Steam reforming of ethanol over Pt-Ni/Al2O3 catalyst

Abstract

This experimental work involves a parametric study of the bimetallic Pt-Ni/δ-Al2O3 catalysts with different Pt and Ni loadings (0.2wt%Pt-10wt%Ni, 0.3wt%Pt-10wt%Ni, 0.2wt%Pt-15wt%Ni, 0.3wt%Pt-15wt%Ni) for hydrogen production by ethanol steam reforming as well as a kinetic investigation of ethanol steam reforming over 0.3wt%Pt-15wt%Ni/δ-Al2O3 catalyst on the basis of power law and Langmuir-Hinshelwood-Hougen-Watson type rate equations. Experimental conditions were adjusted to eliminate coke deposition over the Ni-based catalysts by fixing the steam to carbon ratio at 3.0. The results obtained at 723 K showed that catalysts with 15wt%Ni content were more efficient and the Pt content also affected ethanol steam reforming performance. Also, above 723 K, the catalyst with 0.3wt%Pt-15wt%Ni performed better. Kinetic data were obtained at 723 K over bimetallic 0.3wt%Pt-15wt%Ni/δ-Al2O3 catalyst using three different ethanol and steam compositions at six different space times each. Experimental rate data were used to estimate kinetic parameters of power law and proposed LHHW models by using the differential method of data analysis. The investigation of power law kinetics gave reaction orders of 1.01 and 0.09 with respect to ethanol and steam, respectively, and a reaction rate constant of 9.23 mol.gcat-1.h-1.atm-0.92. The first order dependence of the rate on ethanol concentration was also confirmed by the integral method of data analysis. Both power law and single-site LHHW models gave very good fit to the experimental data.