Biomass gasification kinetics: Influences of pressure and char structure

In this study, the gasification kinetics of chars from different biomass species have been investigated within the temperature range 800-950 degrees C, CO2 concentrations of 10 to 100% v/v, and pressures between 1 and 20 bar using thermogravimetric analysis (TGA). The quartz wool matrix (QWM) method was used to simulate circulating fluidized-bed (CFB) conditions. The reactivity results obtained by the QWM method were compared with those extracted using TGA data. Kinetic data from TGA analyses was found to be compatible for predicting CFB gasification reactivity. Effects of pyrolysis pressure on the chemical structure of char and char conversion reactivities were also investigated. Pressure has been found to have no effect on reactivity during char conversion while having a dramatic effect on chemical and physical structure during the pyrolysis process. The Langmuir-Hinshelwood rate equation represents the pressurized radiata pine char gasification kinetics well. The Langmuir-Hinshelwood expression for studied conditions can be described as RCO2 = 1,22.10(4)e-(163.103/RT) P-CO2/1 + (5, 84.10(-11)e(246.103/RT))P-CO (6,48.10(-4)e(56.103/RT))P-CO2 Kinetic data found in this study are in good agreement with the literature.