Lumping Analysis in Modeling of Binary Cracking Kinetics in Hydrocracking Reactions

Hydrocracking is a conversion process of heavy oil fractions such as naphtha and
middle distillates into lighter products in a relative high pressure and temperature
condition. Hydrocracking process has benefits petroleum industries in producing
high quality products such as diesel, jet fuels and gasoline. In order to predict the
product yields at different operating conditions, it is necessary to have the modelling
of hydrocracking kinetics. In this project, the modelling of binary cracking kinetics
was verified by using discrete lumping approach, which involve carbon number
and true boiling point of hydrocarbon as model compound.
Four hydrocracker models representing four different stoichiometric kernels were
verified at two different temperatures, 663K and 723K to find the exact lumping
system for each model. Lumping analysis for each hydrocracker model was carried
out based on Wei and Kou criteria where the system that disobey the criteria was
classified as not exactly lumpable.
Analysis on the results indicated that carbon number basis produced three exact
lumping systems for model 1 and model 2 of hydrocracker at temperature 663K and
723K. Another analysis on true boiling point indicated that no exact lumping systems
produced as both model 3 and model 4 of the hydrocracker models violated the
criteria stated by Wei and Kuo.