Hot-melting dechlorination pretreatment device for waste plastics

Abstract

According to the waste plastic hot-melting dechlorination pretreatment device, a waste plastic pulverizer is connected into a water-cooling feeding pipe through a controllable feeder, a pyrolysis dry gas injection opening is formed in the top end of the water-cooling feeding pipe, and the bottom end of the water-cooling feeding pipe is connected into a hot-melting dechlorination reactor with a stirring function; a high-temperature hot-melt oil inlet is formed in the upper part of the hot-melt dechlorination reactor, a pyrolysis dry gas stripping distributor is arranged at the lower part of the hot-melt dechlorination reactor, one path of the bottom of the hot-melt dechlorination reactor is connected into a high-speed circulating pipe with a heating function and returns to the upper part of the hot-melt dechlorination reactor through a delivery pump, and the other path is used as a raw material of the pyrolysis liquefaction device; a fuel gas extraction opening in the top of the hot melting dechlorination reactor is connected with the desulfurization dechlorination reactor, one path is used as circulating gas to return to the pyrolysis dry gas injection opening and the pyrolysis dry gas stripping distributor, and the other path is used as pyrolysis dry gas to be discharged.

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 great convenience to people's lives, it has also brought a lot of white pollution. The use cycle of plastics is very short. A large number of plastic products, especially packaging materials, are discarded after about 6-12 months. 40% of plastics are discarded after 1-2 years. The total annual output of plastic waste in the world has reached 50 million tons. In the past few decades, waste plastics have been regarded as part of municipal solid waste (MSW). According to surveys, waste plastics account for 4%-10% (wt) or 10%-20% (v%) in MSW in industrially developed countries, mainly from packaging waste, automobile garbage and processing waste. The percentages of various types of waste plastics are: low-density polyethylene (LDPE) 27%; high-density polyethylene (HDPE) 21%; polypropylene (PP) 18%; polystyrene (PS) 16%; polyvinyl chloride (PVC) 7%. Due to the lack of efficient, clean and large-scale technology, waste plastics have become an environmental problem that needs to be solved in the world.

[0003] In the treatment of urban plastic solid waste, landfill, incineration and recycling are the three main methods. Due to different national conditions, the methods vary from country to country. The United States mainly uses landfill, while Europe and Japan mainly use incineration. At present, rapid pyrolysis / catalytic pyrolysis liquefaction or chemical production of waste plastics has become a hot topic at home and abroad, and is also the waste plastic treatment technology with the most promising industrialization prospects.

[0004] Rapid pyrolysis / catalytic pyrolysis of waste plastics is an effective recycling method that heats waste plastics at high temperatures under oxygen-free or low-oxygen conditions to decompose them and produce valuable products, such as the pyrolysis and liquefaction of waste plastics to produce gasoline, diesel, petroleum wax and other chemical raw materials. However, due to the characteristics of waste plastics such as large size and light weight, difficulty in compression, airtightness, easy expansion, easy melting and bonding, and poor thermal conductivity, it is difficult to solve the problem of continuous feeding and rapid heating. At present, most of the pyrolysis and liquefaction of waste plastics adopt reactor-type intermittent reactions and horizontal rotary kiln reactions, with slow heating rates, severe feed adhesion and coking, low liquid product yield and added value, and difficult to improve processing capacity. It is difficult to scale up the pyrolysis device, and the subsequent processing of chlorine-containing liquid products is difficult, which restricts the efficient and clean large-scale utilization of waste plastics. At present, there is no large-scale waste plastic pyrolysis device in commercial operation. It is urgent to develop waste plastic hot melt dechlorination pretreatment devices and equipment technologies 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 provide a waste plastic hot melt dechlorination pretreatment device in order to overcome the shortcomings of the existing waste plastic pyrolysis liquefaction technology, and to use the waste plastic pyrolysis dry gas and high-temperature oil slurry circulation to carry out 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 coke formation, 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 waste plastic hot-melt dechlorination pretreatment device provided by the present invention comprises a waste plastic crusher connected to a water-cooled feed pipe through a controllable feeder, a pyrolysis dry gas injection port is arranged at the top of the water-cooled feed pipe, and the bottom is connected to a hot-melt dechlorination reactor with stirring; a high-temperature hot-melt oil inlet is arranged at the top of the hot-melt dechlorination reactor, a pyrolysis dry gas stripping distributor is arranged 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 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 is in the shape of a positive cone, a straight tube or an inverted cone, preferably a positive 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 drawings

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

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

[0014] 1. Waste plastic crusher 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 in conjunction with the accompanying drawings and embodiments. 5. Specific implementation methods

[0016] The waste plastic hot melt dechlorination pretreatment device provided by the present invention comprises a waste plastic crusher (1) 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 upper part of the hot melt dechlorination reactor (5) is provided with a high-temperature hot melt oil inlet (4), the lower part is provided with a pyrolysis dry gas stripping distributor (6), the bottom part is connected to a high-speed circulation pipe (8) with heating through a delivery pump (7) and returns to the upper part of the hot melt dechlorination reactor (5), and the other part 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 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 2-30m / 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-cooled jacket, which is in the shape of a positive cone, a straight tube or an inverted cone, preferably a positive 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, heat-conducting 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 a waste plastic crusher (1), and the waste plastic fragments are added to a 20-95°C water-cooled feed pipe (3) through a controllable feeder (2), and fall into a 240-320°C high-temperature oil melt in a hot melt dechlorination reactor (5) with stirring under the influence of pyrolysis dry gas, and are pre-treated by melt dechlorination and desulfurization 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 conveyed under pressure through a conveying pump (7), and a part of it is heated to a temperature 20-60°C higher than that of the high-temperature oil melt through an externally heated high-speed circulation pipe (8) 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 treated 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. The temperature of the molten plastic liquid high-speed circulation pipe (8) after heating 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. 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 can convert 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 more than 95%, which is more than 25 percentage points higher than that of traditional waste plastic pyrolysis technology, ensuring safe, long-term and optimal 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, a pyrolysis dry gas injection port is arranged at the top of the water-cooled feed pipe, and the bottom is connected to a hot melt dechlorination reactor with stirring; a high-temperature hot melt oil inlet is arranged at the top of the hot melt dechlorination reactor, a pyrolysis dry gas stripping distributor is arranged 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 a pyrolysis liquefaction device; The gas extraction outlet at the top of the dechlorination reactor is connected to the desulfurization and dechlorination reactor, one way is used as circulating gas to return to the pyrolysis dry gas injection inlet and the pyrolysis dry gas stripping distributor, and the other way 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 is in the shape of a positive cone, a straight tube or an inverted cone, preferably a positive cone.

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

4. 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, preferably electromagnetic induction heating.

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