Most control loops in many installed control systems use only standard, linear PID controllers. Such situations offer the possibility to improve both control quality and plant operability without additional investments. The design of the new control system for crude oil processing in the PARAMO refinery a.s. in Pardubice, Czech Republic, was divided into three different parts: (1) A new control strategy based on the gain scheduling method for the pressure control and the feedforward method for the level control has been proposed for stabilization of the desalter tank. (2) A special ratio controller connected in cascade to the original flow controllers has been used for the minimization of the temperature difference between the heated streams (not controlled in the original system). (3) A combined feedforward-feedback cascade system has been designed for the feed temperature control. All proposed systems have been tested and set in operation. it has been proven that there is outstanding improvement over the original control system in stabilization of the output temperature, in simplification of the system operability, and in savings of heating medium.