We use multivariable feedback control to reduce variations in flow and back- pressure associated with two industrial separator units forming part of an edible oil refining line. This provides plant operators with a mechanism for increasing process yield without reducing product quality. Actuator limits are a natural consideration in the controller design since increased production rates re- quire actuators to operate on or near their limits. We use recentred barrier function model predictive control in this application and obtain favourable results.