4. High content of sulfur

High content of sulfur usually occurs when burning coal with high-sulfur content, the increasing of sulfur dioxide in flue gas means the more sulfur trioxide; sulfur trioxide can react with the reducing agent--ammonia and generate a large amount of ammonium bisulfate and ammonium sulfate. Ammonium bisulfate is an extremely viscous substance which is very difficult to be removed when adhering to the SCR device; at the same time, the ammonium bisulfate adhering to the surface of tungsten trioxide SCR denitration catalyst, it will continue adsorb fly ash and  resulting catalyst blocking. Ammonium sulfate is a dry powdery substance, when in the case of large amounts of fly ash in the flue gas, both the worn out and blocking of catalyst will be increased.

 

5. Waste incineration, co-firing biomass fuel

Waste incineration power generation and co-firing sewage sludge are the good solutions for solving environmental pollution and energy crisis, but they also put forward higher requirements in the designing, operating of tungsten trioxide SCR denitration catalyst. This is because the content of P, Na, K, CaO is likely ten times the number of ordinary coal, all these elements can cause catalyst poisoning. Due to the strong toxicity of alternative fuels, they will cause great harm to the tungsten trioxide SCR denitration catalyst even though burned in a very short time. Since Chinese have very low environmental awareness, the situation of classifying strictly in widespread municipal solid waste, industrial waste, municipal and industrial sludges is so poor, which causes the smoke and ash content of the alternative fuels complex and can’t clearly distinguish; besides, the many more unknown poisons greatly limit the chemical life assessment and economic analysis of the catalyst.