GEA - Leader in DeNOx
Selective catalytic reduction (SCR) is a means of converting nitrogen oxides, also referred to as nitrogen oxides (NOx). When burning coal, petroleum products, natural gas as well as domestic and hazardous waste for industrial production pollutions are created, that are emitted with off gas. Thus, significant amounts of NOx, one of the main pollutants, forms despite optimized combustion. Through the reaction of nitrogen oxides with other atmospheric constituents, ozone is created and leads to the so-called summer smog. Other reaction products such as nitric acid, reach the water and soil with the precipitation in the form of acid rain. The resulting nitrate accumulation has a negative impact on human, plants and animals. For these reasons almost all industrialized countries have adopted laws to strict nitrogen oxide emissions. GEA is a leader in DeNOx plants worldwide and develops and manufactures highly-efficient denitrification systems, individually tailored for different customer needs. Aqueous ammonia solution or urea is injected into the ductwork upstream of the SCR and evaporates immediately. Two-fluid nozzles (ammonia and compressed air) are used for the injection of the ammonia solution. A system of static mixers installed in the ductwork downstream of the ammonia injection points ensure adequate mixing of ammonia. The gas and ammonia mixture enters the unit from the top and exits horizontally at the bottom. A gas distribution system (swirl breaker) ensures adequate gas distribution over the entire cross-section of the unit. The reaction between ammonia and NOX is enhanced by the presence of the catalyst bed located at the bottom of the unit.