Kinetics of hydrothermal reactions of n-butanol over Pt/Al2O3 catalyst for biopropane fuel gas production

Abstract

Energy defossilisation using drop-in biofuels is an important step towards Net Zero. Producing low-carbon clean-burning propane fuel from biomass provides such additional sustainability benefits. In this work, kinetics of hydrothermal reactions of n-butanol, a biomass-derived feedstock, to produce propane over 5 wt% Pt/Al2O3 catalyst have been studied from 523- 573 K. Experimental data revealed negligible internal and external mass transfer effects and, when fitted to an integral power-rate law equation, gave activation energy of 70 kJ mol−1 (n-butanol reaction order = 1). Furthermore, an appropriate Langmuir-Hinshelwood model was developed, which predicted similar activation energy 62 kJ mol−1. Low adsorption enthalpies for n-butanol (–33.51 kJ mol−1) and water (−18.16 kJ mol−1) indicated weak interactions on the catalyst surface. These agreed with the fast reaction rate of ≈1.0 x 10-5 mol gcat-1 s−1 obtained at ≥ 548 K. As a new research area, generation of such accurate kinetics data will contribute to process development for large-scale biopropane production.