reaction process, making the thermal cracking method the lowest unit oil cost compared to the other two technologies. General waste plastics in domestic garbage undergo high-temperature thermal cracking reaction between 380 and 500°C, with a fast cracking speed and a relatively simple product composition, which can be used as oil products or chemical raw materials.

[0005] CN109401774A discloses a waste plastic continuous thermal cracking system and a thermal cracking method thereof, the system includes a loading device, a feeding device, a thermal cracking reactor and a slag discharge device connected in sequence, and since the plastic is a macromolecular polymer, a non-Newtonian fluid is formed during the heating process, and a screw propeller is used. The plastic liquefaction process of this process is unevenly heated, and coking and fouling are easily generated. CN10461030B discloses a coking method for producing fuel oil from waste plastics, the method is to preheat the high aromatic components and waste plastics or plastic oil in a raw material buffer tank, enter a tubular heating furnace for heating, and then spray into a delayed coking tower for coking reaction, the waste plastics mentioned in the method are one or more of polyethylene, polypropylene and polystyrene, and do not contain polyvinyl chloride (PVC), so it is impossible to process waste plastic raw materials mixed with polyvinyl chloride (PVC). CN112538363A discloses a method for co-converting waste plastics in a delayed coker unit, wherein the waste plastics are converted together with petroleum residue raw materials, wherein the waste plastics are selected from polyethylene, polypropylene, polystyrene, PET and multi-layer plastics with metal added, and also do not include waste plastics of polyvinyl chloride (PVC). The waste plastics form a high-viscosity polymer melt during the melting process, which has a density difference with the hydrocarbon raw material, so the mixed fluid of the hydrocarbon and the polymer melt can cause problems such as blockage and coking of the delayed coking heating furnace tube. Summary of the invention

[0006] The purpose of the present disclosure is to provide a method or system for treating chlorine-containing waste plastics using a delayed coking device, which can mix, melt and dechlorinate waste plastic raw materials, and then mix the dechlorinated liquid waste plastics with high-temperature delayed coking raw materials and enter a delayed coking tower for reaction, thereby achieving dechlorination of waste plastics and resource utilization of waste plastics, and improving the yield of delayed coking products.

[0007] In order to achieve the above-mentioned purpose, the first aspect of the present disclosure provides a method for treating chlorine-containing waste plastics using a delayed coking device, comprising the following steps: S1, heating, mixing and melting the chlorine-containing waste plastic raw materials to be treated in a raw material mixing and melting device to obtain a waste plastic mixture material; mixing the waste plastic mixture material with a high-temperature solvent and then entering a liquefaction dechlorination reactor for dechlorination treatment under stripping conditions to obtain a gas phase material containing hydrogen chloride and a dechlorinated waste plastic liquid phase material; S2, mixing the dechlorinated waste plastic liquid phase material with a first portion of delayed coking raw materials and then entering a coking tower for coking reaction to obtain a coking product; S3, entering a fractionating tower for separation treatment of the coking product to obtain a first dry gas, liquefied gas, a gasoline fraction, a diesel fraction and a wax oil fraction.

[0008] Optionally, in step S1, the weight ratio of the high-temperature solvent to the chlorine-containing waste plastic raw material is (10-1):1, preferably, the temperature of the high-temperature solvent is 300-450°C; preferably, the high-temperature solvent includes the second part of delayed coking raw material; preferably, the conditions of the dechlorination treatment include: reaction temperature 250-430°C, reaction time 0.5h-3h, based on the total feed weight of the waste plastic raw material and the high-temperature solvent, the amount of stripping gas is 0.5-5% by weight of the total feed weight, preferably 1%-2% by weight; the stripping gas is high-temperature steam or nitrogen; preferably, the stripping gas is introduced through the bottom of the liquefied dechlorination reactor; preferably, the chlorine content in the dechlorinated waste plastic liquid phase material is 100-900μg / g.

[0009] Optionally, the method further comprises: before step S1, allowing the delayed coking raw material to enter the bottom of the distillation tower for preheating, and then enter the heating furnace for heating; then dividing the heated delayed coking raw material from the heating furnace into two parts, allowing the first part of the heated delayed coking raw material to be mixed with the dechlorinated waste plastic liquid phase material from the liquefied dechlorination reactor and enter the coking tower; allowing the second part of the heated delayed coking raw material to be mixed with the waste plastic mixed material from the raw material mixing and melting device as the high-temperature solvent; optionally, the outlet temperature of the heating furnace is 480-520°C, and based on the total mass of the material heated in the heating furnace, the steam injection amount of the heating furnace is 0.5-5% by weight, preferably 1-3% by weight.

[0010] Optionally, the raw material mixing and melting device comprises a screw pump; the method comprises: introducing the chlorine-containing waste plastic raw material to be processed into the screw pump through the inlet end of the screw pump, and then mixing and melting under heating conditions under the screw transmission and shearing action of the screw pump, and moving to the outlet end of the screw pump to obtain a waste plastic mixture; then mixing with the second part of the heated delayed coking raw material at the outlet end of the screw pump, and then entering the liquefaction dechlorination reactor; preferably, the weight ratio of the second part of the heated delayed coking raw material to the chlorine-containing waste plastic raw material is 0.1 to 3:1; optionally, the process conditions of the screw pump include: mixing time 5 min to 60 min; outlet temperature 200 to 430°C.

[0011] Optionally, in step S2, the process conditions of the coking reaction include: the top pressure of the coke tower is 0.05-0.6 MPa, preferably 0.1-0.3 MPa; the weight ratio of the chlorine-containing waste plastic raw material to the delayed coking raw material entering the coking tower is 1:1-20, preferably 1:5-15.

[0012] Optionally, the method further comprises: after the dechlorination treatment is completed, stopping the introduction of the stripping gas into the liquefied dechlorination reactor, introducing high-pressure steam into the liquefied dechlorination reactor through the upper part of the liquefied dechlorination reactor, and pressing the dechlorinated waste plastic liquid phase material out of the liquefied dechlorination reactor; Optionally, the method further comprises: discharging the insoluble residue remaining after the dechlorination treatment through the bottom of the liquefied dechlorination reactor.

[0013] Optionally, the method further comprises: allowing the hydrogen chloride-containing gas phase material to enter a hydrogen chloride absorption device under the purging action of a stripping gas, allowing the hydrogen chloride-containing gas phase material to contact a hydrogen chloride absorbent to absorb hydrogen chloride, and obtaining a hydrogen chloride-containing liquid phase and a second dry gas; optionally, the hydrogen chloride absorbent is water or an alkali solution with a pH greater than 7, and the alkali solution is selected from one or more of a sodium hydroxide solution, a potassium hydroxide solution, a calcium hydroxide solution, a sodium bicarbonate solution, a sodium carbonate solution, and an ammonia solution.

