A process and method is provided for operating a small-scale high-throughput gasifier. As is known in the art, the exothermic combustion reactions can be separated from the endothermic gasification reactions. The exothermic combustion reactions can take place in or near the combustor (118) while the endothermic gasification reactions take place in the gasifier (102). Heat from the exothermic zone is transferred to the endothermic reaction zone by circulation of an inert particulate solid such as sand. In order to increase efficiency by reducing heat loss from the gasifier, the gasifier (102) is concentrically-disposed within the endothermic reaction zone of the combustor (118).