Plastic pyrolysis device and plastic pyrolysis method

Abstract

This invention discloses a plastic pyrolysis apparatus and method, belonging to the field of plastic pyrolysis treatment technology. The apparatus includes a plastic pyrolysis module and a pyrolysis oil recovery module. The plastic pyrolysis module is used to pyrolyze the plastic to generate pyrolysis oil and gas. The pyrolysis oil recovery module is used to condense the pyrolysis oil and gas and recover the pyrolysis oil. At least two pyrolysis oil recovery modules are included, each having a recovery temperature range. The recovery temperature ranges of at least two pyrolysis oil recovery modules do not overlap. Each pyrolysis oil recovery module is activated only when the pyrolysis temperature falls within its recovery temperature range. The method includes pyrolyzing the plastic to form pyrolysis oil and gas; dividing the pyrolysis temperature of the plastic pyrolysis; and during the pyrolysis process, performing initial condensation on the pyrolysis oil and gas generated at different pyrolysis temperatures and recovering the pyrolysis oil separately. This allows for the collection of pyrolysis oil with different components in different temperature ranges, improving the pyrolysis oil separation efficiency and resource utilization rate.

Description

Technical Field

[0001] This invention relates to the field of plastic pyrolysis technology, and in particular to a plastic pyrolysis apparatus and a plastic pyrolysis method. Background Technology

[0002] Global annual plastic production has exceeded 400 million tons, with large amounts of plastic waste ending up in landfills, incineration, or entering the natural environment (especially the ocean), causing serious "white pollution." Plastic bags, packaging films, and composite packaging, which are ubiquitous in daily life, are considered low-value waste plastics due to their dirtiness, light weight, mixed composition, and low value. These low-residual-value waste plastics are not recycled, landfills take up space, and incineration has low calorific value and may cause pollution, becoming a persistent problem in urban solid waste management.

[0003] Traditional treatment methods mainly include conventional mechanical recycling (such as melt-re-granulation), landfill, and incineration. Conventional mechanical recycling requires high cleanliness and uniformity of raw materials, achieving a recovery rate of less than 10%, and each recycling cycle leads to performance degradation (downgraded recycling). Furthermore, this method is ineffective for handling mixed or contaminated plastics. Landfill occupies significant land resources, may pollute soil and groundwater with leachate, and wastes the carbon resources contained in the plastics. While incineration can generate electricity, direct incineration may produce toxic gases such as dioxins and furans, and emit large amounts of greenhouse gases (CO2), causing environmental pollution.

[0004] In recent years, plastic pyrolysis has gradually emerged as a market treatment method. Plastic pyrolysis is a process that decomposes large-molecule plastic polymers into smaller molecules through thermochemical reactions in an oxygen-free or oxygen-deficient high-temperature environment. Plastic pyrolysis is a promising chemical recycling technology, providing an important technological path for solving global plastic pollution and achieving closed-loop management of plastics. Pyrolysis oil is one of the main products of plastic pyrolysis, serving as a feedstock that can replace crude oil. Waste plastic pyrolysis units mainly consist of a pyrolysis reactor, a dust-collecting steam drum, a condenser, an oil storage tank, an alkali tank, and a water seal tank. After pyrolysis in the reactor, the pyrolysis oil and gas pass through the dust-collecting steam drum and condenser before entering the oil storage tank for storage. Pyrolysis gas that cannot be condensed is then ignited after passing through the alkali tank and water seal tank. Because the composition of the pyrolysis oil is mixed at different temperatures, current waste plastic pyrolysis units require additional equipment for subsequent refining and separation to achieve high standards, undoubtedly increasing processing costs. Summary of the Invention

[0005] The purpose of this invention is to solve the above-mentioned technical problems and provide a plastic pyrolysis device and a plastic pyrolysis method, which can collect pyrolysis oil with different components in different temperature ranges, thereby improving the pyrolysis oil separation efficiency and resource utilization rate.

[0006] To achieve the above objectives, the present invention provides the following solution: The present invention discloses a plastic pyrolysis device, including a plastic pyrolysis module and a pyrolysis oil recovery module. The plastic pyrolysis module is used to pyrolyze plastic to generate pyrolysis oil and gas. The pyrolysis oil recovery module is used to condense the pyrolysis oil and gas and recover the condensed pyrolysis oil. The pyrolysis oil recovery module includes at least two modules, each of which has a recovery temperature range. The recovery temperature ranges of at least two pyrolysis oil recovery modules do not overlap. Each pyrolysis oil recovery module is activated only when the pyrolysis temperature of the plastic pyrolysis module falls within its recovery temperature range.

