Investigation on low energy-consumed embedded selective catalytic reduction technology for pelletizing flue gas and the CO2 emission reduction assessment

Based on the unique technique property of grate–kiln pellet production process and its demand of ultra-low emission of NO x , a low energy-consumed embedded selective catalytic reduction (SCR) denitration technology was proposed. The temperature of the NO x -containing tributary flue gas was 350–500 °C, which basically accorded with the temperature range of SCR by V 2 O 5 -based catalyst. Considering the potential inhibition effect of high SO 2 concentration (8000–10000 mg/m 3 ) and metal-containing dust in the pelletizing flue gas, the catalyst compositions were optimized to V 2 O 5 (0.5%) and WO 3 (5%), giving NO conversion over 90% with low yield of N 2 O by-product. Compared with the low-medium temperature SCR technology, it was no longer necessary to reheat the flue gas, showing a remarkable CO 2 emission reduction effect. The CO 2 emission reduction ratios were 94% and 66% contributed by the decrease of fuel and electricity consumption for the embedded SCR technology, respectively. The operating cost was also greatly reduced from 11.4 CNY/t-pellet to 3.1 CNY/t-pellet (Chinese Yuan).