Kinetic investigation on steam gasification of charcoal under direct high-flux irradiation

The reaction kinetics of steam gasification of coal are investigated for a quartz tubular reactor containing a fluidized bed and directly exposed to an external source of concentrated radiation. Rate laws are formulated based on elementary reaction mechanisms describing reversible adsorption/desorption processes and irreversible surface chemistry. Assuming plug flow conditions, the rate constants are computed by matching theoretical and experimental results and their temperature dependence is determined by imposing an Arrhenius-type rate law. High-quality syngas containing an equimolar mixture of H-2 and CO, and less than 5% CO2, was produced at above 1400 K. The advantages of using a concentrated radiation source for supplying high-temperature process heat are three-fold: (1) the calorific value of the fuel is upgraded; (2) the gaseous products are not contaminated by combustion by-products; and (3) if the radiation source is derived from renewable energy, e.g. solar energy,