Synthesis of Optimal Batch Distillation Sequences

Overview:

After the original design is completed, optimum Batch Distillation Sequencing/Operation in a chemical plant is usually a matter of trial and error that evolves as operators gain experience with the system. Some predictive tools exist for simulating batch separation systems, and they have been used with success in designing new separation systems and in analyzing existing systems. However, these tools require the user to define all the operation steps for each cut. The number of case studies required to approach an optimum scenario is very large, and is almost impossible to accomplish. Optimal design and operation, however, is the ultimate goal. In this paper we propose how to truly optimize a batch separation sequence. Combining the flowsheeting and modeling features of a process simulator provides an advantageous way to analyze and optimize operating scenarios for optimum batch separation sequencing. This approach is demonstrated with the optimization/debottlenecking of several batch distillation scenarios to separate and recover a heavy product, a partially water-miscible solvent, and water from a batch reactor effluent. Simulations identified a 25% increase in capacity with a minimum capital investment.