LEVEL CONTROLLING PROCESS OF ABSORPTION TOWER IN STACK GAS DESULFURIZATION APPARATUS FOR WET SLAKING GYPSUM PRODUCTION

PURPOSE:To control the level of an absorption tower at a fixed level by inputting the sensed signals for the flow rate in the feed pipe of a liquid or slurry to an absorption tower into a function generator and operating a control valve in a pipeline for discharging the liquid or slurry from the absorption tower by the output signal from the function generator and the output signal from a level controller. CONSTITUTION:The flow rates in a make-up water supply pipe 2 and in a slurry feed pipe 7, to an absorption tower 3 are sensed by flow meters 11, 12, and the values are added and fed to an amplifier or a function generator 14. The level of the washing liq. in the absorption tower 3 is sensed and fed to a level sensing controller 9, and the sensed signal and the output signal from the amplifier or the function generator 14 are added in the second adder 15. A control valve 10 provided in the discharging pipeline for the washing liq. from the absorption tower 3 is operated by the output signal of the adder 15. By this constitution, suitable amt. of the liquid corresponding to the flow rate of the supplied liquid is withdrawn through the pipeline 8 even if the flow rate of the supplied liquid is suddenly changed by the sudden change of the boiler load, and the level of the absorption tower is held almost at a fixed level.