| 摘要 |
<p>PURPOSE:To perform efficient denitration by outputting a pH correction signal for minimizing total utility cost and controlling recirculation quantity and absorbent supply quantity according to the absorbing tower recirculation flow rate and absorbent slurry demand determined on the basis of said signal. CONSTITUTION:An absorbing tower recirculation flow rate demand signal 12 is calculated from the respective output signals, which are obtained from a desulfurization rate object setting device 1, an inlet SO2 densitometer 3 and an exhaust gas flowmeter 4, and an optimum pH value signal 16 while an absorbent slurry flow rate demmand signal 13 is operated from the respective output signals, which are obtained from an absorbent slurry flowmeter 18, the exhaust gas flowmeter 4, the inlet SO2 densitometer 3 and a drain flowmeter 5, and a desulfurization rate signal 32 and the output signal of a pH meter 33 and, from the signals 12, 13, a utility cost signal 14 is calculated through a pump power cost operator 8 and an absorbent cost operator 9 and a pH correction signal 15 is issued so as to minimize said signal 14. By this method, an absorbing tower recirculation pump 21, an absorbent slurry flow rate control valve 22 and control valves 20a, 20b are controlled by the signals 12, 13 based on the optimum pH value signal 16.</p> |
