生物质灰中不同钾盐的转化规律研究

Research on Transformation Rule of Different Potassium Salts in Biomass Ash

以不同形式的钾盐为模型化合物研究了生物质灰中碱金属的转化规律,并结合化学模拟对反应机理作进一步探索。研究发现:KCl倾向于在高温下以气态形式析出而较少参与灰中反应;K_2CO_3易于与灰中的SiO_2反应生成硅酸钾化合物,将K元素固定在灰中;K_2SO_4在1 000℃以上亦与SiO_2反应生成大量的硅酸钙。K_2SO_4的存在所导致的灰熔点降低一般发生在1 000℃以上,而K_2CO_3的存在导致生物质灰在较低温度下即发生熔融结渣。

This paper studies transformation rule of alkali metal in biomass ash by taking different forms of potassium salts as models and further explores reaction mechanism by combining with chemistry models. Research discovers that KCL is inclined to separate out in gas state form under high temperature while less takes part in ash reaction, K2CO3 is liable to react with SiO2 in the ash and generates potassium silicate compound to fix K element in the ash, K2 SO4 may react with SiO2 and generates large amounts of calcium silicate over 1000 ℃. In addition, reduction of ash fusion point caused by existence of K2SO4 generally happens over 1000 ℃, while fusion scorification of biomass ash caused by existence of K2CO3 may happen under lower temperature.