Using Pinch Technology to Explore Trade-Offs Between Energy Cost, Capital Cost, Process Modifications, and Utility Selection

Process design is a complex task. Many decisions regarding feedstock, reaction routes, separation alternatives, heat recovery and utility systems must be made. Each of these decisions, and interactions between them, have a significant impact on the total cost of installing and operatlng a process. Understanding the impact of these decisions in the context of the overall process can lead to significant savings in both capital and operating costs. Full investigation of these interactions through engineering studies is expensive in terms of both time and money, and in most cases is not done. This results in missed opportunities to save energy and capital. Pinch Technology, however, offers a new approach to designing total processes. It provides insight, tools, and methodologies which allow the impact of design decisions to be understood, quantitatively, in the context of the overall process, before detailed engineering studies are required. The development of these capabilities expands Pinch Technology's role in process design far from the early breakthroughs of energy targeting and heat exchanger network design (I). This paper describes the tools and approach involved in determining the trade-offs between capital cost, energy cost, process modifications and utility selection. The application of Pinch' Technology to a Chemi-Thermo Mechanical Pulping process is used to illustrate the approach and the results