Thermodynamic equilibrium analysis of methanol conversion to hydrocarbons using Cantera methodology

Abstract

Reactions associated with removal of oxygen from oxygenates (deoxygenation) are an important aspect of hydrocarbon fuels production process from biorenewable substrates. Here we report the equilibrium composition of methanol-to-hydrocarbon system by minimizing the total Gibbs energy of the system using Cantera methodology. The system was treated as a mixture of 14 components which had CH3OH, C6H6, C 7H8, C8H10 (ethyl benzene), C 8H10 (xylenes), C2H4, C 2H6, C3H6, CH4, H 2O, C, CO2, CO, H2. The carbon in the equilibrium mixture was used as a measure of coke formation which causes deactivation of catalysts that are used in aromatization reaction(s). Equilibrium compositions of each species were analyzed for temperatures ranging from 300 to 1380 K and pressure at 0-15 atm gauge. It was observed that when the temperature increases the mole fractions of benzene, toluene, ethylbenzene, and xylene pass through a maximum around 1020 K. At 300 K the most abundant species in the system were CH4, CO2, and H2O with mole fractions 50%, 16.67%, and 33.33%, respectively. Similarly at high temperature (1380 K), the most abundant species in the system were H2 and CO with mole fractions 64.5% and 32.6% respectively. The pressure in the system shows a significant impact on the composition of species. © 2012 Duminda A. Gunawardena and Sandun D. Fernando.