Enhancing performance of ceramic membranes for recovering water and heat from flue gas

Abstract

Transport membrane condenser can efficiently recover water and heat from wet flue gas. Ceramic membrane is the heat and mass transfer medium in the process. However, the relationship between membrane property and the recovery performance is only partially reported based on current research state. This work focuses on the effects of permeability, material, and ceramic particle size of membrane on the water and heat recovery. Membranes were prepared from three different sizes of coal fly ash and an alumina powder. Water and heat recovery performances of the membranes are experimentally compared. Results indicate that increasing membrane permeability improves water and heat recovery because the resistance of heat and mass transfer is reduced. The alumina membrane performs 3–10% more water recovery than the coal fly ash-based membrane while thermal conductivity of the alumina membrane was 11.5 times that of the coal fly ash-based membrane. Increasing ceramic particle size shows two opposite effects on the water and heat recovery, promotion because of the permeability rising, and undermine because of the thermal conductivity reduction. Low-cost membranes with high permeability and high thermal conductivity are recommended in transport membrane condenser application.