Grate-kiln SNCR/SCR (selective non-catalytic reduction/selective catalytic reduction) denitration and active coke desulfurization combined system and grate-kiln SNCR/SCR denitration and active coke desulfurization combined process

Abstract

The invention belongs to the technical field of industrial waste gas control, and relates to a grate-kiln SNCR / SCR (selective non-catalytic reduction / selective catalytic reduction) denitration and active coke desulfurization combined system. A denitration reductant injector of an SNCR system is communicated with one side, close to a rotary kiln, of a preheating section II; the preheating section II is communicated with an SCR system, and the SCR system is communicated with a drying section II; the drying section II and a preheating section I are communicated with an active coke desulfurizationand adsorption tower. The invention also provides a grate-kiln SNCR / SCR denitration and active coke desulfurization combined process. Flue gases of the rotary kiln enter the preheating section II, and the SNCR system sprays ammonia water into the flue gas inlet side of the preheating section II for denitration; the flue gases enter the SCR system for denitration, and then enter the drying sectionII to be mixed with the flue gases of the drying section I; the mixed gases enter the active coke desulfurization and adsorption tower for desulfurization after passing through an electric dust remover, a main exhaust fan and a flue gas heat exchanger. The grate-kiln SNCR / SCR denitration and active coke desulfurization combined system and the grate-kiln SNCR / SCR denitration and active coke desulfurization combined process have the advantages of improved denitration efficiency, reduced cost, high desulfurization and dust removal efficiency, and capability of meeting ultra-clean requirements.

Description

technical field [0001] The invention belongs to the technical field of industrial waste gas treatment, and in particular relates to a chain grate-rotary kiln pellet flue gas SNCR / SCR denitrification and active coke desulfurization combined system and process. Background technique [0002] The steel plant pellets have a large amount of smoke exhaust, and the main pollutant of the flue gas is NO X , SO 2 and dust, the emission concentration of pollutants is relatively high, while the particulate matter limit of sintering machine and pellet roasting equipment is adjusted to 10mg / Nm 3 , Sulfur dioxide limit adjusted to 35mg / Nm 3 , Nitrogen oxide limit adjusted to 50mg / Nm 3 ; Therefore, the flue gas of the pelletizing plant must choose a process technology with high denitrification, desulfurization and dust removal efficiency and mature technology for flue gas desulfurization, denitrification and dust removal. [0003] Domestic pellet flue gas denitrification technologies are...

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Problems solved by technology

Limestone-gypsum method and ammonia method are widely used, but the exhaust gas temperature is low and the moisture content is high, which will produce "white smoke" phenomenon, which requires whitening treatment of exhaust gas, which increases energy consumption, investment and The operating cost will also increase; activated coke desulfurization is dry desulfurization. Compared with the original flue gas, the temperature of the flue gas after desulfurization will not decrease, the moisture content will not increase, and the phenomenon of "white smoke" will not occur.

[0004] The current denitrification and desulfurization process of pellet flue gas has high cost and low efficiency. Therefore, it is necessary to design a combined system and process of SNCR / SCR denitrification of pellet flue gas and activated coke desulfurization with high efficiency and low cost.

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