METHOD FOR SENSING AMOUNT OF RESIDUAL DUST, COMBUSTION CONTROLLING METHOD AND DUST INCINERATOR

PROBLEM TO BE SOLVED: To perform an appropriate evaluation of an amount of unburnt dust in a dust incinerator in which a hearth is provided with a stoker mechanism, dust is supplied by a pushing-type dust supplying means onto the hearth and then the dust supplied onto the hearth is ignited while the dust is being fed by the stoker mechanism and further to enable a combustion control for completing combustion on the hearth in a combustion region to be positively carried out. SOLUTION: The number of times of pushing-in operation of a dust supplying means 4 and a steam generated amount of a waste heat boiler 7 are detected, an amount of supplied dust is calculated in reference to both a predetermined amount of pushed-in dust in one operation of a dust supplying means 4 and the number of times of pushing-in operation. An amount of burnt dust is calculated in reference to a means combustion heat generating amount of dust, a boiler efficiency of the waste heat boiler 7, and amount of generated steam, a steam enthalpy and a water supplying ethalpy at the waste heat boiler 7. An amount of unburnt dust in the supplied amount of dust is calculated and in the case that the amount of unburnt dust exceeds a predetermined range, an operation of the dust supplying means 4 is restricted and in turn in the case that the amount of unburnt dust is lower than a predetermined range, an operation of the dust supplying mean within a predetermined time is promoted.