Condensation heat transfer characteristics of flue gas moisture recovery using ceramic membranes

Abstract

The use of a ceramic membrane condenser (TMC) can help recover moisture from flue gas, resulting in a reduction in white smoke, smog, and resource conservation. Although several studies have investigated TMC heat and mass transfer and water vapor condensation mechanisms, few have analyzed the effect of membrane area on thermal mass performance. This paper presents a comparative study of ceramic membranes with different pore sizes to address this gap. In this study, the influence of the condensation mechanism along the flow direction on the heat transfer is innovatively analyzed by combining the mass transfer characteristics. The results show that capillary condensation is more pronounced in high-temperature flue gas, which improves heat transfer efficiency and results in a higher wall temperature rise at the flue gas outlet. The capillary condensation mechanism can also increase the condensation depth, facilitating the removal of water vapor. In particular, in the treatment of 10000 m3/h flue gas, the maximum water recovery rate of the 0.4 nm pore size ceramic membrane is 26.6 kg/(m2·h), which is 27.9% higher than that of the 1 μm pore size ceramic membrane. However, it is important to note that nanomembranes cost 4.62 times more than micro membranes under the same flue gas conditions.