Energy Saving Potential and the Efficacy of Using Different Control Strategies for the Heat Exchanger Network Operation

Abstract

Heat exchangers – typically arranged in heat recovery networks – belong to the devices most widely used in industrial production systems. The control performance of heat exchanger network (HEN) operation can be impaired by fouling which builds up on heat-exchange surface. Fouling leads to burning extra fuel to compensate for reduced heat recovery and induces increased costs of cleaning interventions, etc. In this work, a real-life benchmark system is considered. The controlled system represents a HEN coupled with a crude distillation unit (CDU). The mathematical model of HEN with stream splits and interactions between the branches, was built and validated based on real-life data recorded during CDU operation. The use of various control strategies (employing linear control systems with PID controllers) for HEN operation was studied with the aim to maximize heat recovery in the HEN involving splits. Using historical data on HEN operation, simulations of closed-loop control were performed in MATLAB/Simulink environment. The simulation results demonstrated the efficacy of the studied strategies and their potential to achieve energy savings in CDU operation.