METHOD FOR OPERATING HEAT EXCHANGER FOR WASTE HEAT RECOVERY OF EXHAUST GAS TREATMENT FACILITY

摘要

PROBLEM TO BE SOLVED: To prolong the service life of a heat exchanger by reducing its corrosion by high-temperature exhaust gas and to reduce the operating cost of the exchanger by making its maintenance easier. SOLUTION: In an exhaust gas treatment facility which is provided with the heat exchanger 5 on the route 2 of exhaust gas and preheats the air flowing through the exchanger 5 with the waste heat of the exhaust gas, an exhaust gas temperature regulating means 6 is provided in the preceding stage of the exchanger 5 and the temperature of the exhaust gas is regulated by means of the regulating means 6 so that the temperature of the exhaust gas at the inlet of the exchanger 5 may always become equal to or lower than the high temperature corrosion temperature of the heat transfer element of the exchanger 5. In addition, the flow rate of the air flowing through the exchanger 5 is regulated by means of the regulating means 6 so that the temperature of the exhaust gas at the outlet of the exchanger 5 may always become equal to or lower than the low temperature corrosion temperature of the heat transfer element.