[0007] In one embodiment, the system includes two pyrolysis oil recovery modules, one of which has a collection range of below 150°C and above 360°C, and the other has a collection range of 150°C to 360°C.

[0008] In one embodiment, each of the pyrolysis oil recovery modules includes a catalytic steam drum, a primary decolorizing condenser, an oil storage tank, and a secondary decolorizing condenser. The inlet of the catalytic steam drum is connected to the pyrolysis oil and gas outlet of the plastic pyrolysis module, the inlet of the primary decolorizing condenser is connected to the outlet of the catalytic steam drum, the outlet of the primary decolorizing condenser is connected to the inlet of the oil storage tank, and the inlet of the secondary decolorizing condenser is connected to the outlet of the oil storage tank.

[0009] In one embodiment, the primary decolorizing condenser and the secondary decolorizing condenser are respectively in the shape of a first columnar structure and a second columnar structure; in, The inlet of the primary decolorizing condenser is located at the top of the first columnar structure, and the outlet is located at the bottom of the first columnar structure. The inlet of the secondary decolorization condenser is located at the bottom of the second columnar structure, and the outlet is located at the top of the second columnar structure.

[0010] In one embodiment, the catalytic steam drum has a third columnar structure, and a catalyst is provided on the upper part of the catalytic steam drum; the upper part of the primary decolorizing condenser and the lower part of the secondary decolorizing condenser are both cooling layers, and the lower part is both decolorizing layers, with a decolorizing agent provided in the decolorizing layers.

[0011] In one embodiment, the outlet of the primary decolorizing condenser and the inlet of the secondary decolorizing condenser are both connected to the oil storage tank via vertical pipes.

[0012] In one embodiment, the plastic pyrolysis module includes a pyrolysis vessel and a heating device for heating the pyrolysis vessel.

[0013] In one embodiment, the heating device includes an electromagnetic heating device, which includes a heating coil wound around the outside of the pyrolysis vessel.

[0014] In one embodiment, the system further includes a pyrolysis oil recovery module, which is used to re-condense the uncondensed pyrolysis gas in the pyrolysis oil recovery module and recover the condensed pyrolysis oil. The pyrolysis oil recovery module includes a mixing tank and a recooler. The inlet of the mixing tank is connected to part or all of the pyrolysis gas outlet of the pyrolysis oil recovery module, and the outlet of the mixing tank is connected to the recooler. The connecting pipe between the recooler and the mixing tank is a vertical pipe or an inclined pipe inclined towards the mixing tank, so that the recooled oil flows back to the mixing tank.

[0015] In one embodiment, the pyrolysis oil recovery module further includes an alkaline washing tank and a water seal tank. The inlet of the alkaline washing tank is connected to the recooler, and the outlet of the water seal tank is connected to a collection device, a combustion device, or placed above an open flame.

[0016] In one embodiment, a cooling module is further included for providing cooling capacity to the pyrolysis oil recovery module and the pyrolysis oil re-collection module; the cooling module includes a circulating water tank and a circulating water pump, and the circulating water tank provides circulating cooling water to the pyrolysis oil recovery module and the pyrolysis oil re-collection module through the circulating water pump.

[0017] This invention also discloses a method for pyrolysis of plastics, comprising the following steps: The plastic is pyrolyzed to form pyrolysis oil and gas; The pyrolysis temperature of the plastic is divided. During the pyrolysis process, the pyrolysis oil and gas generated at different pyrolysis temperatures are condensed for the first time, and the pyrolysis oil condensed for the first time is recovered.

[0018] In one embodiment, dust removal and catalysis are performed before the first condensation process, and decolorization is performed during the condensation process.

[0019] In one embodiment, the method further includes the following steps: performing a second condensation on the pyrolysis oil and gas after the first condensation, and recovering the pyrolysis oil after the second condensation.

[0020] In one embodiment, the method further includes the following steps: subjecting the pyrolysis gas after secondary condensation to sequential acid-base neutralization and ignition.

[0021] The present invention achieves the following technical effects compared to the prior art: In this invention, during the pyrolysis of plastics in the plastic pyrolysis module, the pyrolysis oil and gas at different pyrolysis temperature ranges are condensed and the pyrolysis oil is recovered, thereby achieving the separation of oils with different components. This eliminates the need for subsequent refining and separation, simplifies the processing steps and equipment, and saves processing costs.

[0022] Other technical solutions of the present invention have achieved the following technical effects compared with the prior art: 1. Adding a catalyst to the catalytic converter can improve the oil yield; 2. Adding a decolorizing agent to the decolorizing condensation tower can decolorize pyrolysis oil without the need for subsequent decolorization, simplifying the processing steps and equipment, and saving processing costs.

[0023] 3. The pyrolysis oil and gas undergo three cooling processes: a primary decolorizing and condensing tower, a secondary decolorizing and condensing tower, and a recooler, which can significantly improve the oil yield. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained by analyzing these drawings without creative effort.

[0025] Figure 1 This is a three-dimensional structural diagram of the plastic pyrolysis device in an embodiment of the present invention; Figure 2 This is a three-dimensional structural schematic diagram of the plastic pyrolysis device from another perspective in an embodiment of the present invention; Figure 3 This is a top view of the plastic pyrolysis apparatus in an embodiment of the present invention; Figure 4 This is a schematic diagram of the pipeline of the plastic pyrolysis device in an embodiment of the present invention.

[0026] Explanation of reference numerals in the attached drawings: 1. Pyrolysis kettle; 2. Catalytic steam drum; 3. Primary decolorization condenser; 4. Oil storage tank; 5. Secondary decolorization condenser; 6. Mixing tank; 7. Recooler; 8. Alkali washing tank; 9. Water seal tank; 10. Gas flow meter; 11. Steam inlet valve; 12. Steam exhaust valve; 13. Heating coil; 14. Vertical pipe; 15. Circulating water tank; 16. Circulating water pump; 17. Heating power supply; 18. Integrated chassis. Detailed Implementation

[0027] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments analyzed and obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0028] The purpose of this invention is to provide a plastic pyrolysis device and a plastic pyrolysis method to solve the problems existing in the prior art. By controlling the temperature in stages during the plastic pyrolysis process, different pyrolysis products of different components can be collected in different temperature ranges, thereby improving the product separation efficiency and resource utilization rate. It also solves the problems of oil and gas decolorization and purification during the pyrolysis process and can be widely used in waste plastic treatment or other scenarios that require plastic pyrolysis.

[0029] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0030] Example 1 like Figures 1 to 4 As shown, this embodiment provides a plastic pyrolysis apparatus, including a plastic pyrolysis module and a pyrolysis oil recovery module. The plastic pyrolysis module is used to pyrolyze plastic to generate pyrolysis oil and gas. The pyrolysis oil recovery module is used to condense the pyrolysis oil and gas and recover the condensed pyrolysis oil. At least two pyrolysis oil recovery modules are included, each having a recovery temperature range. The recovery temperature ranges of at least two pyrolysis oil recovery modules do not overlap. Each pyrolysis oil recovery module is activated only when the pyrolysis temperature of the plastic pyrolysis module falls within its recovery temperature range. During the pyrolysis of plastic by the plastic pyrolysis module, the pyrolysis oil recovery module is activated based on the collection range (recovery temperature range) of the pyrolysis temperature of the plastic, thus recovering the pyrolysis oil generated at different temperatures separately, eliminating the need for additional refining and separation equipment.

[0031] In one embodiment of this invention, two pyrolysis oil recovery modules are included. One module has a collection range below 150°C and above 360°C, while the other has a collection range of 150°C to 360°C. When the plastic pyrolysis module pyrolyzes the plastic, the pyrolysis temperature is first controlled below 150°C (excluding 150°C). At this time, the pyrolysis oil recovery module with a collection range below 150°C and above 360°C can be activated to collect the pyrolysis oil. Then, when the temperature is controlled within the range of 150°C to 360°C, the module with a collection range below 150°C and above 360°C is closed, and the module with a collection range of 150°C to 360°C is activated to collect the pyrolysis oil. After controlling the pyrolysis oil temperature above 360℃ (excluding 360℃), close the pyrolysis oil recovery module with a collection range of 150℃~360℃, and then reopen the pyrolysis oil recovery modules with collection ranges below 150℃ and above 360℃ to collect the pyrolysis oil. Pyrolysis oil from temperatures below 150℃ and above 360℃ is crude oil, while pyrolysis oil from temperatures between 50℃ and 360℃ is kerosene base oil.

