| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a cooler and cooling method for exhaust gas in which removing rate of noxious substances, especially dioxins, is enhanced by controlling the cooling temperature of exhaust gas from a waste incinerator. SOLUTION: High temperature exhaust gas G1 (e.g. about 900 deg.C) from an incinerator 1 is cooled by a gas cooler 2 and introduced to a bug filter 3. During the process, signals V1 , V2 indicative, respectively, of the moisture and the concentration of sulfur oxide or hydrogen chloride in exhaust gas G2 detected by a moisture gauge 8 or a densitometer 9 in a detector 7 are delivered to the operating unit 11 in a controller 10 in order to determine a specified cooling temperature. A signal V3 indicative of the cooling temperature is compared by a comparator 12 with the temperature signal V4 of the exhaust gas G2 detected by a thermometer 13. When it deviates from a specified temperature range, a control signal generator 14 generates a control signal V6 from a deviation signal V5 and delivers it to a control valve 5 in order to regulate spray of cooling water W thus cooling the exhaust gas G2 at a relatively low temperature slightly higher than the dew point. Since no dew is formed even it the dew point is varied due to the properties of the exhaust gas G2 , removing rate of noxious substances is enhanced.</p> |
