A target-evaluation method for heat exchanger network optimisation with heat transfer enhancement

Energy conservation and efficiency improvement are critical problems for industrial process systems. Heat exchanger network retrofit has emerged as a powerful tool for energy-saving and Heat Integration, but the topology modification with new heat exchangers and re-piping is expensive and demands a long payback period. In this study, heat transfer enhancement is deployed in the heat exchanger network retrofit to avoid network topology modification. A target-evaluation method is proposed for heat exchanger network retrofit with the consideration of the thermal efficiency and the level of heat transfer enhancement. Two case studies are conducted to demonstrate the proposed method. The energy-saving of case 1 is 10.6752 MW, which is 13.3% of the original utility loads; 8.0303 MW heat loads are saved in case 2, which is 14.7% of the original utility loads. The results of return on investment indicate that enhancement of the best candidate heat exchanger can bring more energy-saving and better economic efficiency with fewer modifications to the existing heat exchangers, which is also confirmed by sensitivity analysis. The lower temperature effectiveness of the heat exchanger shows great potential for thermal efficiency improvement. The present results highlight the energy-saving effects that heat transfer enhancement has on the heat exchanger network retrofit. The proposed two-stage method supports the further development of energy conservation in different industries.

Automated summary

This study focuses on energy conservation and efficiency improvement for industrial process systems, particularly through heat transfer enhancement in heat exchanger network retrofit. A target-evaluation method is proposed and validated through two case studies, showing that enhancing the best candidate heat exchanger can bring more energy-saving and better economic efficiency.