Sensitivity analysis of industrial heat exchanger network design

Abstract

The problem of interaction between economic design and controller design of heat exchanger network (HEN) is addressed in this work. The feasibility and sensitivity issues are incorporated in the classical design of HEN. HENs in industry seem to be very efficiently operated. The network that may have operated efficiently perhaps is the one that is not fully optimised in term of flexibility and sensitivity. It is important to do synthesis and sensitivity analyses of the designed network. The objective of this paper is to investigate and compare the sensitivity criteria of the originally designed HEN of the fatty acid fractionation process (FAFP) and the new HEN design. In this study, the HEN designs are already fixed at the value of ΔTmin = 40 °C. A new suggested HEN is redesigned from the original HEN of FAFP plant by obeying Pinch Analysis (PA) rules. The new HEN was redesigned by applying the PA stream splitting compared to the original HEN (that has been used in the industry), in which the design is not have stream splitting. The aim of this work is to determine the best optimised design whether the one that not followed Pinch Analysis rules or the other one. Using the new developed FNO HEN methodology framework, sensitivity analysis was applied which consists of two tests: 1) Flexibility Analysis and 2) Sensitivity Analysis. According to the results, the best candidate that satisfies the sensitivity and economy criteria is the new HEN design. It can be concluded that it is important to do stream splitting in order to obtain not only the best HEN in terms of design and economy criteria, but also in the matter of sensitivity criteria.