The SCR process works by injecting ammonia vapour into the flue gas which is then passed over a catalyst bed where the ammonia reacts with the NOx and oxygen to form benign nitrogen and water. Of all of the post combustion NOx reduction technologies SCR is the most effective and is capable of achieving NOx emission reductions of greater than 90 percent with an ammonia slip of less than 2 ppm.

Doosan Babcock offers the complete engineering and supply of new or retrofit SCR systems. Since we are not a catalyst manufacturer nor bound to a particular catalyst type, we select the best and most appropriate system for each individual situation. Similarly Doosan Babcock has the capability to offer all types of ammonia feedstock systems to provide the preferred reagent, including anhydrous ammonia, aqueous ammonia or from urea.

As a boiler OEM and complete air quality control system provider, Doosan Babcock has hands on experience of the importance of integrating the SCR into the design of the boiler and AQCS equipment. In this way we can accommodate important aspects of performance such as increased pressure loss and affect on ID fans, mercury emissions, SO2 to SO3 conversion rates and minimising the potentially negative impact on plant items from factors such as ammonium bisulphate formation.