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

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. (C) 2021 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved.