Waste plastic hot melt dechlorination pretreatment device

Abstract

The waste plastic hot melting dechlorination pretreatment device, a waste plastic crusher is connected with a water-cooled feeding pipe through a controllable feeder, a pyrolysis dry gas injection port is arranged at the top end of the water-cooled feeding pipe, and the bottom end is connected into a hot melting dechlorination reactor provided with stirring; a high-temperature hot melting oil inlet is arranged at the upper portion of the hot melting dechlorination reactor, a pyrolysis dry gas stripping distributor is arranged at the lower portion, and the bottom portion is connected with a high-speed circulating pipe provided with heating through a conveying pump in one way and returns to the upper portion of the hot melting dechlorination reactor in the other way, and serves as raw material of a pyrolysis liquefaction device; a gas exhaust port at the top of the hot melting dechlorination reactor is connected with a desulfurization and dechlorination reactor, one way returns to the pyrolysis dry gas injection port and the pyrolysis dry gas stripping distributor as circulating gas, and the other way is used for discharging pyrolysis dry gas.

Description

1. Technical Field

[0001] The invention provides a waste plastic hot-melt dechlorination pretreatment device, belonging to the field of environmental protection engineering. 2. Background Technology

[0002] While the widespread use of plastics has brought significant convenience to people's lives, it has also led to significant levels of white pollution. Plastics have a very short lifespan. A large number of plastic products, especially packaging, are discarded after approximately 6-12 months, and 40% of plastic is discarded after only 1-2 years. Globally, the annual production of plastic waste has reached 50 million tons. For decades, waste plastics have been included as part of municipal solid waste (MSW). According to surveys, waste plastics account for 4%-10% (wt%) or 10%-20% (v%) of MSW in industrialized countries, primarily from packaging waste, automobile waste, and processing waste. The percentages of various types of waste plastics are as follows: low-density polyethylene (LDPE) 27%; high-density polyethylene (HDPE) 21%; polypropylene (PP) 18%; polystyrene (PS) 16%; and polyvinyl chloride (PVC) 7%. Due to the lack of efficient, clean, and scalable technologies, waste plastics have become a pressing environmental challenge worldwide.

[0003] Landfill, incineration, and recycling are the three primary methods used to treat urban plastic solid waste. These methods vary from country to country due to varying circumstances, with landfill being the primary method in the United States, and incineration being the primary method in Europe and Japan. Currently, rapid pyrolysis / catalytic pyrolysis of waste plastics to liquefy or produce chemicals has become a hot topic both domestically and internationally, and is considered the most promising waste plastics treatment technology for industrialization.

[0004] Rapid pyrolysis / catalytic pyrolysis of waste plastics involves heating waste plastics at high temperatures in the absence of oxygen or low oxygen conditions to decompose them and produce valuable products. This is an effective recycling method, such as pyrolysis and liquefaction of waste plastics to produce gasoline, diesel, petroleum wax, and other chemical raw materials. However, due to the bulky and lightweight nature of waste plastics, their difficulty in compression, airtightness, expansion, melting and bonding, and poor thermal conductivity, continuous feeding and rapid heating are difficult to achieve. Currently, most waste plastic pyrolysis and liquefaction processes use batch reactors and horizontal rotary kilns. These processes result in slow heating rates, severe feed adhesion and coking, low liquid product yields and added value, and difficulty increasing processing capacity. The scale-up of pyrolysis equipment is difficult, and subsequent processing of chlorine-containing liquid products is challenging. These factors hinder the efficient, clean, and large-scale utilization of waste plastics. Currently, there are no large-scale commercial waste plastic pyrolysis plants. There is an urgent need to develop pretreatment equipment and equipment for hot-melt dechlorination of waste plastics to lay the foundation for the clean and efficient pyrolysis of waste plastics to produce high-value products. 3. Summary of the Invention

[0005] The purpose of the present invention is to overcome the shortcomings of the existing waste plastic pyrolysis liquefaction technology and provide a waste plastic hot melt dechlorination pretreatment device. The waste plastic pyrolysis dry gas and high-temperature oil slurry are circulated for hot melt dechlorination and desulfurization pretreatment, so as to solve the difficulties of waste plastic pyrolysis feeding and chlorine and sulfur heteroatom removal through liquid atomization feeding, improve conversion efficiency, inhibit condensation and coking, and realize controllable cracking of waste plastics and efficient, clean and high-value large-scale utilization.

[0006] The technical solution of the present invention:

[0007] The present invention provides a waste plastic hot melt dechlorination pretreatment device, wherein a waste plastic crusher is connected to a water-cooled feed pipe through a controllable feeder, the top of the water-cooled feed pipe is provided with a pyrolysis dry gas injection port, and the bottom end is connected to a hot melt dechlorination reactor with stirring; a high-temperature hot melt oil inlet is provided at the top of the hot melt dechlorination reactor, a pyrolysis dry gas stripping distributor is provided at the bottom, and the bottom is connected to a high-speed circulation pipe with heating through a delivery pump and returns to the top of the hot melt dechlorination reactor, and the other path is used as a raw material for a pyrolysis liquefaction device; the hot melt dechlorination reactor is provided with a high-temperature hot melt oil inlet, a pyrolysis dry gas stripping distributor is provided at the bottom, and the bottom is connected to a high-speed circulation pipe with heating through a delivery pump and returns to the top of the hot melt dechlorination reactor, and the other path is used as a raw material for a pyrolysis liquefaction device; The gas extraction outlet at the top of the chlorine reactor is connected to the desulfurization and dechlorination reactor, one path is used as circulating gas to return to the pyrolysis dry gas injection inlet and the pyrolysis dry gas stripping distributor, and the other path is used as pyrolysis dry gas discharge; the temperature of the water-cooled feed pipe is 20-95°C, the temperature of the high-temperature hot melt oil is 240-320°C, the temperature of the molten plastic liquid high-speed circulation pipe after heating is 20-60°C higher than the high-temperature hot melt oil, the flow rate of the high-speed circulation pipe is 2-30m / s, and the circulation ratio of the molten plastic liquid to the raw material is 1-10:1.

[0008] The outer wall of the water-cooled feed pipe is provided with a water-cooling jacket, which has a shape of a forward cone, a straight tube or an inverted cone, preferably a forward cone.

[0009] The controllable feeder is a rotary feeder, a double-shaft screw feeder or a single-shaft screw feeder.

[0010] The high-speed circulation tube is heated by electromagnetic induction heating, thermal oil heating, steam heating or resistance heating, preferably electromagnetic induction heating.

[0011] The present invention will be described in detail with reference to embodiments. 4. Description of the Figures

[0012] Attachment Figure 1 This is a schematic diagram of the process flow of the waste plastic hot melt dechlorination pretreatment device of the present invention.

[0013] Attachment Figure 1 The drawing settings are as follows:

[0014] 1. Waste plastic pulverizer 2. Controllable feeder 3. Water-cooled feed pipe 4. High-temperature dissolved oil inlet 5. Hot melt dechlorination reactor 6. Pyrolysis dry gas stripping distributor 7. Delivery pump 8. High-speed circulation pipe 9. Desulfurization and dechlorination reactor 10. Pyrolysis dry gas outlet

[0015] The process characteristics of the present invention are described in detail below with reference to the accompanying drawings and embodiments. 5. Specific implementation methods

[0016] The present invention provides a waste plastic hot melt dechlorination pretreatment device, wherein a waste plastic crusher (1) is connected to a water-cooled feed pipe (3) through a controllable feeder (2); the top of the water-cooled feed pipe (3) is provided with a pyrolysis dry gas injection port, and the bottom is connected to a hot melt dechlorination reactor (5) with stirring; the top of the hot melt dechlorination reactor (5) is provided with a high-temperature hot melt oil inlet (4), the bottom is provided with a pyrolysis dry gas stripping distributor (6), and the bottom is connected to a high-speed circulation pipe (8) with heating through a delivery pump (7) and returns to the top of the hot melt dechlorination reactor (5), and the other is used as raw material for external delivery of a pyrolysis liquefaction device; The gas extraction port at the top of the hot melt dechlorination reactor (5) is connected to the desulfurization and dechlorination reactor (9), one path of the gas is returned to the pyrolysis dry gas injection port and the pyrolysis dry gas stripping distributor (6) as circulating gas, and the other path is discharged from the pyrolysis dry gas outlet (10) as pyrolysis dry gas; the temperature of the water-cooled feed pipe (3) is 20-95°C, the temperature of the high-temperature hot melt oil is 240-320°C, the temperature of the molten plastic liquid high-speed circulation pipe (8) after heating is 20-60°C higher than that of the high-temperature hot melt oil, the flow rate of the high-speed circulation pipe (8) is 2-30 m / s, and the circulation ratio of the molten plastic liquid to the raw material is 1-10:1.

[0017] The outer wall of the water-cooled feed pipe (3) is provided with a water-cooling jacket, which has a shape of a forward cone, a straight pipe or an inverted cone, preferably a forward cone.

[0018] The controllable feeder (2) is a rotary feeder, a double-shaft screw feeder or a single-shaft screw feeder.

[0019] The high-speed circulation pipe (8) is heated by electromagnetic induction heating, thermal oil heating, steam heating or resistance heating, preferably electromagnetic induction heating.

[0020] In specific operation, the clean PE and PP waste plastics are sorted through the waste plastic crusher (1), and the waste plastic fragments are added to the water-cooled feed pipe (3) at 20-95°C through the controllable feeder (2). Under the influence of the pyrolysis dry gas, the waste plastic fragments fall into the 240-320°C high-temperature oil melt of the hot melt dechlorination reactor (5) with stirring. The melt dechlorination and desulfurization pretreatment is carried out through stirring and mixing and pyrolysis dry gas stripping. The molten plastic liquid extracted from the bottom of the hot melt dechlorination reactor (5) is pressurized and transported by the delivery pump (7). A part of the molten plastic liquid is heated to 20-60°C higher than the temperature of the high-temperature oil melt through the high-speed circulation pipe (8) with external heating, and then returned to the hot melt dechlorination reactor. (5) The upper part and the other part are sent out as raw materials for the pyrolysis liquefaction device. The pyrolysis dry gas extracted from the top of the hot melt dechlorination reactor (5) is processed by the desulfurization and dechlorination reactor (9) and then returned to the pyrolysis dry gas injection port and the pyrolysis dry gas stripping distributor (6) as circulating gas. The other part is discharged from the pyrolysis dry gas outlet (10) as pyrolysis dry gas. After heating, the temperature of the molten plastic liquid high-speed circulation pipe (8) is 20 to 60 ° C higher than that of the high-temperature hot melt oil, the flow rate of the high-speed circulation pipe (8) is 2 to 30 m / s, and the circulation ratio of the molten plastic liquid to the raw material is 1 to 10:1. Finally, the waste plastics that are easily softened and melted by heat and difficult to feed are turned into liquid feed that is easy to pump.

[0021] The waste plastic hot melt dechlorination pretreatment device converts waste plastics that are easily softened and melted by heat and difficult to feed in the solid phase into liquid plastic melt feed that is very easy to pump. It can realize continuous, large-scale, efficient, clean and high-value pyrolysis utilization of waste plastics, and solves the five common industry problems of waste plastic feed adhesion and coking, difficulty in mixing with high-temperature catalysts, low liquid product yield and added value, difficulty in scaling up pyrolysis equipment, and difficulty in subsequent processing of liquid products containing chlorine. The total yield of liquid products used for pyrolysis is over 95%, which is more than 25 percentage points higher than traditional waste plastic pyrolysis technology, ensuring safe, stable, full and excellent operation of the device.

Claims

1. A waste plastic hot melt dechlorination pretreatment device, which is technically characterized in that a waste plastic crusher is connected to a water-cooled feed pipe through a controllable feeder, the top of the water-cooled feed pipe is provided with a pyrolysis dry gas injection port, and the bottom is connected to a hot melt dechlorination reactor with stirring; the hot melt dechlorination reactor is provided with a high-temperature hot melt oil inlet at the top and a pyrolysis dry gas stripping distributor at the bottom, and the bottom is connected to a high-speed circulation pipe with heating through a delivery pump and returns to the top of the hot melt dechlorination reactor, and the other is used as a raw material for the pyrolysis liquefaction device; The gas extraction outlet at the top of the dechlorination reactor is connected to the desulfurization and dechlorination reactor. One path is used as circulating gas to return to the pyrolysis dry gas injection inlet and the pyrolysis dry gas stripping distributor, and the other path is used as pyrolysis dry gas discharge; the temperature of the water-cooled feed pipe is 20-95°C, the temperature of the high-temperature hot melt oil is 240-320°C, the temperature of the molten plastic liquid high-speed circulation pipe after heating is 20-60°C higher than the high-temperature hot melt oil, the flow rate of the high-speed circulation pipe is 2-30m / s, and the circulation ratio of the molten plastic liquid to the raw material is 1-10:

1.

2. The waste plastic hot melt dechlorination pretreatment device according to claim 1 is characterized in that The outer wall of the water-cooled feed pipe is provided with a water-cooling jacket, which has a shape of a positive cone, a straight pipe or an inverted cone.

3. The waste plastic hot melt dechlorination pretreatment device according to claim 1, characterized in that The controllable feeder is a rotary feeder.

4. The waste plastic hot melt dechlorination pretreatment device according to claim 1, characterized in that The controllable feeder is a double-shaft screw feeder or a single-shaft screw feeder.

5. The waste plastic hot melt dechlorination pretreatment device according to claim 1 is characterized in that The high-speed circulation tube is heated by electromagnetic induction heating, thermal oil heating, steam heating or resistance heating.

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