WO2005028593A1

WO2005028593A1 - A inductrialized process and a device for production of gasoline, diesel oil from waste plastics

Info

Publication number: WO2005028593A1
Application number: PCT/CN2004/001090
Authority: WO
Inventors: De Run Dang
Original assignee: Beijing Dragon New Energy Technology Ltd.
Priority date: 2003-09-25
Filing date: 2004-09-24
Publication date: 2005-03-31
Also published as: CN1223650C; CN1526793A

Abstract

A industrialized process and a device for production of gasoline, diesel oil from waste plastics, the waste plastics polyethylene, polypropylene, polystyrene or polyethylene, polystyrene or polypropylene, polystyrene are mixed in proportion and put into a reactor undergoing heating, liquefaction and pyrolyzing, the reactor has a dual-screw stirrer inside and a thermal medium of fusedsalt fluid layer outside, after that, subject the product to visbreaking, the pyrolyzing gas condenses to liquid, then goes through fractionation in fractionating tower; At the same time the melt plastics in the reactor is continuously pumped to solid-liquid separator, the residue, mud in the reactor are separated effectively and discharged from the separator through the screw extruder at the bottom of the solid-liquid separator, the clean melt plastics returns back to the reactor, after all the above steps, vacuum distillation is carried out. This invention doesn't need complex catalytic cracking device, run sequentially with high oil yield, good oil quality and low cost, it resolves the problem in existing production of gasoline, diesel oil from waste plastics, disposes white pollution effectively.

Description

Method and equipment for producing gasoline and diesel oil from industrial waste plastics

The invention relates to a method and equipment for producing gasoline and diesel oil by using industrial waste plastics, and belongs to the field of petrochemical refining. Background technique

Since the 1970s, many researchers around the world have devoted a lot of manpower and material resources to research on the use of waste plastics to produce gasoline and diesel, especially in China, which is even more prominent. There are as many as 100 publications of patent documents. It is unanimously recognized that the use of waste plastics to produce gasoline and diesel technology is a better method for recycling plastics. According to the currently published patent documents, the existing methods of producing gasoline and diesel from waste plastics mainly adopt complex catalytic cracking technology for waste plastics, and then use direct fire to burn them to form a higher viscosity liquid after oiling. Distillation tower evaporates to obtain finished gasoline and diesel oil. The above methods have the following shortcomings: (1) complex catalytic cracking equipment is required; (2) waste plastic is heated unevenly during the melting process when the fire is directly fired, the temperature is high or low, affecting the plastic cracking depth and coking phenomenon, Decrease the quality of the refined oil; (3) the plasticization of plastics is an endothermic reaction, the thermal conductivity of its material is poor, the time to reach the thermal cracking temperature is long, the heat exchange effect is poor, and the phenomenon of four-wall coking occurs; (4) waste The liquid formed by plasticization of plastic has high viscosity, poor fluidity, and no viscosity reduction device. This material, as the basic raw material for distillation column distillation, will cause a load on the distillation column, generate a large amount of refining oil, and increase the refining cost; (5) There will be a certain amount of dirt, sand, etc. in the process of collection, sorting and blending of waste plastics. There is no separation device to remove the harmful substances, resulting in incomplete slag discharge and continuous operation; (6) Atmospheric or positive pressure operation reduces the oil withdrawal depth and oil conversion rate, and wastes energy. Summary of the invention The technical problem solved by the present invention is to provide a method for producing gasoline and diesel oil by using industrial waste plastics for industrialization without the need for complicated catalytic cracking equipment, which can be continuously produced, high oil conversion rate, good oil quality, low cost, and energy saving. And its equipment, so as to solve the defects of the existing method of producing gasoline and diesel from waste plastics.

The technical solution of the present invention is: A method for producing gasoline and diesel oil by using industrial waste plastics, which is characterized by the following steps:

(1) Blending waste plastic polyethylene, polypropylene, polystyrene, or polyethylene, polystyrene, or polypropylene, polystyrene in proportion;

(2) The above-mentioned mixed waste plastic is propelled into a reaction kettle with a double-spiral belt stirrer and a molten salt heat-conducting medium jacket to heat and liquefy and crack;

(3) The waste plastic in the reaction kettle is cracked by heating, and the material produced by the reaction is subjected to visbreaking, and the cracked gas is condensed to form a liquid, which is sent to a rectification tower for rectification;

(4) At the same time, the plastic melting liquid in the reaction kettle is continuously pumped into the solid-liquid separation tank containing the molten salt separation liquid, and the residue and soil in the reaction kettle are effectively separated, and the residue and soil are passed through the solid-liquid separation tank. The screw extruder at the bottom is discharged out of the cylinder, and the clean plastic melting solution is returned to the reactor;

After completing steps (2), (3), and (4), vacuum distillation is performed.

