Waste hydrofluorocarbon treatment system based on co-pyrolysis of hydrofluorocarbon and plastic

Abstract

The invention discloses a waste hydrofluorocarbon treatment system based on co-pyrolysis of hydrofluorocarbon and plastics, comprising: a plastic treatment device, the plastic treatment device comprises an ultraviolet radiation box, a crushing device and a drying device, the plastic treatment device is used for ultraviolet radiation, crushing and drying of plastics; the co-pyrolysis reactor is used for carrying out co-pyrolysis reaction on the waste hydrofluorocarbon and plastic to obtain a gas-liquid mixture, and the gas-liquid mixture comprises hydrogen fluoride, hydrogen and hydrocarbon; the gas-liquid separation device is used for receiving the generated gas-liquid mixture and separating the gas-liquid mixture into a liquid product and a gaseous product; and the recovery device is used for recovering the liquid product and the gaseous product separated by the gas-liquid separation device. According to the method, the waste hydrofluorocarbon degradation energy consumption can be reduced, combustible gas is generated, and harmless degradation and resource utilization of waste hydrofluorocarbon are achieved.

Description

Technical Field

[0001] The invention relates to a waste hydrofluorocarbon treatment system based on co-pyrolysis of hydrofluorocarbons and plastics, belonging to the technical field of organic waste recycling and treatment. Background Art

[0002] Hydrofluorocarbons are widely used in the refrigeration and air-conditioning industry due to their excellent thermodynamic properties, but they have a high global warming potential and are classified as greenhouse gases. The Kigali Amendment to the Montreal Protocol, adopted in 2016, controls and reduces the production and use of hydrofluorocarbons. On September 15, 2021, the Kigali Amendment officially came into effect in China, and the production and use of hydrofluorocarbons will be frozen at the baseline in 2024. Therefore, in order to avoid the emission of waste hydrofluorocarbons into the atmosphere and aggravate the greenhouse effect, waste hydrofluorocarbons need to be recycled and processed.

[0003] At present, the most common methods for destroying waste HFCs are: incineration, plasma and catalytic degradation. Among them, incineration and plasma have high energy consumption, high operating costs, and also produce toxic substances such as dioxins; catalytic degradation has low energy consumption, but the catalyst is prone to deactivation when degrading waste HFCs, resulting in reduced catalytic effect.

[0004] Waste plastics are a type of solid waste, including polyethylene, polypropylene, polystyrene, etc. It is estimated that the global consumption of plastics will reach more than 700 million tons in 2030. Plastics have the characteristics of high hydrogen / carbon ratio and are often used as hydrogen-rich raw materials to be mixed with organic waste such as biomass for co-pyrolysis reaction to improve the quality of biomass pyrolysis products. The pyrolysis temperature of plastics is lower than that of hydrofluorocarbons.

[0005] The existing methods for destroying waste hydrofluorocarbons have the following problems: high energy consumption, generation of toxic gases such as fluorocarbons and dioxins, and environmental pollution. Summary of the invention

[0006] The purpose of the present invention is to provide a waste hydrofluorocarbon treatment system based on co-pyrolysis of hydrofluorocarbons and plastics, to solve the technical problems of high energy consumption and generation of toxic substances encountered when destroying waste hydrofluorocarbons, and to achieve low-temperature degradation of waste hydrofluorocarbons, harmlessness of degradation products and resource utilization.

[0007] In order to solve the above technical problems, the technical solution adopted by the present invention is: A waste hydrofluorocarbon treatment system based on co-pyrolysis of hydrofluorocarbons and plastics, comprising: Plastic processing device for processing plastics; a co-pyrolysis reactor, used for mixing the waste hydrofluorocarbons and the plastic particles processed by the plastic processing device to perform a co-pyrolysis reaction and obtain a gas-liquid mixture; a gas-liquid separation device, configured to receive the gas-liquid mixture outputted from the co-pyrolysis reactor, and the gas-liquid separation device separates the gas-liquid mixture into a liquid product and a gaseous product; A recovery device is used to recover the liquid product and gaseous product separated by the gas-liquid separation device.

