SCR and SNCR combined denitration technology
SCR and SNCR combined denitration technology
Process principle
SCR/SNCR combined denitration process have the advantages of low investment and high denitrification efficiency , Combining the reducing agent injection technology of SNCR into the furnace with the catalytic reaction by escaped ammonia in SCR process to further remove NOx. The mixed denitrification process uses urea as an absorbent which effectively combines a special SNCR process in the furnace with a simple back-end SCR denitrification reactor.
Chemical principle
CO(NH2)2+ 2NO→ 2N2+CO2+2H2O
CO(NH2)2+ H2O→2NH3+CO2
NO+NO2+2NH3→2N2+3H2O
4NO+4NH3+O2→4N2+6H2O
2NO2+4NH3+O2→3N2+6H2O
Process flow diagram
The main function of equipment and process systems
1.Reducing storage and preparation system: total storage capacity is designed based on the consumption of the boiler denitration devices under BMCR conditions for 5 days .
2.The metering and conveyor systems: filters installed to prevent equipment blockage .
3. Injection system: the reducing agent injected into the furnace at a suitable temperature through the gun .
4. SCR reactor / catalyst system: reactor body is the most important part of the denitration device, The shape is a rectangular cube with side panels on all four walls, forming a cases . The catalyst is arranged inside it .
5. Electrical control system: complete configuration, independent instrumentation and control systems.
Technical characteristics
1. Far less than the cost of traditional SCR systems, it can achieve a denitrification efficiency of 90%.
2. Reduce the usage of SCR catalyst to decrease the conversion of SO2 to SO3 .
3. The corrosion and air preheater blockage caused by SO2/SO3 conversion are minor issues .
4. Smaller than SCR reactor, with better spatial applicability.
5. Denitrification system low resistance, less catalyst, low operating costs.
6. Can safely use urea as a reducing agent, without pyrolysis system.
7. Step by step implementation, phased delivery .