Combustion system with flue gas and fly ash circulation function

Abstract

The invention relates to the technical field of thermal power generation equipment, in particular to a combustion system with a flue gas fly ash circulation function, which comprises an ash conveyer, a fan, and a hearth, a denitration assembly, a dust remover, a desulfurization assembly and a chimney which are communicated in sequence, the dust remover comprises an ash deposition part and an exhaust port, and the desulfurization assembly is communicated with the exhaust port. Fly ash separated from gas by the dust remover and flue gas are mixed and then input into the hearth through the ash conveyer and the fan, so that the temperature and oxygen content of air input into the whole hearth are adjusted, condensation nucleuses are introduced, disturbance of a flow field is enhanced, the combustion atmosphere in the hearth is changed, the mixing efficiency of the gas in the hearth is improved, and the combustion efficiency is improved. And therefore, the generation of reducing substances in the hearth is reduced, the system has the effect of preventing the heating surface from slagging and contamination, and the corrosion damage to the hearth is reduced. In addition, ash-containing flue gas and air enter the hearth respectively, so that the stability of the gas input into the hearth can be ensured, and meanwhile, the abrasion of fly ash to a heating surface can be avoided.

Description

technical field [0001] The invention relates to the technical field of thermal power generation equipment, in particular to a combustion system with a function of circulating flue gas and fly ash. Background technique [0002] In order to ensure that the emission of thermal power generation complies with my country's emission standards, the solution adopted by my country's thermal power generation is low NOx combustion technology. [0003] The low NOx combustion technology adopts staged combustion, and the area near the boiler burner is deeply oxygen-deficient. Although it can effectively reduce the combustion rate and temperature in the combustion area, and suppress the NOx generation under reducing atmosphere conditions, the deep anoxic condition will lead to CO The concentration and carbon content of fly ash increase sharply. In the local strong reducing atmosphere of the furnace, the sulfur in the pulverized coal or the SO2 generated by the combustion reaction will be pa...

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Problems solved by technology

[0003] Low NOx combustion technology adopts staged combustion, and the area near the boiler burner is deeply anoxic. Although it can effectively reduce the combustion rate and temperature in the combustion zone, and suppress the generation of NOX under reducing atmosphere conditions, the deep anoxic condition will lead to CO Concentration and carbon content of fly ash increase sharply. Under the local strong reducing atmosphere in the furnace, the sulfur in the pulverized coal or the SO2 generated by the combustion reaction will be partially converted into H2S. There is a strong positive correlation between the H2S concentration and the CO concentration. As the CO content increases, under high load conditions, H2S is mainly concentrated in the area near the water wall near the side wall of the furnace reduction zone, and as a strong corrosive gas, H2S will cause strong high temperature to the water wall corrosion

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