| 摘要 |
<p>PURPOSE:To prevent scaling by controlling the flow rate or pH of a desulfurizing soln. to a desulfurization tower to regulate the pH of the waste soln. flowing out from a cooling tower to an approximately constant value and controlling the flow rate or pH of the desulfurizing soln. to the cooling tower when the pH exceeds the set value. CONSTITUTION:The waste gas is sent into a cooling tower 2 through a duct 5 and cooled by a cooling liq. injected from a nozzle 6. An acidic gas is simultaneously removed and the gas is sent to a desulfurization tower 3. The pH of a desulfurizing soln. to be supplied to the nozzle 8 of the desulfurization tower 3 is controlled by regulating the opening degree of a valve 15 to make the pH of the desulfurizing soln. measured at the outflow line 20 of the cooling tower 2 almost constant. When the acidity of the waste gas is increased, the pH of the desulfurizing soln. is increased. When the pH exceeds a set value, the opening degree of a valve 54 of a line 19 is regulated to keep the pH of the waste soln. almost constant until the pH of the desulfurizing soln. to the desulfurization tower 3 is fixed. The scaling, gaseous CO2 absorption, acidic gas stripping, etc., due to an increase in the pH can be prevented in this way.</p> |
