Feasibility studies of the exhaust-gas reforming of hydrocarbon and alcohol fuels
The feasibility of a proposed exhaust-gas reforming process, as applied to hydrocarbon and alcohol spark-ignition engine fuels, has been studied. In the first instance, a theoretical approach is reported. Complex chemical equilibria and energy balance software has been developed, and used to simulate exhaust-gas reforming reactions for n-heptane and methanol feedstocks. Engine combustion of reformed fuel compositions thus predicted has then been modelled by means of in-house developed cycle analysis software. An important preliminary part of the cycle simulation exercise was the calculation of reformed fuel laminar flame speed, and hence heat-release duration and commencement values. The results of the simulations have enabled comparisons of predicted engine thermal efficiency and pollutant emission levels for reformed and conventional fuelling strategies. Conclusions of the theoretical studies were sufficiently encouraging to warrant a practical investigation, and hence the design, construction and commissioning of a prototype reforming reactor and test rig are described. A test programme was then conducted, in order that the effect of various relevant parameters on reformer performance could be established. The findings of this study were encouraging in terms of the fuel compositions which could be produced, and in the case of an n-heptane feedstock, results were found to correlate well with those of the earlier predictive work. Major limitations highlighted by the practical work, however, relate to high reformer temperature requirements, and low reformed fuel generation rates. The findings of the studies are drawn together in a discussion of the practical feasibility of a vehicle installation, and project conclusions.