The objective of this work was to develop a mathematical model to simulate the initial fast pyrolysis in biomass gasification in the bubbling fluidised gasifier.

Biomass as a sustainable energy resource will play an important role in future energy supply with biomass gasification as a promising conversion technology and in reducing greenhouse gas emission. In the design of industrial biomass gasification for generation of combustible gases, initial fast pyrolysis of biomass has to be characterised when the gasification process undergoes at high temperatures. This work focuses on modelling of pyrolysis products of biomass using the equilibrium kinetics models, as most research work on modelling of fast pyrolysis of wood has been focussed on total gas composition, and only few experimental works on small scale reveals about the individual gas composition. The work also focuses on the hydrodynamics of steam with the moving sand bed, char and gas to find the time for cease of pyrolysis, which is very short until the steam (gasifying agent) contacts with feed material or the pyrolysis products.

The preliminary results from the modelling of the initial pyrolysis at 873K show that the gas contains 28% H2, 11% CO, 14% CO2, 13% H2O and 7% CH4. The carbon and tar contents are 18% and 8%, respectively. These results are consistent with literature data.

From the results, it is concluded that the model can provide detailed information on the gas composition at different bed temperature at the outlet and allows different operating scenarios to be examined.