Three different catalysts (K2CO3, Na2CO3, Li2CO3) and the mixture [(Na,K)2CO3] were impregnated onto a lignite char to determine the effects of catalyst type and amount of catalyst loading (1–5 wt%) at different reaction temperatures (700–800 °C) on the rate of steam gasification in a thermobalance reactor using large sample weights of up to 1.0 g. The reaction orders with respect to carbon were found to be 2/3 in the case of non-catalytic and Li2CO3-catalytic reactions and zero order for the other cases. In the Na2CO3 and mixed (Na,K)2CO3 catalysed reactions, the reaction rate increased with the reaction temperature and the amount of catalyst loading. Under the same experimental conditions but with 3 wt% catalyst loading, the catalytic activities were found to be ranked as Na2CO3 > mixed (Na,K)CO3 > K2CO3 > Li2CO3. Reactivity enhancement factors for the mixed (Na,K)2CO3 catalysts were found to be arithmetic mean values for the individual carbonates. For the K2CO3 catalysed reaction, a relationship between activation energy and K2CO3 loading was proposed with three different patterns derived from the results of the present and the previous studies. Activation energies and frequency factors of the catalytic reactions were smaller than those of the comparable non-catalytic steam gasification reactions and may be taken as evidence of the influence of a compensation effect in the reaction.