Steady-state control of plate pasteurisers

In the food industry pasteurisation is very commonly carried out using plate heat exchangers. Steady-state analysis of, and experimentation into, the effects of disturbances on the temperatures showed that temperature approach (water inlet temperature minus milk outlet temperature) changed very little. This showed that control based on a steady temperature approach could be effective. A control algorithm that calculates the hot water temperature setpoint, from the pasteurisation temperature setpoint plus an averaged temperature approach, was proposed and tested. The algorithm gave very good disturbance rejection and setpoint tracking.