Ultra-low emission technology of flue gas for chain grate machine and rotary kiln pelletizing is one of the national green low-carbon advanced technology achievements, applicable to the flue gas treatment in the process of rotary kiln pellet production.
This technology utilizes selective non-catalytic reduction (SNCR) and selective catalytic reduction (SCR) denitrification technology, combining with the characteristics of flue gas temperature of the production of grate and rotary kiln, and embedding the denitrification technology into the production process of grate and rotary kiln. Three-stage denitrification system is adopted, the first stage adopts SNCR (850-1150℃) denitrification, the second stage adopts high-temperature and high-dust (320-420℃) SCR denitrification, and the third stage adopts low-temperature (100-180℃) oxidation-assisted semi-dry synergistic denitrification. Three-stage denitrification can realize the denitrification temperature automatically adjustable, NOx to achieve ultra-low emissions. Meet the startup, shutdown and load changes in the process of emission standards, to achieve 100% synchronous operation with the host. It solves the problems that it is difficult to realize ultra-low emission by setting only one stage of denitrification, and it is easy to exceed the standard when the load and temperature change.
There is no need to heating the flue gas, no need to consume supplementary heating energy, low operating cost; there is no problem of corrosion and blockage of GGH heat exchanger, the whole system is relatively simple, with fewer equipments, easy to operate and maintain.
The desulfurization adopts semi-dry desulfurization + bag filter, and under the high SO2 concentration and low exhaust temperature of the flue gas of the pellet, the relationship between bed pressure drop, circulating ash volume, solid-gas ratio in the tower and the efficiency of desulfurization of the circulating fluidized bed (CFB) is optimized and designed to determine the optimal process parameters. The desulfurization system can realize the simultaneous removal of sulfur dioxide and nitrogen oxides in the flue gas, and can meet the requirements of ultra-low emission under high SO2 concentration and low exhaust temperature in the pellet flue gas.
