Mc. Georgiadis et Lg. Papageorgiou, Optimal energy and cleaning management in heat exchanger networks under fouling, CHEM ENG R, 78(A2), 2000, pp. 168-179
This paper addresses the problem of cyclic cleaning and energy scheduling i
n special classes of heat exchanger networks (HENs). A salient characterist
ic of this problem is that the performance of each heat exchanger decreases
with time and can then be restored to its initial state by performing clea
ning operations. Due to the cyclic nature of the schedule, some operations
may span successive cycles (wrap-around) which is taken into account in the
mathematical model. A tight mixed integer linear programming (MILP) model
is presented which is solved to global optimality. A detailed objective fun
ction is used to account for cleaning cost and energy requirements. The for
mulations can model serial and parallel HENs, as well as network arrangemen
ts arising from the combination of these basic cases. The optimization algo
rithm determines simultaneously: (i) the number of cleaning operations requ
ired along with their corresponding timings and (ii) the optimal utility ut
ilization profile over time. A complex heat exchanger network example is pr
esented to illustrate the applicability of the proposed model.