Simulation of the Transient Response of a Fluidized Bed Gasifier for Hybridized Concentrated Solar Thermal Power Plant

Paper in proceeding, 2018

A model to predict the dynamic response of a fluidized bed biomass gasifier (FBG) to changes in air
and fuel feed rates is developed. It extends a previous pseudo-equilibrium model originally developed
for steady-state operation, by considering the accumulation of char and the dynamics in the release of
volatiles during transient periods. The model calculates the gas yields of the main species as well as
char conversion, taking into account chemical reaction, attrition and elutriation. The influence of the
change in fuel and air flowrate, on the syngas flowrate, heating value, and bed inventory of char is
analyzed. Two transient periods in an FBG after a change of feed rate are shown: a devolatilization
transient, lasting a few seconds, followed by a longer transient (from minutes to hours) resulting from
the char accommodation until a new steady state is reached. The model is being used to assess the
dynamic performance of the backup and storage system in biomass-hybridized concentrated solar
power (CSP) plants.