Evaluation of the use of hydrated ethanol in different concentrations in reformers coupled with internal combustion engines 2021-36-0029

In recent years, fossil fuel dependence has generated a worldwide concern about the environmental consequences arising from its burning. The high oil demand has also generated the risk of shortage for this mineral and, consequently, of the products derived from it. Ethanol onboard reforming is regarded as a prominent technology that is able to recover waste heat from the exhaust system of internal combustion engines, as well as reduce emissions. The process is based on exploring the potential of endothermic reactions to convert hydrated ethanol into high energy density products, such as hydrogen and methane. This paper had the objective of implementing a thermodynamics and chemical kinetics model to evaluate the effects of ethanol-water content, reactor inlet temperature and ethanol to exhaust gas ratio in the reformate composition and reformer process efficiency using a platinum-based catalyst. The main reforming mechanisms for these conditions are ethanol thermal decomposition and water-gas shift reaction, which are primary influenced by temperature and ethanol, water, carbon monoxide and carbon dioxide concentrations. The conducted simulations showed that ethanol conversion was relevantly observed for temperatures above 500 °C. Furthermore, it also indicated that hydrogen yield increases with greater water content in the feedstock, whilst reformer process efficiency increases with lower water contents. The best results were observed for 750 °C, anhydrous ethanol and an ethanol to exhaust gas ratio of 5:95, resulting in reformer process efficiency of 1.09. At these conditions, ethanol conversion is at its maximum and water-gas shift reaction equilibrium is shifted towards the reactants.