A garbage incineration system and method using catalytic combustion to prevent low-temperature synthesis of dioxins

Abstract

The invention discloses a garbage incineration system and method for preventing dioxin low-temperature synthesis by catalytic combustion. The garbage incineration system comprises a garbage incinerator, a high-temperature heat exchanger, a high-temperature dust collector, a catalytic combustion device, a low-temperature heat exchanger and a flue gas purification device. The flue gas discharged by garbage incineration is cooled by the high-temperature heat exchanger and then passes through the high-temperature dust collector to remove most of the solid substances such as dust and carbon particles in the flue gas, thereby removing the catalyst for the low-temperature synthesis of dioxin. The purified flue gas enters the catalytic combustion device, and the carbon particles and carbon-containing organic matter in the flue gas are converted into carbon dioxide and water after catalytic combustion, thereby eliminating the carbon particles and carbon-containing organic matter necessary for the low-temperature synthesis of dioxin. Within the range of 200°C to 400°C for the low-temperature synthesis of dioxin, the flue gas lacks the catalyst, carbon particles and carbon-containing organic matter required for the low-temperature synthesis of dioxin, thereby effectively preventing the low-temperature synthesis of dioxin and reducing the pollution of garbage incineration to the environment.

Description

Technical Field

[0001] The invention relates to a garbage incineration technology, and in particular to a garbage incineration system and method for preventing low-temperature synthesis of dioxins by catalytic combustion. Background Art

[0002] Waste incineration has the advantages of reducing volume, harmlessness and resource utilization, and has been rapidly promoted and applied. However, the process of waste incineration produces highly toxic dioxins, which threaten the living environment of human beings. During the process of waste incineration, dioxins are generated in two ways: in the furnace and at low temperature in the tail flue.

[0003] Through the "3T+E" process, that is, controlling: the incineration temperature, the residence time of the flue gas in the furnace, the gas-solid turbulence of the flue gas and the amount of excess air, the generation of dioxins in the furnace can be effectively controlled. The principle of low-temperature synthesis of dioxins in the tail flue is that when the flue gas temperature in the tail flue is in the range of 200℃ to 400℃, certain metal compounds in the fly ash act as catalysts to react the carbon particles and carbon-containing organic matter of the garbage that are not fully burned with chlorine to generate dioxins. Since the furnace temperature of the garbage incinerator is above 800℃, and the flue gas at the chimney inlet is generally below 200℃, the flue gas generated by garbage incineration will inevitably experience the temperature area of ​​low-temperature synthesis of dioxins, and the low-temperature synthesis reaction of dioxins will inevitably occur. In order to prevent dioxins produced by waste incineration from entering the atmosphere with flue gas, waste incineration plants spray activated carbon into the tail flue during flue gas purification to adsorb dioxins in the flue gas, and capture the activated carbon through a dust removal device and enter it into the fly ash collected by the dust collector. The fly ash is eventually discharged into the environment, and the dioxins in the fly ash pose an environmental risk. Summary of the invention

[0004] To overcome the above-mentioned deficiencies of the prior art, the present invention aims to provide a waste incineration system and method for preventing low-temperature synthesis of dioxins by catalytic combustion, thereby effectively preventing low-temperature synthesis of dioxins during waste incineration.

[0005] To achieve the above object, the technical solution adopted by the present invention is:

[0006] A garbage incineration system utilizing catalytic combustion to prevent low-temperature synthesis of dioxins, comprising a garbage incinerator, a high-temperature heat exchanger, a high-temperature dust collector, a catalytic combustion device, a low-temperature heat exchanger, and a flue gas purification device;

[0007] The smoke exhaust port of the waste incinerator is connected to the high-temperature heat exchanger, and the smoke outlet of the high-temperature heat exchanger is connected to the high-temperature dust collector. The high-temperature dust collector collects most of the solid matter such as dust and carbon particles in the smoke. The smoke outlet of the high-temperature dust collector is connected to the catalytic combustion device. The carbon particles and carbon-containing organic matter in the smoke are converted into non-toxic carbon dioxide and water through the catalytic combustion device. The smoke outlet of the catalytic combustion device is connected to the low-temperature heat exchanger, and the smoke outlet of the low-temperature heat exchanger is connected to the smoke purification device. The smoke is discharged after it meets the standards after purification.