[0008] Compared with the prior art, the technical effects achieved by adopting this technical solution are as follows: the plastic processing device of the waste hydrofluorocarbon processing system is used to disinfect, crush and dry plastics; the co-pyrolysis reactor is used to mix the waste hydrofluorocarbons with plastic particles and to undergo a co-pyrolysis reaction to obtain a gas-liquid mixture, wherein the gas-liquid mixture includes hydrogen fluoride, hydrogen and hydrocarbons; the gas-liquid separation device is used to separate the generated gas-liquid mixture into liquid products and gaseous products; and the recovery device is used to recover the separated liquid products and gaseous products.

[0009] In one example of the present invention, the waste hydrofluorocarbon treatment system further includes: a waste hydrofluorocarbon transport unit for transporting waste hydrofluorocarbons to the co-pyrolysis reactor; and a plastic transport unit for transporting plastics to the co-pyrolysis reactor.

[0010] Compared with the prior art, the technical effect achieved by adopting this technical solution is as follows: the waste hydrofluorocarbon conveying unit is used to convey the waste hydrofluorocarbons to the co-pyrolysis reactor, and the plastic conveying unit is used to convey the plastic to the co-pyrolysis reactor.

[0011] In one example of the present invention, the plastic processing device includes an ultraviolet irradiation box, a crushing device, a first preheater and a drying device, wherein the first preheater is located between the crushing device and the drying device. The waste hydrofluorocarbon transport unit includes a first pipeline, which is used to connect the waste hydrofluorocarbon transport unit; a hydrofluorocarbon storage tank, which is arranged on the first pipeline and is used to provide waste hydrofluorocarbons; a hydrofluorocarbon transport pump, which is arranged on the first pipeline and is used to pump hydrofluorocarbons to the co-pyrolysis reactor; the gas-liquid separation device is connected to the co-pyrolysis reactor through the second preheater and the first preheater in sequence; the gas-liquid mixture generated by the co-pyrolysis reactor first passes through the first preheater to preheat the plastic, and then passes through the second preheater to preheat the waste hydrofluorocarbons; the gas-liquid mixture after passing through the first preheater and the second preheater enters the gas-liquid separation device and is separated into liquid products and gaseous products.

[0012] Compared with the prior art, the technical effects achieved by adopting this technical solution are as follows: the first pipeline is used to connect the waste hydrofluorocarbon transport unit; the hydrofluorocarbon storage tank is arranged on the first pipeline and is used to provide waste hydrofluorocarbons; the hydrofluorocarbon transport pump is arranged on the first pipeline and is used to pump the hydrofluorocarbons to the co-pyrolysis reactor; the second preheater is arranged on the first pipeline and is located between the hydrofluorocarbon transport pump and the co-pyrolysis reactor, and is used to preheat the waste hydrofluorocarbons and cool the gas-liquid mixture output by the co-pyrolysis reactor. The plastic conveyor belt is used to connect the plastic transport unit and the plastic processing device; the first preheater is arranged on the plastic conveyor belt and is located between the crushing device and the drying device, and is used to preheat the plastic particles and cool the gas-liquid mixture output by the co-pyrolysis reactor.

[0013] In one example of the present invention, the waste hydrofluorocarbon treatment system also includes: a second pipeline for connecting the condenser and the gas-liquid separation device; a condenser, which is arranged on the second pipeline and is used to condense the gas-liquid mixture output by the second preheater; and a valve, which is arranged on the second pipeline and is located between the condenser and the gas-liquid separation device.