[0032] In one embodiment of this example, each pyrolysis oil recovery module includes a catalytic converter 2, a primary decolorizing condenser 3, an oil storage tank 4, and a secondary decolorizing condenser 5. The primary decolorizing condenser 3 and the secondary decolorizing condenser 5 are respectively shaped like a first columnar structure and a second columnar structure. The inlet of the catalytic converter 2 is connected to the pyrolysis oil and gas outlet of the plastic pyrolysis module, and the outlet of the catalytic converter 2 is connected to the inlet of the primary decolorizing condenser 3, which is located at the top of the tower body (first columnar structure). The outlet of the primary decolorizing condenser 3 is connected to the inlet of the oil storage tank 4, which is located at the bottom of the tower body (first columnar structure). The outlet of the oil storage tank 4 is connected to the inlet of the secondary decolorizing condenser 5, which is located at the bottom of the tower body (second columnar structure), and its outlet is located at the top of the tower body (second columnar structure). The pyrolysis oil and gas produced by the pyrolysis of the plastic pyrolysis module first enter the catalytic steam drum 2, where the pyrolysis oil and gas react with the catalyst to increase the oil yield. After being catalyzed by the catalyst, the pyrolysis oil and gas enter the first-stage decolorizing condenser 3 for condensation and reaction with the decolorizing agent. Then, both the condensed pyrolysis oil and the uncondensed pyrolysis gas are fed into the oil storage tank 4. Subsequently, the pyrolysis oil is stored in the oil storage tank 4, while the pyrolysis gas enters the second-stage decolorizing condenser 5 for condensation and reaction with the decolorizing agent again. The condensed pyrolysis oil falls into the oil storage tank 4 under gravity, while the uncondensed pyrolysis gas is discharged from the second-stage decolorizing condenser 5.

[0033] In one embodiment of this example, the catalytic steam drum 2 has a third columnar structure. An interlayer exists in the upper part of the catalytic steam drum 2, which is used to add a catalyst. Pyrolysis oil and gas enter from the middle or bottom of the catalytic steam drum 2 and react with the catalyst in the upper interlayer.

[0034] In one embodiment of this invention, the upper layer of both the primary decolorizing condenser 3 and the secondary decolorizing condenser 5 is a cooling layer used to cool the pyrolysis oil and gas, and the lower layer of both the primary decolorizing condenser 3 and the secondary decolorizing condenser 5 is a decolorizing layer containing a decolorizing agent. The cooled pyrolysis oil reacts with the decolorizing agent in the lower layer of the decolorizing layer.

[0035] In one embodiment of this example, the oil storage tank 4 is a horizontal oil tank. The inlet and outlet of the oil storage tank 4 are located at the top of both ends, which increases the movement path of the pyrolysis oil and gas, so that as much condensed pyrolysis oil as possible is stored in the oil storage tank 4.

[0036] In one embodiment of this invention, the outlet of the primary decolorizing condenser 3 is connected to the inlet of the oil storage tank 4 via a vertical pipe 14. The inlet of the secondary decolorizing condenser 5 is connected to the outlet of the oil storage tank 4 via a vertical pipe 14.

[0037] In one embodiment of this invention, the inlet of the catalytic steam drum 2 is equipped with a steam inlet valve 11. The outlet of the secondary decolorization condenser 5 is equipped with a steam exhaust valve 12. The steam inlet valve 11 and steam exhaust valve 12 of the corresponding pyrolysis oil recovery module are activated when the pyrolysis temperature of the plastic pyrolysis module falls within the recovery temperature range of that module.

[0038] In one embodiment of this invention, the plastic pyrolysis module includes a pyrolysis vessel 1 and a heating device for heating the pyrolysis vessel 1. The plastic is pyrolyzed through the pyrolysis vessel 1. Typically, the top of the pyrolysis vessel 1 has a feed inlet and an oil / gas outlet. Plastic is added by opening the feed inlet at the top of the pyrolysis vessel 1. Pyrolysis oil / gas is discharged through the pyrolysis oil / gas outlet and then received by the corresponding pyrolysis oil recovery module (the inlet of the catalytic converter 2).

[0039] In one embodiment of this invention, the heating device includes an electromagnetic heating device, which includes a heating coil 13. The heating coil 13 is wound around the outside of the pyrolysis vessel 1 to heat the plastic inside the pyrolysis vessel 1 and provide heat for the pyrolysis of the plastic.

