Experimental study on water recovery and SO2 permeability of ceramic membranes with different pore sizes

In this study, the water recovery performance from flue gas with ceramic membrane tubes of different pore sizes 30, 50, and 200 nm was experimentally studied. The effects of flue gas temperature, flue gas flow rate, water coolant temperature, and water coolant flow rate on the water recovery performance were analyzed. In addition, in the experimental study of SO₂ permeability, the pH of the water coolant inlet and outlet was measured using a pH meter to analyze the SO₂ permeability of ceramic membranes during the water recovery process. The results show that the water recovery performance of the 50 nm pore size ceramic membrane is better than that of the other two types of ceramic membrane in most cases. The maximum amount of reclaimed water and the highest water recovery rate are 4.82 kg/(m²·h) and 80.3%, respectively. Under the same SO₂ concentration condition, the SO₂ permeation flux of the 30 nm pore size ceramic membrane is smallest, and that of the 200 nm membrane is the largest. When the SO₂/N₂ mixed gas flow rate is 6 L/min, the SO₂ permeation flux of the 30 and 200 nm membranes is 0.407 and 0.635 mmol/(m²·h), respectively. The ceramic membrane with smaller pore size can block more SO₂ permeation, while the ceramic membrane with larger pore size can remove SO₂ better.