A method for treating chlorine-containing organic waste

Abstract

The present invention provides a method for treating chlorine-containing organic waste, which relates to the fields of chemical industry and environmental protection technology. The present invention uses an efficient and environmentally friendly plasma reactor to treat chlorine-containing organic waste. The characteristics of plasma high temperature, high energy density and rapid reaction are utilized to enable a small reactor to have a large processing capacity. By controlling the temperature of the reaction, the chlorine-containing organic waste can be fully cracked and converted into high-value-added products, obtaining solid products mainly composed of carbon and phosphorus and gaseous products mainly composed of acetylene and hydrogen chloride; the solid products are sent to the downstream cement plant to prepare calcium phosphate cement; the gaseous products are sent to the downstream polyvinyl chloride production section to prepare vinyl chloride monomer, or after purification and separation by conventional separation means such as absorption and adsorption, they are used for other process purposes, thus realizing the resource utilization of hazardous waste. In addition, the entire process is a closed cycle, does not require incineration, does not generate other waste, and does not generate dioxins, and can achieve zero emissions of pollutants.

Description

Technical Field

[0001] The present invention relates to the technical field of chemical industry and environmental protection, and in particular to a method for treating chlorine-containing organic waste. Background Art

[0002] Chlorinated organic waste primarily originates from industries such as printing and dyeing, metallurgy, electronics, pharmaceuticals, and chemicals. Almost all chlorinated organic waste is toxic, hazardous, and difficult to degrade. It exhibits environmental persistence, bioaccumulation, long-distance migration, and biohazardous properties. In recent years, as the nation's environmental standards have increased, research into chlorinated organic waste treatment technologies has become increasingly important, with significant public interest in harmless treatment methods.

[0003] The treatment of chlorine-containing organic waste in my country mainly follows the goals of volume reduction, harmlessness and resource utilization. Although there are many methods for the treatment of chlorine-containing organic waste, they all have certain problems. Although the landfill method is simple and easy to implement, it has the risk of harmful substances penetrating into the soil and polluting groundwater, and it occupies a large amount of land resources; incineration is currently the most commonly used method, with a large treatment capacity, good volume reduction effect, a full range of treatment types and simple operation, but the incineration fly ash contains a large amount of dioxins, which pollute the air and fail to achieve the goal of waste resource utilization. The pyrolysis and gasification methods for treating chlorine-containing organic waste have the advantages of good volume reduction effect, reduced dioxin emissions, and the production of resource products such as synthesis gas. However, due to their low temperatures, conventional pyrolysis and gasification will still produce a certain amount of dioxins, causing serious damage to the human body and the environment. Summary of the Invention

[0004] The present invention aims to provide a method for treating chlorine-containing organic waste, enabling harmless treatment and high-value-added utilization of chlorine-containing, high-boiling-point organic waste, reducing environmental pollution and addressing the poor mass and heat transfer performance of chlorine-containing, high-boiling-point organic waste in conventional pyrolysis technology. Furthermore, the method is adaptable to the raw materials and has no specific requirements for the composition and composition of the chlorine-containing, high-boiling-point organic waste, eliminating the need for pretreatment.

[0005] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0006] The present invention provides a method for treating chlorine-containing organic waste, comprising the following steps:

[0007] The chlorine-containing organic waste is introduced into an arc plasma reactor for cracking reaction, and the cracking products are quenched and subjected to gas-solid separation;

[0008] The temperature of the cracking reaction is 1500~3500K;

[0009] The chlorine-containing organic waste contains carbon, hydrogen, chlorine and phosphorus elements; the cracking products include solid-phase products and gas-phase products, the solid-phase products are mainly carbon and phosphorus elements, and the gas-phase products are mainly acetylene and hydrogen chloride.

[0010] Preferably, the arc starting gas of the arc plasma reactor is one or more of argon, nitrogen, hydrogen, natural gas and methane.

[0011] Preferably, the chlorine-containing organic waste is introduced into the arc plasma reactor using a carrier gas; the carrier gas is one or more of argon, nitrogen, hydrogen, natural gas and methane.

[0012] Preferably, the chlorine-containing organic waste is introduced into the arc plasma reactor above or below the arc.

[0013] Preferably, the quenching is wall-type heat exchange quenching or direct quenching.

[0014] Preferably, the cooling medium used for the quenching is water or working gas; the working gas is one or more of argon, hydrogen, natural gas and methane; the direction in which the cooling medium is sprayed into the quenching device is radial or tangential.

