DUST REMOVING METHOD FOR PRESSURIZED FLUIDIZED BED BOILER

摘要

PROBLEM TO BE SOLVED: To provide a dust removing method for a pressurized fluidized bed boiler achieving an appropriate fly ash composition in high-temperature exhaust gas in accordance with a difference of types of burned coal, change in the combustion state and change in particle size distribution of ash dust etc. and preventing wear of piping and a cyclone due to ash dust.

SOLUTION: In the dust removing method for the pressurized fluidized bed boiler to supply high-temperature exhaust gas discharged from the pressurized fluidized bed boiler to the cyclone to remove ash dust in the exhaust gas, the fly ash composition in the exhaust gas entering to the cyclone is measured, and the supply amount of coal as fuel to be supplied to the pressurized fluidized bed boiler or the addition amount of coal particles as a desulfurizing agent is adjusted so that based on the measurement value, the fly ash composition in the exhaust gas satisfies the following formulas: (1) SiO2(chemical analysis value)≤40 wt.%; (2) SiO2-1.3 Al2O3(chemical analysis value)≤15 wt.%; and (3) (SiO2-1.3 Al2O3)-CaO-CaCO3-CaSO4-Fe2O3(chemical analysis value)≤-20 wt.%.

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