A process for the simultaneous removal of nitrogen oxides and sulphur oxides from a gas stream.

摘要

Nitrogen oxides and sulphur oxides are simultaneously removed from a gas stream containing also free oxygen in addition to said oxides by using a metal-containing acceptor for accepting sulphur oxides as metal sulphate and by adding ammonia or an ammonia precursor to the gas stream for the reduction of the nitrogen oxides to nitrogen. The metal sulphate-loaded acceptor is regularly regenerated by means of a reducing gas containing a small quantity of hydrogen sulphide. Before re-use the regenerated acceptor is subjected to a separate oxidative treatment with a free oxygen-containing gas other than the gas stream to be treated, which free oxygen-containing gas is introduced co-currently in relation to the reducing gas. In a preferred embodiment the hydrogen sulphide-containing reducing gas and the free oxygen-containing oxidation gas are supplied co-currently in relation to the gas stream to be treated.