The principle and process of SNCR (Selective Non-Catalytic Reduction) denitration are as follows:
Principle：
SNCR denitrification technology is a selective non-catalytic reduction technology, which achieves the purpose of reducing NOx emissions by injecting ammonia water or urea solution into high-temperature combustion tail gas to reduce ammonia and NOx to generate nitrogen and water vapor. This technique does not require a catalyst and is therefore referred to as "non-catalytic reduction".
In the SNCR denitrification process, the reducing agent (such as ammonia water, urea solution, etc.) decomposes at high temperature (generally 850℃ ~1100℃) to produce active groups such as NH3, which chemically react with NOx in the flue gas to generate N2 and H2O. Due to the high temperature of the reaction, spraying is required in the high temperature region of the furnace.
Process：
Urea solution preparation and storage system: The urea storage system, the urea solution preparation system and the urea solution storage system are centrally arranged to form a urea supply station.
Injection system: The injection position is generally set at the tail of the combustion furnace or the upper part of the combustion chamber, so that injection can be carried out in high temperature areas. The spray system includes spray guns, pipes, valves, and the like for uniformly spraying the reducing agent into the furnace.
Control System: The control system is used to monitor and control the SNCR denitrification process, including the preparation, dilution, injection, mixing and other processes of reducing agent. Through real-time monitoring of furnace temperature, NOx concentration and other parameters, the control system can automatically adjust the injection amount and speed of reducing agent to achieve the best denitrification effect.
Monitoring system: The monitoring system is used to monitor various parameters in the SNCR denitrification process in real time, such as furnace temperature, NOx concentration, ammonia escape amount, etc. By installing equipment such as oxygen analysis, ammonia analysis, temperature and pressure monitoring, it can be discovered and treated in time Abnormal conditions to ensure the stable operation of SNCR denitrification system.
In SNCR denitrification process, the key factors affecting the denitrification effect include temperature, injection position and injection amount of reducing agent, etc. Therefore, when designing and running SNCR denitrification system, these factors need to be fully considered, and corresponding measures should be taken for optimization and control.