[0014] Optionally, the chlorine-containing waste plastic is a thermoplastic plastic, and optionally, the chlorine-containing waste plastic comprises PVC and other optional thermoplastic plastics; optionally, the other thermoplastic plastics are selected from a mixture of one or more of LDPE, HDPE, PS and PP; optionally, the content of PVC in the chlorine-containing waste plastic is less than 10% by weight;

[0015] The delayed coking raw material has a residual carbon value of 3 to 15% by weight and a distillation range of greater than 350° C. Optionally, the delayed coking raw material is selected from one or more of heavy crude oil, acid-containing crude oil, vacuum residue oil, atmospheric residue oil, vacuum wax oil, coking wax oil, deasphalted oil, hydrocracking tail oil, coal tar, shale oil, tank bottom oil, coal liquefaction residual oil, waste plastic cracking wax oil or other secondary processed distillate oils.

[0016] The second aspect of the present disclosure provides a system for treating chlorine-containing waste plastics using a delayed coking device, the system comprising: a delayed coking raw material inlet, a raw material mixing and melting device, a liquefaction dechlorination reactor, a coking tower and a fractionation tower; the raw material mixing and melting device is respectively provided with a raw material inlet and a mixed material outlet; the raw material inlet introduces waste plastic raw materials; the liquefaction dechlorination reactor is provided with a raw material inlet to be dechlorinated, a stripping medium inlet, a gas phase outlet and a dechlorinated liquid phase outlet; the raw material inlet to be dechlorinated is connected with the mixed material outlet of the raw material mixing and melting device, and a high-temperature solvent inlet is further provided on a connecting pipeline between the mixed material outlet of the raw material mixing and melting device and the raw material inlet to be dechlorinated of the liquefaction dechlorination reactor, the high-temperature solvent inlet is close to the mixed material outlet; the stripping medium inlet introduces stripping gas through a pipeline; the coking tower is provided with a coking material inlet and a coking product outlet; the coking material inlet is respectively connected with the dechlorinated liquid phase outlet of the liquefaction dechlorination reactor and the delayed coking raw material inlet;

[0017] The fractionation tower is provided with a coking product inlet, a first dry gas outlet, a liquefied gas outlet, a gasoline fraction outlet, a diesel fraction outlet and a wax oil fraction outlet; the coking product inlet is connected to the coking product outlet of the coking tower.

[0018] Optionally, the system further comprises a hydrogen chloride absorption device and a heating furnace; the raw material mixing and melting device is a screw feeding device; the screw feeding device comprises a waste plastic silo and a hot screw pump; the hot screw pump is provided with a waste plastic inlet and a molten mixed material outlet, the waste plastic inlet is communicated with the outlet of the waste plastic silo, and the waste plastic inlet is formed as a raw material inlet of the raw material mixing and melting device; the molten mixed material outlet is communicated with the raw material inlet to be dechlorinated of the liquefied dechlorination reactor; the hydrogen chloride absorption device is provided with a hydrogen chloride-containing gas phase inlet, a second dry gas outlet and a hydrogen chloride-containing liquid phase outlet; the hydrogen chloride-containing gas phase inlet is connected to the liquefied dechlorination reactor; The gas phase outlet of the reactor is connected; the bottom of the fractionating tower is also provided with a first delayed coking raw material heating inlet and a first delayed coking raw material heating outlet; the heating furnace is provided with a raw material inlet to be heated and a heated raw material outlet, and the delayed coking raw material inlet of the system is connected with the raw material inlet to be heated through a raw material pipeline; the heated raw material outlet is connected with the coking material inlet of the coking tower through a first pipeline; at least part of the raw material pipeline is located at the bottom of the fractionating tower; preferably, the heated raw material outlet is connected with the high-temperature solvent introduction port through a second pipeline; optionally, the system includes a plurality of the liquefied dechlorination reactors and a plurality of the coking towers.

[0019] Through the above technical scheme, the present disclosure provides a method and system for treating chlorine-containing waste plastics using a delayed coking device. The present disclosure heats, mixes and melts chlorine-containing (PVC) waste plastic raw materials in a raw material mixing and melting device, and can preliminarily mix and melt the waste plastics; and then mixes with a high-temperature solvent to further heat and reduce the viscosity of the preliminarily melted waste plastics, which is convenient for transportation, and can also improve the subsequent dechlorination efficiency and avoid coking caused by uneven heating during the dechlorination process. Dechlorination treatment is carried out under stripping conditions in a liquefied dechlorination reactor, and the chlorine decomposition products in the waste plastics are quickly separated from the oil phase and enter the gas phase, which greatly improves the chlorine removal rate, avoids chlorine in the raw materials from entering the subsequent units, and reduces the corrosion pressure of subsequent equipment. The dechlorinated waste plastic liquid phase material is mixed with the delayed coking raw material to reach the coking reaction temperature through heat exchange, and the dechlorinated waste plastic liquid phase material is directly heated without using a heating furnace, which avoids the coking problem of the furnace tube during the heating process of the dechlorinated waste plastic liquid phase material. The present disclosure reacts the waste plastics with the delayed coking raw materials to obtain more gasoline and diesel components, and through the existing delayed coking device, the waste plastics are recycled as green resources.

[0020] Other features and advantages of the present disclosure will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] 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:

[0022] Figure 1 A process flow chart of a method for treating chlorine-containing waste plastics using a delayed coking unit provided in the present invention.

[0023] Description of Reference Numerals

[0024] 1-waste plastic silo, 2-hot screw pump, 3-liquefaction dechlorination reactor, 4-hydrogen chloride absorption device, 5-delayed coking tower, 6-heating furnace, 7-fractionation tower, 8-raw material pipeline, 9-pipeline, 10-second pipeline, 11-third pipeline, 12-first pipeline, 13-pipeline, 14-pipeline, 15-pipeline, 16-pipeline, 17-pipeline, 18-pipeline, 19-pipeline, 20-pipeline, 21-pipeline, 22-pipeline, 23-gasoline fraction, 24-diesel fraction, 25-wax oil fraction, 26-pipeline DETAILED DESCRIPTION

[0025] 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.

[0026] In the present disclosure, unless otherwise stated, the words "first", "second", "third", etc. are used only to distinguish different components and do not have actual meanings such as the order of connection. In the present disclosure, the directional words used, such as "upper, lower, top, bottom", generally refer to the upper and lower, top and bottom of the device in normal use. "Inside and outside" refer to the outline of the device.

