哈密煤温和液化固体产物热解过程中硫的变迁规律

利用固定床反应器研究了哈密煤温和液化固体产物（MLS）在热解过程中含硫气体的释放规律以及不同形态硫的变迁规律，并分析了矿物质对硫变迁规律的影响。结果表明，在实验考察的条件范围内，MLS热解过程中大部分的硫残留在半焦中，仅有不到10%的硫迁移到焦油中或转化为含硫气体逸出。热解生成的含硫气体以H₂S为主，当热解温度为400℃时H₂S的逸出速率达到最大。通过改进方法测定了MLS及其热解半焦中各种形态硫的含量，发现MLS热解过程中以硫化物硫和有机硫的分解和转化为主。随着热解温度的升高，MLS中有机硫逐渐分解并以含硫气体的形式逸出；当热解温度低于600℃时，MLS中硫化物硫逐渐转化为含硫气体、有机硫和少量的黄铁矿硫；当热解温度高于600℃时，MLS中碱性矿物质吸收气相中的H₂S转化为硫化物硫，硫化物硫缓慢增加。醋酸酸洗可以保留MLS中大部分的硫化物硫，且酸洗后MLS热解生成的H₂S逸出速率增大，峰温向低温方向移动；当热解温度高于600℃时，有机硫和硫化物硫的脱硫反应速率降低，并且MLS中的碱性矿物质与H₂S反应生成金属硫化物，导致H₂S逸出速率明显降低。

Transformation of sulfur forms during pyrolysis of mild liquefaction solid product of Hami coal

The sulfur-containing gases evolution and the transformation of sulfur during pyrolysis of mild liquefaction solid product (MLS) were studied in a fixed-bed reactor. Meanwhile, the effects of mineral matters on the sulfur transformation were explored. The results show that most of the sulfur remains in the char under the experimental conditions in this work. Less than 10% of the sulfur migrates into tar and sulfur-containing gases. The sulfur-containing gases generated in pyrolysis is mainly H₂S. In addition, the generation rate of H₂S reaches the maximum when MLS is pyrolyzed at 400 ℃. The contents of various forms of sulfur in both MLS and its pyrolysis char were determined by the modified method. The analysis shows that the decomposition and conversion of sulfide sulfur and organic sulfur are the main reactions of sulfur-containing matters during the pyrolysis process of MLS. As the pyrolysis temperature increases, the organic sulfur in MLS gradually decomposes and is converted into sulfur-containing gases. When the temperature is lower than 600 ℃, the sulfide sulfur in MLS is gradually transformed into sulfur-containing gases, organic sulfur and a small amount of pyrite sulfur. When the pyrolysis temperature is higher than 600 ℃, the alkaline minerals in MLS would absorb H₂S and convert into sulfide sulfur. Consequently, the content of sulfide sulfur slowly increases. Acetic acid pickling treatment can retain most of the sulfide sulfur in MLS. After pickling, the generation rate of H₂S during MLS pyrolysis increases, and the peak temperature shifts to the lower temperature. When the pyrolysis temperature is over 600 ℃ the desulfurization reaction rate of the organic sulfur and sulfide sulfur decreases. Meanwhile, the alkaline minerals in MLS can react with H₂S to form metal sulfides, leading to a significant decrease in H₂S generation rate.