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Abstract
For many years the only generaJIy available basic heat transfer data of sufficient accuracy for heat exchanger design was for the flow through and over banks of circular tubes. The need for small size and lightweight heat exchangers in all varieties of powered vehicles from automobiles to spacecraft, as well as in a multitude of other applications, has resulted in the development of many heat transfer surfaces that are much more compact than can be practically realized with circular tubes. In addition many of these surfaces possess other characteristics that are superior to circular tubes. However, lack of basic heat transfer and flow friction design data, and a lack of understanding of the basic mechanisms involved, for a long period of time restricted their use to heat exchangers that could be developed by cut-and-try methods.
In this work a model representing one of the seven plate fin heat exchangers enclosed in the cold box of Sidi Kerir Petrochemicals Co. (Sidpec) ethylene plant was developed. This model was used to predict the outlet temperatures of the hot and cold streams from the exchanger (one hot and six cold streams) when the inlet conditions are known, and this model was validated by comparing the model calculated results to the actual plant operating data. The results of the comparison had shown good agreement between the model results and the real operating data for the heat exchanger.
The model was also used to examine the effect of any suspected fouling after several years of operation or in the future - under any unusual circumstances like that caused by hydrate fonnation or that may arise from contaminants in the process fluids like seal oil with refrigerant streams - on the performance of the exchanger, and the results had shown that the fouling has a slight effect on the cold streams outlet temperature and the hot stream outlet temperature
The sensitivity analysis applied on the model illustrated the main parameters that have the greatest influence on the model calculated results, and this had shown that the thennal resistance in the hot side has a slightly higher effect than that in the cold side.