SCR+SNCR+low nitrogen combustion transformation
Low nitrogen combustion technology:
Low-nitrogen combustion technology is based on the formation mechanism of nitrogen oxides, mainly through the use of air staged combustion, fuel staged combustion, flue gas recirculation and low-nitrogen burners and other methods to reduce the amount of nitrogen oxides generated during pulverized coal combustion.
In the case of using general coal quality, low-nitrogen combustion technology can reduce nitrogen oxide emissions by 35% to 55% and achieve emission reduction targets. To further reduce NOX emissions, flue gas denitrification technology must be further adopted, that is, a process combining SCR, SNCR, and low-nitrogen combustion technology. SCR and SNCR methods can greatly reduce NOX emissions to 200mg/m3, but its equipment is expensive and its operating costs are high. Measures to suppress NOX generation: Reduce the peak temperature of the boiler and reduce the amount of pulverized coal in the combustion area. Reduce the oxygen concentration (that is, reduce the excess air coefficient), and block some of the secondary air ducts. In order to ensure the output of the boiler, some pulverized coal and air can be put into the upper part of the boiler to control the amount of combustion-supporting air in the central area of the combustion flame, shorten the residence time of the combustion products in the high-temperature flame area, and avoid the simultaneous existence of high temperature and high oxygen concentration. A reburning zone is set up in the furnace, and the hydrocarbon root CHi and incomplete combustion products CO, H2, C and CnHm generated by combustion in the main combustion zone are used to reduce NO to N2. Measures to reduce NOX emissions: Three-dimensional combustion technology (wall-type tangential-circle burner) Wall-type exhaust air system Secondary air burner swinging horizontally and vertically at the same time New WR rich and light pulverized coal burner + offset perimeter air + SOFA burner. Features of low-nitrogen combustion technology: Simple system, easy to transform, low investment and operating costs, it is an economical and effective technical measure. If the optimized design or transformation effect is good for some coal types, it is not necessary to install denitrification equipment, saving a huge amount of energy. Investment and operating costs, while greatly reducing secondary cycle pollution.