Catalytic Effects of Main Metals in Coal Ash on Advanced Reburning of Pulverized Coal

To further reduce the NOx emission from power plants, an experimental study on the NO reduction during advanced reburning with reburning fuel of raw coal and coals loaded with four kinds of main metals in coal ash (Na, K, Fe, Ca) was performed in a two-staged drop flow reactor (TSDFR). The results show that the metals in coal ash can affect the NO reduction during advanced reburning to different degrees, depending on the original fraction of oxygen (OFO, the volumetric concentration of oxygen in the flue gas which is entering into the reburning zone). When the OFO is between 2.75 and 5.36%, NaOH and KOH have a significant catalytic effect on NO reduction, producing an obvious increase in NO reduction efficiency, whereas the catalysis of FeCl3 and Ca(OH)2 is weak. By comparing the conversion of five main products during the reactions when using raw coal and coals loaded with different metals as reburning fuel, it is found that some types of metals can improve the NO reduction in reburning via increasing th...