Simulation of Heat and Mass Transfer in Pulverized Coal Boiler Based on Gaseous Combustion Through Phase Separation Technique

Abstract

In order to meet the current environmental protection ultralow pollutant emission requirements, onestep combustion is changed into twostep combustion by splitphase gasification combustion technology, and doublefurnace structure, graded air distribution, calcium injection desulfurization, and combined denitrification with selective noncatalytic reduction (SNCR) and selective catalytic reduction (SCR) are adopted to reduce pollutant emissions. ansys was used to establish a twodimensional steadystate structure model of pulverized coal boiler with a doublefurnace. Finite element analysis was carried out on the combustion in 54 MW, 56 MW, and 58 MW working conditions under different calciumsulfur (Ca/S) ratios. The results showed that the desulfurization efficiency increased gradually when the Ca/S ratio was between 1.0 and 2.6 under the three working conditions. The desulfurization efficiency has no noticeable change when it is between 2.6 and 2.8, and begins to decline when it is greater than 2.8. The optimal calciumsulfur ratio is obtained when the calciumsulfur ratio is 2.6, and the SO2 concentration at the outlet of the furnace is reduced to 0.0001 mg/m3. By controlling the highest temperature in the furnace and adjusting the amount of denitrification agent, the nitrogen oxide emission at the outlet of the furnace is reduced to 0.87 mg/m3.