山西“两高”煤灰分对石灰石助熔机制影响的研究

Study on effect of Shanxi high ash content and ash fusion temperature coals on fluxing mechanism of limestone

以山西"两高"煤为研究对象,考察了洗选改变灰分对添加助熔剂Ca CO3的影响。研究发现,随着洗煤灰分的降低,煤灰中二氧化硅含量及硅铝比(Si/Al)降低,煤灰流动温度降低至液态排渣气流床气化所需温度时,Ca CO3的添加比例与洗煤高温下生成的矿物质种类及其含量相关,经过洗选降低灰分后的FH与SH洗煤,通过添加一定比例的助熔剂Ca CO3,高温下煤灰渣类型由结晶渣变为玻璃体渣,排渣温度范围宽,能够很好地满足气流床气化液态排渣的要求,洗选与添加Ca CO3助熔剂配合使用的方式,可以有效调控山西"两高"煤灰流动性质。

The floated coal samples with different ash contents were obtained by coal washing, and the effect ofash content on addition of fluxing CaCO3 was investigated. The results show that silica content and silicon toaluminum ratio （ Si / Al） of ash decrease with decreasing ash content. The AFTs of coal ashes change withincreasing CaCO3 addition. The additive CaCO3 content is closely related to the mineral formed at hightemperatures and their contents. Furthermore, for the FH and SH coals after floatation, the viscosity of slag withCaCO3 addition exhibits a behavior of glass slag, and also has a large slagging temperature range. The propertiesof the floated coal ash slags with CaCO3 addition well meet the requirement of slag tapping in entrained flowgasifier. It is an effective way for Shanxi high ash content and ash fusion temperature coals to combine coalwashing and CaCO3 adding to adjust the ash flow properties in entrained flow gasification.