APPARATUS FOR CONTROLLING CONCENTRATION OF SO2 AT OUTLET OF WET WASTE GAS DESULFURIZATION EQUIPMENT

摘要

PURPOSE:To keep the concn. of outlet SO2 constant regardless of the load of a boiler, by detecting the concn. and pH value of outlet SO2 and changing pH of a recirculation liquid corresponding to the detected values and, at the same, time controlling the flow amount of an absorbent. CONSTITUTION:The concn. of outlet SO2 is detected by the outlet SO2 concn. detector 15 arranged to an exhaust duct 9 after SOx-removal and the output signal thereof is inputted to a SO2 concn. regulator 16 to be compared with a preset outlet SO2 concn. value and feedback control is performed. The output signal of the SO2 concn. regulator 16 is inputted to an upper and lower value limiter 17. Further, pH of a recirculation liquid is detected by a pH detector 14 and the detection signal is inputted to a pH regulator 10 and compared with the set value from the upper and lower value limiter 17 to perform feedback control and, by the output signal from said detector 14, the opening degree of a flow control valve 11 is controlled.