Experimental study on performance of a direct contact flue gas condensing waste heat recovery device

Proposes a direct contact flue gas condensing waste heat recovery device, which carries out countercurrent heat transfer between low-temperature spray aqueous solution and high-temperature flue gas to recover condensing waste heat from the flue gas of gas-fired boiler. Sets up an experimental bench using a wall-mounted gas-fired boiler as a flue gas source. Studies the influences of spray water temperature, liquid-gas ratio and spray height on the waste heat recovery performance of the device. The results show that when the spray water temperature is 20 ℃, the liquid-gas ratio is 13, and the spray height is 1.26 m, the device can decrease the smoke exhaust temperature from 102 ℃ to 33 ℃, with the waste heat recovery efficiency up to 14%.