Performance investigation of a counterflow packing tower for flue gas waste heat recovery

Abstract Direct emission of flue gas waste heat into the environment causes a great waste of energy. In order to recover the waste heat of the flue gas efficiently, a counterflow packing tower for flue gas waste heat recovery is presented. In this paper, the mathematical model of the counterflow packing tower is established and experiments were conducted for model validation. A Genetic Algorithm based approach was proposed to obtain the correlation equations of the heat and mass transfer coefficient between the flue gas and cooling water. The performance of the counterflow packing tower under different operational conditions is studied with the mathematical model. Results indicate that: (1) For different packing heights, the relative position of the maximum diffusion flux remains unchanged, which is 0.2 in this study. (2) The effectiveness of CFPT of the counterflow packing tower is positively correlated with the flue gas inlet temperature, the flue gas inlet humidity ratio, the cooling water mass flow rate and the packing height. When the flue gas inlet temperature is 75–95 °C, the cooling water inlet temperature is 20–26 °C, the effectiveness of CFPT is about 50–67%.