Abstract

MEJIA-SUAREZ, D.A. et al. Synthesis of alternative designs in the retrofit of heat exchanger networks. Rev. Mex. Ing. Quím [online]. 2010, vol.9, n.1, pp.99-123. ISSN 1665-2738.

This work proposes a Mixed-Integer Nonlinear Programming model for the simultaneous retrofit of heat exchanger networks, HEN, which takes into account: (i) the placement, modification and reassignment of existing exchangers, (ii) additional exchangers, (iii) HEN topology, (iv) utility costs and (v) investment costs. In addition, the model formulation incorporates re-piping costs that account to limit the number of reassignments of the available equipments. The network superstructure proposed by Yee and Grossmann (1990) is considered in this paper. This superstructure introduces redundant characteristics which involves important combinatorial problems even for small instances of the retrofit problem. On the other hand, since the developed model involves nonconvex terms, a nondeterministic solution methodology can converge to a suboptimal point. A methodology to facilitate the search for good alternative solutions is described also in this work, so the designer will have diverse options to consider and, besides the total annualized cost, different network features can be taking into account in the final selection of the retrofit design.

Keywords : heat exchanger networks; HENs retrofit; simultaneous design and optimization; thermal integration; effcient use of energy and heat recovery.