Total Cost Targeting for Heat Exchanger Networks Including Pumping Costs

摘要

A total cost targeting method for the heat exchanger network (HEN) design problem isrnpresented, which combines existing targeting methods for grass-roots design with a newrnmethod for targeting pumping costs (i.e., optimizing the pressure drops of streams). Thernoverall targeting problem is formulated so as to minimize the total annual cost, whichrnincludes the capital costs of heat exchangers and pumping devices, as well as thernutilities costs and the electricity costs to run the pumping equipment. This leads to arnproblem that can be solved as a non-linear optimization problem. The resulting solutionrnof this mathematical model gives the optimal pressure drops and film heat-transferrncoefficients of the streams. Therefore, neither the heat-transfer coefficients nor thernallowable pressure drops are fixed, as is the case with previous targeting methods basedrnon pinch technology. An example is presented to illustrate the targeting of heatrnexchanger networks using the proposed approach.