Professor Stan Golunski, Deputy Director of the newly established Cardiff Catalysis Institute, in collaboration with engineers at Brunel and Birmingham Universities, is investigating the feasibility of an on-board exhaust gas reforming system to improve combustion and recover waste heat. In the exhaust gas fuel-reforming method, part of the engine exhaust gas reacts with small amounts of engine fuel in a mini-reactor fitted in the exhaust gas recirculation (EGR) loop to produce gaseous fuel named reformed EGR (REGR), which contains H2, CO, CH4, and CO2. The REGR gas is fed back to the engine inlet. (Earlier post.)
The Cardiff-Brunel-Birmingham team will study how the addition of these reformed mixtures affects engine combustion, performance and emissions with the Institute identifying stable catalysts that will perform the reforming reaction. Initially the research will focus on diesel engines but the potential of exhaust gas reforming to achieve benefits in gasoline engines will also be evaluated.
In a 2006 study, Golunski and Dr. Athanasios Tsolakis at the University of Birmingham examined the limited number of design parameters that can maximize the engine-reformer system efficiency while improving vehicle emissions, and concluded that further catalyst design was required to optimize such an exhaust-gas reformer system.
...we examine the limited number of design parameters that can allow us to maximize the engine-reformer system efficiency while improving vehicle emissions. In principle, this balance requires that the endothermic hydrogen-generating reactions (steam reforming and dry reforming) are promoted at the expense of the exothermic reactions (oxidation, water-gas shift and methanation). In practice, an oxidation function is necessary for generating heat to drive the endothermic reactions, particularly at low exhaust gas temperatures. Water-gas shift and methanation respond to changes in size and aspect ratio of the reformer, but the ideal configuration for suppressing these CO-consuming reactions does not favour the efficient endothermic reactions at all operating conditions. Our results imply that the optimum exhaust-gas reformer cannot be achieved through reactor engineering alone, but will require further catalyst design.—Tsolakis and Golunski
Results from the new study could lead to new advances in engine design which can be used in conjunction with other technologies currently used to improve CO2 emissions, such as weight reduction of vehicles, start-stop fuelling, and the switch to hybrid and diesel cars.
The project is one of the first undertaken by the Cardiff Catalysis Institute, which is part of the University’s School of Chemistry. Officially launched on 13 October, the Institute aims to establish a center of excellence for catalysis within the UK that builds upon the current strengths in research at Cardiff.
Chemistry at Cardiff already has excellence in heterogeneous catalysis, homogeneous catalysis and biocatalysis. The aim is to bring these together within a single institute so that they can grow and provide the focal point for interdisciplinary interactions within Cardiff and externally with academia and industry.—Professor Graham Hutchings, director of the Institute
P Leung, A Tsolakis, J Rodriguez-Fernandez, S Golunski (2010) Raising the fuel heating value and recovering exhaust heat by on-board oxidative reforming of bioethanol. Energy Environ. Sci., doi: 10.1039/b927199f
A Abu-Jrai, A Tsolakis, K Theinnoi, A Megaritis, SE Golunski (2008) Diesel exhaust-gas reforming for H2 addition to an aftertreatment unit. Chem. Eng. J. doi: 10.1016/j.cej.2007.12.028
A Tsolakis and SE Golunski (2006) Sensitivity of process efficiency to reaction routes in exhaust-gas reforming of diesel fuel. Chem. Eng. J. 117 doi: 10.1016/j.cej.2005.12.017