Method and device for preparing sodium carbonate by recycling tail gas of coal-fired boiler

A technology for a coal-fired boiler and a waste heat recovery device, which is applied in separation methods, chemical instruments and methods, fuels, etc., can solve the problem of not being able to fundamentally solve the problem of environmental pollution caused by a large amount of carbon dioxide emissions, and improve the utilization rate of raw materials and combustion efficiency. , the effect of reducing consumption

Inactive Publication Date: 2013-02-20

GUANGDONG DAZHONG AGRI SCI CO LTD

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Problems solved by technology

[0003] In order to protect the environment on which human beings depend, our country has invested a lot of manpower and material resources to remediate the tail gas of coal-fired boilers, but the existing control and reduction of sulfur dioxide and carbon dioxide The main method of desulfurization and dust is to treat the sulfur dioxide in the tail gas through dr...

Abstract

The invention relates to a method and a device for preparing sodium carbonate by recycling tail gas of a coal-fired boiler. The method comprises the steps of mixing coals and a desulfurizing agent to prepare desulfurized coals, and feeding the desulfurized coals into the boiler for burning; recycling waste heat of the tail gas; conducting dust removal on the tail gas; collecting and compressing the tail gas; and introducing the compressed tail gas into a reaction tank for chemical reaction to prepare sodium carbonate. According to the method, not only can the tail gas of the coal-fired boiler be treated, the pollution on the environment is alleviated, but also carbon dioxide in the tail gas can be used as a raw material to prepare sodium carbonate, so that the method has a good popularization and application value and a good commercial value. The device provided by the invention comprises a waste heat recovery device, a dust removal device, a compressor, the reaction tank and a sodium carbonate recovery system, wherein the waste heat recovery device is connected with an exhaust port of the coal-fired boiler, and a film filter device is arranged on a gas inlet of the boiler. The device is simple in structure, high in fuel burning efficiency, low in environmental pollution, beneficial to environmental protection and strong in practicability.

Application Domain

Dispersed particle filtrationSolid fuels +2

Technology Topic

PhysicsSodium carbonate +10

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Examples

Experimental program(2)

Example Embodiment

[0056] Example 1.

[0057] Such as figure 1 As shown, the method for preparing soda ash by recycling the tail gas of a coal-fired boiler of the present invention includes the following steps:

[0058] Step (1): After crushing the coal used by the coal-fired boiler 1 and adding a desulfurizer, the desulfurized coal is prepared and put into the boiler 1 for combustion; the coal is processed before combustion, so that the sulfur-containing substances after the combustion of the boiler 1 remain In the ash and slag, the content of sulfur dioxide in the tail gas discharged by the boiler 1 can be effectively reduced, and the pollution to the environment can be reduced.

[0059] Further, a membrane filter device 7 is provided at the air inlet 12 of the boiler 1. The membrane filter device 7 is an oxygen-enriched membrane filter device 7. The membrane separation layer of the oxygen-enriched membrane filter device 7 can allow oxygen to pass through and prevent The nitrogen gas passes through, and therefore, the concentration of oxygen entering the boiler 1 can be increased, thereby effectively improving the combustion efficiency of coal and increasing the utilization rate of raw materials.

[0060] The desulfurizer of this embodiment is made by mixing the following raw materials in weight percentage:

[0061] 50 parts of basic copper carbonate

[0062] Silica 20 parts

[0063] 30 parts of alumina.

[0064] Step (2): The tail gas after combustion of the coal-fired boiler 1 is introduced into the waste heat recovery device 2, so that the temperature of the tail gas is cooled and the heat energy in the tail gas is recovered; the temperature of the tail gas after the combustion of the boiler 1 is still at a relatively high level and is discharged into the atmosphere The waste heat recovery device 2 is used to recover the heat in the exhaust gas of the boiler 1, so that the temperature of the exhaust gas after heat recovery is reduced to 100℃, which can improve the utilization efficiency of coal, reduce energy consumption and reduce Cost of production.

