There is great interest in producing hydrogen from renewable sources such as biomass rather than from fossil fuels. This paper presents new experimental results at different pyrolysis temperature and development of a dynamic model for a biomass pyrolysis/steam reforming process in a two stage fixed bed reactor. The model considers the hydrodynamics of the fixed bed reactor, the interfacial mass and energy transfer between the fluid-solid systems and the porous catalyst, and the energy transfer on a kinetic model. The 2D dynamic model resulted in a system of partial differential equations which was solved numerically in gPROMS (R). The model was validated with the experimental results. The model predictions show good agreement with the experimental results. The model can be used as a useful tool for design, operation, optimisation and control of the biomass steam gasification process. (C) 2014 Elsevier Ltd. All rights reserved.