[0014] Compared with the prior art, the technical effects achieved by adopting this technical solution are as follows: the second pipeline is used to connect the condenser and the device; the condenser is arranged on the second pipeline, and is used to condense the gas-liquid mixture output by the second preheater; the valve is arranged on the second pipeline, and is located between the condenser and the gas-liquid separation device, so as to reduce the pressure of the gas-liquid mixture in the second pipeline and control the flow rate of the gas-liquid mixture.

[0015] In one example of the present invention, the waste hydrofluorocarbon treatment system also includes: a liquid product collector, which is used to recover and store the liquid product output by the gas-liquid separator; a gas separator, which is used to separate hydrogen fluoride from the gaseous product output by the gas-liquid separator; and a carbon dioxide capture device, which is used to separate carbon dioxide from the gaseous product output by the gas separator and output hydrogen and gaseous hydrocarbons.

[0016] Compared with the prior art, the technical effects achieved by adopting this technical solution are as follows: a liquid product collector is used to recover and store the liquid product output by the gas-liquid separator; a gas separator is used to separate hydrogen fluoride from the gaseous product output by the gas-liquid separator; a carbon dioxide capture device is used to separate carbon dioxide from the gaseous product output by the gas separator, and finally outputs hydrogen and gaseous hydrocarbon components, which can be used as fuel.

[0017] In one embodiment of the present invention, the mass ratio of waste hydrofluorocarbons to plastics is 1:9 to 9:1.

[0018] Compared with the existing technology, the technical effects achieved by adopting this technical solution are: The mass ratio of waste hydrofluorocarbons to plastics is 1:9~9:1, which can reduce the degradation temperature of waste hydrofluorocarbons and improve the degradation efficiency of waste hydrofluorocarbons.

[0019] In one example of the present invention, the co-pyrolysis temperature of waste hydrofluorocarbons and plastics is set to 600°C.

[0020] Compared with the existing technology, the technical effect achieved by adopting this technical solution is as follows: the co-pyrolysis temperature of waste hydrofluorocarbons and plastics is greater than 400°C, which can realize the degradation of waste hydrofluorocarbons and plastics.

[0021] After the present invention adopts the above technical solution, the following technical effects can be achieved: 1. As a hydrogen-rich material, plastic can provide sufficient hydrogen atoms for the degradation of waste hydrofluorocarbons and improve the defluorination rate of waste hydrofluorocarbons.

[0022] 2. The pyrolysis temperature of plastics is lower than that of waste hydrofluorocarbons. The free radicals generated by the pyrolysis of plastics will react with waste hydrofluorocarbons, which can reduce the degradation temperature of waste hydrofluorocarbons and thus reduce the energy consumption of the degradation of waste hydrofluorocarbons.

[0023] 3. Waste hydrofluorocarbons and plastics are co-pyrolyzed to produce hydrogen fluoride, hydrogen and hydrocarbons, which can be used as industrial raw materials and fuels; and no toxic substances such as dioxins are generated, reducing the emission of toxic substances.

[0024] 4. The gas-liquid mixture generated by waste hydrofluorocarbons and plastics in the co-pyrolysis reactor flows through the first preheater and the second preheater before being input into the condenser, transferring heat to the plastic particles and waste hydrofluorocarbons in the first preheater and the second preheater respectively, thereby recovering energy from the gas-liquid mixture and achieving a preliminary cooling effect on the gas-liquid mixture. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a schematic diagram of the structure of a waste hydrofluorocarbon treatment system based on co-pyrolysis of hydrofluorocarbons and plastics provided in Example 1 of the present invention.