[0065] Step (3): The exhaust gas after the waste heat recovery is introduced into the dust removal device 3 to recover the dust in the exhaust gas. Preferably, the dust removal device 3 can adopt a bag filter, which is also called a filter type dust collector. It is a dry high-efficiency dust collector that can use a bag filter element made of fiber woven fabric to trap dust-containing gas. The solid particles in the boiler exhaust are intercepted and recovered to avoid direct discharge of exhaust dust to the atmosphere, which can effectively reduce the environmental pollution of the dust in the boiler exhaust and reduce the fine particles with a diameter less than PM2.5 The emission of particles.

[0066] Step (4): The exhaust gas after the waste heat recovery is introduced into the compressor 4 to gather and compress the exhaust gas; the compressor 4 plays two roles. One is to gather a large amount of exhaust gas from the boiler 1 to increase the unit volume. The gas concentration of, provides conditions for subsequent reuse; the second is to compress the collected tail gas to facilitate the subsequent passing of the tail gas into the reaction tank 5 to complete the conversion to soda ash. Further, the pressure value of the compressed tail gas is 1 standard atmospheric pressure. After the collected tail gas of the boiler 1 is pressurized, the air concentration per unit volume is increased, which is beneficial to increase the reaction speed after being passed into the reaction tank 5. Improve the efficiency of exhaust gas treatment.

[0067] Step (5): Pass the compressed tail gas into a reaction tank 5 containing ammonia brine; the reaction tank 5 contains an aqueous ammonia solution. Specifically, it is formed by the reaction of quicklime and water, and carbon dioxide is easily used. The principle of producing soda ash by reacting with an aqueous ammonia salt solution is to adsorb carbon dioxide gas in the tail gas of the boiler 1 to reduce the emission of carbon dioxide gas and to produce soda ash without secondary pollution by-product, which has significant economic benefits.

[0068] Step (6): The soda ash slurry in the reaction tank 5 is sent to the soda ash recovery system 6 to prepare soda ash. The soda ash recovery system 6 is used to dehydrate and recover the soda ash slurry prepared in the reaction tank 5 to obtain the finished soda ash.

[0069] A device for recovering and utilizing the tail gas of a coal-fired boiler 1 to prepare soda ash, including a waste heat recovery device 2, a compressor 4, a reaction tank 5, and a soda ash recovery system 6 connected in sequence, and the waste heat recovery device 2 and the exhaust gas of the coal-fired boiler 1 口11 Connection.

[0070] Wherein, the reaction tank 5 includes two intermittently operated first reaction tank 51 and second reaction tank 52, and the first reaction tank 51 and the second reaction tank 52 are arranged side by side. The first reaction tank 51 and the second reaction tank 52 are arranged side by side. During the working process, the two reaction tanks 5 are turned on alternately. The ammonia brine in the first reaction tank 51 absorbs saturated carbon dioxide and then passes through the soda ash recovery system 6 for subsequent operations At the same time, the second reaction tank 52 is opened to continue to absorb the carbon dioxide in the tail gas, and the two reaction tanks 5 alternately react in turn, which can ensure the uninterrupted continuous operation of the tail gas of the boiler 1 and improve efficiency.

Example Embodiment

[0071] Example 2.

[0072] The method for preparing soda ash by recycling the tail gas of a coal-fired boiler 1 of the present invention includes the following steps:

[0073] Step (1): After crushing the coal used by the coal-fired boiler 1 and adding a desulfurizer, the desulfurized coal is prepared and put into the boiler 1 for combustion; the coal is processed before combustion, so that the sulfur-containing substances after the combustion of the boiler 1 remain In the ash and slag, the content of sulfur dioxide in the tail gas discharged by the boiler 1 can be effectively reduced, and the pollution to the environment can be reduced.

[0074] Further, a membrane filter device 7 is provided at the air inlet of the boiler 1. The membrane filter device 7 is an oxygen-enriched membrane filter device 7. The membrane separation layer of the oxygen-enriched membrane filter device 7 can allow oxygen to pass through and prevent nitrogen. By this, the concentration of oxygen entering the boiler 1 can be increased, thereby effectively improving the combustion efficiency of coal and increasing the utilization rate of raw materials.

[0075] The desulfurizer of this embodiment is made by mixing the following raw materials in weight percentage:

[0076] Basic zinc carbonate 90 parts

[0077] Silica 5 parts

[0078] 5 parts of attapulgite clay powder.

