Economic Optimization of Internal Thermally Coupled Air Separation Column Configurations

An internal thermally coupled air separation column (ITCASC) process is an effective energy-saving technology in the air separation process. However, a large economic investment is a crucial factor for the widespread use of this technology in practical applications. In this article, an alternative configuration design, namely, top-integrated (T-ITCASC), bottom-integrated (B-ITCASC), and top-bottom-integrated ITCASC (T-B-ITCASC) with a focus on energy savings and economic feasibility are studied. A rigorous optimization based on a nonlinear interior-point algorithm was developed by integrating the dynamic model into the optimization formulation. In the context of ITCASC process design and optimization, numerical simulations demonstrated that T-ITCASC, B-ITCASC, and T-B-ITCASC configurations improved energy-saving potential and reduced capital investment, compared to the F-ITCASC and conventional air separation column (CASC) configurations. Among these optimized configurations, the T-B-ITCASC configuration is preferred.