OVERALL SITE OPTIMIZATION BY PINCH TECHNOLOGY

Abstract

the continuous rise in energy cost and dwindling of conventional energy resources, the technocrats and scientists are under constant pressure to evolve procedures, tools and processes, which can account for energy auditing and can convert raw materials to products with consumption of minimum energy. The Process Integration, a process-engineering tool, has evolved with time as a reliable application tool, which addresses such problems. Heat and Power integration is a key feature of this Process Integration and can proved to be an enabling tool to decrease energy consumption of a process by cutting down its inherent energy losses caused due to faulty design and integration. Energy integration of a given process can fetch higher dividends to an existing industry. The dividends can further be enhanced with all the processes in a site integrated in an optimized manner. Total Site Integration can be achieved using tools such as -Pinch Technology, SitEModelling, Utility Level Optimization, Linear programming (LP) / Mixed Integer Linear programming (MTLP), Evolutionary Algorithm, Simultaneous Optimization and Heat Integration, Graphical Approach, Total Flow sheet Optimization and Expert System Approach. Out of these tools Pinch Technology is a prominent tool because it allows the operator and designer to take part in each step of Process Integration, and that is uncommon with other tools. The present work is related to heat integration of different processes available in an overall site. A hypothetical site having six processes was considered by taking the data of different processes from open literature. All the six processes contain different number of hot and cold streams ranging from three to five hot streams to three to five cold streams. iii As a first step, all the six processes were optimized separately and the (Atmin )opt values were computed. It was found that the values range from 8°C to 26°C. Then all these six processes were taken together and optimized. During this stage, the utilities available in different processes are shared amongst themselves. The results obtained from total site integration shows a total saving of Rs. 6,03,14,125 per year, which is nearly 11.3 % of the total site annual consumption of utilities. From the study, it can be concluded that even though all processes were running under optimal conditions in a site, higher savings can be achieved by integrating these processes through site integration.