به كار گيري برنامه ريزي رياضي با در نظر گرفتن P دلتا در طراحي شبكه مدل هاي حرارتي

Heat Exchanger Network Design with Pressure Drop Consideration Using Mathematical Programming

Both in pinch technology and mathematical programming, it is assumed that a single stream passes through either tubes or shells throughout its temperature span. Therefore a unique heat transfer coefficient can be used. This approach in many cases can cause a significant deviation between targeting and design stages. In this article an algorithm based on MINLP model used for HEN grassroot design with pressure drop consideration is suggested that has the following advantages: the pressure drop in each side of the exchanger (shell or tubes) can be assessed, heat transfer coefficient will be calculated based on maximum pressure drop to reduce the area of heat exchanger, heat transfer coefficient for individual heat exchanger can be determined and possibility of passing a stream through shell in one segment and in tubes in another segment in overall temperature span can be considered. The proposed model was compared with the results of two different case studies solved by Panjeh Shahiʹs method. The comparison shows reduction of more than 36% in area of the exchangers, confirming the fact that more accurate evaluation of heat transfer coefficient for each individual stream can lead to a better network design.