The blending ratio in the waste plastic in the step (1) is polyethylene: polypropylene: polystyrene 0.8 ~ 1.2: 0.8 ~ 1.2: 0.7 ~ 0.9, or polyethylene: polystyrene 0.8 ~ 1.2: 0.3 to 0.5 or polypropylene: polystyrene 0.8 to 1.2: 0.3 to 0.5, where the preferred ratio is polyethylene: polypropylene: polystyrene 1: 1: 0.8, or polyethylene: polystyrene : 0.4 ~ 0, or polypropylene: polystyrene is 1: 0.4.

The reaction kettle in the step (2) is a tank-shaped reactor or a vertical reactor, and the molten salt temperature is 200 ° C-800 ° C, preferably 450 ° C ~ 550 ° C.

The heating and liquefaction cracking temperature of the plastic in the step (2) is 350 ° C ~ 400 ° C.

The double ribbon stirrer in the step ( ² ) is a double ribbon stirrer in which the outer ribbon rotates clockwise, the inner ribbon rotates counterclockwise, and the distance between the outer ribbon and the inner wall of the reactor is 2 mm to 5 mm.

The viscosity reduction method in the step (3) is a viscosity reduction kettle or other mild low temperature cracking method. The viscosity-reducing kettle body is a horizontal cylindrical shape. The longitudinal fire tubes are arranged in the kettle. The bottom of the kettle is equipped with a sedimentation tank. The upper center of the kettle is connected to the steamer tower. The viscosity-reducing temperature of the plastic liquid in the kettle is 250 ° C ~ 300. ° C.

The solid separation cylinder in the step (4) is a cone, the upper end of the cylinder is connected to the gas phase outlet of the reaction kettle, the lower end of the cylinder is provided with a screw extruder, a material inlet is provided at the tangential line of the cylinder, and the reaction kettle is discharged. The slag port is connected in series with the material inlet of the solid-liquid separation tank via a pump. The filling amount of the salt-melt separation liquid is 2/5-3/5 of the total volume of the solid-liquid separation tank, and the molten salt temperature is 350 ° C ~ 400 ° C.

The vacuum distillation in the step (5) consists of a mechanical vacuum pump, a vacuum cylinder, a control valve, and a vacuum gauge, wherein the pressure distribution is: the working pressure of the reactor-0.02 kg to -0.08 kg, and the working pressure of the solid-liquid separation cylinder is -0.02 kg ~ -0.08 kg, the working pressure of the viscosity reducing kettle is -0.02 kg ~ -0.08 kg.

The equipment for realizing the above-mentioned industrialized waste plastics production of gasoline and diesel oil includes a feeding device, a cracking reaction device, and a refined pomegranate part, which is characterized in that: (1) the cracking reaction device is an inner band double (inner and outer) ribbon stirring And a reaction device equipped with a heat conducting medium jacket (or a barrier) externally; (2) further comprising a viscosity reduction device connected to a gas-phase outlet end of the reaction device for reducing viscosity, and a solid-liquid for discharging slag The separation device, the upper part of the viscosity reduction device is connected with the fine grit portion, the slag discharge port of the reaction device is connected in series with the material inlet of the solid-liquid separation device, and the gas-phase outlet of the reaction device is connected with the solid-liquid separation device outlet. The bottom of the distillation column in the limulus part is connected to a solid-liquid separation device. The waste plastic is pushed into the reaction device by the feeding device for heating and liquefaction cracking. The cracked material enters the viscosity reduction device through the gas phase outlet of the reaction device for visbreaking and cracking. The cracked gas passes through the condenser to form a liquid, which is then sent to the distillation section. Distillation is performed. The heavy oil at the bottom of the rectification part enters the solid-liquid separation device and then returns to the reaction device for re-cracking. At the same time, the plastic melting liquid in the reverse device is continuously pumped into the solid-liquid separation device and discharged to the reaction device. The residue and soil are effectively separated. The residue and soil are discharged out of the cylinder through a screw extruder provided at the bottom of the solid-liquid separation device, and the clean plastic melt liquid is returned to the reaction device to be cracked. Reduce the pressure of steamed gizzards to improve the dial-up rate and conversion rate of oil products.