[0040] In one embodiment of this invention, the electromagnetic heating device further includes a heating power supply 17 to provide power to the heating coil 13.

[0041] In one embodiment of this invention, the pyrolysis reactor 1 is equipped with a temperature detection device, such as a thermometer, thermometer, thermocouple, temperature sensor, or temperature transmitter. Based on the heating temperature of the pyrolysis reactor 1 detected by the temperature detection device, the steam inlet valve 11 and the steam outlet valve 12 of the pyrolysis oil recovery module corresponding to the collection range are opened. Therefore, preferably, the steam inlet valve 11 and the steam outlet valve 12 can be solenoid valves, and the steam inlet valve 11 and the steam outlet valve 12 are communicatively connected to the temperature detection device, automatically opening and closing according to the detection results of the temperature detection device.

[0042] In one embodiment of this invention, a pyrolysis oil recovery module is further included. This module is used to re-condense the uncondensed pyrolysis gas in the pyrolysis oil recovery module and recover the condensed pyrolysis oil. The pyrolysis oil recovery module includes a mixing tank 6 and a recooler 7. The inlet of the mixing tank 6 is connected to the pyrolysis gas outlet of the pyrolysis oil recovery module (secondary decolorization condensation tower 5), and the outlet of the mixing tank 6 is connected to the inlet of the recooler 7, which is located above the mixing tank 6. The uncondensed pyrolysis gas, after being processed by the pyrolysis oil recovery module, first passes through the mixing tank 6 and then enters the recooler 7 for re-condensation. The condensed pyrolysis oil falls back into the mixing tank 6 under gravity, achieving the final recovery of residual pyrolysis oil from the pyrolysis gas. Each pyrolysis oil recovery module can be connected to a separate pyrolysis oil recovery module, or all pyrolysis oil recovery modules can be connected to a single pyrolysis oil recovery module. Because the oil mixing tank 6 contains residual oil, a single treatment cannot recover much pyrolysis oil. Therefore, it is recommended that all pyrolysis oil recovery modules be connected to a single pyrolysis oil recovery module. That is, the outlet of the secondary decolorization condenser 5 of all pyrolysis oil recovery modules is connected to the inlet of the oil mixing tank 6 of one pyrolysis oil recovery module.

[0043] In one embodiment of this invention, the pyrolysis oil recovery module further includes an alkaline washing tank 8 and a water seal tank 9. The inlet of the alkaline washing tank 8 is connected to the outlet of the recooler 7, and the outlet of the water seal tank 9 is connected to a collection device, a combustion device, or placed above an open flame. The pyrolysis gas discharged from the recooler 7 enters the alkaline washing tank 8, where it is neutralized with the alkaline solution to remove acidic components. The alkaline washing tank 8 is connected to the water seal tank 9 to prevent external air from entering the device. The discharged pyrolysis gas is either used as fuel in the combustion device or directly placed on an open flame for ignition. The non-condensable gas treatment mainly includes combustible gases such as methane, ethane, propane, and ethylene.

[0044] In one embodiment of this example, a gas flow meter 10 is provided at the outlet of the water seal tank 9.

[0045] In one embodiment of this example, the mixing tank 6 is a horizontal tank. The inlet of the mixing tank 6 is located at the top of the front end of the tank body, and the outlet of the mixing tank 6 is located at the top of the rear end of the tank body. The inlet of the recooler 7 is located at the bottom, and the outlet is located at the top; the inlet of the recooler 7 is connected to the outlet of the mixing tank 6, and the outlet of the recooler 7 is connected to the alkaline washing tank 8.

[0046] In one embodiment of this invention, a cooling module is further included. The cooling module provides cooling capacity to the pyrolysis oil recovery module and the pyrolysis oil re-recovery module. The cooling module includes a circulating water tank 15 and a circulating water pump 16. The circulating water tank 15 provides circulating cooling water to the pyrolysis oil recovery module (primary decolorization condenser 3 and secondary decolorization condenser 5) and the pyrolysis oil re-recovery module (recooler 7) through the circulating water pump 16.

[0047] In one embodiment of this invention, the plastic pyrolysis module, the pyrolysis oil recovery module, the cooling module, and the pyrolysis oil re-collection module are integrated on the integrated chassis 18 to form a skid-mounted device that is easy to move and install.

