A Thermodynamic Study on Oxidative Dry Reforming of Ethanol for Syngas Production

Abstract Oxidative dry reforming of ethanol is a promising route to utilize CO₂, a greenhouse gas and ethanol, a renewable feedstock in the production of synthesis gas (syngas-a mixture of H₂ and CO). It is a feedstock for Fischer-Tropsch (F-T) process to produce synfuels and valuable chemicals. Syngas is mainly produced by dry reforming of methane, but its continuous deployment urges to find an alternative feedstock such as ethanol. The present work aims to simulate syngas production from ethanol focusing on the reduction of carbon formation and energy requirement. Thermodynamic equilibrium analysis for dry reforming and oxidative dry reforming of ethanol are carried out following Gibbs free energy minimization method using Aspen Plus simulation tool. The reaction temperature and feed mole ratio (O₂/CO₂/ethanol) are varied to obtain equilibrium moles of different products including solid carbon at atmospheric pressure. Syngas yield increases from 1 to 5.2 moles with a suitable ratio of H₂/CO when temperature is increased from 500 to 800 ⁰C at CO₂/ethanol mole ratio of 1 at atmospheric pressure. The addition of oxygen does not affect syngas production much but drastically reduces carbon formation and the amount of energy requirements. Carbon formation becomes negligible when 0.2 moles O₂ in feed stream is added at 775 ⁰C and atmospheric pressure, while in the absence of oxygen 0.392 moles carbon is formed at the otherwise identical operating conditions. At above conditions, addition of 0.2 moles of O₂ co-feed can reduce energy requirements of the reformer up to 13.35%.