煤直接液化残渣的热解特性研究

利用热重、固定床热解和红外光谱技术研究煤直接液化残渣的热解特性及热解产物分布、组成和性质,考察了热解回收油品的适用条件。结果表明,450℃~500℃下神华煤液化残渣(SHR)和胜利煤液化残渣(SLR)热解油产率分别约为32%和20%,450℃后升高温度对油产率影响不大,但会使热解油中沥青烯(A)含量增加。SHR的热解油主要是己烷可溶物组分(HS),与SHR中HS结构相似。但SLR的热解油中A组分含量接近50%。SHR中的HS组分在热解时的聚合并不明显;而SLR中的HS组分在热解过程中伴随明显的聚合,导致热解油中含有大量的沥青烯。在400℃~500℃,两种残渣中A均有向热解油转化的趋势,而且SLR中A组分表现出了较大的逸出能力。但从热解产物组成分布分析,A的逸出还是少量的,一部分分解产生油品,一部分与前沥青烯和四氢呋喃不溶物(THFIS)一起形成了半焦。

Pyrolysis behavior of direct coal liquefaction residues

The behavior of two direct coal liquefaction residues under pyrolysis conditions were carried out using thermogravimetric analysis, temperature programmed pyrolysis technique and FT-IR analysis. The optimized conditions for oil recovery from the residues were also studied. The oil yields from the pyrolysis of liquefaction residues (SHR and SLR) of Shenhua and Shengli coals at 450℃~500℃ are 32% and 20%, respectively. An increase in pyrolysis temperature above 450℃ has no effect on the oil yield, but makes the asphaltene content in oil arise. The hexane soluble fraction is a main fraction in the oil from SHR, while the oil from SLR contains about 50% of asphaltene. The hexane soluble fraction in SHR is not obviously polymerized during pyrolysis, while that in SLR is significantly polymerized during pyrolysis and resulted in an increase in asphaltene yield. At 400℃~500℃ the asphaltene fraction of both residues tends to release as oil, and companied with the increase of preasphaltene and tetrahydrofuran insoluble fractions especially for SLR.