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The effect of sulphur on a rhodium reformer catalyst was determined in the partial oxidation of n-heptane. The yield loss of the catalyst upon sulphur addition appeared to almost instantaneous and not progressive in time (i.e. it reaches a plateau). Up to ppm levels, the direct yield loss appeared to be linearly related to the sulphur level in the fuel and is of the order of around 3% per ppm of sulphur in the fuel. Sulphur adsorption on rhodium catalyst sites was found to be reversible. The original activity of the catalyst was quickly restored when changing to a sulphur free fuel. The effect of sulphur on the rhodium catalyst does not depend on the structure of the sulphur species. Based on this work, a 10 ppm sulphur maximum seems to be a sufficiently tight specification with respect to the stability of an appropriate reformer catalyst. By contrast, the presence of other species in fuels can cause irreversible and progressive catalyst deterioration.

Because reformer technology can be used in conjunction with advanced internal combustion engine technology, it is important to be able to formulate fuels that are compatible with both reformers and ICEs It has been found that most hydrocarbon species typically present in gasoline can be reformed with relative ease. The exception is that olefinic species of carbon number 6 and above are relatively much harder to reform. It is shown how a reformer compatible gasoline fuel with high octane can be blended. For Diesel fuels, synthetic ‘Gas to Liquid’ fuels are generally less susceptible to coking and hence superior to petroleum-derived fuels, for use with an onboard reformer.