This paper outlines the successful application of an adaptive control metho
d in an industrial environment. The control strategy incorporated MRAC (Mod
el Reference Adaptive Control) using an adaptive PID where the adaptive par
ameter was estimated using a macroscopic energy balance over the control zo
ne based on the concept of a tracking error trajectory. Success is demonstr
ated in a plant for sugar production where the formation of candy, due to i
ncorrect management, the steam flow to the evaporators prevented the sugar
syrups leaving the system to pass to the centrifugal screens. This stopped
production three or four times a day for 30 min, leading to serious problem
s in relation to cost and quality, the evaporators being very sensitive to
temperature changes. (C) 2000 Society of Chemical Industry.