The shape of the above reaction device may be a trough type or a vertical type, and its heat transfer medium is molten salt, and the temperature of the molten salt is 200 ° C ~ 800 ° C; the double spiral ribbon stirrer is an internal and external spiral ribbon stirrer. The opposite direction, and the outer spiral belt rotates clockwise, the inner spiral belt rotates counterclockwise, and the rotation of the outer spiral belt pushes the solids to the slag discharge. The gap between the outer spiral belt and the inner wall of the reaction kettle is 2mm ~ 5mm; the viscosity reduction device is a viscosity reduction kettle or other mild low temperature cracking device, in which the viscosity reduction kettle body is a horizontal cylinder and the longitudinal fire tubes are arranged in the kettle The bottom of the kettle is equipped with a sedimentation tank. The upper center of the kettle is connected to the distillation tower. The viscosity reduction temperature of the plastic liquid in the kettle is 250 ° C ~ 300 ° C. The solid-liquid separation device uses a solid-liquid separation cylinder. The cylinder is a cone. The upper end of the cylinder is connected to the gas phase outlet of the reactor. The lower end of the cylinder is equipped with a screw extruder. A material inlet is provided at the tangent line of the cylinder. The slag outlet of the reaction kettle is connected to the solid and liquid separation cylinder material inlet through a pump. The filling amount of the separation liquid is 2/5 to 3/5 of the total volume of the solid-liquid separation cylinder, and the molten salt temperature is 350 ° C to 400 ° C. It is used to deposit the residues such as soil, sand and gravel that have entered the solid-liquid separation device to a certain amount, and discharge them out of the solid-liquid separation device. It is based on the principle of incompatibility between organic and inorganic materials and the characteristics of different specific gravity of various materials. In the solid-liquid separation device, the oil and molten salt are incompatible, and the specific gravity of the oil is lighter than the specific gravity of the molten salt. Therefore, the oil floats out of the molten salt liquid level, passes through the outlet on the solid-liquid separation device, passes through the gas-phase outlet of the reaction device, enters the reaction device, and enters the solids, sand, and other residues of the solid-liquid separation device, because the specific gravity is heavier than the molten salt. While sinking into the bottom of the solid-liquid separation device, when a certain amount is deposited, the screw extruder will discharge it. After that, the soil and sand in the reaction device are replaced, which prolongs the operation cycle of the reaction device and enables continuous production.

Compared with the prior art, the present invention has the following advantages:

1. Due to the incorporation of a certain proportion of polystyrene, the complex catalytic cracking unit is omitted, and high-grade gasoline and diesel can be produced without using a catalyst.

As we all know, waste plastics are high-molecular polymers, simple polyethylene or polypropylene plastics. During the thermal cracking process, the oil produced is mainly linear paraffins and olefins. If used as gasoline products, its octane number is low. If a certain proportion of polystyrene plastics is properly blended, the aromatic content in gasoline products will be increased, and the gasoline brittleness value will be improved. It will be able to produce high-grade gasoline products for automobiles. For diesel products, the straight chain The high alkane content, the higher the cetagon number, is similar to straight run diesel products. Therefore, the implementation of the present invention can completely produce qualified gasoline and diesel products in the process flow of a set of production equipment.

2. Molten salt is used as the heat-conducting medium in the reaction kettle, which completely solves the defects caused by the uneven heating of the waste plastic during the melting process, the temperature is high or low, which affects the plastic cracking depth and coking phenomenon. The use of waste plastics to produce gasoline and diesel is completely endothermic and the reaction plastics can be oiled by absorbing heat. This process is a change process. However, the thermal conductivity of plastic is poor. Given a high or low temperature and uneven heating surface, it will affect the plasticization or cracking depth of the plastic. In order to solve this defect, the heat conducting medium in the jacket of the reaction kettle of the present invention is a molten salt. Molten salt is the most ideal heat-conducting medium and has been widely used in the fields of petroleum and chemical industry. It can be adjusted to the mix ratio to adjust the heat-conducting temperature from 200 ° C to 800 ° C. The operation flexibility is great. The implementation of the solution using the molten salt as the heat conduction medium of the present invention completely solves the defects caused by the uneven heating surface, the temperature is high or low, which affects the plastic cracking depth and coking phenomenon caused by direct fire.