[0048] In one embodiment of this invention, pressure gauges and temperature gauges are installed on the pyrolysis reactor 1, the oil storage tank 4, and the oil mixing tank 6. Pressure gauges and pH gauges are installed on the alkaline washing tank 8. Pressure gauges are installed on the water seal tank 9.

[0049] In one embodiment of this example, a specific experimental example is provided: The plastic pyrolysis device includes a plastic pyrolysis module, a pyrolysis oil recovery module, a pyrolysis oil re-collection module, and a cooling module. Two pyrolysis oil recovery modules are connected in parallel between the plastic pyrolysis module and the pyrolysis oil re-collection module. The collection ranges of the two pyrolysis oil recovery modules are below 150℃ and above 360℃, and 150℃~360℃, respectively.

[0050] Process flow: I. Production Start heating coil 13 to heat pyrolysis kettle 1. Waste plastic is decomposed by heat in pyrolysis kettle 1 to produce pyrolysis oil and gas. When the temperature of pyrolysis reactor 1 is below 150℃ or above 360℃, the steam inlet valve 11 and exhaust valve 12 of the pyrolysis oil recovery module, which collects oil within the range of below 150℃ and above 360℃, are opened. The pyrolysis oil gas enters the catalytic steam drum 2, where the heavy fraction is liquefied by cooling. The dust that enters with the pyrolysis oil gas is stored at the bottom of the catalytic steam drum 2 along with the heavy fraction (later discharged by opening the exhaust port at the bottom of the catalytic steam drum 2). The pyrolysis oil gas reacts with the catalyst in the catalytic layer of the catalytic steam drum 2, increasing the oil yield. Then, the pyrolysis oil gas undergoes primary cooling, liquefaction, and decolorization in the first-stage decolorization condenser 3. The liquefied pyrolysis oil then enters the catalytic steam drum 2. The pyrolysis gas that cannot be liquefied during the first cooling is buffered in the oil storage tank 4. It then enters the secondary decolorization and condensation tower 5 for secondary cooling and decolorization. The liquefied pyrolysis oil flows back to the oil storage tank 4 for buffering. The pyrolysis gas that cannot be liquefied after secondary cooling in the secondary decolorization and condensation tower 5 enters the oil mixing tank 6. After being cooled by the recooler 7 above the oil mixing tank 6, it enters the alkaline washing tank 8 below the water level to remove the fine dust and neutralize and remove acidic components. Finally, the pyrolysis gas enters the water seal tank 9 and is then discharged after being measured by the gas flow meter 10. When the pyrolysis gas is discharged, the outlet is placed above a continuous open flame for ignition to avoid the generation of odors nearby.

[0051] When the temperature of pyrolysis reactor 1 is between 150℃ and 360℃, the steam inlet valve 11 and the steam outlet valve 12 of the pyrolysis oil recovery module with a collection range of 150℃ to 360℃ are opened for processing and collection. The specific process is as described above.

[0052] II. Conditions for completion of pyrolysis The heating power of the heating coil 13 remains unchanged, but the temperature of the pyrolysis vessel 1 decreases. No liquid oil flowed out of the sight glass of oil mixing tank 6, and no pyrolysis gas was discharged from the outlet of water seal tank 9; When the above three conditions are met, the pyrolysis of the raw materials in pyrolysis vessel 1 is completed.

[0053] III. Shutdown Procedure After the pyrolysis of the raw materials is completed, adjust the heating power of heating coil 13 to 1.2 times the original power and continue heating for half an hour; After heating for half an hour, turn off heating coil 13 to stop heating, and then open the drain valve of water seal tank 9 to enter the cooling process.

[0054] IV. Cooling and Slag Removal Cool the pyrolysis reactor 1 to below 50°C and release the pyrolysis oil from the catalytic steam drum 2, oil storage tank 4 and oil mixing tank 6. Open the feed inlet of pyrolysis reactor 1 and remove the carbon slag inside pyrolysis reactor 1. When opening the feed inlet, be careful not to face the feed inlet to prevent flash explosions that may occur when the raw materials are not completely pyrolyzed, which could cause personal injury.

[0055] Operating procedures: General operating steps: Preparation → Loading → Closing the feed inlet → Starting heating → Pyrolysis completed → Cooling → Slag discharge I. Preparatory Work (a) Check the sealing of the electrical circuits, water circuits, and gas circuits to see if they are normal; (ii) In the laboratory, turn on the ventilation system (air exchange rate ≥ 15 times / hour); (III) Raw material processing: Crush the plastic into ≤5mm particles and pre-dry it to a moisture content of <5%; (iv) Cooling water: Replenish the cooling water in the circulating water tank 15 immediately; (v) Open the catalytic layer of catalytic steam drum 2 and the decolorization layer of cooling tower, and add or replace the catalyst and decolorizing agent.

