Kinetics of the steam reforming of dimethyl ether over CuFe2O4/γ-Al2O3

Kinetics of the steam reforming of dimethyl ether (SRD) over a novel CuFe2O4/gamma-Al2O3 bifunctional catalyst are investigated in a fluidized bed reactor under the following operating conditions: temperature, 250-400 degrees C; steam to DME ratio (S/DME), 3-8; space time, 0.1-2.3 g(caralyst)h(g(carbon))(-1). A kinetic scheme with three different reaction steps (DME hydrolysis, methanol steam reforming and reverse WGS reaction) is assumed for the global SRD process, and different Langmuir-Hinshelwood-Hougen-Watson (LHHW) expressions are considered for the equation rate of each reaction step. The calculation of the kinetic parameters of best fit for each model is conducted by nonlinear multiple regression in Matlab. The method consists in minimizing the sum of squares of the residual errors between the experimental data and data calculated by the model assuming plug flow for the gas, perfect mix for the catalyst and isothermal regime. The discrimination of different models is conducted by means of the analysis of variance (ANOVA) statistical test. As a result, the selected kinetic model describes accurately the whole composition of the reaction medium at zero time on stream in the SRD process. This model takes into account the attenuating effect of both reactants (water and DME/methanol) on the reaction rate for every reaction step and it assumes that water adsorbs on both the acid and the metallic sites. (C) 2016 Elsevier B.V. All rights reserved.