3. The reactor of the present invention is provided with an internal and external double-spiral stirrer, which completely solves the poor thermal conductivity of the materials in the endothermic reaction of plasticization of oil, which is likely to cause uneven heating of the reaction materials, inconsistent cracking depth, and is accompanied by The defect of local coking.

Plastic oilization is an endothermic reaction, but its material has poor thermal conductivity and takes a long time to reach the thermal cracking temperature, which can easily cause the reaction material to be heated unevenly, the cracking depth to be inconsistent, and the phenomenon of local coking. In order to solve this defect, the present invention is provided with an inner and outer double ribbon stirrer in the reaction kettle. The outer ribbon rotates clockwise and the inner ribbon rotates counterclockwise. During operation, the inner and outer ribbons rotate in opposite directions to form a layer. The impact of the flow produces turbulence, which allows the plastic oil to fully exchange heat and speed up the cracking rate. The outer spiral ribbon is kept at a distance of 2mm to 5mni from the inner wall of the tank-shaped reaction kettle. The outer spiral ribbon can be scraped off at any time during rotation due to the reaction of the wall Coke, thereby ensuring the heat transfer effect of molten salt into the kettle.

4. Viscosity reduction measures have been adopted to reduce the viscosity of the oil products, improve the light oil yield of the refinery, and reduce the refining ratio of the refinery tower.

The liquid formed after the waste plastics are oiled has high viscosity and poor fluidity. This material, as the basic raw material for the distillation of the distillation column, will cause a load on the distillation column, generate a large amount of refining oil, and increase the refining cost. In order to solve this defect, other mild low-temperature cracking methods such as viscosity reduction kettles are used to reduce the viscosity of the oil products, improve the light oil yield of the refinery, and reduce the refining oil in the distillation column.

5. If the plastic is not cleaned during collection, sorting and blending, there will be a certain amount of dirt, sand, etc. If this harmful substance is not removed, it will affect the operation cycle of the reactor and prevent continuous production. In order to solve this problem, the present invention uses a solid-liquid separation tank to discharge mud, sand, and other sludge. Role.

The invention is based on the principle of incompatibility between organic and inorganic materials and the characteristics of different specific weights of various materials. The high-temperature pump continuously passes the slag discharge port of the reaction kettle through the pipeline to drive the materials in the reaction kettle to the In the solid-liquid separation tank, the oil and molten salt are immiscible, and the specific gravity of the oil is lighter than the specific gravity of the molten salt, so the oil floats out of the molten salt liquid level and enters the gas phase outlet of the reaction kettle through the outlet on the solid-liquid separation tank. , Into the reactor. Residues such as soil and sand entering the solid-liquid separation tank are sunk into the bottom of the solid-liquid separation tank because the specific gravity is heavier than molten salt. When a certain amount is deposited, the screw extruder will discharge it. After that, the soil and sand in the reactor were replaced, which extended the operation cycle of the reactor and enabled continuous production.

6. The present invention is implemented based on the principle that the boiling point of the distillate decreases as the external pressure decreases. The reduced pressure distillation is implemented in each link, which improves the withdrawal rate of the oil product, thereby improving the conversion rate of the oil product and saving. energy.

In short, the present invention does not require complicated catalytic cracking equipment, can be continuously produced, has a high oil conversion rate, good oil quality, and a high cost, saves energy, thereby solving the existing waste plastic production gasoline and diesel technology and equipment. Defects, effective treatment of white pollution, is a method of solid waste resource treatment. BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic structural diagram of a device for producing gasoline and diesel in the present invention. detailed description

Example 1

In the first step, waste plastic polyethylene, polypropylene, and polystyrene are blended at a ratio of 1: 1: 0.8, such as 100 kg of polyethylene, 100 kg of polypropylene, and 80 kg of polystyrene;

