Optimum design of a deep cooling tower for waste heat and water recovery from humid flue gas

Abstract

In order to efficiently recover the waste heat and gaseous water from humid flue gas, a deep cooling tower was designed to explore the heat and mass transfer performance, we optimized the design of tower equipment and absorption heat pump system. The running resistance of total tower is less than 240 Pa, the structured packing can reach the maximum heat transfer power under liquid to gas ratio of 3.5 L/Nm3, 3.0 L/Nm3 and 2.5 L/Nm3, respectively. Under gas velocity of 2.5 m/s, the heat transfer capacity is 54.1–149.2 W m−2 K−1, mass transfer capacity is 0.72–2.02 g m−2 s−1. The coefficient of performance of absorption heat pump can reach 1.71, for a 140 MW boiler, the energy recovery capacity can reach 24 MW and the water recovery capacity can reach 34 m3/h, the emission reductions of CO2, dust, SO2 and NOx can reach 7324 kg/h, 1992 kg/h, 219 kg/h and 109 kg/h, respectively.