[0056] II. Loading (a) Loading requirements: Open the feed inlet of pyrolysis reactor 1, add raw materials to ≤70% of the capacity, and then close the feed inlet; Precautions: Check if the inlet gasket is aged or damaged; tighten the inlet locking bolts symmetrically in multiple stages. (II) Heating and Monitoring At a rate of 10℃ / min, the pyrolysis vessel 1 is heated to the target temperature, and the appropriate heating power is adjusted according to the rated heating rate. Keep the ventilation system running throughout the entire process; Monitor pressure throughout the process (<5KPA); temperature of heating coil 13 (<100℃); The entire process involves monitoring the pyrolysis gas output to ignite the open flame, preventing the flame from going out and avoiding backfire.

[0057] III. Electromagnetic heating device (a) Turn on the main power supply → Start the heating system → Adjust the heating power Recommended temperature for PE / PP: 380℃~450℃ (II) Start the circulating water pump 16 → Confirm that the condensate outlet temperature is <30℃ Recommendation: Heat 2% of the raw material weight of water in pyrolysis reactor 1, preheat to 120℃ under no-load conditions → test airtightness. IV. Product Collection (a) Liquid oil classification and collection: Crude oil: fraction before 150℃ or after 360℃; kerosene base oil: fraction between 150℃ and 360℃; (II) Solid Residue Treatment: It is mainly carbon black, and may contain inorganic fillers and impurities; Cool down to <50℃ → Open the feed inlet → Remove the carbon slag; (III) Treatment of Non-condensable Gases: It mainly contains flammable gases such as methane, ethane, propane, and ethylene; the gasbag collects or vents the gas to a safe area for ignition. V. Shutdown Procedure (i) Turn off the electromagnetic heating device → allow it to cool naturally to below 150℃; (ii) Turn off circulating water pump 16 → drain residual liquid from condenser tube; (III) Cleaning of pyrolysis vessel 1: Use a ceramic spatula to remove coke buildup on the inner wall; (iv) Turn off the main power supply and ventilation system; (v) Remove excess catalyst and decolorizing agent; VI. Process Parameter Reference Table 1

[0058] Table 2

[0059] Example 2 This embodiment provides a plastic pyrolysis method, which can be implemented using the plastic pyrolysis apparatus in Embodiment 1, or other plastic pyrolysis apparatuses. Specifically, this plastic pyrolysis method includes the following steps: The plastic is pyrolyzed to form pyrolysis oil and gas; The pyrolysis temperature of the plastic is divided. During the pyrolysis process, the pyrolysis oil and gas generated at different pyrolysis temperatures are condensed for the first time, and the pyrolysis oil condensed for the first time is recovered.

[0060] In one embodiment of this example, dust removal and catalysis are performed before the first condensation process, and decolorization is performed during the condensation process.

[0061] In one embodiment of this example, the following steps are also included: performing a second condensation on the pyrolysis oil and gas after the first condensation, and recovering the pyrolysis oil after the second condensation.

[0062] In one embodiment of this example, the following steps are also included: subjecting the pyrolysis gas after secondary condensation to acid-base neutralization and ignition treatment in sequence.

[0063] Specific examples have been used to illustrate the principles and implementation methods of this invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of this invention. Furthermore, those skilled in the art will recognize that, based on the ideas of this invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this invention.

Claims

1. A plastic pyrolysis apparatus, comprising a plastic pyrolysis module and a pyrolysis oil recovery module, wherein the plastic pyrolysis module is used to pyrolyze plastic to generate pyrolysis oil and gas, and the pyrolysis oil recovery module is used to condense the pyrolysis oil and gas and recover the condensed pyrolysis oil, characterized in that... The pyrolysis oil recovery module includes at least two modules, each of which has a recovery temperature range. The recovery temperature ranges of at least two pyrolysis oil recovery modules do not overlap. Each pyrolysis oil recovery module is activated only when the pyrolysis temperature of the plastic pyrolysis module falls into its recovery temperature range.

2. The plastic pyrolysis apparatus according to claim 1, characterized in that, It includes two pyrolysis oil recovery modules, one of which has a collection range of below 150°C and above 360°C, and the other has a collection range of 150°C to 360°C.

