The running resistance in gas-gas heat(GGH)exchanger of desulfurization system of the No.1unit in Beijing Thermal Power Plant was too high.Several factors were considered as the main reasons

such as the excess gas flow in desulfurization system(compared with the design value)

unreasonable strip shape selection for heat exchange component in GGH

increasing viscosity of ash in flue gas

and relatively low pressure at inlet and outlet of the desulfurization booster fan.Thus

transformation of heat exchange component in GGH was conducted.The DNF thin steel corrugated plate was changed into L type large channel corrugated plate.For the improved unit

the net gas temperature can reach the design value(80℃)

and the running resistance of the GGH and the booster fan current were both kept at a relatively low level

under various loads conditions.When the boiler ran with full load

under the condition that the net gas outlet temperature was 89℃and the resistance at one side of the GGH was 270Pa(design value 500Pa)

the running resistance in GGH decreased by 1.23kPa(at one side);the booster fan current dropped by 61A;and the electricity consumption decreased by 550(kW.h)/ h.The daily saved electricity reached up to 13 200kW.h.