Kinetic Model For Catalytic Cracking Of Hydrogenated Gas Oil By Structure-oriented Lumping

It is important for the refining industry to understand the composition and structure of the feedstock as well as the mechanism of reaction process on the molecular scale.A molecular kinetic model for catalytic cracking of hydrogenated gas oil was developed by the structureoriented lumping(SOL)method combined with Monte Carlo(MC)simulation.SOL was applied to describe the structure of hydrocarbons and establish reaction rules.Firstly,multi-techniques such as NMR and GC×GC/TOFMS were used to characterize the properties of the feedstock.According to the analysis,hydrocarbon molecules were constructed by 19 structural increments,and 3000 virtual molecules were drawn out to reflect the feedstock in multiple perspectives.The molecular matrix was optimized continuously by comparing the calculated and experimental data of the feedstock properties.Thus,hydrogenated gas oil could be quantitatively described.Secondly,73 reaction rules have been formulated to form the catalytic cracking reaction network according to carbon ion reaction mechanism and characteristics of hydrogenated gas oil;drawing on classical linear free energy relationship theory,the rate constants were calculated by beding divided into tiers;the modified Runge-Kutta algorithm was used to solve the reaction network,and more than 15000 virtual molecules were generated,eventually a molecular kinetic model for catalytic cracking of hydrogenated gas oil was constructed.At last,the calculated values of product distribution were compared with the experimental data form confined fluidized bed reactor unit,the kinetic model was verified by optimizing each model parameter continuously.In order to verrify the accuracy of the model,the product properties such as the content of typical molecules and the properties of gasoline and diesel as well as the adaptability of the model to the reaction process under different technological conditions were investigated.The results show that the calculated and experimental values are consistent,which suggested that the SOL model is feasible.