1 Department of Chemistry, Technical University of Denmark2 Centre for Catalysis and Sustainable Chemistry, Department of Chemistry, Technical University of Denmark
The present invention concerns the selective removal of nitrogen oxides (NOx) from gases. In particular, the invention concerns a process, a highly alkali metal resistant heteropoly acid promoted catalyst and the use of said catalyst for removal of NOx from exhaust or flue gases, said gases comprising alkali or earth alkali metals. Such gases comprise for example flue gases arising from the burning of biomass, combined biomass and fossil fuel, and from waste incineration units. The process comprises the selective catalytic reduction (SCR) of NOx, such as nitrogen dioxide (NO2) and nitrogen oxide (NO) with ammonia (NH3) or a nitrogen containing compound selected from ammonium salts, urea or a urea derivative or a solution thereof as reductant.