A mathematical model of indirectly heated biomass gasification was developed consisting of chemical reaction and heat transfer submodels was developed.The chemical reaction submodel could predict the main components of the product gas as well as the external heat required for biomass gasification.The heat transfer submodel could estimate the total thermal resistance and heat transfer rate of heat pipe.Based on the analysis of two submodels

a heat pipe biomass gasifier was designed.Experiments were carried out in the heat pipe biomass gasifier to validate the chemical reaction submodel.The results showed that the chemical reaction submodel was accurate for the prediction of the main components of the product gas.The percentage of hydrogen in the product gas was about 50%—60% and the heating value of the product gas could reach 10 MJ·m-3 in the heat pipe biomass gasifier.