Analysis of reaction path and different lumped kinetic models for asphaltene hydrocracking

The product distribution of asphaltenes hydrocracking was studied in an autoclave with decalin as the liquid-phase system at different reaction temperatures and times to elucidate the relevant reaction mechanism. The results showed that the reaction products might be reversely condensed to generate secondary asphaltenes, resulting in a trend of first increasing and then decreasing the yields of some products at 420 degrees C. The significant yield increase of gas and gasoline at 420 degrees C might be due to the cracking of saturated and aromatic fractions to form light fractions. The conclusion was drawn the reaction behavior of asphaltenes hydrocracking under the research conditions followed the first-order reversible reaction kinetics by the reaction kinetic analysis, which further supported the inference that some products could recondense to form secondary asphaltenes. The four-lumped, five-lumped, and six-lumped models were constructed to study in depth the reaction behavior of asphaltene hydrocracking in the current system, and the results showed that the more similar the structure and composition of the reaction products to asphaltenes, the faster the reaction rate of their condensation to asphaltenes. Furthermore, the higher the temperature was more favorable to improve the selectivity and yield of transportation fuel diesel under the temperature of 380 degrees C-420 degrees C by the analysis of the ratio of rate constant. Although the applicability of lumped model was not positively correlated with the number of lumps, it is concluded that the six lumped model was the best model among the three models from the combined analysis of the applicability and the richness of the reaction information of the model.