Due to severe fouling in the heat-transfer units, the target temperatures of process streams in a heat exchanger network (HEN) may not always be achievable after a sufficiently long period of operation. To circumvent this practical problem, the conventional cost-optimal HEN design should be modified to accommodate online cleaning operations via proper allocation of area margins, bypasses, spares, and auxiliary heaters/coolers. For the purpose of facilitating solution convergence of the corresponding optimization problem, the candidate units for incorporating margins and the corresponding bypasses are identified on the basis of test runs in this study and, also, extra constraints on the spares formulated according to a set of heuristic rules to further reduce the search space. A solvable MINLP model can then be constructed by including these test findings and heuristic constraints. From the optimum solution, one could then obtain the proper refinements to any given design to facilitate implementation of an optimal cleaning schedule. Finally, the optimization results of extensive case studies are also presented in this article to demonstrate the feasibility and effectiveness of the proposed approach.
All Science Journal Classification (ASJC) codes
- Chemical Engineering(all)
- Industrial and Manufacturing Engineering