[0026] In the figure, 1-hydrofluorocarbon storage tank, 2-hydrofluorocarbon transport pump, 3-first preheater, 4-co-pyrolysis reactor, 5-ultraviolet irradiation box, 6-crushing device, 7-second preheater, 8-drying device, 9-condenser, 10-valve, 11-gas-liquid separation device, 12-liquid product collector, 13-gas separator, 14-carbon dioxide capture device. DETAILED DESCRIPTION

[0027] In order to have a clearer understanding of the technical features, purposes and effects of the present invention, an embodiment of the present invention is now described with reference to the accompanying drawings. Obviously, the described embodiment is only one embodiment of the present invention, not all embodiments. All other embodiments obtained by ordinary technicians in this field without creative work within the spirit and principles of the present invention are within the scope of protection of the present invention. Example 1

[0028] like Figure 1 As shown, the present invention provides a waste hydrofluorocarbon treatment system based on co-pyrolysis of hydrofluorocarbons and plastics, comprising: A plastic processing device, the plastic processing device comprises an ultraviolet irradiation box 5, a crushing device 6 and a drying device 8, and the plastic processing device is used to process plastic; A co-pyrolysis reactor 4, which is a pyrolysis reactor for mixing waste hydrofluorocarbons with plastics to perform a co-pyrolysis reaction to obtain a gas-liquid mixture, wherein the gas-liquid mixture includes hydrogen fluoride, hydrogen and hydrocarbons; A gas-liquid separation device, the gas-liquid separation device is used to receive the generated gas-liquid mixture and separate it into a liquid product and a gaseous product; The recovery device is used to recover the liquid product and gaseous product separated by the gas-liquid separation device.

[0029] Preferably, the co-pyrolysis reactor 4 is made of a material resistant to corrosion by hydrogen fluoride, or the inner surface is coated with a coating resistant to corrosion by hydrogen fluoride.

[0030] The working principle of the waste hydrofluorocarbon treatment system is as follows: the waste hydrofluorocarbons in the hydrofluorocarbon storage tank 1 first flow through the second preheater 3 through the hydrofluorocarbon transport pump 2 for preliminary heating, and then flow into the co-pyrolysis reactor 4; the plastic passes through the ultraviolet irradiation box, the crushing device, the first preheater, and the drying device in sequence through the plastic conveyor belt and then enters the co-pyrolysis reactor 4. The co-pyrolysis reaction of the waste hydrofluorocarbons and the plastics is an endothermic reaction, and the outside world provides heat for the co-pyrolysis reactor 4 to achieve the co-pyrolysis of the waste hydrofluorocarbons and the plastics in the co-pyrolysis reactor 4.

[0031] The gas-liquid mixture generated by the co-pyrolysis of waste hydrofluorocarbons and plastics flows out from the co-pyrolysis reactor 4, transfers heat to the plastic particles and the waste hydrofluorocarbons through the first preheater 7 and the second preheater 3 in sequence, then flows into the condenser for further cooling, and then flows into the gas-liquid separation device 11 to be separated into liquid products and gaseous products after being depressurized by the valve 10; the liquid product separated by the gas-liquid separation device 11 flows out from the bottom of the gas-liquid separation device 11 and is collected in the liquid product collector 12; the gaseous product separated by the gas-liquid separation device 11 first flows through the gas separator 13 to recover the hydrogen fluoride component therein, and then flows through the carbon dioxide capture device 14 to separate the carbon dioxide therein, and finally obtains a combustible gas containing hydrogen and gaseous hydrocarbons, which can be used as a fuel or as an industrial raw material.

