燃煤电厂脱硝工艺对其粉煤灰性质的影响

摘要

The denitration is a signiifcant means of controlling NOx pollution, to improve level of building materials recycling and using stability of lfy ash after denitration. The lfy ash before and after denitration were as objects of study. The chemical composition, mineral composition and artical size were studied and analyzed by Cement chemical analysis method, XRD diffraction analyzer and Mastersizer.The form and content of ammonium salt from lfy ash after denitration were focused on. The research results indicate that the partical size of lfy ash after denitration increase a little under normal working condition of denitration,but chemical composition, mineral composition and pH has not been inlfuenced and water demand ratio has not changed. The strength activity index of lfy ash after denitration decrease little. The effect of denitration on pozzolanic activity of lfy ash is very little.There are NH3, (NH4)2SO4 and NH4HSO4 in lfy ash after denitration.And the content are connected with ammonia escape level and density of SO2 of reactor.%脱硝是治理燃煤产生NOx污染的重要技术手段，为了提高脱硝后粉煤灰的建材资源化利用水平，以脱硝与未脱硝粉煤灰为研究对象，利用水泥化学分析方法、XRD分析仪和激光粒度仪等手段研究其化学组成、矿物组成和粒径分布等基本性质的变化规律，并分析了脱硝后含氮物质在粉煤灰中的含量和存在形式。结果表明，正常脱硝工况下，粉煤灰粒径较脱硝之前有所增大，而对化学组成、矿物组成、pH值和需水量比等性质几乎无影响；脱硝后的粉煤灰强度活性指数较未脱硝降低不明显，脱硝对火山灰活性影响很小；脱硝后粉煤灰中含氮物质主要为粉煤灰吸附的脱硝剂NH3和残留脱硝副产物NH4HSO4、(NH4)2SO4，其量与反应器氨逃逸水平和SO2浓度有关。