Rigorous multiple utility targeting in heat exchanger networks

This article presents a non-graphic procedure for utility targeting in heat exchanger networks. It successfully finds the minimum needs of hot and cold utilities stratified according to their temperature levels. This promotes efficient energy use by guiding the design to avoid using hot utilities at unnecessarily high temperatures and cold utilities at unnecessarily low temperatures. Another feature is the rigorous evaluation of the thermodynamic properties of process streams, without assuming constant heat capacities or ad hoc linearizations of enthalpy–temperature relationships. The biggest advantage of this approach is that the utility targeting results are more accurate than those of methods that adopt such simplifying assumptions. The procedure uses a global line search optimization technique for utility targeting and its computational effort is well within the capabilities of current personal computers.

► A procedure for utility targeting in heat exchanger networks is proposed.
► It finds the minimum needs of hot and cold utilities at each temperature.
► Procedure helps efficient energy use by avoiding needlessly hot or cold utilities.
► Thermodynamic properties of the process streams are rigorously evaluated.
► Computational effort is within the capability of current personal computers.