Denitration Practice Of SVW’s#1Boiler

With the increasing severity of the environmental protection issues, more and moreattention from the society and enterprises has been paid to the boiler pollutants emissionreduction, particularly the oxynitride. In accordance with the relevant requirement ofSinopec Corp. and the "Standard for Power Plant Air Pollutant Emission", thedenitration revamp on SVW’s#1boiler is urgently required.Through the study on the denitration technology status home and abroad and thedenitration schemes, a denitration proposal for#1boiler which combines theimprovement during and after the combustion has been proposed, i.e. firstly to reducethe NOx emission to lower than500mg/Nm3by decreasing the flash point duringcombustion inside furnace, then to make the NOx lower than the required standard ofthe environmental protection authority by installing the proven SCR system in the flueduct. Since the actual lean coal with low heat value and volatiles has been used insteadof the design soft coal with high heat value and low volatiles, various supporting andstabilization measures for combustion have been explored on what role such measurescan play in denitration during burning while assuring the heat efficiency of boiler.Practice shows that reduction of NOx inside the furnace and increase of boiler heatefficiency can both be achieved by using technical measures like the horizontalrich-lean burner, shutter pulverized coal fine enrichment, adding high-positionburn-out wind, etc to revamp the existing burning system. After modification, the NOxemission at the air preheater outlet of#1boiler has been reduced to lower than500mg/Nm3from the previous800mg/m3. In the meanwhile, the boiler operates stablywhile the NOx emission at the outlet of SCR system is declined to lower than100mg/m3with the boiler heat efficiency rise to92.45%from87.88%and all othereconomic index no lower than that before modification.