This study presents a simple approach for the exergy analysis of heat exchanger networks (HENs). This approach is based on approximating the irreversibility distribution ratio () and the exergy destruction of a HEN in a large natural gas refinery, without needing to design the individual heat exchangers. Only the thermodynamics properties and the temperatures of the hot and cold streams at the inlets and outlets of the heat exchangers, as well as a model assuming for temperature distributions along the exchangers, are required. The exergy efficiencies and destructions were calculated for the individual heat exchangers and therefore for the HEN by superposing them. Also, and Bejan number were obtained by approximating irreversibilities arising from the heat transfer and pressure drop due to fluid friction. The total () in the whole network was 0.188, with a Bejan number of 0.842. The results showed that the main source of the exergy destruction in the whole heat exchanger network of the plant is the irreversibility arising from heat transfer and the heat transfer irreversibility contribution to the total irreversibility in all the HENs was 84.2%. Moreover, the overall exergetic efficiency was 63.34%, which shows a great potential for improvement in the network system under consideration.

中文翻译：

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多换热器网络火用分析：一种基于不可逆分配比的方法

本研究提出了一种用于热交换器网络 (HEN) 火用分析的简单方法。该方法基于大型天然气精炼厂中 HEN 的不可逆分配比 () 和火用破坏的近似计算，无需设计单独的热交换器。只需要热力学性质和热交换器入口和出口处的热流和冷流的温度，以及假设沿着交换器的温度分布的模型。计算了各个热交换器的火用效率和破坏，因此通过叠加计算了 HEN 的火用效率和破坏。此外，Bejan 数是通过近似由流体摩擦引起的传热和压降产生的不可逆性获得的。全网总()为0.188，贝詹数为0.842。结果表明，全厂换热网络火用破坏的主要来源是传热不可逆性，传热不可逆性对所有HEN总不可逆性的贡献率为84.2%。此外，整体能量效率为63.34%，这表明所考虑的网络系统具有巨大的改进潜力。