Flue Gas Desulfurization With CO₂Kept Via Absorption By Sodium Acetate

With the attention on the problem of shortage of resources and greenhouse effect, research on carbon dioxide (CO2) resource applications became more and more deeper. Since most of these CO2come from flue gas of thermal power plants, steel mills, lime kilns and other emissions, it’s necessary to remove SO2from flue gas before CO2capture. On the one hand, it can avoid to reduce the purity of the CO2and utilization of absorptive solution. On the other hand, the desulfurization agents should be used without loss of CO2in the desulfurization process, in order to avoid decrease of CO2trapping agent efficiency, and captured CO2amount, which will reduce value of CO2. Therefore, its necessary to explore a desulfurization agent, which can remove SO2from flue gas without loss of CO2in the desulfurization.Selective desulfurization from flue gases was investigated by absorption method using sodium acetate. The absorbent was regenerated by calcium carbonate with gypsum as by-product. Compared to sodium citrate, desulfurization by sodium acetate will significantly reduce the cost and side reactions. This study was divided into three steps:absorption, oxidation, and regeneration. Effects of different factors on desulfurization efficiency, oxidation rate, and regeneration were investigated under static condition. What’s more, dynamic test equipment was built to test feasibility of the technology.Results indicated that the absorption ability of the absorbent(0.08mol·L-1)was inversely propotional to the temperature. The best conditions for oxidation are as follows:catalyst of manganese sulfate0.03mol·L-1, rotational speed400r·min-1, airflow rate150mL·min-1, pH=4.0and temperature90℃. For the regeneration process, around0.7g calcium carbonate should be added to the absorbent and reacted at90℃. After5times’regeneartion, the breakthrough time of the regenerated absorbent was almost the same as fresh one; while the saturated absorption capacity decreased a bit. The technology was feasible via tested by the dynamic test.