Question: The series of well-mixed stirred-tank chemical reactors for a first-order chemical reaction with negligible heat of reaction is shown in Figure. Each reactor has a mass in the tank, which has the same temperature as the liquid and represents substantial energy accumulation. (This is a simplified representation of a packed bed, with the masses being the catalyst.) The concentration of the effluent from the last reactor is controlled by adjusting the heating medium valve.
(a) Discuss the effect of the masses on the control performance in response to feed stream temperature variations.
(b) Discuss the effect of the masses on the control performance in response to feed stream concentration variations.
(c) Draw general conclusions about the effects of the masses on the disturbance responses in (a) and
(b) and on set point changes.
