吸热型碳氢燃料的结焦研究Ⅰ含硫抑制剂

Study on coking of endothermic hydrocarbon fuels Ⅰ Sulf-inhibitor

在连续进样微反测焦系统上考察了二硫化碳、噻酚等含硫化合物添加前后碳氢燃料S1裂解结焦速率的变化。结果显示,两种含硫抑制剂均可明显降低燃料裂解时的结焦速率,二硫化碳的抑制效果较好,可以使初始结焦速率降低90%。同时,气相色谱的分析结果显示,含硫抑制剂对燃料裂解产物的分布情况有一定影响,促进了烯烃选择性的提高,有利于改善燃料的吸热能力。利用扫描电镜以及元素分析手段对焦形态结构和元素组成的研究结果显示,含硫抑制剂还有利于改善焦的形态结构以及氢碳元素组成,对清焦工作有一定帮助。

To suppress the coke formation during utilization of hydrocarbon fuel is the key factor in practice. A set of chromatographic reactor system was set up for determining the coke deposition produced in the cracking process of endothermic hydrocarbon fuel. The chromatographic system was useful for study on coking mechanism through online analysis of products distribution. The system is suitable for studying coking inhibition over a wide range of conditions. Endothermic hydrocarbon fuel S-1 was selected as cracking feedstock. The effect of coking inhibitors carbon bisulfide and thiophene on the cracking of S-1 were studied, including coking rate, products distribution, weight loss of metal carrier, functions and properties of the coke. The functions and properties of coke formed on the metal carrier were characterized through SEM photographs. The results show that the coking rate of endothermic hydrocarbon fuel could be effectually restrained by sulfur-inhibitors. It is also found that carbon bisulfide is the better one that could decrease 90% of initial coking rate, while thiophene could decrease 40%. The distribution of paraffin and alkene in gas products was investigated on chromatographic system, and the alkene product distributions in cracking reactions is increased by carbon bisulfide and thiophene, which is beneficial for the improvement of endothermic property of fuel. Sulfur-inhibitor improves the configuration and hydrogen-carbon ratio of coke, which is in favor of coke-cleanup. Sulfur-inhibitor could also decrease the weight loss of metal carrier.