[0032] The outlet of the hydrofluorocarbon transport pump 2 is connected to the cold fluid inlet of the second preheater 3 through the first pipeline, and the cold fluid outlet of the second preheater 3 is connected to the inlet of the co-pyrolysis reactor 4 through the first pipeline. The ultraviolet irradiation box 5 is provided with an ultraviolet irradiation lamp to irradiate the plastic flowing through, and the outlet of the ultraviolet irradiation box 5 is connected to the inlet of the crushing device through a plastic conveyor belt; the crushing device 6 is a crusher, which can be a hammer crusher or other crusher, and the crusher crushes the plastic flowing through into plastic particles with a diameter of 6-9 mm, and the outlet of the crushing device 6 is connected to the cold fluid inlet of the first preheater 7 through a plastic conveyor belt; the first preheater 7 preheats the plastic particles, and the cold fluid outlet of the first preheater 7 is connected to the inlet of the drying device 8 through a plastic conveyor belt; the drying device 8 is a vacuum drying box, which vacuum dries the plastic particles input by the crushing device 6, with a vacuum degree of 133 Pa and a drying temperature of 100°C-180°C, and the outlet of the drying device 8 is connected to the inlet of the co-pyrolysis reactor 4 through a plastic conveyor belt. The outlet of the co-pyrolysis reactor 4 is connected to the hot fluid inlet of the first preheater 7 through a second pipeline, the hot fluid outlet of the first preheater 7 is connected to the hot fluid inlet of the second preheater 3 through a second pipeline, the hot fluid outlet of the second preheater 3 is connected to the hot fluid inlet of the condenser 9 through a second pipeline, the hot fluid outlet of the condenser 9 is connected to the inlet of the valve 10 through a second pipeline, and the outlet of the valve 10 is connected to the inlet of the gas-liquid separation device 11; the outlet at the bottom of the gas-liquid separation device 11 is connected to the inlet of the liquid product collector 12; the outlet at the top of the gas-liquid separation device 11 is connected to the inlet of the gas separator 13, and the outlet of the gas separator 13 is connected to the inlet of the carbon dioxide capture device 14.

[0033] Preferably, the waste hydrofluorocarbon delivery unit further comprises a hydrofluorocarbon storage tank 1, and the hydrofluorocarbon storage tank 1 is used to store waste hydrofluorocarbons.

[0034] Preferably, the second pipeline is made of a material resistant to corrosion by hydrogen fluoride, or the inner surface is coated with a coating resistant to corrosion by hydrogen fluoride.

[0035] Furthermore, the waste hydrofluorocarbon treatment system destroys waste HFC-134a. 5g of low-density polyethylene and 5g of HFC-134a are weighed and transported to the co-pyrolysis reactor 4 after treatment, and co-pyrolyzed at a temperature of 600°C. Waste hydrofluorocarbons and plastics are co-pyrolyzed to generate hydrogen fluoride, hydrogen and hydrocarbons, with yields of approximately 39.22 wt%, 0.46 wt% and 60.32 wt%, respectively.

[0036] Finally, it is noted that Example 1 is only used to illustrate the technical solution of the present invention, and the parts not designed in detail are common knowledge of ordinary technicians in the field. The protection scope of the present invention shall be based on the content of the claims, and any equivalent transformation based on the technical features of the present invention, or modification of the technical solution recorded in the above examples, is also within the protection scope of the present invention.

Claims

1. A waste hydrofluorocarbon treatment system based on co-pyrolysis of hydrofluorocarbons and plastics, characterized in that: include: Plastic processing device for processing plastics; A co-pyrolysis reactor (4) for mixing the waste hydrofluorocarbons and the plastic particles processed by the plastic processing device to perform a co-pyrolysis reaction and obtain a gas-liquid mixture; a gas-liquid separation device (11), used for receiving the gas-liquid mixture outputted from the co-pyrolysis reactor (4), and the gas-liquid separation device (11) separates the gas-liquid mixture into a liquid product and a gaseous product; A recovery device, wherein the recovery device is used to recover the liquid product and the gaseous product separated by the gas-liquid separation device (11).

2. A waste hydrofluorocarbon treatment system based on co-pyrolysis of hydrofluorocarbons and plastics as claimed in claim 1, characterized in that: The plastic processing device comprises an ultraviolet irradiation box (5), a crushing device (6), a first preheater (7) and a drying device (8), wherein the first preheater (7) is located between the crushing device (6) and the drying device (8).

