Pyrolysis and Gasification Experiments of Biomass under Elevated Pressure Condition

Abstract

This paper reports on the pyrolysis and CO₂-gasification of various biomass materials in a pressurized thermobalance. In particular, the primary yields of total volatiles, tar and non-condensable gases, together with the composition of non-condensable gases, are measured as a function of temperature at 1 atm and 10.8 ata. The use of a high-intensity infrared heating source, in conjunction with a non-absorbing carrier gas (viz. argon), is reported to reduce the significance of secondary gas-phase pyrolysis reactions. Linear trends with atomic H/C ratio are observed in the tar yield, CH₄ yield and total volatile yield during pyrolysis. The gasification kinetics of biomass chars (pyrolysed to 700°C at a medium heating rate) have also been measured by measuring the rate of weight loss during reaction with CO₂, as a function of temperature. First-order kinetic rate constants are then determined by fitting the weight loss data using a random pore model. The results indicate that the gasification rate of biomass char increases as pressure increases.