Gasification kinetics of char from olive tree pruning in fluidized bed

The gasification rate of char from olive tree pruning was measured in a fluidized bed at temperatures between 760 and 900 °C. Experiments were carried out using gas mixtures containing H2O, CO2, H2, CO and N2 in various proportions. Two kinetic equations were obtained, one for the char gasification rate with H2O, taking into account the inhibition effect of H2, and another for gasification with CO2, including the inhibition effect of CO. The kinetic expressions account for the effect of temperature, gas composition, and the extent of carbon conversion. The influence of the gas composition and temperature was expressed by the Langmuir-Hinshelwood model, whereas an nth order kinetic model was used to account for the variation of the reaction rate with the extent of conversion. The reaction rate with H2O was observed to be 3-4 times faster than that with CO2. Inhibition effects caused by CO and H2 were significant. It was found that the gasification rate in a mixture containing CO2 and H2O simultaneously can be estimated from addition of the individual rates with CO2 and H2O.