[0008] Furthermore, a temperature sensor is provided at the flue gas outlet of the high-temperature dust collector to monitor the flue gas temperature.

[0009] Furthermore, the dust removal material of the high temperature dust collector is a porous filter metal material, a porous ceramic filter material or a porous composite filter material.

[0010] Furthermore, the catalyst of the catalytic combustion device is a palladium catalyst or a platinum catalyst.

[0011] Furthermore, the catalyst of the catalytic combustion device is cadmium oxide, manganese oxide, iron oxide, cobalt oxide or copper oxide.

[0012] Furthermore, the catalyst substrate used in the catalytic combustion device is a porous ceramic substrate, a porous metal substrate or a porous composite substrate.

[0013] A method for incinerating garbage by using catalytic combustion to prevent low-temperature synthesis of dioxins comprises the following steps:

[0014] Step 1: Pass the high-temperature flue gas generated by the incineration of garbage in the garbage incinerator into the high-temperature heat exchanger to cool the high-temperature flue gas and reduce the flue gas temperature to 450℃±50℃;

[0015] Step 2: The cooled flue gas is passed into a high-temperature dust collector for dust removal and purification. The high-temperature dust collector collects most of the solid matter such as dust and carbon particles in the flue gas;

[0016] Step 3: The flue gas purified by the high-temperature dust collector enters the catalytic combustion device, and the residual carbon particles and carbon-containing organic matter in the flue gas undergo catalytic oxidation reaction with oxygen under the action of the catalyst to generate carbon dioxide and water;

[0017] Step 4: The flue gas after dust removal and catalytic combustion is passed into the low-temperature heat exchanger, and the flue gas temperature is reduced to below 200°C through the low-temperature heat exchanger;

[0018] Step 5: The low-temperature flue gas enters the flue gas purification device and is discharged after completing the deacidification, dust removal, and dioxin removal purification measures and meeting the standards.

[0019] The beneficial effects of the present invention are:

[0020] The waste incineration system for preventing low-temperature synthesis of dioxins by catalytic combustion of the present invention comprises a waste incinerator, a high-temperature heat exchanger, a high-temperature dust collector, a catalytic combustion device, a low-temperature heat exchanger and a flue gas purification device; the flue gas discharged by waste incineration in the waste incinerator reaches a temperature of 450°C±50°C after being cooled by the high-temperature heat exchanger, and the temperature range is higher than the low-temperature synthesis temperature range of dioxins, and dioxins will not be synthesized in this link; then the flue gas passes through the high-temperature dust collector to remove most of the solid substances such as dust and carbon particles in the flue gas, not only removing the catalyst for low-temperature synthesis of dioxins, but also avoiding the dust and carbon particles in the flue gas from wearing and poisoning the catalyst of the subsequent catalytic combustion device, and avoiding the clogging of the catalytic combustion device; the purified flue gas enters the catalytic combustion device, and the unburned carbon particles and carbon-containing organic matter remaining in the flue gas are converted into carbon dioxide and water after catalytic combustion within the temperature range of 450°C±50°C, thereby eliminating the carbon particles and carbon-containing organic matter necessary for the low-temperature synthesis of dioxins. The flue gas after catalytic combustion has its heat release temperature reduced to below 200°C in the low-temperature heat exchanger, and experiences a temperature range of 400°C to 200°C. Within the range of 200°C to 400°C for the low-temperature synthesis of dioxins, the flue gas lacks the catalyst, carbon particles and carbon-containing organic matter required for the low-temperature synthesis of dioxins, which effectively prevents the low-temperature synthesis of dioxins and reduces the pollution of the environment caused by waste incineration.