In the second step, the waste plastics blended in the above proportion are propelled by a hydraulic propeller with a double ribbon stirrer inside, and a tank-shaped or vertical reactor equipped with molten salt as a heat conducting medium jacket is heated for liquefaction cracking, The salt temperature is 45CTC, and the heating and liquefaction cracking temperature in the reaction kettle is 350 ° C; In the third step, the waste plastic in the reaction kettle is cracked by heating. The material produced by the reaction enters the visbreaking kettle or other mild low-temperature cracking device for visbreaking distillation. The visbreaking temperature is 25 (TC, the cracked gas is condensed by the condenser). Form a liquid and send it to a distillation tower for rectification;

In the fourth step, at the same time, the plastic melting solution in the reaction kettle continuously flows into the solid-liquid separation tank containing the molten salt separation liquid through the pump to effectively separate the residue and soil in the reaction kettle, and the residue and soil pass through the solid-liquid. The screw extruder at the bottom of the separating cylinder is discharged out of the cylinder, and the clean plastic melting solution is returned to the reaction kettle;

In the completion of the above steps, vacuum distillation was performed, in which the working pressure of the reactor was about -0.04 kg to -0.06 kg, and the working pressure of the solid-liquid separation tank was about -0.04 kg to -0.06 kg. The pressure ranges from -0.04 kg to -0.06 kg.

Example 2

In the first step, waste plastic polyethylene and polystyrene are used at a ratio of 1: 0.4 ^, such as 100 kg of polyethylene and 40 kg of polystyrene;

In the second step, the waste plastics blended according to the above ratio are propelled by a hydraulic propeller with a double-spiral stirrer inside, and a trough or vertical reactor equipped with molten salt as a heat conducting medium jacket. In the reactor, Heating liquefaction cracking, molten salt temperature is 550 ° C, heating reactor liquefaction temperature 450 ° C;

In the third step, the waste plastic in the reaction kettle is cracked by heating. The material produced by the reaction enters the visbreaking kettle or other moderate low-temperature cracking device for visbreaking distillation. The visbreaking temperature is 300 ° C. The cracked gas is condensed by the condenser to form a liquid. , Sent to the distillation column for rectification;

In the fourth step, at the same time, the plastic melting solution in the reaction kettle is continuously pumped into the solid-liquid separation tank containing the molten salt separation liquid through the pump to effectively separate the residue and soil in the reaction kettle, and the residue and mud pass through the bottom of the tank The screw extruder is discharged out of the cylinder, and the clean plastic melting solution is returned to the reactor;

After completing the steps (2), (3), and (4), a reduced pressure steamer is implemented. The working pressure of the reactor is -0.04 to -0.08 kg, and the working pressure of the solid-liquid separation tank is -0.04 to -0.08 kg. The working pressure of the sticky kettle is -0.04 ~ -0.08 kg.

Example 3

In the first step, thermoplastic waste plastics such as polypropylene and polystyrene are blended at a ratio of 1: 0.4. Such as 100 kg of polypropylene and 40 kg of polystyrene;

In the second step, the waste plastics blended according to the above proportion are propelled by a hydraulic propeller with a double-spiral stirrer inside, and a reaction kettle equipped with molten salt as a heat conducting medium jacket is heated to liquefy. The molten salt temperature is 500 V. The heating liquefaction temperature in the reaction kettle is 380 ° C.

In the third step, the waste plastic in the reaction kettle is cracked by heating. The material produced by the reaction enters the visbreaking kettle for visbreaking cracking and steaming. The visbreaking temperature is 280 ° C. The cracked gas is condensed by the condenser to form a liquid, which is sent to rectification. Column for rectification;

After completing steps (2), (3), and (4), vacuum distillation is performed, in which the working pressure of the reaction kettle is -0.04 to -0.08 kg, and the working pressure of the solid-liquid separation tank is -0.04 to -0.08 kg, which reduces viscosity. The working pressure of the kettle is -0.04 ~ -0.08 kg.

