Power plants as well as many industrial sites, such as cement, waste incinerators, glass manufacturing plants or refineries must increasingly be equipped with a NOx reduction system. This system is usually either SNCR (non-catalytic process) or SCR (catalytic method) in which either an ammonia or urea reagent is injected.
In Europe new legislation in the context of the IPPC Directive, reviewed under the name of the Industrial Emissions Directive impose on industrial sites, new values to achieve in the reduction of emission of gases. These texts relate in particular to the emissions of nitrogen oxides. Beyond this European Directive, additional restrictions have to be followed at a national and local level.