| 摘要 |
<p>PROBLEM TO BE SOLVED: To efficiently perform oxidation of calcium sulfite by using an ORP detector equipped with a plurality of comparison liquid tanks and performing measurement while successively changing over the comprison liquid tanks in a flue gas desulfurization method in which oxygen is passed into absorption liquid containing calcium sulfite to oxidize it and gypsum is produced. SOLUTION: In a flue gas desulfurization process in which exhaust gas containing sulfur oxide is treated by absorption liquid containing a calcium compound, an ORP(oxidation-reduction potential) measurement tank 30 is partitioned into A-C tanks 31-33 in the case of detection of ORP in absorption liquid. In the A, B tanks 31, 32, a valve 39 is opened to pass air 34 into the B tank 32 and ORP of absorption liquid is measured by ORP electrodes 35, 36. After definite time elapses, a valve 40 is opened to start ventilation of air 36 into the C tank 33. At a point of time when ORPs of the C, B tanks 33, 32 are made equal, the valve 39 is closed and the deviation of ORPs detected by ORP electrodes 35, 37 is outputted as a deviation signal 42. Flow rate of air 34 is controlled and stable oxidation control is maintained.</p> |