[0015] Preferably, the chlorine-containing organic waste further contains oxygen and / or iron; when the chlorine-containing organic waste contains oxygen, the molar content of carbon in the chlorine-containing organic waste is not less than 3 times the molar content of oxygen.

[0016] Preferably, the solid phase product is sent to a cement plant to prepare calcium phosphate cement.

[0017] Preferably, the gaseous product is sent to a vinyl chloride production section.

[0018] Preferably, the arc plasma reactor is a magnetic rotating arc plasma reactor.

[0019] The present invention provides a method for treating chlorine-containing organic waste, comprising the following steps: introducing the chlorine-containing organic waste into an arc plasma reactor for a cracking reaction, and quenching and performing gas-solid separation on the obtained cracking products; the cracking reaction temperature is 1500-3500 K; the chlorine-containing organic waste contains carbon, hydrogen and chlorine elements; the cracking products include solid-phase products and gas-phase products, the solid-phase products are mainly carbon and phosphorus elements, and the gas-phase products are mainly acetylene and hydrogen chloride.

[0020] The present invention uses an efficient and environmentally friendly plasma reactor to treat chlorinated organic waste. The plasma's high temperature, high energy density, and rapid reaction characteristics allow a small reactor to have a large processing capacity. By controlling the reaction temperature, the chlorinated organic waste can be fully cracked and converted into high-value-added products, resulting in solid products primarily composed of carbon and phosphorus and gaseous products primarily composed of acetylene and hydrogen chloride. The solid products are sent to a downstream cement plant to produce calcium phosphate cement; the gaseous products are sent to a downstream polyvinyl chloride production section to produce vinyl chloride monomer, or, after purification and separation using conventional separation methods such as absorption and adsorption, used in other processes, thus achieving resource utilization of hazardous waste. Furthermore, the entire process is a closed cycle, requiring no incineration, generating no other waste, and preventing the generation of dioxins, achieving zero pollutant emissions.

[0021] Furthermore, the high temperature and enthalpy characteristics of arc plasma technology, coupled with the steep thermal gradient within the reactor, enhance mass and heat transfer, resolving the issue of poor mass and heat transfer and the generation of dioxins associated with conventional pyrolysis of chlorinated organic waste. This method also offers excellent adaptability to feedstocks, eliminating the need for pretreatment of chlorinated organic waste. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a process flow chart for treating chlorine-containing organic wastes according to the present invention;

[0023] Figure 2 TEM image of the solid product obtained by cracking Example 1;

[0024] Figure 3 This is an SEM image of the gas product obtained by cracking in Example 1;

[0025] Figure 4 This is a gas chromatogram of the gas product obtained by cracking in Example 1;

[0026] Figure 5 TEM image of the solid product obtained by cracking Example 2;

[0027] Figure 6 This is a gas chromatogram of the gas product obtained by cracking in Example 2;

[0028] Figure 7 This is a SEM image of the solid product obtained by cracking Example 3;

[0029] Figure 8 The gas chromatogram of the gas product obtained by cracking in Example 3 is shown in FIG.

[0030] Figure 9 The gas chromatogram of the gas product obtained by cracking in Example 4 is shown in FIG. DETAILED DESCRIPTION

[0031] The present invention provides a method for treating chlorine-containing organic waste, comprising the following steps:

[0032] The chlorine-containing organic waste is introduced into an arc plasma reactor for cracking reaction, and the cracking products are quenched and subjected to gas-solid separation;

[0033] The temperature of the cracking reaction is 1500~3500K;

[0034] The chlorine-containing organic waste contains carbon, hydrogen, chlorine and phosphorus elements; the cracking products include solid-phase products and gas-phase products, the solid-phase products are mainly carbon and phosphorus, and the gas-phase products are mainly acetylene and hydrogen chloride.

[0035] In the present invention, the chlorine-containing organic waste may contain oxygen and / or iron in addition to chlorine, carbon, hydrogen and phosphorus. When the chlorine-containing organic waste contains oxygen, the molar content of carbon in the chlorine-containing organic waste is not less than 3 times the molar content of oxygen. The present invention prevents the generation of carbon monoxide and reduces the acetylene yield by controlling the molar content of carbon in the chlorine-containing organic waste to be not less than 3 times the molar content of oxygen. The present invention has no special requirements for the form of the chlorine-containing organic waste, and it can be any of liquid, solid or gaseous. In the present invention, the chlorine-containing organic waste is preferably chlorine-containing high-boiling organic waste. The present invention has no special requirements for the source of the chlorine-containing organic waste, and any chlorine-containing organic waste from a source well known in the art can be used, such as the bottom liquid produced during the distillation of chlorine-containing organic solvents, which includes one or more of tetrachloroethylene, tetrachloroethane, hexachloroethane, hexachlorobutadiene and hexachlorobenzene in composition.