[0027] The first aspect of the present disclosure provides a method for treating chlorine-containing waste plastics using a delayed coking device, such as Figure 1 As shown, the following steps are included:

[0028] S1, heating, mixing and melting the chlorine-containing waste plastic raw material to be treated in a raw material mixing and melting device 2 to obtain a waste plastic mixed material; mixing the waste plastic mixed material with a high-temperature solvent and entering a liquefaction dechlorination reactor 3 for dechlorination treatment under stripping conditions to obtain a gas phase material containing hydrogen chloride and a dechlorinated waste plastic liquid phase material;

[0029] S2, mixing the dechlorinated waste plastic liquid phase material with the first part of delayed coking raw materials and then entering the coking tower 4 for coking reaction to obtain a coking product;

[0030] S3, allowing the coking product to enter a fractionation tower 7 for separation treatment to obtain a first dry gas, liquefied gas, a gasoline fraction, a diesel fraction and a wax oil fraction.

[0031] The present invention provides a method for treating chlorine-containing waste plastics using a delayed coking device. The present invention heats, mixes and melts chlorine-containing (PVC) waste plastic raw materials in a raw material mixing and melting device, and can preliminarily mix and melt the waste plastics; and then mixes with a high-temperature solvent to further heat and reduce the viscosity of the preliminarily melted waste plastics, which is convenient for transportation, and can also improve the subsequent dechlorination efficiency and avoid coking caused by uneven heating during the dechlorination process. Dechlorination treatment is carried out under stripping conditions in a liquefied dechlorination reactor, and the chlorine decomposition products in the waste plastics are quickly separated from the oil phase and enter the gas phase, which greatly improves the chlorine removal rate, avoids chlorine in the raw materials from entering the subsequent units, and reduces the anti-corrosion pressure of subsequent equipment. The dechlorinated waste plastic liquid phase material is mixed with the delayed coking raw material to reach the coking reaction temperature through heat exchange, and the dechlorinated waste plastic liquid phase material is directly heated without using a heating furnace, which avoids the coking problem of the furnace tube during the heating process of the dechlorinated waste plastic liquid phase material. The present invention reacts the waste plastics with the delayed coking raw materials to obtain more gasoline and diesel components, and through the existing delayed coking device, the waste plastics are recycled as green resources.

[0032] In the present disclosure, the liquefaction dechlorination reactor, coking tower, and fractionation tower used are all conventional devices selected in the art. For example, the liquefaction dechlorination reactor can be a reactor such as a high-pressure reactor.

[0033] In one embodiment, in step S1, the weight ratio of the high temperature solvent to the chlorine-containing waste plastic raw material is (10-1):1. Preferably, the temperature of the high temperature solvent is 300-450°C; preferably, the high temperature solvent includes a second portion of delayed coking raw material.

[0034] In a preferred embodiment, the conditions of the dechlorination treatment include: a reaction temperature of 250 to 430° C., a reaction time of 0.5 to 3 hours, an amount of stripping gas of 0.5 to 5% by weight, preferably 1% to 2% by weight, based on the total weight of the feed of the waste plastic raw material and the high-temperature solvent; the stripping gas is high-temperature steam or nitrogen; preferably, the stripping gas is introduced through the bottom of the liquefied dechlorination reactor.

[0035] In one embodiment, the chlorine content in the dechlorinated waste plastic liquid phase material is 100 to 900 μg / g, which greatly reduces the chlorine content of the waste plastic.

[0036] In one embodiment, if Figure 1 As shown, the method further comprises: before step S1, allowing the delayed coking raw material to enter the bottom of the fractionation tower 7 for preheating, and then enter the heating furnace 6 for heating;

[0037] Then, the heated delayed coking raw material from the heating furnace 6 is divided into two parts, and the first part of the heated delayed coking raw material is mixed with the dechlorinated waste plastic liquid phase material from the liquefied dechlorination reactor 3 and enters the coking tower 5; the second part of the heated delayed coking raw material is used as the high-temperature solvent and mixed with the waste plastic mixed material from the raw material mixing and melting device 2;

[0038] Optionally, the outlet temperature of the heating furnace is 480-520° C., and based on the total mass of the material heated in the heating furnace 6, the amount of steam injected into the heating furnace is 0.5-5% by weight, preferably 1-3% by weight.

[0039] The present invention allows the delayed coking raw materials to enter the bottom of the distillation tower for preheating, which can further improve the heat utilization rate in the system; a part of the heated high-temperature delayed coking raw materials is used as a high-temperature solvent to mix with the waste plastic mixed material from the raw material mixing and melting device 2, so as to achieve further viscosity reduction and temperature increase of the material, which is beneficial to subsequent dechlorination treatment.

[0040] In a further embodiment, Figure 1 As shown, the raw material mixing and melting device 2 includes a screw pump; the method includes:

[0041] The chlorine-containing waste plastic raw material to be treated is introduced into the screw pump through the inlet end of the screw pump, and then mixed and melted under heating conditions under the screw transmission and shearing action of the screw pump, and moved to the outlet end of the screw pump to obtain a waste plastic mixed material; and then mixed with the second part of the heated delayed coking raw material at the outlet end of the screw pump, the mixed material enters the liquefaction dechlorination reactor 3.

[0042] In a preferred embodiment, the weight ratio of the second portion of heated delayed coking raw material to the chlorine-containing waste plastic raw material is 0.1 to 3:1;

[0043] Optionally, the process conditions of the screw pump include: mixing time of 5 min to 60 min; outlet temperature of 200 to 430°C.

[0044] In one embodiment, in step S2, the process conditions of the coking reaction include: the top pressure of the coke tower is 0.05-0.6 MPa, preferably 0.1-0.3 MPa; the weight ratio of the chlorine-containing waste plastic raw material to the delayed coking raw material entering the coking tower 4 is 1:1-20, preferably 1:5-15.

[0045] In one embodiment, if Figure 1 As shown, the method further includes: allowing the hydrogen chloride-containing gas phase material to enter the hydrogen chloride absorption device 4, allowing the hydrogen chloride-containing gas phase material to contact with the hydrogen chloride absorbent to absorb hydrogen chloride, and obtain a hydrogen chloride-containing liquid phase and a second dry gas;

[0046] Optionally, the hydrogen chloride absorbent is water or an alkali solution with a pH greater than 7, and the alkali solution is selected from one or more of sodium hydroxide solution, potassium hydroxide solution, calcium hydroxide solution, sodium bicarbonate solution, sodium carbonate solution, and ammonia water. In the dechlorination process of the present invention, under the purging action of the stripping gas, the hydrogen chloride obtained by dechlorination quickly enters the hydrogen chloride absorption device for absorption and removal, thereby improving the removal efficiency of chlorine.

