CO2 quality control through scrubbing in oxy-fuel combustion: An evaluation of operational pH impacts, and prediction of SO2 absorption rate at steady state

摘要: Abstract Oxy-fuel combustion is a promising CCS technology which being demonstrated prior to commercialisation. While the flue gas in oxy-fuel concentrated CO 2 , it contains impurities such as SO . The elimination of can provide clean stream ready for storage. This paper understand absorption scrubbing relevant those used technology. Steady state experiments were conducted continuous well stirred reactor rate /CO into total concentration 0.28 M mixtures NaHSO 3 and NaHCO simulating liquids formed by scrubbers using NaOH reagent at solution pH values from 4 7 with exiting concentrations 19 ppm 1500 ppm constant 70%. Online measurement included phase liquid pH, offline (aq), HCO − S (IV), 2− (VI) after each experiment. Three aspects investigated impacts on chemistry, significance sulphur was found be related effectiveness Na + effective ratio defined this dependent. At pH  99% effective. It reduces dramatically 5 less than 15% above 7. With regard carbon based species also absorbed, super saturation (aq) observed pH > 5.5. increases 6 below negligible. increase some operational window may an upper limit where starts decreases maximum lower half Both decrease initially stay stable caused reversible reaction hydrolysis confirmed equilibrium sodium solutions. Operation within region (pH 5–6) recommended, depending scrubber design. operation exit produced varied region. rates obtained steady predicted model instantaneous assumption. generally overestimates indicating kinetic limitation water low values. analysis controlling regions indicates that side mass transfer resistance Liquid becomes more important higher