Development of a Partitioning Kinetic Model of Biomass Gasification in Supercritical Water with a Fluidized Bed Reactor

Biomass supercritical water gasification technology is considered an effective way to realize the utilization of biomass, and further development of this technology depends on an accurate kinetic model. In this work, the reactor was distributed into a nozzle affected zone, a dense phase zone, and a freeboard zone according to the characteristic of the physical and chemical field, and a reaction kinetic model suitable for each zone was developed, which could be used for dynamic and scale-up studying of the reactor. First, three groups of gasification experiments (feedstock and biochar with low and high concentrations) were conducted to obtain the gas yield for calculation of the kinetic parameter, and obtain the evolution of the specific area of biochar for the calculation of the porous structure constant ψ. Then, detailed reaction pathways for biomass and biochar were proposed and a random pore kinetic model taking specific surface area into account was developed based on the first order of each reactant.