[0047] In one embodiment, if Figure 1 As shown, the method further includes: after the dechlorination treatment is completed, the stripping gas is stopped from being introduced into the liquefied dechlorination reactor 3, and high-pressure steam is introduced into the liquefied dechlorination reactor through the upper part of the liquefied dechlorination reactor 3 to pressurize the dechlorinated waste plastic liquid phase material out of the liquefied dechlorination reactor 3.

[0048] In one embodiment, the method further comprises: discharging the insoluble residue remaining after the dechlorination treatment through the bottom of the liquefaction dechlorination reactor. The present invention can selectively separate impurities such as metals and fibers in the waste plastics that cannot be oiled through the liquefaction dechlorination reactor, and the quality of the petroleum coke is not lost while the waste plastics are recycled.

[0049] In one embodiment, the waste plastic raw material includes a mixture of PVC and one or more selected from LDPE, HDPE, PS, and PP; optionally, the weight content of the PVC is less than 10 weight %;

[0050] The delayed coking raw material includes vacuum residue oil, distillate oil with a residual carbon value of 3 to 15%, and a distillation range of greater than 350° C., preferably selected from one or more of heavy crude oil, acid-containing crude oil, atmospheric residue oil, vacuum wax oil, coker wax oil, deasphalted oil, hydrocracking tail oil, coal tar, shale oil, tank bottom oil, coal liquefaction residual oil, waste plastic cracking wax oil or other secondary processed distillate oils.

[0051] The second aspect of the present disclosure provides a system for treating chlorine-containing waste plastics using a delayed coking device, such as Figure 1 As shown, the system comprises: a delayed coking raw material inlet, a raw material mixing and melting device 2, a liquefaction dechlorination reactor 3, a coking tower 5 and a fractionation tower 7;

[0052] The raw material mixing and melting device 2 is provided with a raw material inlet and a mixed material outlet; the raw material inlet is used to introduce waste plastic raw materials;

[0053] The liquefied dechlorination reactor 3 is provided with an inlet for the raw material to be dechlorinated, an inlet for the stripping medium, a gas phase outlet and a dechlorinated liquid phase outlet; the inlet for the raw material to be dechlorinated is connected with the mixed material outlet of the raw material mixing and melting device 2, and a high-temperature solvent inlet is also provided on the connecting pipeline between the mixed material outlet of the raw material mixing and melting device 2 and the inlet for the raw material to be dechlorinated of the liquefied dechlorination reactor 3, and the high-temperature solvent inlet is close to the mixed material outlet; the stripping medium inlet introduces stripping gas through a pipeline;

[0054] The coking tower 5 is provided with a coking material inlet and a coking product outlet; the coking material inlet is respectively connected to the dechlorination liquid phase outlet of the liquefied dechlorination reactor 3 and the delayed coking raw material inlet;

[0055] The fractionation tower is provided with a coking product inlet, a first dry gas outlet, a liquefied gas outlet, a gasoline fraction outlet, a diesel fraction outlet and a wax oil fraction outlet; the coking product inlet is connected to the coking product outlet of the coking tower 7.

[0056] In a specific embodiment, the system includes multiple liquefied dechlorination reactors 3 and multiple coking towers 5, and the multiple liquefied dechlorination reactors are connected in parallel, and the multiple coking towers are also connected in parallel to improve the overall processing efficiency of the system. Figure 1 As shown, the system includes two liquefied dechlorination reactors and two coking towers. The specific connection mode in the brackets of multiple devices of the same type connected in parallel can be set according to actual needs.

[0057] In one embodiment, if Figure 1 As shown, the system further includes a hydrogen chloride absorption device 4 and a heating furnace 6;

[0058] The raw material mixing and melting device 2 is a screw feeding device; the screw feeding device includes a waste plastic silo 1 and a hot screw pump; the hot screw pump is provided with a waste plastic inlet and a molten mixed material outlet, the waste plastic inlet is connected to the outlet of the waste plastic silo, and the waste plastic inlet is formed as the raw material inlet of the raw material mixing and melting device; the molten mixed material outlet is connected to the raw material inlet to be dechlorinated of the liquefied dechlorination reactor 3;

[0059] The hydrogen chloride absorption device 4 is provided with a hydrogen chloride-containing gas phase inlet, a second dry gas outlet and a hydrogen chloride-containing liquid phase outlet; the hydrogen chloride-containing gas phase inlet is connected to the gas phase outlet of the liquefied dechlorination reactor 3;

[0060] The bottom of the fractionation tower 7 is also provided with a first inlet for heating the delayed coking raw material and a first outlet for heating the delayed coking raw material;

[0061] The heating furnace 6 is provided with a raw material inlet to be heated and a heated raw material outlet. The delayed coking raw material inlet of the system is connected with the raw material inlet to be heated through a raw material pipeline; the heated raw material outlet is connected with the coking material inlet of the coking tower 5 through a first pipeline; at least part of the raw material pipeline is located at the bottom of the fractionation tower 7;

[0062] Optionally, the heated raw material outlet is connected to the high-temperature solvent inlet through a second pipeline;

[0063] Optionally, the inlet of the raw material to be heated of the heating furnace 6 is also connected to the wax oil fraction outlet of the distillation tower 7 .

[0064] In a specific implementation manner, Figure 1 As shown, the system comprises: a delayed coking raw material inlet, a raw material mixing and melting device, a liquefaction dechlorination reactor 3, a coking tower 5, a fractionating tower 7, a hydrogen chloride absorption device 4 and a heating furnace 6; the raw material mixing and melting device is respectively provided with a raw material inlet and a mixed material outlet; the raw material inlet introduces waste plastic raw materials, and the mixed material outlet of the raw material mixing and melting device 2 introduces an external high-temperature solvent through a high-temperature solvent introduction pipeline;

[0065] The liquefied dechlorination reactor 3 is provided with an inlet for the raw material to be dechlorinated, an inlet for the stripping medium, a gas phase outlet and a dechlorinated liquid phase outlet; the inlet for the raw material to be dechlorinated is connected with the mixed material outlet of the raw material mixing and melting device 2; and a high-temperature solvent inlet is also provided on the connecting pipeline between the mixed material outlet of the raw material mixing and melting device 2 and the inlet for the raw material to be dechlorinated of the liquefied dechlorination reactor 3, the high-temperature solvent inlet is close to the mixed material outlet, and the stripping medium inlet introduces stripping gas through a pipeline;

