渣油悬浮床加氢裂化反应机理研究

 在高压反应釜中模拟悬浮床加氢裂化反应，考察了辽河稠油在H₂氛围下的热裂化反应和油溶性分散型Ni催化剂存在下的悬浮床加氢裂化反应结果的差别，也对比了两者的气体产物组成、反应生焦及催化剂的SEM形貌和反应生焦的元素分析结果，以探讨渣油悬浮床加氢裂化反应机理。结果表明，悬浮床加氢裂化反应与热裂化反应相比，气体产物分布没有差别，轻油收率略有降低，但其生焦量却大幅降低，说明悬浮床加氢裂化反应主要按自由基热反应机理进行，分散型催化剂的存在只是起到促进加氢反应速率的作用。加氢裂化反应生焦的Ni含量显著增加，其来源应为催化剂，由此可以断定催化剂在反应前期促进加氢反应速率，抑制反应的裂化和生焦，反应后期被反应过程中生成的焦炭严密包裹，成为焦炭沉积的场所，因此减少了反应器壁的结焦。

STUDY ON MECHANISM OF SLURRY PHASE HYDROCRACKING RESIDUE REACTION

In order to study the reaction mechanism of slurry phase hydrocracking, a slurry phase hydrocracking reaction was simulated in an autoclave, and the difference of the thermal-cracking reaction under the presence of H₂ of Liaohe heavy oil(LHHO) and the slurry phase hydrocracking reaction catalyzed by the oil-soluble dispersed Ni catalyst were investigated, also the compositions of gas products, the SEM images of coke and catalyst and the element analyses of cokes produced from the two reactions were compared. The results showed that there was no difference between the compositions of gas products of the two reactions, but the light oil yield of hydrocracking reaction decreased a little and its coke yield decreased more greatly, indicating that the slurry phase hydrocracking reaction was following the free radical thermal cracking mechanism. The action of disperser catalyst was only to promote the hydrogenation speed. The Ni content of slurry phase hydrocracking coke was remarkable increased, which should be from the oil-soluble dispersed Ni catalyst. Thus it is concluded that the effect of catalyst in reaction was to promote hydrogenation speed and to inhibit cracking reaction and coke formation in the initial period, then the catalyst became the location of coke deposition, resulting in the formation of wall-phase coke decrease in the end period.