[0036] In the present invention, the chlorinated organic waste is preferably introduced into the arc plasma reactor above or below the arc, more preferably above the arc. This facilitates full utilization of the heat in the arc region, ensuring more uniform mixing of the chlorinated organic waste with the plasma and a more thorough cracking reaction.

[0037] The present invention has no particular requirements for the method of introducing the chlorinated organic waste into the arc plasma reactor. Specifically, the chlorinated organic waste can be introduced into the arc plasma reactor by pumping or by conveying it with a carrier gas. Preferably, the chlorinated organic waste is introduced into the arc plasma reactor using a carrier gas; the carrier gas is preferably one or more of argon, nitrogen, hydrogen, natural gas, and methane. The present invention does not impose any particular restrictions on the flow rate of the carrier gas, as long as it can smoothly introduce the chlorinated organic waste into the arc plasma reactor.

[0038] In the present invention, the arc plasma reactor is preferably a magnetic rotating arc plasma reactor; the arc starting gas of the arc plasma reactor is preferably one or more of argon, nitrogen, hydrogen, natural gas and methane.

[0039] By adjusting the feed ratio of the ignition gas, carrier gas, and chlorine-containing organic waste, the present invention can adjust the hydrogen-carbon ratio of the plasma system, thereby regulating the product composition. In this invention, when the carbon content in the plasma system exceeds the hydrogen content, the resulting product is primarily a solid-phase product (primarily composed of carbon and phosphorus, more specifically, carbon in the form of carbon black and / or graphene). When the carbon content in the plasma system is less than the hydrogen content, the resulting product is primarily a gas-phase product (primarily composed of acetylene and hydrogen chloride).

[0040] In the present invention, the temperature of the cracking reaction is preferably 1500-3500K, more preferably 1700-3200K, further preferably 2000-3000K, and most preferably 2300-2700K.

[0041] The present invention preferably controls the temperature of the cracking reaction by controlling the input power, feed amount and plasma temperature, that is, the temperature of the entire plasma system after the chlorine-containing organic waste is mixed with the plasma.

[0042] The present invention controls the temperature of the cracking reaction within the above range to ensure that the cracking products include solid products and gaseous products, wherein the solid products are mainly carbon and phosphorus, and the gaseous products are mainly acetylene and hydrogen chloride.

[0043] In the present invention, the cracking reaction is a millisecond-level cracking reaction. After the cracking reaction, the particles automatically enter the quenching device under the driving effect of the flow of the carrier gas and the arc starting gas.

[0044] In the present invention, the quenching is preferably performed by partition-type heat exchange quenching or direct quenching. The cooling medium used in the quenching is preferably water or a working gas. The working gas is preferably one or more of argon, nitrogen, hydrogen, natural gas, and methane. In the present invention, the cooling medium is preferably injected into the quenching device in a radial or tangential direction, more preferably in a radial direction. Injecting the cooling medium in a radial direction allows for better mixing with the cracked gas, resulting in a better cooling effect.

[0045] In the present invention, the temperature of the cracking product after quenching is preferably room temperature to 200° C. The present invention utilizes quenching to prevent acetylene from cracking at high temperatures for a long time, and also to avoid the formation of dioxins.

[0046] The present invention has no special requirements for the gas-solid separation method, and gas-solid separation can be achieved according to conventional techniques in the art; specifically, for example, a cyclone separator is used for gas-solid separation.

[0047] After completing the gas-solid separation, the present invention obtains solid phase products and gas phase products. The solid phase products are mainly carbon and phosphorus. More specifically, the carbon exists in the form of carbon black and / or graphene; the gas phase products are mainly acetylene and hydrogen chloride (excluding carrier gas and arc starting gas).

[0048] In the present invention, the solid phase product is preferably sent to a cement plant to prepare calcium phosphate cement; the gas phase product is preferably sent to a vinyl chloride production section, or is purified and separated by conventional separation means such as absorption and adsorption for use in other processes.

[0049] Figure 1 The processing flow chart of chlorine-containing organic waste of the present invention is as follows: Figure 1 As shown, the present invention introduces chlorine-containing organic waste into an arc plasma reactor for cracking reaction, quenches the obtained cracking products and separates gas and solid to obtain solid phase products mainly composed of carbon and phosphorus and gas phase products mainly composed of acetylene and hydrogen chloride.