[0066] The coking tower 5 is provided with a coking material inlet and a coking product outlet; the coking material inlet is respectively connected to the dechlorination liquid phase outlet of the liquefied dechlorination reactor 3 and the delayed coking raw material inlet;

[0067] The fractionation tower 7 is provided with a coking product inlet, a first dry gas outlet, a liquefied gas outlet, a gasoline fraction outlet, a diesel fraction outlet and a wax oil fraction outlet; the coking product inlet is connected to the coking product outlet of the coking tower;

[0068] The raw material mixing and melting device is a screw feeding device; the screw feeding device comprises a waste plastic silo 1 and a hot screw pump 2; the hot screw pump 2 is provided with a waste plastic inlet and a molten mixed material outlet, the waste plastic inlet is connected with the outlet of the waste plastic silo 1, and the waste plastic inlet is formed as the raw material inlet of the raw material mixing and melting device; the molten mixed material outlet is connected with the raw material inlet to be dechlorinated of the liquefied dechlorination reactor 3;

[0069] The hydrogen chloride absorption device 4 is provided with a hydrogen chloride-containing gas phase inlet, a second dry gas outlet and a hydrogen chloride-containing liquid phase outlet; the hydrogen chloride-containing gas phase inlet is connected to the gas phase outlet of the liquefied dechlorination reactor 3;

[0070] The bottom of the fractionation tower 7 is also provided with a first inlet for heating the delayed coking raw material and a first outlet for heating the delayed coking raw material;

[0071] The heating furnace 6 is provided with an inlet for raw materials to be heated and an outlet for heated raw materials. The delayed coking raw material inlet of the system is connected with the inlet for raw materials to be heated through a raw material pipeline; the heated raw material outlet is connected with the coking material inlet of the coking tower 5 through a first pipeline; at least part of the raw material pipeline is located at the bottom of the distillation tower 7; the heated raw material outlet is connected with the high-temperature solvent inlet through a second pipeline.

[0072] The process flow of the system provided by the above specific embodiments in the present disclosure specifically includes: Figure 1 As shown:

[0073] The delayed coking raw material enters the bottom of the fractionation tower 7 through the raw material pipeline 8 for heat exchange, and then enters the heating furnace 6 through the pipeline 9 and the raw material inlet to be heated for heating; the cleaned and crushed waste plastic enters the waste plastic inlet of the hot screw pump 2 from the outlet of the waste plastic silo 1;

[0074] The waste plastics are mixed and melted during the transportation process of the hot screw pump 2, and the high-temperature solvent inlet on the connecting pipeline between the molten mixed material outlet of the hot screw pump 2 and the raw material inlet to be dechlorinated of the liquefied dechlorination reactor 3 is connected to the heated raw material outlet of the heating furnace through a second pipeline, which is used to further introduce a second part of the high-temperature delayed coking raw material into the obtained molten mixed material for heating, dilution and viscosity reduction; and then they are jointly transported to the liquefied dechlorination reactor 3 (the two liquefied dechlorination reactors 3 can be fed in sequence, such as mixing the waste plastic mixed material from the raw material mixing and melting device 2 with the high-temperature solvent and then introducing it into the first liquefied dechlorination reactor, and then continuing to mix the waste plastic mixed material from the raw material mixing and melting device 2 with the high-temperature solvent After mixing, the mixture is introduced into a second liquefied dechlorination reactor), high-temperature steam or nitrogen is introduced into the liquefied dechlorination reactor 3 from the pipeline 21 through the bottom, so that the HCl decomposition product of PVC in the waste plastic quickly enters the gas phase, and then the gas phase material containing hydrogen chloride enters the hydrogen chloride absorption device 4 through the pipeline 26, so that the gas phase material containing hydrogen chloride contacts with the hydrogen chloride absorbent to absorb hydrogen chloride, and obtains a hydrogen chloride-containing liquid phase and a second dry gas, the hydrogen chloride-containing liquid phase is discharged through the liquid phase outlet at the bottom of the hydrogen chloride absorption device 4, and the second dry gas is discharged through the second dry gas outlet at the top of the hydrogen chloride absorption device 4; the second gas phase is mixed with the first dry gas drawn out from the top outlet of the fractionation tower 7 through the pipeline 16 and then enters the subsequent treatment device;

[0075] After the dechlorination treatment is completed, the pipeline 21 is stopped to introduce gas into the liquefied dechlorination reactor 3, and high-pressure steam is introduced into the liquefied dechlorination reactor 3 from the upper part through the pipeline 20, and the dechlorinated waste plastic liquid phase material is discharged from the liquefied dechlorination reactor 3 through the pipeline 18; further, the insoluble residue remaining at the bottom of the liquefied dechlorination reactor 3 is discharged through the bottom of the liquefied dechlorination reactor 3 and the pipeline 19; and then mixed with the first part of the high-temperature thermal delayed coking raw material flow from the heating furnace 6 transported through the first pipeline 12, and then introduced into each coking tower 5 through the pipeline 13 for coking reaction;

[0076] The coking reaction product is drawn out through pipeline 14 and enters into distillation tower 7 through pipeline 15, where it is divided into first dry gas, gasoline fraction, diesel fraction and wax oil fraction, which are drawn out of the distillation tower through pipelines 17, 23, 24 and 25 respectively.

[0077] In the following examples and comparative examples, the kinematic viscosity test (200° C.) was performed on the dechlorinated waste plastic liquid phase material obtained by dechlorination treatment using a rotational viscosity test method;

[0078] The XRF method was used to test the residual chlorine content in the waste plastic raw materials and the dechlorinated waste plastic liquid materials obtained by dechlorination treatment.

[0079] Example 1

[0080] Plastic packaging materials containing LDPE, HDPE, PS, PP and PVC (mass percentage of 4:4:8:3:1) were crushed and dried as waste plastic raw materials, and catalytic cracking wax oil (properties listed in Table 1) was used as a high-temperature solvent. Figure 1 The process flow shown specifically includes the following steps:

[0081] The above-mentioned waste plastic raw materials are mixed and melted through a screw feeding device, and then the waste plastic mixture is mixed with catalytic cracking wax oil at the outlet end of the screw pump (catalytic cracking wax oil is used as a high-temperature solvent, the temperature is 300°C, and the weight ratio of the high-temperature solvent to the waste plastic raw materials is 3:1), and then transported to the liquefaction dechlorination reactor; wherein the process conditions of the screw feeding device include: mixing time 15min; outlet temperature 275°C;

[0082] In this embodiment, the liquefied dechlorination reactor adopts a high-pressure reactor with stirring; nitrogen is introduced into the reactor as a stripping gas for purging, and the gas in the reactor is discharged; the temperature of the high-pressure reactor is set to 375°C, the reaction time is 1h, and dechlorination treatment is carried out; the amount of stripping gas is 10% by weight of the total weight of the feed; a gas phase material containing hydrogen chloride and a dechlorinated waste plastic liquid phase material are obtained, and the gas phase material containing hydrogen chloride enters a hydrogen chloride absorption device under nitrogen purge to absorb and remove hydrogen chloride, and the hydrogen chloride absorbent is a NaOH aqueous solution; a dechlorinated waste plastic liquid phase material (recorded as FSL-1) is obtained, and the properties of FSL-1 are listed in Table 2.

