Handling of acids from compressed oxyfuel-derived CO2

摘要

Sulfur dioxide (SO2) is removed from a carbon dioxide feed gas by maintaining the feed gas at elevated pressure(s) in the presence of oxygen (O2), water and NOx for a period of time sufficient to convert SO2 to sulfuric acid and NOx to nitric acid and produce SO2-depleted, NOx-lean carbon dioxide gas. The invention resides in separating the sulfuric and nitric acids from said SO2-depleted, NOx-lean carbon dioxide gas, and then neutralizing the acids by reaction with an alkaline sorbent in an acid/sorbent reactor system to produce sorbent-derive sulfate. The method has particular application in the removal of SO2 and NOx from flue gas produced by oxyfuel combustion of a carbonaceous fuel.