Heat exchanger network synthesis using HENCALC (a MATLAB computer program) and Second Law insights

A MATLAB computer program, HENCALC, was written to generate (for heat exchanger networks), plots of hot and cold composite curves, hot and cold stream temperatures at the pinch, the minimum utilities needed, estimated exchanger area, estimated minimum number of heat exchangers, and a plot of estimated total annualized cost of energy and capital, as a function of minimum approach {dollar}Delta{dollar}T.; A restructured grid diagram for the design of HENS is proposed, and is discussed in detail. It includes stream flow heat capacities, and their ratio at heat exchangers.; Three heat exchanger network (HEN) problems were studied using HENCALC: a 5-stream HEN that requires both hot and cold utilities, a 4-stream HEN that requires only one utility (i.e., a threshold HEN), and a complex 10-stream crude oil distillation HEN.; HEN designs were developed for each of these problems by using the Second Law insight method. This method utilizes a set of common-sense Second Law guidelines to detect and eliminate Second Law errors from a design.; An existing crude oil distillation HEN was found to have several Second Law errors. When these were eliminated, 20.4 MW of fired heat was saved. This new design is also superior to a retrofit, reported in the literature, that was developed using the pinch design method. The pinch design, which still retains some Second Law errors, requires 6.5 MW more than the Second Law insight design.