PURPOSE: To treat the waste liquid from a wet type stack gas treatment device without producing HCl by immobilizing the HCl carried from waste gases as calcium chloride in the final, and immobilizing dithionate compounds as calcium sulfate.
CONSTITUTION: The waste gas contg. HCl and SO2 discharged from a coal firing boiler 1 evaporates and dries the waste liquid 4 sprayed in a spray dryer 3, and flows together with solids of calcium chloride and solids of calcium sulfate into an air heater 5, and further it flows via a dry type dust collector 6 into an absorption tower 8, whereby gypsum 13 and filtrate 14 are obtained. Then, part of the filtrate 14 is fed into an adsorbent tank 16, and the balance is fed into a neutralizing tank 17, where it is added with Ca(OH)2 18, after which the slurry is fed to a classifier 19. The overflowed waste liquid 4 wherein calcium chloride and calcium dithionate are dissolved is fed to the dryer 3, where it is spray dried, whereby it is immobilized as calcium chloride and calcium sulfate.
TATANI ATSUSHI
IIDA KOUZOU
UGAWA NAOHIKO
OKINO SUSUMU
