Oxides of nitrogen can cause severe atmospheric, environmental and health problems. KC Cottrell ensures that all facilities producing NOx can meet all their legal obligations and thus prevent such problems by using our robust and effective De-NOx systems.

SCR process is using reductant to take place selective chemical reaction with nitrogen oxide (mainly NO, NO2) under the effect of catalyst and then generate nitrogen and water.

SCR reactor is installed between boiler economizer and air pre-heater. The reaction temperature range is 320℃-420℃.

The reductant of SCR process can be liquid ammonia, urea and ammonia.

SCR process chemical reaction equation is as below
4NH3＋4NO＋O2＝4N2＋6H2O
4NH3＋2NO2＋O2＝3N2＋6H2O
2CO(NH2)2＋4NO＋O2=4N2＋4H2O＋2CO2
2CO(NH2)2＋2NO2＋O2=3N2＋4H2O＋2CO2

The reductant is core in the SCR process. Design and selection of catalyst is determined by gas condition and composition. The major elements which will affect design are NOx removal rate, NH3 escape rate and volume of catalyst. At present, main types of catalyst are plate type, honeycomb type, corrugated type.

SCR flue gas De-NOx process is the most mature and reliable technology. The max De-N0x efficiency is over 90%.The SCR process guarantees not only De-NOx efficiency but also effective control of NH3 escape rate and conversion rate of SO2 into SO3.

SNCR process is using reductant to take place non-selective chemical reaction with nitrogen oxide (mainly NO, NO2) without catalyst and then generate nitrogen and water.

The boiler furnace is a reactor in SNCR and there’s no need of catalyst.
The reaction temperature range is 850℃-1250℃.
The reductant of SNCR process can be liquid ammonia, urea and ammonia.

SNCR process chemical reaction equation is as below
4NH3＋4NO＋O2＝4N2＋6H2O
4NH3＋2NO2＋O2＝3N2＋6H2O
2CO(NH2)2＋4NO＋O2=4N2＋4H2O＋2CO2
2CO(NH2)2＋2NO2＋O2=3N2＋4H2O＋2CO2
SNCR De-NOx efficiency is 20% – 70%