SNCR denitration process

SNCR denitration process

System process diagram

Technical principle of SNCR denitration equipment:
The technology of SNCR denitration equipment is to inject NH3, urea and other reducing agents into the boiler furnace for selective reaction with NOx without catalyst, so it is necessary to add reducing agents in the high temperature area. The reducing agent is sprayed into the area where the furnace temperature is 850-1100℃, and it is rapidly thermally decomposed into NH3, which reacts with NOx in the flue gas to generate N2 and water. In the range of 850-1100℃, the main reaction of NH3 or urea to reduce NOx is:
NH3 is a reducing agent 4NH3 + 4NO +O2 → 4N2 + 6H2O
Urea is the reducing agent NO+CO(NH2)2 +1/2O2 → 2N2 + CO2 + H2O
The technology uses the furnace as the reactor. The denitration efficiency of SNCR flue gas denitration technology is generally 30% to 80%, which is greatly affected by the boiler structure size. With SNCR technology, the current trend is to replace ammonia with urea as the reducing agent.
Technical features of SNCR flue gas denitrification:
The equipment is simple, and there is no need to change the equipment settings of the existing boilers, just add an ammonia or urea storage tank, an ammonia or urea injection device and its injection port on the basis of the existing coal-fired boiler;
The equipment operation investment is small, only cheap urea or liquid ammonia is needed;
Small resistance: small influence on the normal operation of the boiler;
Small equipment footprint: The required smaller ammonia or urea storage tanks can be placed on the boiler steel frame without additional space budget.