Development of a dimensionless and dynamic model of the three-phase trickle bed reactor in light naphtha isomerization process: effects of axial mass dispersion and liquid-solid mass transfer on isomers concentration

Abstract

This study develops a general dimensionless model for a three-phase trickle bed reactor in the light naphtha isomerization process. The simulations are accomplished to study its conduct. The model brings up a one-dimensional axial dispersed flow to characterize dispersity and liquid-solid mass transfer in the forms of dimensionless Peclet and mass Stanton numbers under adiabatic conditions. It considers the essential reactions extant in the isomerization process comprising isomerization, hydrogenation, and hydrocracking reactions applying a precise approach of dimensionless kinetic equations and rate constants. The Crank–Nicolson method and a nonstandard finite difference approach are utilized for large systems of time-spatial PDEs to resolve the dynamic reactor model with MATLAB software. The aim is to elucidate how these large systems of PDEs and nonlinear ODEs can be solved with a comprehensive computation in the form of physical dimensionless numbers. The isomers compositions estimated with the suggested model are in corroboration simulation results obtained by empirical information. The dynamics are evaluated to consider the system conduct with a variation in the hydrogen concentration of the feedstock.