Technological process for flue gas purification

Abstract

The invention discloses a technological process for flue gas purification, including the steps of flue gas desulphurization, dust collection and denitration, wherein above 300 DEG C, the flue gas is pThe invention discloses a technological process for flue gas purification, including the steps of flue gas desulphurization, dust collection and denitration, wherein above 300 DEG C, the flue gas is processed by the operation of dust collection by a high temperature bag type dust collector made of metal fibre filter materials, and then is processed by the operation of denitration by a selective carocessed by the operation of dust collection by a high temperature bag type dust collector made of metal fibre filter materials, and then is processed by the operation of denitration by a selective catalytic reduction denitration reactor. The invention can effectively give full play to the advantages of the single technology of dust collection, desulphurization and denitration, avoids the disadvantalytic reduction denitration reactor. The invention can effectively give full play to the advantages of the single technology of dust collection, desulphurization and denitration, avoids the disadvantages of the single technology, and especially enables the SCR denitration to have higher activity under the high temperature of the flue gas, thereby greatly reducing the adverse effect on the SCR detages of the single technology, and especially enables the SCR denitration to have higher activity under the high temperature of the flue gas, thereby greatly reducing the adverse effect on the SCR denitration; further more, SCR catalyst which has a smaller passage and a larger surface area can be used, and the heat energy of the high temperature flue gas not only can be utilized by an air preheatnitration; further more, SCR catalyst which has a smaller passage and a larger surface area can be used, and the heat energy of the high temperature flue gas not only can be utilized by an air preheater AH, but also can be further utilized by installing a waste heat boiler, thereby simplifying and shortening the entire technological process.er AH, but also can be further utilized by installing a waste heat boiler, thereby simplifying and shortening the entire technological process.

Description

technical field [0001] The invention relates to a flue gas purification (desulfurization, dust removal, denitrification) process flow. Background technique [0002] The existing filter materials mainly include various chemical fiber woven fabrics or needle-punched felts, whose working temperature is below 260°C, and are widely used in bag-type dust collectors in coal-fired power plants, metallurgy, cement and other industries. There are only high-temperature electrostatic precipitators and ceramic fiber and porous ceramic precipitators, but the reliability of the former is poor, and the resistance of the latter is very large, so it has not been widely used. [0003] The metal fiber filter material mainly made of stainless steel fiber and iron-chromium-aluminum fiber is a new type of filter material, which has a higher service temperature and higher strength than glass fiber and chemical fiber. The stainless steel fiber filter material can be used for a long time below 450 °...

AI Technical Summary

Problems solved by technology

The disadvantage is that the catalyst is in the high dust flue gas, and its service life will be affected by the following factors

[0008] ① K, C in fly ash a , S I 、A s Contaminate or poison the catalyst;

[0010] ③ If the flue gas temperature is too high, the catalyst will sinter or fail;

[0014] The second arrangement is Figure 1-2 In the high-temperature and low-dust arrangement shown, the denitrification reactor is placed between the high-temperature electrostatic precipitator (H-ESP) and the air preheater behind the economizer (300-400°C). Ash pollutes the catalyst, wears and clogs the denitrification reactor, but it is difficult for the general electrostatic precipitator to operate normally at a high temperature of 300-400 ° C, and the reliability is not high, so it is generally not used

[0015] The third arrangement is Figure 1-3 In the low-temperature and low-dust arrangement shown, the denitrification reactor is placed after the wet FGD system, and the catalyst will not be affected by fly ash and SO 3 However, due to the low smoke temperature, it is generally necessary to use a gas-gas heat exchanger or add a fuel or natural gas burner to increase the smoke temperature to the activation level of the catalyst, increasing energy consumption and operating costs

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