Waste heat recovery device and waste heat recovery method

摘要

PROBLEM TO BE SOLVED: To provide a waste heat recovery apparatus capable of managing temperature of preheated combustion air while suppressing a decrease in an energy efficiency.SOLUTION: An apparatus for recovering a waste heat from a heating furnace for heating a steel material is provided that comprises: a heat exchanger for preheating a combustion air supplied to the heating furnace; a waste heat recovery boiler for recovering a sensible heat of a waste gas discharged from the heating furnace; a first waste gas flow path that connects the heating furnace and heat exchanger together; a second waste gas flow path that connects the heat exchanger and the waste heat recovery boiler together; a bypass flow path that bypasses the heat exchanger and connects the heating furnace and the waste heat recovery boiler together; a thermometer for measuring a temperature of the combustion air after passing through the heat exchanger; and a mechanism for adjusting a flow rate of the waste gas that is flowed to the bypass path such that a temperature measured by the thermometer is equal to or lower than a predetermined temperature. It is preferred that the apparatus for recovering a waste heat from a heating furnace further comprises a mechanism for adjusting a flow rate of the waste gas which is flowed to the first waste gas flow path based on measurement result of the thermometer.SELECTED DRAWING: Figure 1