CN1172110C - Waste plasma high temperature treatment process and equipment - Google Patents

Abstract

The present invention relates to a technology and a device for treating waste plasma beams at high temperature, which comprises: waste to be treated is put in a chamber, and the waste is heated and decomposed by using plasma beams under the inert environment. Compared with the prior art, by using the technology and the device of the present invention, the decomposition rate of the waste is increased, the generation amount of carbon dioxide is reduced, and the secondary pollution for the environment is reduced.

Description

Waste plasma high temperature treatment process and equipment

technical field

The invention relates to a process and equipment for treating waste, in particular to a process and equipment for treating waste at high temperature using plasma technology.

Background technique

There are many ways to deal with waste, and the most ideal way is to recycle, so that waste can be turned into useful resources. However, not all wastes can be recycled economically. A large amount of wastes (such as hazardous wastes) have a high resource cost, even exceeding their utilization value. Such wastes are usually landfilled or incinerated. method for processing.

Landfilled waste (especially hazardous waste) will waste a lot of land resources, and the escaped gas and seeped liquid will form secondary pollution into the atmosphere or soil, which is still an unacceptable source of pollution. Therefore, landfill is only a mitigation measure to environmental pollution, not the final solution. This landfill method will inevitably make human beings face the pollution problem of a large amount of landfill waste after several years, which will inevitably lead to further treatment measures.

Waste incineration can solve the environmental pollution problem of waste to a certain extent, but the chemical nature of incineration is an oxidation reaction, and the carbon in waste (especially organic waste) is oxidized into carbon dioxide and discharged into the atmosphere. Carbon dioxide is a recognized greenhouse gas that increases the temperature of the earth with additional adverse effects on the environment. Therefore, incineration treatment actually transforms one form of pollution into another form of environmental damage, and it is not a satisfactory solution, especially when incinerating hazardous waste, it often cannot effectively destroy its harmful components. , and even more harmful substances such as dioxin may be formed during incineration and discharge.

In recent years, many countries have proposed the use of plasma high temperature (above 3000°C) for waste treatment (especially for hazardous waste treatment), the treatment effect is obviously better than incineration, and the destruction of harmful and toxic components is more thorough.

For example, Carter et al. U.S. Patent No. 5,280,757 discloses the application of an arc plasma torch in a reactor to gasify municipal solid waste, resulting in a product containing a medium-quality gas and a slag with less toxic element precipitation .

U.S. Patent No. 4,644,877 to Barton et al. relates to the use of an arc plasma torch to destroy polychlorinated biphenyls (PCBs). The waste is atomized and ionized by the arc plasma torch, then cooled and recombined into gases and particulate objects in the reaction chamber. US Patent No. 4,431,612 to Bell et al. discusses the treatment of hazardous waste such as PCBs in a transferred arc plasma furnace with hollow graphite electrodes.

In U.S. Patent No. 5,284,503 to Butler, a process is disclosed for the reclamation of lead-contaminated soil and waste battery material whereby the soil forms a ceramicized slag. Combustible gases and lead ceramics produced from spent battery casings are best conveyed to conventional smelting furnaces for their fuel use.

In US Patent No. 4,479,443 to Faldt et al., the use of an arc discharge plasma torch to thermally decompose waste is disclosed. Waste material in the form of solid particles must be introduced downstream of the arc to avoid clogging of the nozzle due to particle adhesion. Oxidants such as oxygen and air and waste are mixed either before heating, during heating by means of nozzle gases, or after heating. In order to completely oxidatively decompose the waste, a sufficient amount of oxidizing agent is required.

US Patent No. 4,644,877 to Barton et al. discloses a DC arc plasma burner for high temperature pyrolysis of waste materials. An organic liquid is used to ignite and stabilize the plasma arc, a toroidal electromagnetic field coil is used to collimate the plasma, and a high pressure air source is used to rotate the arc. Take steps to feed the waste material downstream of the arc to prevent interfering with the formation or occurrence of the plasma arc. On the basis of the patent's teaching that no inert gases are used to ignite or sustain the plasma, this burner is only suitable for low temperature applications. The reaction chamber after the burner is used to mix the gas and particulate matter which is quenched and neutralized with an alkaline spray liquid. A mechanical scrubber is used to separate the gas, which is exhausted with an extraction fan.

US Patent No. 4,886,001 to Chang et al. discloses an improvement to the above-described system of Barton et al. The modification is to replace the miscible mixture of methyl ethyl ketone and methanol solution with water or methanol, which is used to mix with the waste material containing PCBs before introduction into the DC arc type plasma torch, and to use pure oxygen instead of air as nozzle gas. The purpose of these changes is to increase the rate at which waste is processed. In addition, the use of solid separators is described, which utilizes a partial vacuum to separate the carrier gas.

The existing plasma waste treatment technology has a common disadvantage, that is, the treatment process is carried out in a non-vacuum state, so that the treatment process will inevitably involve air, and the oxygen in the air will decompose the carbon in the waste. Oxidation to generate carbon dioxide or carbon monoxide (eventually further oxidized to carbon dioxide). As mentioned earlier, the emission of carbon dioxide gas will cause another form of damage to the environment. It is especially unacceptable that due to the presence of carbon in the exhaust gas, it is the formation of dioxin (dioxin is formed in hydrogen, Formed under the condition that elements such as carbon, chlorine exist,) created conditions, and dioxin has been a kind of recognized material that has serious harm to human health.

content of the invention

The purpose of the present invention is to overcome the above-mentioned shortcomings of the prior art, provide a new waste treatment process and equipment, and further reduce environmental pollution.

The waste plasma high-temperature treatment process of the present invention includes placing waste to be treated in a chamber of a furnace body, forming an inert environment in the chamber, and using plasma beams to heat and decompose the waste.

