Based on the MATLAB/Simulink platform

a numerical simulation of SO_2 and NO_x generated in circulating fluidized bed(CFB) furnace was carried out by establishing a mathematical model of desulfurization and denitrification and a mathematical model of flow

heat transfer and combustion of a 350 MW CFB boiler. The change of pollutants concentration in the furnace during the load-changing process is given. Moreover

the influences of parameters such as calcium-sulfur molar ratio

primary and secondary air ratio and upper and lower secondary air ratio on the original SO_2 and NO_x emission concentrations in the furnace are analyzed. The results show that

increasing the molar ratio of calcium to sulfur can quickly reduce SO_2 emissions. After the load is reduced

the SO_2 emission mass concentration can be reduced to the concentration level before the load is reduced when the molar ratio of calcium to sulfur increases from 2.0 to 2.2. Lowering the primary and secondary air ratio can effectively reduce the SO_2 and NO_x emissions. After the load is increased

the NO_x emission mass concentration is lowered to a level lower than that before the load is increased when the primary air volume ratio is reduced from 48% to 42%. After the load is reduced

the SO_2 emission mass concentration can be reduced to the level before the load is reduced when the primary air volume ratio is reduced from 48% to 45%. Increasing the upper and lower secondary air ratios can also reduce NO_x emissions

but it will lead to an increase in SO_2 emission mass concentration. Therefore

it is necessary to increase the ratio of calcium to sulfur to control SO_2 emissions while increasing the upper and lower secondary air ratios to regulate NO_x emissions.