Indirectly heated biomass gasification using a latent heat ballast. Part 2: modeling

Experiments carried out in an indirectly heated biomass gasifier successful ly demonstrated that throughput and gas heating value could be increased by using a latent heat ballast. A mathematical model describing heat transfer and chemical reaction in the system was developed. The heat transfer submo del is accurate to within 13 K for both ballasted and unballasted scenarios . However, the chemical submodel, based on thermodynamic equilibrium calcul ations, proved inadequate and underpredicted cooling times during the pyrol ysis phase of the process by about 50%. Improvement was made by substitutin g the measured product gas composition for the calculated gas composition. (C) 2001 Elsevier Science Ltd. All rights reserved.