Reaction kinetics and reactor modeling for fuel processing of liquid hydrocarbons to produce hydrogen: isooctane reforming Original Research Article

A mathematical model was developed in the framework of the process simulator Aspen Plus® in order to describe the reaction kinetics and performance of a fuel processor used for autothermal reforming of liquid hydrocarbons. Experimental results obtained in the facilities of Argonne National Laboratories (ANL) when reforming isooctane using a ceria-oxide catalyst impregnated with platinum were used in order to validate the reactor model. The reaction kinetics and reaction schemes were taken from published literature and most of the chemical reactions were modeled using the Langmuir–Hinshelwood–Hougen–Watson (LHHW) formulation to account for the effect of adsorption of reactants and products on the active sites of the catalyst. The water-gas-shift (WGS) reactor used to reduce the concentration of CO in the reformate was also modeled. Both reactor models use a simplified formulation for estimating the effectiveness factor of each chemical reaction in order to account for the effect of intraparticle mass transfer limitations on the reactor performance. Since the data in the literature on kinetics of autothermal reforming of liquid hydrocarbons using CeO2-Pt catalyst is scarce, the proposed kinetic model for the reaction network was coupled to the sequential quadratic programming (SQP) algorithm implemented in Aspen Plus® in order to regress the kinetic constants for the different reactions. The model describes the trend of the experimental data in terms of hydrogen yield and distribution of products with a relative deviation of ±15% for reforming temperatures between 600 and 800 °C and reactor space velocities between 15 000 and 150 000 h−1.