14种典型含硫化合物在200—330℃温度区间、在有低硫褐煤和硫抑制剂存在条件下的加水热模拟实验结果表明,大多数结构类型的含硫化合物是结构不稳定的化合物,它们的热稳定性差异很大,不同结构类型的含硫化合物所对应的热解温度不同,它们在不同温度段产物的分布也不尽相同,这表明单个硫化合物的地球化学行为差异很大,而单个有机硫化合物在有机质热成熟过程中的转换特征基本上可以依据其生成硫化氢、二次含硫化合物以及大分子含硫化合物的量来描述。另一方面,硫化氢作为主要热解产物表明硫化合物分解生成硫化氢是有机硫化合物成熟转化的主要机理性过程。在所调查的化合物中,苯并噻吩、二苯并噻吩、二苯硫和噻蒽等在最高热解温度下也不发生任何化学反应,表明这些化合物代表了稳定型结构的硫化合物,这与这些化合物广泛存在于成熟原油和沉积有机质中的状况是一致的。上述结果还显示含硫化合物的种类和结构类型是受有机质的成熟度或演化阶段控制的。
A total of fourteen individual model sulfur compounds were investigated using laboratory hydrous pyrolysis under conditions of constant temperature between 200 and 330 ℃ and in the presence of low sulfur brown coal. The results show that most of the compounds were reactive with great variation in their thermal stabilities, and in their maximum temperature of thermal decomposition and as well as in their sulfur product distribution, these demonstrate that the geochemical behaviors of the individual sulfur compounds are also in great variation. However, analysis of sulfur species in the pyrolysis products of the reactive compounds suggests that the geochemical transformation of organic sulfur could be principally characterized in terms of the formation and distribution of hydrogen sulfide, secondary sulfur compounds and macromolecular sulfur. Also, as hydrogen sulfide is the predominant pyrolysis product, its formation proves to be the primary and the most significant mechanism for organic sulfur transformation during the maturation process. Among these investigated compounds, benzothiophene, dibenzothiophene and thianthrene are stable at the highest pyrolysis temperature and suggest that these compounds are geochemical stable compounds and this is consistent with that these compounds are widely existence in the mature petroleum and sedimentary organic matter. Above results also suggest that the speciation and structural types of sulfur compounds identified in petroleum and sedimentary organic matter may largely controlled by the organic matter maturity and evolution stages.