Hydrogen production from bioethanol fuel mixtures via exhaust heat recovery in diesel engines: A promising route towards more energy efficient road vehicles

Abstract

Bioethanol has been considered a potential alternative to the conventional fossil fuels in transportation sector as well as a hydrogen carrier. This study proposes a thermochemical recovery pathway to extend the use of bioethanol in compression ignition engines through catalytic exhaust gas reforming of ethanol-biodiesel-diesel blends into hydrogen. The aim is to improve the heat recovery of the engine exhaust gas and increase the on-board production of hydrogen which can potentially partially replace the diesel fuel in the engine. Results indicate that the effectiveness of the reforming process mainly depends on the blend composition, reforming temperature, and oxygen to carbon ratio (O/C). It is deduced that ethanol content in the fuel blend has a key role in sustaining catalyst activity and hydrogen production. Overall, the study highlights the positive impact and practicality of recovering exhaust heat using the ethanol-biodiesel-diesel blends. This implementation can result in noticeable improvements in emission reduction of diesel powertrains once the reformate is fed back into the engine.