Experimental Study on Limestone-Gypsum Wet Desulphurization with Simulated Flue Gas under Oxygen-Enriched Combustion

To study the efficiency of limestone-gypsum wet flue gas desulfurization under oxygen-enriched combustion, the desulfurization test is conducted on the self-established experiment rig. Through controlling the CO₂ concentration(the volume fractions as 14%, 60%, 70%, 80% and 90%) in the desulfurization system, the impacts of different flue gas velocity, liquid gas ratio, inlet SO₂ concentration, and slurry pH value on the SO₂ absorption characteristics under the oxygen-enriched combustion atmosphere are studied. It is discovered that with the increase of flue gas velocity and inlet SO₂ concentration, and the decrease of gas liquid ratio and slurry pH value, the desulfurization efficiency drops; the higher CO₂ concentration in the system, the lower desulfurization efficiency is observed. Meanwhile, under different CO₂ concentration atmosphere and slurry pH value, the gypsum crystal grain size is studied by using the laser particle analyzer and the gypsum is scanned by using the SEM electron microscope, from which it shows that the slurry pH value and the CO₂ concentration do not have obvious impacts on the crystallization of gypsum.