Oxygen removal during the direct liquefaction of low-rank materials: Stoichiometric considerations

Two mechanisms of oxygen removal which may occur during the conversion of low-rank materials into transport fuels are compared. Alternative reaction pathways are assumed and the stoichiometries of these are used as the basis of the analysis. Conditions at which the two deoxygenation routes lead to the same profitability of process are determined. Similarly, conditions at which lower-rank materials can compete with higher-rank materials are defined. Comparison with coal liquefaction data suggests that, at the same energy price, lower-rank feedstock can compete with higher-rank material in self-contained processes where the processing costs, exclusive of the costs of reducing gas, are similar on a feed energy basis.