3. The plastic pyrolysis apparatus according to claim 1 or 2, characterized in that, Each of the pyrolysis oil recovery modules includes a catalytic steam drum, a primary decolorizing condenser, an oil storage tank, and a secondary decolorizing condenser. The inlet of the catalytic steam drum is connected to the pyrolysis oil and gas outlet of the plastic pyrolysis module. The inlet of the primary decolorizing condenser is connected to the outlet of the catalytic steam drum, and the outlet of the primary decolorizing condenser is connected to the inlet of the oil storage tank. The inlet of the secondary decolorizing condenser is connected to the outlet of the oil storage tank.

4. The plastic pyrolysis apparatus according to claim 3, characterized in that, The first-stage decolorizing condensing tower and the second-stage decolorizing condensing tower have a first columnar structure and a second columnar structure, respectively. in, The inlet of the primary decolorizing condenser is located at the top of the first columnar structure, and the outlet is located at the bottom of the first columnar structure. The inlet of the secondary decolorization condenser is located at the bottom of the second columnar structure, and the outlet is located at the top of the second columnar structure.

5. The plastic pyrolysis apparatus according to claim 4, characterized in that, The catalytic steam drum has a third columnar structure, and a catalyst is provided at the top of the catalytic steam drum; the upper part of the primary decolorizing condenser and the lower part of the secondary decolorizing condenser are both cooling layers, and the lower part is a decolorizing layer, which contains a decolorizing agent.

6. The plastic pyrolysis apparatus according to claim 4 or 5, characterized in that, The outlet of the primary decolorizing condenser and the inlet of the secondary decolorizing condenser are both connected to the oil storage tank via vertical pipes.

7. The plastic pyrolysis apparatus according to claim 1, characterized in that, The plastic pyrolysis module includes a pyrolysis vessel and a heating device for heating the pyrolysis vessel.

8. The plastic pyrolysis apparatus according to claim 7, characterized in that, The heating device includes an electromagnetic heating device, which includes a heating coil wound around the outside of the pyrolysis vessel.

9. The plastic pyrolysis apparatus according to claim 1, characterized in that, It also includes a pyrolysis oil recovery module, which is used to re-condense the uncondensed pyrolysis gas in the pyrolysis oil recovery module and recover the condensed pyrolysis oil. The pyrolysis oil recovery module includes a mixing tank and a recooler. The inlet of the mixing tank is connected to part or all of the pyrolysis gas outlet of the pyrolysis oil recovery module, and the outlet of the mixing tank is connected to the recooler. The connecting pipe between the recooler and the mixing tank is a vertical pipe or an inclined pipe inclined towards the mixing tank, so that the recooled oil flows back to the mixing tank.

10. The plastic pyrolysis apparatus according to claim 9, characterized in that, The pyrolysis oil recovery module also includes an alkaline washing tank and a water seal tank. The inlet of the alkaline washing tank is connected to the recooler, and the outlet of the water seal tank is connected to a collection device, a combustion device, or placed above an open flame.

11. The plastic pyrolysis apparatus according to claim 9, characterized in that, It also includes a cooling module for providing cooling capacity to the pyrolysis oil recovery module and the pyrolysis oil re-collection module; the cooling module includes a circulating water tank and a circulating water pump, and the circulating water tank provides circulating cooling water to the pyrolysis oil recovery module and the pyrolysis oil re-collection module through the circulating water pump.

12. A method for pyrolyzing plastics, characterized in that, Includes the following steps: The plastic is pyrolyzed to form pyrolysis oil and gas; The pyrolysis temperature of the plastic is divided. During the pyrolysis process, the pyrolysis oil and gas generated at different pyrolysis temperatures are condensed for the first time, and the pyrolysis oil condensed for the first time is recovered.

13. The plastic pyrolysis method according to claim 12, characterized in that, Dust removal and catalysis are performed before the first condensation process, and decolorization is carried out during the condensation process.

14. The plastic pyrolysis method according to claim 12 or 13, characterized in that, It also includes the following steps: The pyrolysis oil and gas after the first condensation are subjected to a second condensation, and the pyrolysis oil after the second condensation is recovered.

15. The plastic pyrolysis method according to claim 14, characterized in that, It also includes the following steps: The pyrolysis gas after secondary condensation is subjected to acid-base neutralization and ignition treatment in sequence.

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