An experimental study of a compact autothermal gasoline reformer for the producation of hydrogen

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Shaw, Adam Matthew
Autothermal reforming , Isooctane
The experimental analysis of an autothermal gasoline reformer for use in an auxiliary power unit was undertaken. The development of these auxiliary power units has the potential to create positive economical and environmental benefits. It will provide the necessary energy and heating while utilizing a fuel with a well established infrastructure. Autothermal reforming is a process in which both oxygen and steam are combined with a hydrocarbon fuel over a catalyst bed in order to produce a hydrogen rich gas stream. This process utilizes an exothermic partial oxidation reaction to promote the hydrogen efficient, endothermic steam reforming reaction. The main goals of this study were to design and test the operating conditions of a new autothermal reformer and to determine an operational envelope for the reactor. Furthermore, the data collected was used to validate a numerical model of the reactor that would assist in the development of future compact autothermal reformers. A compact autothermal reformer has been designed with the capability to produce detailed wall and centerline temperature profiles during operation. During the experimental phase of this project, a strong relationship between the main input variables (the oxygen to carbon and steam to carbon ratios) and the performance characteristics of the reactor was found. For the range of experimental conditions tested, the highest molar percent of hydrogen in the reformate for a gas hourly space velocity of 20,000h-1 was found at an oxygen to carbon ratio of 1.0 and a steam to carbon ratio of 2.0. Performance characteristics used for the reactor were the lower heating value, the percent hydrogen yield and fuel conversion, and were found to have maximum values of 46.0%, 47.6% and 67.7% respectively. Carbon deposition on the catalyst bed was found to be significant under certain operating conditions, but had a very small effect on the final conditions of the ATR. The computational fluid dynamics model was shown to have fairly accurate predictions for the temperature profiles as well as the reformate compositions when compared to the experimental data. A number of recommendations have been made to the experimental and numerical studies. It is likely that if employed in future testing, they would improve the overall performance of the compact autothermal reformer.
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