CO2 quality control by scrubbing in oxy-fuel combustion prior to compression: Relating pH to the liquid composition from absorption of SO2 into sodium based solutions to identify an operational pH window

摘要: Abstract Oxy-fuel combustion is an emerging technology to mitigate CO2 emissions from power plants. Compared with other capture technologies, gas impurities in oxy-fuel flue are highly concentrated, among which SO2 of concern. Sodium based quench units have been used oxyfuel projects directly cool the prior compression and also remove SO2. However, high concentration can interfere Dynamic transient experiments were therefore conducted a semi-batch well stirred reactor (WSR) study mechanisms absorption mixtures both SO2/N2 SO2/CO2 into sodium aqueous solutions, measurements rate decreasing liquid pH during experiments. The liquids analysed by ion chromatography (IC) acid titration equilibrium calculations estimate sulfur carbon species formed liquid. dynamic results for show three regions behaviour as reduced experiments, namely, region 1 constant at values above 8.32 (this being 9.65 experiments); 2 where 4.22 (from 4.82 SO2/N2); 3 rapidly pH, below (4.82 SO2/N2). From analyses thermodynamic it concluded that associated consumption OH− give SO32−, HCO3−/SO32− formation HSO3−, H2O accumulation HSO3− operational recommended be 2, low loss expected. An window thereby defined terms upper lower limits. found related solutions when inlet proximately 3000 ppm, narrows concentrations solutions. secondarily