加氢裂化精制段芳烃饱和深度对断侧链和开环反应的影响

Influence of Aromatic Saturation Depth in Hydrocracking Hydrotreating Section on Side Chain Breaking Reaction and Ring Opening Reaction of Cyclic Hydrocarbons

通过调节加氢裂化精制段工艺条件参数得到不同芳烃饱和率的精制油,按照烃分子的环结构数目进行分类和数据处理,并结合反应热力学数据研究了芳烃饱和深度对精制段的断侧链和开环反应的影响。结果表明:加氢裂化精制段的断侧链反应以一环烃为主,且芳烃饱和率提高,烷基苯环π键向烷基环己烷σ键的转化,使得反应物形成正碳离子的稳定性降低,这可能是导致断侧链反应平衡常数变小和反应速率变慢的主要原因;低芳烃饱和率下,含硫化合物(噻吩类)等环状烃分子加氢脱除是开环反应的主体,随着芳烃饱和率提高,四环及以上环状烃分子发生开环反应转化为低环数环状烃,而三环及以下环状烃主要发生芳烃饱和反应转化为相同环数的环烷烃。

Refined products with different aromatic saturation ratios were obtained by adjusting the process parameters of the hydrocracking hydrotreating section,of which the classification and data processing were conducted based on the number of ring structures of hydrocarbon molecules.Moreover,the influence of aromatic saturation depth on the side chain breakage and ring opening reactions in the hydrotreating section was studied based on the reaction thermodynamic data.The results show that monocyclic hydrocarbons are the major reactants of the side chain breaking reaction in the hydrotreating section.As the saturation rate of aromatic hydrocarbons is increased,the conversion of alkyl benzene to alkyl cyclohexane resulted in the decreasing stability of carbonium ions from reactants,which may be the main reason for the decline of the side chain breaking reaction equilibrium constant and low reaction rate.Under low aromatic saturation ratios,the hydrogenation for removal of cyclic hydrocarbon molecules such as sulfur-containing compounds(thiophenes)is the major process of ring opening reaction;with the increasing of the aromatic saturation rate,cyclic hydrocarbon molecules with four or more rings can be converted to low ring number cyclic hydrocarbons through ring opening reaction,while cyclic hydrocarbons with three or less rings are mainly converted into cycloalkanes with the same ring number through aromatic saturation reaction.