Thermodynamic analysis of hydrogen production from ethanol-glycerol mixture through steam and dry reforming

Z.Y. Zakaria^a,*, M. Jusoh^a, A. Johari^a, T.A.T.Abdullah^a, M.H. Hasim^a, K.Kidam^a, W.R.W. Sulaiman^b, M.J. Kamaruddin^a

Abstract

Thermodynamic properties of ethanol-glycerol steam and dry reforming have been studied with the method of Gibbs free energy minimization for hydrogen production. Equilibrium compositions were determined as a function of H₂O/ethanol-glycerol molar ratios (WEG)(1:6-6:1) and CO₂/ethanol-glycerol molar ratios (CEG)(1:6-6:1) where ethanol-glycerol is 1:1; reforming temperatures (573-1273 K) at different pressures (1-20 bar). Optimum conditions for hydrogen production are different for both steam and dry glycerol reforming. The optimum hydrogen formation for glycerol dry reforming are temperatures 1073-1273 K and CEG of 6:1 at 1 bar pressure, whereas for glycerol steam reforming, the optimum temperature is above 1073 K and WEG ratio 6:1 and 1 bar. Higher pressure and higher WEG/CEG ratio do not encourage hydrogen formation. Under identified optimum conditions, carbon formation can be thermodynamically inhibited.

Keywords: ethanol-glycerol mixture, dry reforming, steam reforming, hydrogen production