[0083] Example 2

[0084] The same method as in Example 1 was adopted, except that the temperature of the high-pressure reactor was set to 275° C., and the rest was the same as in Example 1; a dechlorinated waste plastic liquid phase material (denoted as FSL-2) was obtained, and the properties of FSL-2 are listed in Table 2.

[0085] Example 3

[0086] The same method as in Example 1 was adopted, the weight ratio of the catalytic cracking wax oil introduced at the outlet of the hot screw pump to the waste plastic raw material was 1:1; the temperature of the high-pressure reactor was set to 350°C, and the rest was the same as in Example 1; a dechlorinated waste plastic liquid phase material (denoted as FSL-3) was obtained, and the properties of FSL-3 are listed in Table 2.

[0087] Example 4

[0088] The same method as in Example 1 was adopted, except that vacuum residue A was used as the high-temperature solvent (properties are listed in Table 1), the weight ratio of vacuum residue A (temperature of 300° C.) introduced at the outlet of the hot screw pump to the waste plastic raw material was 3:1; the temperature of the high-pressure reactor was set at 350° C.; the rest was the same as in Example 1; and a dechlorinated waste plastic liquid phase material (denoted as FSL-4) was obtained, and the properties of FSL-4 are listed in Table 2.

[0089] Example 5

[0090] The same method as in Example 1 was adopted, except that vacuum residue A was used as the high-temperature solvent, and the weight ratio of vacuum residue A (temperature of 300° C.) introduced at the outlet of the hot screw pump to the waste plastic raw material was 3:1; the temperature of the high-pressure reactor was set to 400° C.; the rest was the same as in Example 1; and a dechlorinated waste plastic liquid phase material (denoted as FSL-5) was obtained. The properties of FSL-5 are listed in Table 2.

[0091] Comparative Example 1

[0092] The catalytic cracking wax oil was directly introduced into the liquefaction dechlorination reactor without introducing the waste plastic raw material, and the liquid phase material (denoted as D-1) was treated under the same dechlorination treatment conditions. The properties of D-1 are listed in Table 2.

[0093] Comparative Example 2

[0094] The same method as in Example 1 was adopted, except that no high temperature solvent was introduced, and the rest was the same as in Example 1; a dechlorinated waste plastic material (D-2) was obtained, and the properties of D-2 are listed in Table 2.

[0095] The following examples are used to conduct a coking experiment on waste plastics after dechlorination treatment.

[0096] In the following Examples 6 to 10 and Comparative Examples 3 to 4, the temperature of the waste plastic oils FSL-1 to FSL-5 was 350°C, and the temperature of the vacuum residues A and B was 500°C.

[0097] The coking tests in the following Examples 6 to 10 and Comparative Examples 3 to 4 were carried out in a laboratory apparatus (autoclave).

[0098] Example 6

[0099] The liquefied waste plastic oil FSL-1 in Example 1 was mixed with vacuum residue A to carry out a coking test. The weight ratio of the liquefied waste plastic oil to the vacuum residue A was 4:3, the reaction temperature was 480°C, and the distribution of the obtained coking reaction products is shown in Table 3.

[0100] Example 7

[0101] The liquefied waste plastic oil FSL-2 in Example 2 was mixed with vacuum residue oil A to carry out a coking test. The weight ratio of the liquefied waste plastic oil to the vacuum residue oil A was 2:6. The reaction temperature was 480°C. The distribution of the obtained coking reaction products is shown in Table 3.

[0102] Example 8

[0103] The liquefied waste plastic oil FSL-3 in Example 3 was mixed with vacuum residue oil B to carry out a coking test. The mass ratio of the liquefied waste plastic oil to the vacuum residue oil was 4:7, the reaction temperature was 480°C, and the distribution of the obtained coking reaction products is shown in Table 3.

[0104] Example 9

[0105] The liquefied waste plastic oil FSL-4 in Example 4 was mixed with vacuum residue oil B to carry out a coking test. The weight ratio of the liquefied waste plastic oil to the vacuum residue oil B was 2:7, the reaction temperature was 480°C, and the distribution of the obtained coking reaction products is shown in Table 3.

[0106] Example 10

[0107] The liquefied waste plastic oil FSL-5 in Example 5 was mixed with vacuum residue oil B to carry out a coking test. The weight ratio of the liquefied waste plastic oil to the vacuum residue oil B was 3:7, the reaction temperature was 480°C, and the distribution of the obtained coking reaction products is shown in Table 3.

[0108] Comparative Example 3

[0109] The coking test was conducted using vacuum residue A at a reaction temperature of 480°C. The distribution of the coking reaction products is shown in Table 3.

[0110] Comparative Example 4

[0111] The coking test was conducted using vacuum residue B at a reaction temperature of 480°C. The distribution of the coking reaction products is shown in Table 3.

