Steam gasification of a refuse derived char: reactivity and kinetics

A char was obtained from a commercial pilot-scale gasifier, which had been operating with a refuse derived fuel (RDF). Using this char, steam gasification experiments were then performed in a 15.6 mm i.d. packed bed tubular reactor. The effect of reaction temperature was studied (800 °C to 900 °C), and also the partial pressure of steam were in the range 33.3 kPa to 66.7 kPa. With the aid of the Shrinking-Core and the Uniform-Reaction models, kinetic parameters were estimated (apparent activation energy varied from 96 kJ mol⁻¹ to 162 kJ mol⁻¹). It was also found that at lower carbon conversions (e.g. 10% to 60%) the RDF-derived char appeared to be more reactive than other bio-chars reported in the literature. However, at higher conversions (>60%), its apparent reactivity decreased with carbon conversion, thereby behaving in a similar manner to chars derived from coal.