Start-up, shutdown, and transition timescale analysis in biomass reactor operations

Abstract

The time required to achieve steady state operation is an important factor in biomass conversion reactors, especially at a pilot or higher scale. The present work analyses the start-up, shutdown, and transient timescales of the laboratory-scale biomass reactor set-up using theoretical framework, for the case study of biomass torrefaction. The experimental time series temperature data is analyzed to infer the transient behaviors of the reactor, as well as how it changes with reactor scaling. Thermal mass of the reactor played a significant part in the reactor's temporal response to changes, and it was demonstrated to possibly achieve a reasonable temporal response time at scale. A series of start-up and cooling operation strategies are devised to optimize the time and feedstock consumption requirements. The learning is applied to the case of transitioning between two reactor operating conditions where rapid start-up or cooling procedure proved more time-efficient and feedstock-efficient. The insights learned provide a basis for a more comprehensive study of the reactor transitional operations that can be encapsulated into an automated control system to minimize human intervention.