灰分对高硫煤热解部分气化硫变迁的影响

采用分步脱除矿物质方法,对义马原煤及HCl,HCl-HF,HCl-HNO₃处理后煤样,分别在固定床反应器中考察了热解部分气化下硫的脱除规律.结果表明:一方面在热解过程中原煤及酸处理煤样H₂S和COS的析出均呈双峰趋势,其析出值主要受温度、原煤中灰分和HNO₃氧化作用;另一方面,在部分气化和酸处理后煤样热解半焦在600℃～900℃范围内硫脱除率可达50%～80%,800℃时,无机硫可完全脱除.而原煤热解半焦总硫,无机硫的脱除率在700℃时最大.气化温度的升高,加强了碱性矿物质的固硫作用,其结果是900℃气化时,总硫和无机硫脱除率降低.酸处理后有机硫含量基本保持不变,其噻吩结构只随碳骨架的气化而析出.

The Effect of Minerals on Transformation of Sulfur During Pyrolysis and Partial Gasification

In this study, the effect of acid treatment of Yima coal on predesulfurization during pyrolysis and partial gasification were investigated. The coal was treated with HCl, HCl-HF and HCl-HNO3 solution, in which different minerals were eliminated. The whole process could be divided into pyrolysis and partial gasification. In pyrolysis process, the evolution of H2S and COS show two peaks, which were 450 degrees C and 600 degrees C respectively. At high temperature, the amount of H2S evolution from acid treated coal was markedly increased compared to the raw coal through the elimination of minerals. In the case of HCl-HNO3 treated sample, the H2S evolution in the low temperature region, below 500 degrees C, was reduced and the COS evolution in higher temperature region, above 500 degrees C, was increased by the chemical oxidation. In the partial gasification process, the sulfide sulfur removal of acid treated coal char was increased, reached about 100% at 800 degrees C. The maximum of total and sulfide sulfur removal of parent coal char were 46.39% and 52.97% at 700 degrees C. Compared to acid treated coal char, the effect of alkaline minerals for fixing sulfur was strengthened with increasing the temperature. The organic sulfur of acid treated coal char was released with carbon gasification, and the value could be constant.