21. Heat Integration Across Plants Considering Distance Factor

Heat integration across plants is an extension of conventional heat integration in a single plant for further improving energy efficiency. This chapter addresses the application of both Pinch Analysis and Mathematical Programming on solving heat integration problems across plants. For heat integration across plants, the required pipelines between plants is much longer than heat integration within a single plant, so more attentions must be paid on distance factor as it incurs more expense. A number of factors can affect the final design of pipelines between plants, for example, direct and indirect heat integration, the connection patterns between plants, the selection of intermediate fluid, etc. In this chapter, three connection patterns (series, split, parallel) for interconnectivity of individual plants in an area are presented. Each connection pattern has different performance on energy saving and pipeline length. To determine the energy target for the three connection patterns, a graphical methodology is presented. In addition, Mathematical Programming is used to determine the optimal design considering both direct and indirect heat integration. Parameters of intermediate fluid can be also optimized if indirect heat integration is applied. Some case studies are illustrated to demonstrate the capabilities of the presented models and graphic tool.