元素硫促进原油烃类热裂解及其对TSR作用启动机制的影响

Promotion of thermal cracking of crude oils by elemental sulfur and its effect on the initiation mechanism of TSR

利用S提供石英管封闭反应体系中的初始H_(2)S,通过原油与硫酸钙或硫酸镁在含水条件下的热模拟实验对比研究S对原油烃类热裂解过程及热化学硫酸盐还原(TSR)作用启动机制的影响。结果表明,在大于336℃含水实验条件下,烃类能够在短时间内将S全部还原成H_(2)S。H_(2)S对原油热裂解成气有明显促进作用,使烃类气体和CO_(2)的产率显著增加,同时提高气体的干燥系数。S还原生成的H_(2)S易与烃类反应生成不稳定含硫化合物,该有机硫中间体在S催化烃类热裂解过程发挥重要作用。结合实验中生成H_(2)S的δ^(34)S和生成气体的H_(2)S/S^(0)发现,硫酸镁比难溶的硫酸钙更易启动TSR反应。

In this study,hydrothermal pyrolysis experiments were conducted using a quartz-tube system with calcium sulfate or magnesium sulfate and elemental sulfur.We examined the effect of elemental sulfur on the thermal cracking of crude oil and the initiation mechanism of TSR.Our results showed that hydrocarbons completely reduced elemental sulfur to H_(2)S in a short time above 336℃.Meanwhile,the presence of H_(2)S significantly promoted the thermal cracking of crude oil into gas,which increased the gas yield and dryness.The H_(2)S generated by the reduction of elemental sulfur easily reacted with hydrocarbons to generate labile sulfur compounds(LSC),which may play a significant role in the thermal cracking of hydrocarbons catalyzed by elemental sulfur under our experimental conditions.Furthermore,MgSO_(4) is more effective for the onset of TSR relative to CaSO_(4) based on sulfur isotopes of H_(2)S and the ratio of H_(2)S/S^(0).