Abstract
Total site heat integration provides more energy saving opportunities than conventional heat integration within single process. Some total site design methods including direct integration using process streams and indirect integration using intermediate-fluid circuit have been proposed during these years. In these works, it is found that direct heat integration can recover more heat, require less heat transfer area, but incur higher cost in pipeline compared with indirect heat integration. However, most research focused on total site heat integration with considering only indirect heat integration or direct heat integration, no methodology simultaneously considered both direct and indirect heat integration. Therefore, some optimal designs will be missed by using current total site integration methodologies for they do not fully utilize the features of indirect and direct heat integration. In this work, the situation that only applying direct heat integration, only applying indirect heat integration and applying both heat integration in total site heat integration are analyzed. The new idea allows the direct and indirect heat integration to be considered simultaneously. The application of the new methodology can bring a significant energy saving in total site.