[0050] The treatment method provided by the present invention uses chlorinated organic waste as raw material and employs plasma technology to achieve harmless treatment and high-value-added utilization of chlorinated organic waste, reducing environmental pollution and addressing the poor mass and heat transfer performance of chlorinated organic waste in conventional pyrolysis technology. Furthermore, the present invention has good adaptability to raw materials, and the chlorinated organic waste does not require pretreatment.

[0051] The cracking process of chlorine-containing organic waste is carried out in a high-temperature environment of thousands of degrees in plasma. Only millisecond-level cracking reactions are required to obtain acetylene-rich cracking gas. The processing time is short, the processing volume is large, the process flow is simple, no catalyst is required, and it is economical and efficient. The utilization rate of raw materials is high, and the conversion rate of chlorine-containing organic waste is greater than 90%. The entire process does not produce other solid waste or wastewater, does not produce dioxins, and is environmentally friendly.

[0052] The following is a detailed description of the method for treating chlorine-containing organic waste provided by the present invention in conjunction with the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0053] Example 1

[0054] Chlorine-containing high-boiling organic waste (specifically, waste liquid recovered from a certain company's distillation tower) is transported into a thermal plasma reactor using a carrier gas through a peristaltic pump. The reactor is a magnetic rotating arc plasma reactor. Both the carrier gas and the arc starting gas are hydrogen. The input power is 25kW, and the flow rate of the arc starting gas hydrogen is 0.2 Nm 3 / h, the carrier gas hydrogen flow rate is 3 Nm 3 / h, the cracking reaction temperature is 2500 K. The cracking products are rapidly cooled by circulating water to room temperature, thereby stopping the thermal decomposition of the gas phase products, increasing the acetylene content in the cracking gas, and avoiding the decomposition reaction of acetylene at high temperature. After gas-solid separation of the cracking products, gas phase products and solid phase products are obtained, and the determination is carried out by gas chromatography external standard method (see Figure 4 ), it was determined that the gaseous product was a gas mixture with an acetylene volume content of 5.07% and a hydrogen chloride volume content of 16.43% (a cracking gas rich in acetylene, hydrogen chloride, methane (0.83%), ethylene (1.53%), and hydrogen (75.89%)). After analysis and calculation, the yield of the main reaction product acetylene was 80.4%. Elemental analysis using SEM-EDS revealed that the solid product was mainly composed of carbon and phosphorus, with carbon accounting for 68.57% and phosphorus accounting for 28.35%. Figure 2 and Figure 3 TEM and SEM images of the solid product obtained by cracking Example 1; Figure 2 and Figure 3 It can be seen that the carbon is mainly nano carbon black particles.

[0055] Example 2

[0056] Chlorine-containing high-boiling organic waste (specifically, waste liquid recovered from a certain company's distillation tower) is atomized by argon and enters the thermal plasma reactor. The thermal plasma reactor uses a hydrogen-argon mixture as the arc gas, with an input power of 20 kW and an argon flow rate of 0.2 Nm 3 / h, the carrier gas hydrogen flow rate is 3 Nm 3 / h, the cracking reaction temperature is 3000 K. The cracking products are directly and rapidly cooled with water to room temperature, thereby terminating the thermal decomposition of the gas phase products, increasing the acetylene content in the cracking gas, and avoiding the decomposition reaction of acetylene at high temperature. After gas-solid separation, the cracking products are analyzed by gas chromatography external standard method (see Figure 6 ) quantitatively obtained a gas mixture containing 5.96% by volume of acetylene and 30.26% by volume of hydrogen chloride (a cracked gas rich in acetylene, hydrogen chloride, methane (0.73%), ethylene (1.37%), hydrogen (54.42%), and argon (7.28%)) and a solid product mixed with carbon and phosphorus. Quantitative analysis and calculation showed that the yield of the main reaction product, acetylene, was 79.1%. TEM characterization of the solid product of Example 2 was performed, and the results are shown in FIG. Figure 5 ,Depend on Figure 5 It can be seen that carbon is mainly a mixture of graphene and nano carbon black particles.

