Directing against the difficult problem for putting the correction of secondary air flow rate and oxygen content in flue gas of boilers equipped with 2×330 MW units into automitic control mode

the optimization of combustion control system for said boilers has been carried out;the pressure control of secondary air at oullet of the air preheater being changed from fixed value control to slide pressure control along with load variation of the units;the correction of open dagree for secondary air damper in the oxygen-correcting circuit has been changed to correct the secondary air pressure;the secondary air damper at each level is controlled by open-loop according to coal feed commands of corresponding coal pulverizer.After optimization

the economic efficiency of boilers has been substantially enhanced

the temperature of discharged flue gas being decreased by 4.03 ℃

the coal consumption of units being lowered by 0.19 g/(kW·h)

the power consumption of primary air fan being decreased 0.30%

the power consumption of forced draft fan being lowered 0.03%

the power consumption of induced draft fan being decreased 0.10%

the auxiliary power comsumption in whole plant being lowered by 0.43%.