3. A waste hydrofluorocarbon treatment system based on co-pyrolysis of hydrofluorocarbons and plastics as claimed in claim 2, characterized in that: Also includes: A waste hydrofluorocarbon transport unit, used for transporting waste hydrofluorocarbons to the co-pyrolysis reactor (4); The waste hydrofluorocarbon transport unit comprises: a first pipeline, the first pipeline being used to connect a waste hydrofluorocarbon transport unit; A hydrofluorocarbon storage tank (1), the hydrofluorocarbon storage tank (1) being arranged on the first pipeline, and the hydrofluorocarbon storage tank (1) being used to provide waste hydrofluorocarbons; A hydrofluorocarbon transport pump (2), the hydrofluorocarbon transport pump (2) being arranged on the first pipeline, the hydrofluorocarbon transport pump (2) being used to pump the hydrofluorocarbon to the co-pyrolysis reactor (2); a second preheater (3), the second preheater (3) being arranged on the first pipeline, and the second preheater (3) being located between the hydrofluorocarbon transport pump (2) and the co-pyrolysis reactor (4); The gas-liquid separation device (11) is connected to the co-pyrolysis reactor (4) via a second preheater (3) and a first preheater (7) in sequence; the gas-liquid mixture generated by the co-pyrolysis reactor (4) first passes through the first preheater (7) to preheat plastics, and then passes through the second preheater (3) to preheat waste hydrofluorocarbons; the gas-liquid mixture after passing through the first preheater (7) and the second preheater (3) enters the gas-liquid separation device (11) and is separated into a liquid product and a gaseous product.

4. A waste hydrofluorocarbon treatment system based on co-pyrolysis of hydrofluorocarbons and plastics as claimed in claim 3, characterized in that: Also includes: A plastic transport unit, used for transporting the plastic to the co-pyrolysis reactor (4); The plastic transport unit comprises: A plastic conveyor belt, the plastic conveyor belt being used to connect the plastic transport unit and the plastic processing device; The first preheater (7) is arranged on the plastic conveyor belt.

5. A waste hydrofluorocarbon treatment system based on co-pyrolysis of hydrofluorocarbons and plastics as claimed in claim 4, characterized in that: The ultraviolet irradiation box (5) irradiates the plastic for 24 hours; The pulverizing device (6) pulverizes the plastic irradiated by the ultraviolet irradiation box (5) to obtain plastic particles, wherein the diameter of the obtained plastic particles is 6 to 9 mm; The drying device (8) performs vacuum drying on the plastic particles input from the crushing device (6), the vacuum degree is 133 Pa, and the drying temperature is 100° C. to 180° C.

6. A waste hydrofluorocarbon treatment system based on co-pyrolysis of hydrofluorocarbons and plastics as claimed in claim 3, characterized in that: Also includes: The condenser (9) is used to condense the gas-liquid mixture output by the second preheater (3).

7. A waste hydrofluorocarbon treatment system based on co-pyrolysis of hydrofluorocarbons and plastics as claimed in claim 6, characterized in that: Also includes: a second pipeline, used for connecting the condenser (9) and the gas-liquid separation device (11); A valve (10), wherein the valve (10) is arranged on the second pipeline, and the valve (10) is located between the condenser (9) and the gas-liquid separation device (11).

8. A waste hydrofluorocarbon treatment system based on co-pyrolysis of hydrofluorocarbons and plastics as claimed in claim 1, characterized in that: Also includes: A liquid product collector (12), used for recovering and storing the liquid mixture; A gas separator (13), used for separating hydrogen fluoride from the gaseous product; The carbon dioxide capture device (14) is used to separate the carbon dioxide in the gaseous product and output hydrogen and gaseous hydrocarbons.

9. A waste hydrofluorocarbon treatment system based on co-pyrolysis of hydrofluorocarbons and plastics as claimed in claim 1, characterized in that: The mass ratio of the waste hydrofluorocarbon to the plastic is 1:9 to 9:

1.

10. A waste hydrofluorocarbon treatment system based on co-pyrolysis of hydrofluorocarbons and plastics as claimed in claim 1, characterized in that: The co-pyrolysis temperature in the co-pyrolysis reactor (4) is greater than 400°C.

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