PURPOSE: To prevent the excessive supply of limestone while a stable desulfurization ratio is held at the time of the rapid rising in the load of a boiler, by together using the bubbling by air and the rapid charging of a limestone slurry to the liquid sump part of an absorbing tower corresponding to the increase in the load quantity of a boiler.
CONSTITUTION: The amount and SO2-concn. of combustion exhaust gas 2 and the pH value of the slurry in the liquid sump part within the recirculation tank 3 of an absorbing tower are detected by detectors 14, 15, 19 to be inputted to an operator 18. When the information of a boiler load ratio is detected from the amount of combustion gas and the rising signal of the change in the load of the boiler is detected, a signal 21 is outputted from the operator 18 to open an air amount control valve 22 and air is supplied to a flow passage 24 by a pump 23 and the slurry in the tank 3 is bubbled to perform decarbonization. The operator 18 calculates the reguired supply amount of limestone from the change ratio of the amount and change ratio of SO2-concn. of combustion exhaust gas and the pH value of the recirculation solution in the tank 3 and a limestone slurry supply amount control valve 12 is controlled on the basis of the calculated value to supply a predetermined amount of the limestone slurry to the tank 3.
ARASHI NORIO
KAJI RYUICHI
| JPS59156417A | 1984-09-05 |