摘要
In this study,vapor recompression and heat integration assisted distillation arrangements with either the low or high pressure in the reflux drum are proposed to reduce and/or eliminate the application of the costly refrigerant for the separation of n-heptane and isobutanol mixture.The high-pressure arrangement with vapor recompression and heat integration is the most attractive among these four intensified configurations since it can reduce total annual cost by 18.10%,CO_(2) emissions by 75.01%based on natural gas(78.78%based on heavy oil fuel),and second-law efficiency by 61.20%compared to a conventional refrigerated distillation system.Furthermore,exergy destruction in each component is calculated for the heat integration configurations and is shown in pie diagrams.The results demonstrate that the high-pressure configuration presents unique advantages in terms of thermodynamic efficiency compared to the low-pressure case.In addition,dynamic control investigation is performed for the economically efficient arrangement and good product compositions are well controlled through a dual-point temperature control strategy with almost negligible product offsets and quick process responses when addressing 20%step changes in production rate and feed composition.Note that there are no composition measurement loops in our developed control schemes.