[0057] Example 3

[0058] Chlorine-containing high-boiling organic waste (specifically, waste liquid recovered from a certain company's distillation tower) is atomized by argon and enters the thermal plasma reactor. The thermal plasma reactor uses argon as the arc starting gas, with an input power of 15kW and an argon flow rate of 0.2 Nm 3 / h, the carrier gas argon flow rate is 3 Nm 3 / h, the cracking reaction temperature is 3500 K. The cracking products are directly and rapidly cooled with argon gas to room temperature, thereby terminating the thermal decomposition of the gas phase products, increasing the acetylene content in the cracking gas, and avoiding the decomposition reaction of acetylene at high temperature. After gas-solid separation, the cracking products are analyzed by gas chromatography external standard method (see Figure 8 ) quantitatively obtained a gas mixture (rich in acetylene, hydrogen chloride, methane (0.57%), ethylene (1.83%), argon (77.19%) cracked gas) with a volume content of 4.3% acetylene and 16.12% hydrogen chloride, and a solid product mixed with carbon and phosphorus. Quantitative analysis and calculation showed that the yield of the main reaction product, acetylene, was 49.2%. The solid product of Example 2 was characterized by SEM, and the results are shown in FIG. Figure 7 ,Depend on Figure 7 It can be seen that carbon is mainly a mixture of graphene and nano carbon black particles.

[0059] Example 4

[0060] Chlorine-containing high-boiling organic waste (with the same composition as the waste liquid in Example 1) was transported into the thermal plasma reactor using a carrier gas through a peristaltic pump. The reactor was a magnetic rotating arc plasma reactor. Both the carrier gas and the arc starting gas were methane. The input power was 23 kW, and the flow rate of the arc starting gas methane was 0.2 Nm 3 / h, the carrier gas methane flow rate is 3 Nm 3 / h, the cracking reaction temperature is 2500 K. The cracking products are rapidly cooled by circulating water to room temperature, thereby stopping the thermal decomposition of the gas phase products, increasing the acetylene content in the cracking gas, and avoiding the decomposition reaction of acetylene at high temperature. After gas-solid separation of the cracking products, gas phase products and solid phase products are obtained, and the determination is carried out by gas chromatography external standard method (see Figure 9 The gaseous product was determined to be a gas mixture containing 26.17% acetylene by volume and 67.28% hydrogen chloride by volume (a cracked gas rich in acetylene, hydrogen chloride, methane (5.31%), and ethylene (1.27%)). Quantitative analysis and calculation showed that the yield of the main reaction product, acetylene, was 84.6%. The solid product showed no significant morphological changes compared to Example 1.

[0061] Comparative Example 1

[0062] The only difference from Example 3 is that the input power is increased, the temperature in the plasma region is raised to about 5000 K, the acetylene content in the cracking gas products decreases to 0.09%, the ethylene content is 0.005%, the methane content is 0.002%, the hydrogen chloride content remains basically unchanged, and the rest is argon. The amount of solid products is significantly increased.

[0063] It can be seen from the results of Example 3 and Comparative Example 1 that when the temperature of the cracking reaction is too high, the acetylene content in the cracking gas will be reduced.

[0064] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A method for treating chlorine-containing organic waste, characterized in that: The following steps are involved: The chlorine-containing organic waste is introduced into an arc plasma reactor for cracking reaction, and the cracking products are quenched and subjected to gas-solid separation; The chlorine-containing organic waste is introduced into an arc plasma reactor by using a carrier gas; the carrier gas is one or more of argon, nitrogen, hydrogen, natural gas and methane; The temperature of the cracking reaction is 2300~3500K; The chlorine-containing organic waste contains carbon, hydrogen, chlorine and phosphorus elements; The cracking products include solid-phase products and gas-phase products. The solid-phase products are mainly carbon and phosphorus elements, and the gas-phase products are mainly acetylene and hydrogen chloride.

2. The processing method according to claim 1, characterized in that The arc starting gas of the arc plasma reactor is one or more of argon, nitrogen, hydrogen, natural gas and methane.

3. The processing method according to any one of claims 1 to 2, characterized in that The chlorine-containing organic waste is introduced into the arc plasma reactor above or below the arc.

4. The processing method according to claim 1, characterized in that The quenching is wall-type heat exchange quenching or direct quenching.

5. The processing method according to claim 1 or 4, characterized in that: The cooling medium used for quenching is water or working gas; the working gas is one or more of argon, hydrogen, natural gas and methane; the direction in which the cooling medium is sprayed into the quenching device is radial or tangential.

6. The processing method according to claim 5, characterized in that: The chlorine-containing organic waste also contains oxygen and / or iron elements; when the chlorine-containing organic waste contains oxygen elements, the molar content of carbon elements in the chlorine-containing organic waste is not less than 3 times the molar content of oxygen elements.

7. The processing method according to claim 1, characterized in that The solid phase product is sent to a cement plant to prepare calcium phosphate cement.

8. The processing method according to claim 1, characterized in that The gaseous product is sent to the vinyl chloride production section.

9. The processing method according to any one of claims 1 to 2, characterized in that: The arc plasma reactor is a magnetic rotating arc plasma reactor.

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