[0021] Furthermore, a temperature sensor is set at the flue gas outlet of the high-temperature dust collector, and the flue gas temperature is monitored by the temperature sensor. Then, the combustion conditions of the waste incinerator are adjusted to ensure that the temperature of the high-temperature flue gas is reduced to 450℃±50℃ after passing through the high-temperature heat exchanger. Under the premise of ensuring that the flue gas temperature is not lower than 400℃, the flue gas temperature is reduced as much as possible.

[0022] In the catalytic combustion device, the residual carbon particles and carbon-containing organic matter in the flue gas undergo catalytic oxidation reaction with oxygen under the action of the catalyst, avoiding the generation of dioxins at low temperature. The generated products are carbon dioxide and water, which do not pollute the environment and are safe and environmentally friendly. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 Schematic diagram of the system structure of the present invention

[0024] In the figure: 1-waste incinerator, 2-high temperature heat exchanger, 3-high temperature dust collector, 4-temperature sensor, 5-catalytic combustion device, 6-low temperature heat exchanger, 7-flue gas purification device. DETAILED DESCRIPTION

[0025] The present invention is further described in detail below with reference to specific embodiments, but is not intended to limit the present invention.

[0026] like Figure 1 As shown, the garbage incineration system of the present invention utilizes catalytic combustion to prevent low-temperature synthesis of dioxins, including a garbage incinerator 1, a high-temperature heat exchanger 2, a high-temperature dust collector 3, a temperature sensor 4, a catalytic combustion device 5, a low-temperature heat exchanger 6, and a flue gas purification device 7.

[0027] The smoke exhaust port of the waste incinerator 1 is connected to the high-temperature heat exchanger 2, and the high-temperature flue gas discharged from the waste incinerator 1 is cooled by the high-temperature heat exchanger 2. The smoke outlet of the high-temperature heat exchanger 2 is connected to the high-temperature dust collector 3, and the high-temperature dust collector removes most of the solid substances such as dust and carbon particles in the flue gas. The smoke outlet of the high-temperature dust collector 3 is connected to the catalytic combustion device 5, and the carbon particles and carbon-containing organic matter are burned at a lower ignition temperature with the help of a catalyst, so that the organic waste gas is decomposed into non-toxic carbon dioxide and water. The smoke outlet of the catalytic combustion device 5 is connected to the low-temperature heat exchanger 6, and the smoke temperature is reduced to below 200°C by the low-temperature heat exchanger 6. The smoke outlet of the low-temperature heat exchanger 6 is connected to the smoke purification device 7, and the smoke is further purified by the smoke purification device. The smoke is discharged into the atmosphere under the condition that the environmental protection emission requirements are met.

[0028] A temperature sensor 4 is arranged at the flue gas outlet of the high-temperature dust collector 3, and the flue gas temperature is monitored by the temperature sensor 4, and then the combustion conditions of the waste incinerator 1 are adjusted to ensure that the temperature of the high-temperature flue gas is reduced to 450°C±50°C after passing through the high-temperature heat exchanger 2.

[0029] The dust removal material of the high temperature dust collector 3 may be a porous metal filter material, a porous ceramic filter material, or other porous composite filter materials.

[0030] The catalyst of the catalytic combustion device 5 can be a precious metal catalyst palladium or platinum, or a non-precious metal catalyst, such as cadmium metal oxide, manganese metal oxide, iron metal oxide, cobalt metal oxide or copper metal oxide. The catalyst matrix can also be a porous ceramic matrix, a porous metal matrix, or a porous composite matrix.

[0031] Based on the above waste incineration system, the present invention also provides a waste incineration method using catalytic combustion to prevent low-temperature synthesis of dioxins, comprising the following steps:

[0032] Step 1: Pass the flue gas generated by garbage incineration into a high-temperature heat exchanger to cool the high-temperature flue gas, and reduce the flue gas temperature to 450℃±50℃;

[0033] Step 2: The cooled flue gas is passed into a high-temperature dust collector for dust removal and purification. The high-temperature dust collector removes most of the solid matter such as dust and carbon particles in the flue gas;