The waste plasma high-temperature treatment equipment of the present invention includes a furnace body and a plasma beam generator installed on the furnace body, the furnace body has at least one chamber, and the electrodes and gas input pipes of the plasma beam generator extend into To the chamber, the gas input pipe of the plasma beam generator is connected with an inert gas source, and the chamber is connected with an inert environment generating device.

The "inert environment" referred to in the present invention refers to an environment that does not have an oxidation effect on carbon, such as a vacuum negative pressure environment, an inert gas environment (such as nitrogen, argon, helium), and the like.

The technology provided by the present invention overcomes the shortcoming of prior art preferably, because it is to treat waste with plasma high temperature under inert condition, thereby has following advantage:

1. Due to the anaerobic or anoxic environment under vacuum conditions, the carbon separated from the waste will not be oxidized under the high temperature of the plasma, so that the volume of the gas discharged during the treatment process will be reduced, and the emission of harmful carbon dioxide gas will be reduced. bottomed out.

2. Under the action of high temperature plasma, the separated carbon will remain in the treatment chamber, and form a stable, harmless and sometimes usable residue with other non-gasifiable components.

3. Due to the lack of carbon in the discharged gas, the conditions for the formation of dioxins are destroyed, which is conducive to avoiding the secondary pollution of dioxins.

The present invention will be described in detail below with reference to the accompanying drawings and examples.

Description of drawings

Accompanying drawing is the equipment schematic diagram of implementing process of the present invention.

The symbols in the drawings indicate: 1. plasma beam generator, 2. gas input pipe, 3. power cord, 4. cooler, 5. air pump, 6. furnace chamber, 7. plasma beam, 8. waste, 9. pressure sensor.

Detailed ways

As shown in the figure, the waste plasma high-temperature treatment process of the present invention includes placing the waste to be treated in a chamber 6 of a furnace body, forming an inert environment in the chamber 6, and using a plasma beam to heat and decompose the waste .

The inert environment can be vacuum environment, nitrogen environment, helium environment or argon environment.

The process may also include the step of degassing the chamber 6 during the pyrolysis process.

The waste is decomposed by high temperature plasma under vacuum negative pressure, and its decomposition efficiency will be higher than that of non-vacuum state.

The waste plasma high-temperature treatment equipment of the present invention comprises a furnace body and a plasma beam generator 1 installed on the furnace body, the furnace body has at least one chamber 6, electrodes and gas input of the plasma beam generator 1 The pipe 2 extends into the chamber 6, the gas input pipe 2 of the plasma beam generator is connected with an inert gas source, and the chamber 6 is connected with the inert environment generating device.

The apparatus may also include a gas removal device in communication with the chamber.

The inert environment generating device and the gas removing device may be a vacuum pumping device.

The described vacuum device includes an air pump 5, and a cooler 4 is connected to the pipeline connecting the air pump.

The inert environment generating device may also be an inert gas input device and a vacuum pumping device communicated with the chamber 6 .

A pressure sensor 9 may be provided on the chamber 6, and the sensor 9 is connected with the gas removal device.

Accompanying drawing has provided the structural schematic diagram of the equipment of the present invention, wherein the high-temperature plasma gas 7 that plasma generator 1 produces heats and decomposes waste 8, and waste 8 is placed in the sealed processing chamber 6, is treated by air pump 5 The gas in the cavity 6 is forced to be exhausted after being cooled by the cooler 4 . The vacuum degree inside the processing chamber 6 is detected by the pressure sensor 9, and the signal is fed back to the air pump 5 to adjust the gas discharge speed so that the processing chamber 6 is always at a certain vacuum degree. The input gas of the plasma generator 1 can use the gas which does not contain oxygen.

The above description of the invention with reference to the accompanying drawings and the embodiments is only illustrative, not limiting. Obviously, many modifications can be made on the basis of the present invention without departing from the essence of the present invention.

Claims (10)

1. Waste plasma high-temperature treatment process, characterized in that the process includes placing the waste to be treated in a furnace chamber, forming an inert environment in the chamber, and using plasma beams to heat and decompose the waste. 2. The high-temperature plasma treatment process for waste according to claim 1, wherein the inert environment is a vacuum environment. 3. The waste plasma high-temperature treatment process according to claim 1, wherein the inert environment is a nitrogen environment, a helium environment or an argon environment. 4. The waste plasma high-temperature treatment process according to any one of claims 1-3, characterized in that the process further includes the step of removing the gas in the chamber (6) during the thermal decomposition process. 5. A high-temperature plasma treatment equipment for waste, comprising a furnace body and a plasma beam generator (1) installed on the furnace body, the furnace body has at least one chamber (6), and the plasma beam generator (1) electrode and gas input pipeline (2) are inserted in the chamber (6), it is characterized in that, the gas input pipeline (2) of described plasma beam generator is connected with an inert gas source, and The chamber (6) is connected with an inert environment generating device. 6. The waste plasma high-temperature treatment equipment according to claim 5, characterized in that the equipment further comprises a gas removal device communicated with the chamber. 7. The waste plasma high-temperature treatment equipment according to claim 6, characterized in that said inert environment generating device and gas removing device are a vacuum pumping device. 8. The waste plasma high-temperature treatment equipment according to claim 7, characterized in that, the vacuum pumping device includes an air pump (5), and a cooler (4) is connected to the pipeline connected to the air pump. 9. The waste plasma high-temperature treatment equipment according to claim 5, characterized in that said inert environment generating device is an inert gas input device and a vacuum pumping device communicated with said chamber (6). 10. The waste plasma high-temperature treatment equipment according to any one of claims 6-9, characterized in that a pressure sensor (9) is provided on the chamber (6), and the sensor (9) is connected to the gas The exclusion device is connected.

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