[0112] Embodiment 11

[0113] Plastic packaging materials containing LDPE, HDPE, PS, PP and PVC (mass percentage is 4:4:8:3:1) are crushed and dried to serve as the waste plastic raw materials, and vacuum residue A is used as the delayed coking raw material. Figure 1 The process flow shown specifically includes the following steps:

[0114] The delayed coking raw material vacuum residue A enters the bottom of the fractionation tower for preheating, and then enters the heating furnace for heating; the outlet temperature of the heating furnace is 480° C., and the steam injection amount is 2% by weight; the heated delayed coking raw material is divided into two parts, the weight ratio of the first part (entering the coking tower): the second part (as a high-temperature solvent) is 7:3;

[0115] The waste plastic raw materials are mixed and melted through a screw feeding device, and then conveyed to the liquefaction dechlorination reactor; wherein the process conditions of the screw feeding device include: mixing time of 15 minutes; outlet temperature of 375°C; and the molten mixed material is mixed with the second part of the heated delayed coking raw materials at the outlet of the screw feeding device (the second part of the heated delayed coking raw materials is used as a high-temperature solvent, the temperature is 480°C, and the weight ratio of the high-temperature solvent to the solid waste plastic raw materials is 3:1);

[0116] A high-pressure reactor with stirring was used; nitrogen was introduced into the reactor as a stripping gas for purging, and the gas in the reactor was discharged; the temperature of the high-pressure reactor was set at 375° C., the reaction time was 1 hour, and dechlorination treatment was performed; the amount of stripping gas was 2% by weight of the total weight of the feed; a gas phase material containing hydrogen chloride and a dechlorinated waste plastic liquid phase material were obtained, and the gas phase material containing hydrogen chloride entered a hydrogen chloride absorption device under nitrogen purge to absorb and remove hydrogen chloride, and the hydrogen chloride absorbent was a NaOH aqueous solution; a dechlorinated waste plastic liquid phase material (recorded as FSL-6) was obtained; the properties are listed in Table 2.

[0117] After the dechlorinated waste plastic liquid phase material is mixed with the first part of the delayed coking raw material after heating from the heating furnace (the weight ratio of the first part of the delayed coking raw material after heating to the solid waste plastic raw material is 7:1), it enters the coking tower for reaction, wherein the process conditions of the coking reaction include: coke tower top pressure 0.1MPa; reaction temperature 480℃, reaction time 4h; the delayed coking reaction product is introduced into the fractionation tower for separation. The product distribution is listed in Table 3.

[0118] Example 12

[0119] The method of Example 11 is adopted, and the difference from Example 11 is that the weight ratio of the first part (entering the coking tower): the second part (as the high temperature solvent) is 17:3;

[0120] The weight ratio of the first part of the delayed coking raw material after heating to the solid waste plastic raw material entering the coking tower is 17:1, and the weight ratio of the second part of the delayed coking raw material after heating as a high-temperature solvent to the solid waste plastic raw material is 3:1, and the temperature is 480° C. The rest of the process is the same as in Example 11. The product distribution is listed in Table 3.

[0121] Table 1 Properties of solvent wax oil and vacuum residue

[0122]

[0123]

[0124] Table 2 Properties of liquefied waste plastic oil

[0125]

[0126] According to Table 2, compared with Comparative Example 2, the method provided by the present disclosure can reduce the viscosity and efficiently dechlorinate chlorine-containing waste plastics, the dechlorination rate can reach more than 87%, and the chlorine content of the waste plastics after dechlorination can reach 100-900 μg / g.

[0127] Table 3 Distribution of waste plastic oil coking products

[0128]

[0129]

[0130] According to the data in Table 3, compared with the comparative example 3 in which only vacuum residue A is used for coking reaction, the vacuum residue A and dechlorinated waste plastics are coking reacted together in Examples 6 to 7 and Example 11 of the present disclosure, which can improve the resource utilization of waste plastics, increase the yield of delayed coking products, and reduce the coke yield.

[0131] Compared with comparative example 4 in which only vacuum residue B is used for coking reaction, vacuum residue B and dechlorinated waste plastic are coking reacted together in examples 8 to 10 of the present disclosure, which can improve the resource utilization of waste plastics, increase the yield of delayed coking products, and reduce the coke yield.

[0132] Comparing Example 11 with Example 12, it can be seen that the weight ratio of the first part of the delayed coking raw material after heating to the solid waste plastic raw material in Example 11 is 7:1, which satisfies the weight ratio of the chlorine-containing waste plastic raw material to the delayed coking raw material entering the coking tower 4 is in the range of 1:5 to 15. The product distribution obtained in Example 11 is better, such as liquefied gas and C 5 The yield of the ~180℃ fraction is higher and the coke yield is lower.

[0133] 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.

[0134] 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.

[0135] 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 treating chlorine-containing waste plastics using a delayed coking device, characterized in that: The following steps are involved: S1. The chlorine-containing waste plastic raw material to be treated is heated, mixed and melted in a raw material mixing and melting device (2) to obtain a waste plastic mixed material; the waste plastic mixed material is mixed with a high-temperature solvent and then enters a liquefaction dechlorination reactor (3) for dechlorination treatment under stripping conditions to obtain a gas phase material containing hydrogen chloride and a dechlorinated waste plastic liquid phase material; wherein the high-temperature solvent comprises a second part of delayed coking raw material; wherein the weight ratio of the high-temperature solvent to the chlorine-containing waste plastic raw material is (10-1):1, and the temperature of the high-temperature solvent is 300-450°C; S2, mixing the dechlorinated waste plastic liquid phase material with the first portion of delayed coking raw material and then entering a coking tower (5) for a coking reaction to obtain a coking product; wherein the process conditions of the coking reaction include: a coking tower top pressure of 0.1-0.3 MPa; a weight ratio of the chlorine-containing waste plastic raw material to the delayed coking raw material entering the coking tower (5) of 1:5-15; S3, allowing the coking product to enter a fractionation tower (7) for separation treatment to obtain a first dry gas, liquefied gas, a gasoline fraction, a diesel fraction and a wax oil fraction.

2. The method according to claim 1, characterized in that In step S1, the conditions of the dechlorination treatment include: a reaction temperature of 250-430°C, a reaction time of 0.5h-3h, an amount of stripping gas of 0.5-5% by weight of the total weight of the feed of the waste plastic raw material and the high-temperature solvent; the stripping gas is nitrogen or high-temperature steam.

3. The method according to claim 2, characterized in that Based on the total weight of the feed of the waste plastic raw material and the high-temperature solvent, the amount of the stripping gas is 1% to 2% by weight of the total weight of the feed.

4. The method according to claim 2, characterized in that: The stripping gas is introduced through the bottom of the liquefaction dechlorination reactor.

5. The method according to claim 2, characterized in that: The chlorine content in the dechlorinated waste plastic liquid phase material is 100~900μg / g.

6. The method according to claim 1 or 2, characterized in that: The method further includes: Before step S1, the delayed coking raw material enters the bottom of the fractionation tower (7) for preheating, and then enters the heating furnace (6) for heating; Then, the heated delayed coking raw material from the heating furnace (6) is divided into two parts, and the first part of the heated delayed coking raw material is mixed with the dechlorinated waste plastic liquid phase material from the liquefied dechlorination reactor (3) and enters the coking tower (5); and the second part of the heated delayed coking raw material is used as the high-temperature solvent and mixed with the waste plastic mixed material from the raw material mixing and melting device (2).

