Hybrid two-step optimization of internally heat-integrated distillation columns

Abstract

Heat integration is one of the most used energy conservation methods in chemical processes, and it typically involves the heat transfer from the vapor stream entering a condenser and the liquid stream entering a reboiler. Nevertheless, this work exploits the idea of heat integration between stages in which heat is supplied at a temperature higher than that at the condenser in a high-pressure column and heat is received at a temperature lower than that at the reboiler in a low-pressure column. Since stages between column are subject to heat integration, a large combinatorial problem arises. Thus, this work proposes a hybrid optimization procedure consisting of two steps: The solution of a deterministic optimization (i.e., MILP problem) and stochastic optimization (e.g., Simulated annealing) to take advantage of the strong points from each optimization technique.