[0079] Step (2): The tail gas after the combustion of the coal-fired boiler 1 is introduced into the waste heat recovery device 2, so that the temperature of the tail gas is cooled and the heat energy in the tail gas is recovered; the temperature of the tail gas after the combustion of the boiler 1 is still at a relatively high level and is discharged into the atmosphere The waste heat recovery device 2 is used to recover the heat in the exhaust gas of the boiler 1, so that the temperature of the exhaust gas after heat recovery is reduced to 80℃, which can improve the utilization efficiency of coal, reduce energy consumption, and reduce Cost of production.

[0080] Step (3) The tail gas after the waste heat recovery is introduced into the dust removal device 3 to recover the dust in the tail gas. Preferably, the dust removal device 3 can adopt a bag filter, which is also called a filter type dust collector. It is a dry high-efficiency dust collector that can use a bag filter element made of fiber woven fabric to trap dust-containing gas. The solid particles in the boiler exhaust are intercepted and recovered to avoid direct discharge of exhaust dust to the atmosphere, which can effectively reduce the environmental pollution of the dust in the boiler exhaust and reduce the fine particles with a diameter less than PM2.5 The emission of particles.

[0081] Step (4): The exhaust gas after the waste heat recovery is introduced into the compressor 4 to gather and compress the exhaust gas; the compressor 4 plays two roles. One is to gather a large amount of exhaust gas from the boiler 1 to increase the unit volume. The gas concentration of, provides conditions for subsequent reuse; the second is to compress the collected tail gas to facilitate the subsequent passing of the tail gas into the reaction tank 5 to complete the conversion to soda ash. Further, the pressure value of the compressed tail gas is 2 standard atmospheric pressures. After the collected tail gas of the boiler 1 is pressurized, the air concentration per unit volume is increased. After being passed into the reaction tank 5, it is beneficial to increase the reaction speed and increase The efficiency of exhaust gas treatment.

[0082] Step (5): Pass the compressed tail gas into a reaction tank 5 containing ammonia brine; the reaction tank 5 contains an aqueous ammonia solution. Specifically, it is formed by the reaction of quicklime and water, and carbon dioxide is easily used. The principle of preparing soda ash by reacting with an aqueous ammonia salt solution is to adsorb carbon dioxide gas in the tail gas of the boiler 1 to reduce carbon dioxide gas emissions while preparing by-product soda ash without secondary pollution, which has significant economic benefits.

[0083] Step (6): The soda ash slurry in the reaction tank 5 is sent to the soda ash recovery system 6 to prepare soda ash. The soda ash recovery system 6 is used to dehydrate and recover the soda ash slurry prepared in the reaction tank 5 to obtain the finished soda ash.

[0084] A device for recovering and utilizing the tail gas of a coal-fired boiler 1 to prepare soda ash, including a waste heat recovery device 2, a dust removal device 3, a compressor 4, a reaction tank 5, and a soda ash recovery system 6, which are connected in turn, the waste heat recovery device 2 and the coal-fired boiler 1 is connected to the exhaust port 11.

[0085] Wherein, the reaction tank 5 includes two intermittently operated first reaction tank 51 and second reaction tank 52, and the first reaction tank 51 and the second reaction tank 52 are arranged side by side. The first reaction tank 51 and the second reaction tank 52 are arranged side by side. During the working process, the two reaction tanks 5 are turned on alternately. The ammonia brine in the first reaction tank 51 absorbs saturated carbon dioxide and then passes through the soda ash recovery system 6 for subsequent operations At the same time, the second reaction tank 52 is opened to continue the absorption treatment of carbon dioxide in the tail gas, and the two reaction tanks 5 alternately react in turn, which can ensure the uninterrupted continuous operation of the tail gas of the boiler 1 and improve efficiency.

[0086] Further, a stirrer 8 is provided in the reaction tank 5. In the process of absorbing carbon dioxide, continuous stirring can increase the reaction speed and efficiency.

[0087] For technical features not explained in this embodiment, the explanation in Embodiment 1 is adopted, and will not be repeated here.

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Method and device for preparing sodium carbonate by recycling tail gas of coal-fired boiler

AI-Extracted Technical Summary

Problems solved by technology

Abstract

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Description & Claims & Application Information

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