The industrialized waste plastics production gasoline and diesel equipment in the above embodiments of the present invention includes a hydraulic feeder 1, a double spiral belt stirrer 3, a reaction kettle 2 equipped with a molten salt heat conducting medium jacket 4, and a viscosity reduction kettle. 5, steamer tower 6, solid-liquid separation cylinder 7, screw extruder 8, high temperature slurry pump 9, mixed oil condenser 10, mixed oil receiving rainbow 11, vacuum cylinder 12, vacuum pump 13, rectification tower 14, reboiler It consists of the main equipment such as condenser 15, gasoline condenser 16, gasoline receiving rainbow 17, diesel condenser 18, diesel receiving rainbow 19, metering pump 20, etc. Waste plastic does not need to be cleaned after collection, and it can be used to remove dirt, sand, metal, etc. After blocking the impurities, polyethylene, polypropylene, polystyrene, or polyethylene, polystyrene, or polypropylene, polystyrene is blended in the proportion described in the method of the present invention, and the hydraulic feeder 1 is pushed into the tank. The reactor in the shape or vertical reactor 2 is melted at a negative pressure of -0.02 to 0.08 kg and a temperature of 200 ° C to 800 ° C. At the same time, the double spiral belt stirrer 3 in the reactor 2 is rotated to make the material in the reactor 2 Speed up the heat exchange cracking, the cracked gas enters through the gas-phase outlet of reactor 2 Viscosity reducing kettle 5, the kettle body of the viscosity reducing kettle 5 is a horizontal cylindrical shape, the longitudinal fire tube is arranged in the kettle, the bottom of the kettle is provided with a sedimentation tank, the upper center of the kettle is connected to the distillation tower, and the temperature of the viscosity reducing kettle 2 is 250 ° C ~ 300 ° C, negative pressure 0.02 ~ 0.08 kg pressure, the cracked gas from the reactor 2 will polymerize in the flow pipeline, and the macromolecular hydrocarbon forming liquid with a boiling point greater than 250 ° C-300 ° C In the state of falling into the viscosity reduction kettle 5, gaseous hydrocarbons with a boiling point of less than 250 ° C to 300 ° C enter the mixed oil condenser 10 through the steaming tower, and the condensed liquid flows into the mixed oil receiving tank 11, and the mixed liquid is driven in by the metering pump 20. Under the action of the reboiler, the rectification tower 14 and the fine stilt tower 14 emit gasoline, and the gaseous hydrocarbons of the gasoline are condensed by the gasoline condenser 16 to form a liquid that enters the gasoline receiving rainbow 17, and the diesel gaseous hydrocarbons in the tower are condensed by the diesel condenser 18 The liquid enters the diesel receiving tank 19, and the heavy oil at the bottom of the tower enters the solid-liquid separation cylinder 7 and returns to the reaction kettle 2 for cracking. The solid separation iris 7 is a cone. The upper end of the cylinder is connected to the gas phase outlet of the reactor 2. The lower end of the cylinder is set There is a screw extruder. A material inlet is provided at the tangential line of the cylinder. The slag discharge port of the reactor 2 is connected to the material inlet of the solid-liquid separation tank 7 through a pump. The filling volume of the salt melt separation liquid is the total volume of the solid-liquid separation tank. 2/5 ~ 3/5, molten salt temperature is 350 ° C ~ 400 ° C. The double spiral ribbon agitator 3 in the reaction kettle 2 constantly pushes the plastic liquid with soil and sand to the slag discharge port during the rotation. The high temperature slurry pump 9 drives the plastic liquid into the solid-liquid separation tank. After the separation, the clean plastic liquid is returned to the reaction kettle 2 through the gas-phase outlet of the reaction kettle 5. After a certain amount of soil and sand is deposited, it is discharged from the cylinder by the screw extruder.

Claims

Rights request

1. The method for producing gasoline and diesel oil from industrial waste plastics, which includes the following steps:

(4) At the same time, the plastic melting solution in the reaction kettle is continuously pumped into the solid-liquid separation tank containing the molten salt separation liquid, and the residues and soil in the reaction kettle are effectively separated, and the residues and soil are passed through the solid-liquid separation tank. The screw extruder at the bottom is discharged out of the cylinder, and the clean plastic melting solution is returned to the reaction kettle. In steps (2), (3), and (4), vacuum distillation is performed.

2. The method for producing gasoline and diesel oil from industrial waste plastics according to claim 1, characterized in that: the blending ratio of the waste plastics in the step (1) is polyethylene glycol: polypropylene: polystyrene 0.8 to 1.2: 0.8 to 1.2: 0.7 to 0.9, or polyethylene: polystyrene 0.8 to 1.2: 0.3 to 0.5, or polypropylene: polystyrene 0.8 to 1.2: 0.3 to 0.5.