[0034] Step 3: The flue gas purified by the high-temperature dust collector enters the catalytic combustion device, and the residual carbon particles in the flue gas and the carbon-containing organic matter in the flue gas undergo catalytic oxidation reaction with oxygen under the action of the catalyst to generate carbon dioxide and water;

[0035] Step 4: The flue gas after dust removal and catalytic combustion is passed into the low-temperature heat exchanger, and the flue gas temperature is reduced to below 200° C. by the low-temperature heat exchanger 6;

[0036] Step 5: The low-temperature flue gas enters the flue gas purification device, and after completing purification measures such as deacidification, dust removal, and dioxin removal, it is discharged into the atmosphere under the condition that environmental emission requirements are met.

[0037] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, a person skilled in the art should understand that the specific implementation modes of the present invention can still be modified or replaced by equivalents, and any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be included in the scope of the claims.

Claims

1. A method for incinerating garbage by using catalytic combustion to prevent the low-temperature synthesis of dioxins, characterized in that: The incineration system comprises a garbage incinerator (1), a high-temperature heat exchanger (2), a high-temperature dust collector (3), a catalytic combustion device (5), a low-temperature heat exchanger (6) and a flue gas purification device (7); The smoke outlet of the waste incinerator (1) is connected to the high-temperature heat exchanger (2), and the smoke generated by the waste incineration is passed into the high-temperature heat exchanger to cool the high-temperature smoke, and the smoke temperature is reduced to 450°C±50°C; the smoke outlet of the high-temperature heat exchanger (2) is connected to the high-temperature dust collector (3), and the high-temperature dust collector removes dust and carbon particles in the smoke. The smoke outlet of the high-temperature dust collector (3) is connected to the catalytic combustion device (5), and the carbon particles and carbon-containing organic matter in the smoke are converted into non-toxic carbon dioxide and water through the catalytic combustion device (5). The smoke outlet of the catalytic combustion device (5) is connected to the low-temperature heat exchanger (6), and the smoke outlet of the low-temperature heat exchanger (6) is connected to the smoke purification device (7). After the smoke is purified and meets the standards, it is discharged; The waste incineration method specifically comprises the following steps: Step 1: passing the high-temperature flue gas generated by the incineration of waste in the waste incinerator (1) into the high-temperature heat exchanger (2) to cool the high-temperature flue gas, thereby reducing the temperature of the flue gas to 450° C.±50° C.; Step 2: The flue gas after cooling is passed into a high-temperature dust collector (3) for dust removal and purification, and the high-temperature dust collector (3) removes dust and carbon particles in the flue gas; a temperature sensor (4) is arranged at the flue gas outlet of the high-temperature dust collector (3), and the flue gas temperature is monitored by the temperature sensor (4); Step 3: The flue gas purified by the high-temperature dust collector (3) enters the catalytic combustion device (5), where the residual carbon particles and carbon-containing organic matter in the flue gas undergo a catalytic oxidation reaction with oxygen under the action of the catalyst to generate carbon dioxide and water; Step 4: the flue gas after dust removal and catalytic combustion is passed into a low-temperature heat exchanger (6), and the flue gas temperature is reduced to below 200° C. by the low-temperature heat exchanger (6); Step 5: The low-temperature flue gas enters the flue gas purification device (7), and is discharged after the deacidification, dust removal, and dioxin removal purification measures are completed; The catalyst of the catalytic combustion device (5) is a palladium catalyst or a platinum catalyst; The catalyst substrate used in the catalytic combustion device (5) is a porous ceramic substrate, a porous metal substrate or a porous composite substrate.

2. The method for incinerating garbage by utilizing catalytic combustion to prevent low-temperature synthesis of dioxins according to claim 1, characterized in that: The dust removal material of the high-temperature dust collector (3) is a porous metal filter material, a porous ceramic filter material or a porous composite filter material.

3. The method for incinerating garbage by utilizing catalytic combustion to prevent low-temperature synthesis of dioxins according to claim 1, characterized in that: The catalyst of the catalytic combustion device (5) is cadmium metal oxide, manganese metal oxide, cobalt metal oxide or copper metal oxide.

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