Method for simultaneous absorption of sulfur dioxide and nitric oxide from flue gas

摘要

The simultaneous abatement of NO and SO.sub.2 in flue gas is provided by an absorption process and apparatus utilizing an absorbent composition comprising an aqueous solution of chelates and sulfite salt for NO abatement and amine SO.sub.2 absorbents such as piperazinones, morpholinones, piperidines, piperazines, piperazinediones, hydantoins, triazinones, pyrimidinones, oxazolidones, etc. for SO.sub.2 abatement. SO. sub.2 is thermally stripped from the spent absorbent and recovered. Metal chelates oxidized to an inactive state as a side-reaction are electrochemically reduced. An anionic exchange membrane in the electrochemical cell regenerates heat stable amine salt byproducts to be converted back to useable amine sorbent, and facilitates removal from the absorbent solution of other waste salts.