The design characteristics

operation situation and optimization scheme of the desulfurization system are introduced. Taking the wet flue gas desulfurization(WFGD) system of a 700 MW coal-fired unit as an example

the main factors affecting the station auxiliary power rate

including the power consumption equipment

sulfur content in the coal

desulfurization efficiency

desulfurization system operation mode

limestone quality

and so on

are analyzed. The specific measures to reduce the station auxiliary power rate of desulfurization system are determined

namely

adjusting the coal distribution mode of two boilers

determining the desulfurization efficiency and optimal operation combination of circulating slurry pump at different loads

adjusting the number of circulating slurry pump in a single boiler desulfurization system from 3～5 to 2

and clearing the slurry nozzle and branch nozzle of absorption tower

reducing the pressure at the circulating slurry pump outlet. After these measures were implimented

the liquid/gas ratio of the desulfurization system was effectively improved

the sulfur capacity of the absorption tower increased from 0.87% to 1.24% at full load

and the station auxiliary power rate of the WFGD system reduced from 1.038% to 0.733%. The operation economy of the WFGD system was improved.