3. The method for producing gasoline and diesel oil from industrial waste plastics according to claim 1, characterized in that the preferred blending ratio in the waste plastics in step (1) is polyethylene: polypropylene: poly Styrene is 1: 1: 0.8, or polyethylene: polystyrene is 1: 0.4 ~ 0, or polypropylene: polystyrene is 1: 0.4.

4. The method for producing gasoline and diesel oil from industrial waste plastics according to claim 1, characterized in that: in the step (2), there is a double-spiral stirrer inside, and a reaction kettle jacketed with a molten salt heat-conducting medium is externally installed. It is a tank reactor or a vertical reactor.

5. The method for producing gasoline and diesel oil from industrial waste plastics according to claim 1, characterized in that the temperature of the molten salt is 200 ° C-800 ° C, preferably 450 ° C ~ 550 ° C.

6. The method for producing gasoline and diesel oil from industrial waste plastics according to claim 1, characterized in that the heating and liquefaction cracking temperature of the plastic in the step (2) is 350 ° C to 400 ° C.

7. The method for producing gasoline and diesel oil from industrial waste plastics according to claim 1, characterized in that: the double-threaded belt agitator in the step (2) is a clockwise rotation of the outer spiral belt and a counter-clockwise rotation of the inner spiral belt. Rotate the double spiral ribbon stirrer with a distance between the outer spiral ribbon and the inner wall of the reactor of 2mm to 5mm.

8. The method for producing gasoline and diesel oil from industrial waste plastics according to claim 1, characterized in that: the viscosity reduction method in the step (3) is a viscosity reduction kettle or other mild low temperature cracking method, wherein the viscosity reduction The kettle body is a horizontal cylindrical shape, with longitudinal fire tubes arranged in the kettle, a bottom of the kettle is provided with a deposition tank, the center of the upper part of the kettle is connected to the steaming tower, and the viscosity reduction temperature of the plastic liquid in the kettle is 250 ° C ~ 300 ° C.

9. The method for producing gasoline and diesel oil from industrial waste plastics according to claim 1, characterized in that: the solid separation iris in step (4) is a cone, and the outlet at the upper end of the cylinder is connected to the gas phase outlet of the reactor, The lower end of the cylinder is equipped with a screw extruder. A material inlet is provided at the tangent line of the cylinder. The slag outlet of the reaction kettle is connected in series with the material inlet of the solid-liquid separation cylinder through a pump. The total volume is 2/5 ~ 3/5, and the molten salt temperature is 350 ° C ~ 400 ° C.

10. The method for producing gasoline and diesel oil from industrial waste plastics according to claim 1, characterized in that: the pressure distribution of the reduced pressure steam distillation in the step (5) is: working pressure of the reactor-0.02 kg ~- 0.08 kg, the working pressure of the solid-liquid separation tank is -0.02 kg to -0.08 kg, and the working pressure of the viscosity reduction kettle is -0.02 kg to -0.08 kg.

11. Equipment for the production of gasoline and diesel oil from industrial waste plastics, including the feeding device, cracking reaction device, and refined pomegranate, which is characterized by: (1) The cracking reaction device described is internally double (inside and outside) spiral ribbon stirring And a reaction device equipped with a jacket (or barrier) of a thermally conductive medium; (2) a viscosity-reducing device connected to the gas-phase outlet end of the reaction device, a solid-liquid separation device for discharging slag, and a viscosity-reducing device The upper part is connected to the rectification section, the slag discharge port of the reaction device is connected in series with the material inlet of the solid-liquid separation device, the gas-phase outlet of the reaction device is connected to the solid-liquid separation device outlet, and the The bottom is connected to a solid-liquid separation device.

12. The equipment for producing gasoline and diesel oil from industrial waste plastics according to claim 11, characterized in that: the shape of the reaction device can be a trough type or a vertical type, and its heat conducting medium is molten salt, and the temperature of the molten salt 200 ° C ~ 800 ° C.

13. The equipment for producing gasoline and diesel oil from industrial waste plastics according to claim 11, characterized in that: said double-spiral ribbon stirrer is an inner and outer spiral ribbon stirrer, the inner and outer spiral belts rotate in opposite directions, and the outer spiral belt Rotate clockwise, the inner spiral belt rotates counterclockwise. The rotation direction of the outer spiral belt pushes the solids to the slag discharge opening. The distance between the outer spiral belt and the inner wall of the reactor is 2mm ~ 5mm.