7. The method according to claim 6, characterized in that The outlet temperature of the heating furnace is 480-520° C., and the amount of steam injected into the heating furnace is 0.5-5% by weight, based on the total mass of the material heated in the heating furnace (6).

8. The method according to claim 7, characterized in that Based on the total mass of the material heated in the heating furnace (6), the amount of steam injected into the heating furnace is 1-3% by weight.

9. The method according to claim 6, characterized in that The raw material mixing and melting device (2) comprises a screw pump; the method comprises: The chlorine-containing waste plastic raw material to be treated is introduced into the screw pump through the inlet end of the screw pump, and then mixed and melted under heating conditions under the screw drive and shearing action of the screw pump, and moved to the outlet end of the screw pump to obtain a waste plastic mixed material; and then mixed with the second part of the heated delayed coking raw material at the outlet end of the screw pump, and then enters the liquefaction dechlorination reactor (3).

10. The method according to claim 9, characterized in that The weight ratio of the second part of heated delayed coking raw materials to the chlorine-containing waste plastic raw materials is 0.1-3:

1.

11. The method according to claim 9, characterized in that The process conditions of the screw pump include: mixing time of 5 min to 60 min; outlet temperature of 200 to 430°C.

12. The method according to claim 2, characterized in that: The method further comprises: after the dechlorination treatment is completed, the introduction of the stripping gas into the liquefied dechlorination reactor (3) is stopped, high-pressure steam is introduced into the liquefied dechlorination reactor through the upper part of the liquefied dechlorination reactor (3), and the dechlorinated waste plastic liquid phase material is pressed out of the liquefied dechlorination reactor (3).

13. The method according to claim 12, characterized in that The method further comprises: discharging the insoluble residue remaining after the dechlorination treatment through the bottom of the liquefaction dechlorination reactor (3).

14. The method according to claim 12, characterized in that The method further includes: The gaseous material containing hydrogen chloride is allowed to enter the hydrogen chloride absorption device (4) under the purging action of the stripping gas, and the gaseous material containing hydrogen chloride is brought into contact with the hydrogen chloride absorbent to absorb hydrogen chloride, thereby obtaining a hydrogen chloride-containing liquid phase and a second dry gas.

15. The method according to claim 14, characterized in that The hydrogen chloride absorbent is water or an alkali solution with a pH greater than 7, and the alkali solution is selected from one or more of sodium hydroxide solution, potassium hydroxide solution, calcium hydroxide solution, sodium bicarbonate solution, sodium carbonate solution, and ammonia water.

16. The method according to claim 1, characterized in that The chlorine-containing waste plastic is a thermoplastic plastic; the residual carbon value of the delayed coking raw material is 3-15% by weight, and the distillation range is greater than 350°C.

17. The method according to claim 16, characterized in that The chlorine-containing waste plastics include PVC and optionally other thermoplastics.

18. The method according to claim 17, characterized in that The other thermoplastics are selected from a mixture of one or more of LDPE, HDPE, PS and PP.

19. The method according to claim 17, characterized in that The PVC content in the chlorine-containing waste plastic is less than 10 weight % and greater than 0.

20. The method according to claim 16, characterized in that The delayed coking raw material is selected from one or a mixture of heavy crude oil, acidic crude oil, vacuum residue oil, atmospheric residue oil, vacuum wax oil, coking wax oil, deasphalted oil, hydrocracking tail oil, coal tar, shale oil, tank bottom oil, coal liquefaction residual oil and waste plastic cracking wax oil.

21. A system for treating chlorine-containing waste plastics using a delayed coking device according to the method of claim 1, characterized in that: The system comprises: a delayed coking raw material inlet, a raw material mixing and melting device (2), a liquefaction dechlorination reactor (3), a coking tower (5) and a fractionating tower (7); The raw material mixing and melting device (2) is respectively provided with a raw material inlet and a mixed material outlet; the raw material inlet is used to introduce waste plastic raw materials; The liquefied dechlorination reactor (3) is provided with an inlet for a raw material to be dechlorinated, an inlet for a stripping medium, a gas phase outlet and a dechlorinated liquid phase outlet; the inlet for the raw material to be dechlorinated is connected to the mixed material outlet of the raw material mixing and melting device (2), and a high-temperature solvent inlet is also provided on the connecting pipeline between the mixed material outlet of the raw material mixing and melting device (2) and the inlet for the raw material to be dechlorinated of the liquefied dechlorination reactor (3), and the high-temperature solvent inlet is close to the mixed material outlet; the stripping medium inlet is introduced with stripping gas through a pipeline; The coking tower (5) is provided with a coking material inlet and a coking product outlet; the coking material inlet is respectively connected to the dechlorination liquid phase outlet of the liquefied dechlorination reactor (3) and the delayed coking raw material inlet; The fractionation tower is provided with a coking product inlet, a first dry gas outlet, a liquefied gas outlet, a gasoline fraction outlet, a diesel fraction outlet and a wax oil fraction outlet; the coking product inlet is connected to the coking product outlet of the coking tower (5).

22. The system according to claim 21, characterized in that The system further comprises a hydrogen chloride absorption device (4) and a heating furnace (6); The raw material mixing and melting device (2) comprises a waste plastic silo (1) and a hot screw pump; the hot screw pump is provided with a waste plastic inlet and a molten mixed material outlet, the waste plastic inlet is connected to the outlet of the waste plastic silo, and the waste plastic inlet forms a raw material inlet of the raw material mixing and melting device; The molten mixed material outlet is connected to the inlet of the raw material to be dechlorinated of the liquefied dechlorination reactor (3); The hydrogen chloride absorption device (4) is provided with a hydrogen chloride-containing gas phase inlet, a second dry gas outlet and a hydrogen chloride-containing liquid phase outlet; the hydrogen chloride-containing gas phase inlet is connected to the gas phase outlet of the liquefaction dechlorination reactor (3); The bottom of the fractionation tower (7) is also provided with a first inlet for heating the delayed coking raw material and a first outlet for heating the delayed coking raw material; The heating furnace (6) is provided with an inlet for raw materials to be heated and an outlet for heated raw materials. The delayed coking raw material inlet of the system is connected to the inlet for raw materials to be heated via a raw material pipeline; the outlet for heated raw materials is connected to the coking material inlet of the coking tower (5) via a first pipeline; at least part of the raw material pipeline is located at the bottom of the fractionating tower (7).

23. The system according to claim 22, characterized in that The heating raw material outlet is connected to the high-temperature solvent inlet through a second pipeline.

24. The system according to claim 22, characterized in that The system comprises a plurality of the liquefaction dechlorination reactors and a plurality of the coking towers.

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