灰化方式对煤基固体混合燃料灰分理化特性的影响

Effects of ashing method on ash physicochemical characteristics of coal-based solid fuel blends

灰化方式和温度对固体燃料灰成分有显著影响,而目前关于灰化方式对气化残炭及其与烟煤混合燃料灰分特性的研究较少。探究不同的灰化方式和成灰温度对煤基固体混合燃料灰分理化特性的影响,重点对比传统高温制灰方式(815℃)与低温等离子灰化方法(<200℃)对煤基固体混合燃料灰理化特性的影响与反应机理。试验结果表明:除水煤浆气化残炭的低温灰外,其余各样品的低温灰均在400~600℃出现了较大的失重峰,这是低温灰中未完全氧化有机物的燃烧过程。高温灰和低温灰中成分的主要差异体现在Ca元素上,高温灰中的Ca主要以CaSO4形式存在,而低温灰中的Ca则以CaS,CaCO3等多种形态存在。Fe元素在低温灰中存在形式为FeS2,在高温灰中则以主要以Fe2O3的形式存在。评估掺混燃烧的灰样特性时,要考虑到不同燃料中矿物质的交互作用。研究工作有助于加深对固体燃料掺烧过程灰行为的认识,促进气化残炭的大规模、高效、安全利用。

Ashing method and temperature have significant influences on the ash compositions of solid fuel.However,there are few studies on the ash characteristics of residual carbon and its blends with bituminous coal affected by ashing method.In the exploration on the influence of different ashing methods and temperatures on the ash physicochemical characteristics of coal-based solid fuel blends,the focus laid on the impact of the traditional ash preparation method(815℃)and the lowtemperature plasma ashing method(<200℃)on physicochemical characteristics and reaction mechanisms of the ash generated from coal-based solid-fuel blends.The experimental results show that low-temperature ash of all samples,except residual carbon of coal−water−slurry gasification,has a large weight loss peak in 400-600℃,which is due to the combustion process of the incomplete oxidized organic matter in the low-temperature ash.The main difference between high-temperature ash and low-temperature ash is their formations of Ca element.The Ca in high-temperature ash mainly exists in the form of CaSO4,while that in low-temperature ash is of various forms,such as CaS and CaCO3.Iron element exists as FeS2 in low-temperature ash,while mainly exists in the form of Fe2O3 in high-temperature ash.The interaction of minerals in different fuels should be taken into account when ash samples characteristics of the blends after co-combustion are evaluated.The research is conductive to deepen the understanding of the ashing behaviors in the blending and burning process of solid fuels,and promote the large-scale,efficient and secure utilization of gasification residual carbon.