Development of Controller for Disturbances Rejection of Torrefaction Reactor with High Thermal Inertia

This paper presents the analysis of the ability of disturbance rejection in the control systems of a torrefaction reactor with high thermal inertia. An electrical heating coil around the reactor is used to maintain the temperature and Nitrogen gas is purged to maintain inert environment. Main disturbance of the system is this Nitrogen gas flow variation to the reactor chamber. This gas flow will drop the temperature of the reactor chamber and change the rate of convection heat loss by forced convection. Changing the rate of heat loss will change the model parameters. In the study four control structures were simulated and compared the performances. The simulation shows that the cascade controller successfully rejects the disturbance of the drop of chamber temperature, but it is not successful in rejection of the disturbance by change of convection heat loss rate of the reactor chamber. Adaptive controlling is not effective as it takes a large amount of time to get adapted. A model based modified controller which is developed based on the model is proposed. This controller successfully rejects both disturbances.