The comparison of a lignite char, subbituminous coal char, and a bituminous coal char used in the reaction with steam to produce hydrogen

The use of coal as carbon source in the char-steam reaction to produce hydrogen gas over the temperature range 700-800 C (973-1,073 K) at atmospheric pressure has been studied in detail. Velva lignite has properties which give its char superior reactivity over those of the other coals tested. Catalysis with alkali carbonates enhanced the reactivity of Velva char substantially, whereas demineralization reduced the reactivity to a relatively constant value over the temperature range studied by removing inorganic material and altering the surface characteristics of the coal. Char produced from a Wyodak subbituminous coal and River King bituminous coal were much less reactive than Velva in the absence of catalyst but responded positively to the addition of alkali carbonates. Upon demineralization, these coals also showed reduced reactivity and altered surface features. This paper discusses the results of the experiments in terms of the reactivity data, SEM photos and elemental mapping, organic properties as determined from {sup 13}C NMR and ESCA spectroscopy, and inorganic content of the substrates.