Combustion Simulation Of 660MW Boiler In Zhundong Coal Fired Plant

Zhundong coal has the advantages of stable combustion,high volatile content,combustibility and low price.However,Na,K and alkali metals and their oxides in Zhundong coal are relatively high.The content of Na₂O in ash is more than 5%,and in some mining areas it is as high as 10%.Existing burning experience shows Zhundong coal is a kind of seriously polluted coal,which is prone to alkali metal condensation and contamination.Besides,the high moisture content and low ash melting point of Zhundong coal make the existing utility boilers burn only a certain proportion of Zhundong coal,which can not be fully burned or used in large proportion.Through the combination of coal quality analysis experiment and numerical simulation,this paper analyzed and predicted the risk of condensation contamination and contamination under different working conditions in the whole-fired Zhundong coal of unit boilers.It was found that under the condition of full-fired Zhundong coal,condensation contamination and slagging would occur in different degrees in all working conditions except the lowest load stable combustion condition.Slagging,and with the increase of load,the degree of slagging gradually deepens,and the unit will stop operation at full load.If effective measures can not be taken to control the alkali metals in coal,the water wall will be seriously corroded or even burst in the case of serious contamination and slagging,which will affect the economic and safe operation of power plants.Based on the analysis of the simulation results,reasonable suggestions are given for the arrangement of furnace burner and secondary tuyere to reduce the risk of contamination.