Coke oven flue gas desulfurization and denitrification purification process and device

Abstract

The invention relates to a coke oven flue gas desulfurization and denitrification purification process and a device, wherein flue gas is effectively desulfurated at low temperature through a rotating spray semi-dry method before denitrating, then is denitrated by utilizing a selective catalytic reduction method and utilizing an ammonia gas which is obtained by evaporating surplus ammonia water in a coking plant steamed ammonia section as a reducing agent, a denitration process is completed in a dust removal denitration integration device, dust in flue gas is removed and particulate matter is filtered out before denitrating, and the particulate matters in flue gas which is filtered and reactants which are generated through desulfurization are conveyed into a circulating ash solution preparation unit which is arranged in a desulfurization system through a desulfurization ash collecting transportation device, and are conveyed to the top portion of a desulfurization tower through a solution transportation unit to participate in the flue gas desulfurization process after being prepared to be a circulating ash solution, thereby enabling unreacted desulfurizer to be fully utilized. The coke oven flue gas desulfurization and denitrification purification process and the device combine rotating spray drying desulfurization method and a low temperature selective catalytic reduction (SCR) denitrification, achieve efficient desulfurization and denitrification of coke oven flue gas, and are simple in technological process, small in floor space and less in equipment investment.

Description

technical field [0001] The invention relates to the technical field of coke oven flue gas purification, in particular to a coke oven flue gas desulfurization and denitrification combined purification process and device. Background technique [0002] In recent years, the state has clarified that SO in coke oven flue gas in the coking industry 2 , NO X emission concentration index, the requirement for SO 2 , NO X emissions are strictly controlled. Coal-fired power plants have a large amount of flue gas, SO 2 and NO X The concentration is high, which seriously pollutes the air environment. The work of desulfurization and denitrification was carried out early. The current technology is quite mature, and the effect of desulfurization and denitrification is remarkable. However, for coke oven flue gas, due to its own characteristics, power plant desulfurization and denitrification technology is not suitable for desulfurization and denitrification of coke oven flue gas. The sp...

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Problems solved by technology

[0005] (3) For new coking plants, the NO X The content is effectively controlled at 3 ; but for existing enterprises or special regions, it is impossible to meet NO by improving the coke oven heating process X Emission standards require that post-flue gas denitrification measures must be taken

[0007] (5) The actual operation of the coke oven shows that with the increase of the age of the coke oven, the furnace wall will inevitably leak; Catalyst is a potential threat and can cause permanent damage to the catalyst

[0008] Because the coke oven flue gas temperature is lower than the operating temperature of conventional SCR catalysts in power plants, and the flue gas contains SO 2 , directly using the conventional SCR denitrification process of the power plant will generate a large amount of ammonium sulfate salt, which will block the catalyst, and the viscous components such as tar in the flue gas will adhere to the surface of the catalyst, causing permanent damage and unable to perform normal denitrification

Therefore, direct use of normal temperature wet desulfurization in power plants will cause the coke oven flue gas temperature to fail to meet the emission requirements

Although the problem of low temperature can be solved by heating the flue gas of the coke oven, it will cause waste of energy and increase the primary investment and operating costs

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