WASTE GAS REPEATER FOR FLUE GAS TREATMENT EQUIPMENT

摘要

PROBLEM TO BE SOLVED: To reduce the use amt. of a heat medium to be circulated and to reduce the size of the device by disposing a heat medium heater for heating a heat medium when the temp. of the waste gases delivered from a reheater for reheating the waste gases from a flue gas dessulfurizer by the heat medium is lower than a prescribed temp. in the mid-way part of the heat transfer tube group in this reheater. SOLUTION: While the untreated waste gases 2 from a boiler are passed downward in a heat recovering device 3, the heating of the heat medium 5 flowing upward in the heat transfer tube group 6 is executed. The waste gases 2 lowered in the temp. are subjected to a desulfurization treatment with the flue gas dessulfurizer 1 and are then introduced into the reheater 4. In such a case, the circular part in the upper part of the heat transfer tube group 7 of the reheater 4 are cut and a horizontal header-like heat medium-vapor mixing pipe 17 is connected as a heat medium heater 16 to this cut part. Plural vapor injecting pipes 19 are connected at required intervals longitudinally to this heat medium-vapor mixing pipe 17. The flow rate control valves 25 in vapor pipes 20 connected thereto via a header 30 are so controlled as to be opened when the detected temp. of a waste gas duct 22 is lower than a reference temp.