Renewable syngas production from thermal cracking of glycerol over praseodymium-promoted Ni/Al2O3 catalyst

In this study, the kinetics of glycerol pyrolysis over a 3wt%Pr-20wt%Ni/77wt%alpha-Al2O3 catalyst was investigated. The catalyst was synthesized via wet-impregnation method and was characterized using temperature-programmed calcination (TPC), temperature-programmed reduction (TPR), N-2-physisorption, FESEM imaging, X-ray diffraction and CO2-/NH3-temperature-programmed desorption (TPD). The catalytic activity of the as-synthesized 3 wt% Pr-Ni/alpha-Al2O3 catalyst was evaluated in a stainless steel fixed bed reactor at temperatures that ranged from 973 K to 1073 K and a weight-hourly-space velocity (WHSV) of 4.5 x 10(4) ml g(-1) h(-1) under the atmospheric condition. The main gaseous products from catalytic glycerol pyrolysis were H-2, CO, CO2 and CH4 (descending ranking) with the highest H-2 formation rate and H-2 yield of 0.02593 mol g cat(-1) s(-1) and 29.04%, respectively. The analysis of the kinetic data obtained from the glycerol pyrolysis showed activation energy of 37.36 kJ mol(-1). Based on the mechanistic modeling, it can be deduced that the rate determining step of the glycerol pyrolysis was via a single site associative adsorption with molecular surface reaction as the rate-determining step. (C) 2016 Elsevier Ltd. All rights reserved.