基于(火积)的SSOT装置换热网络能量利用效率的分析研究

(火积)的概念可以描述物体传递热量的能力,基于(火积)的能量利用效率可作为评价热量合理利用的依据。建立基于(火积)的换热网络的能量利用效率的数学模型,并提出相应的计算步骤,以最大能量回收为目标,通过对某单段单程加氢裂化(SSOT)实际生产装置进行换热网络能量利用效率的分析研究,验证(火积)传递效率的合理性。结果表明:分析SSOT装置的原始换热网络时,得出公用工程HU1、HU3、CU6、CU7的(火积)耗散率较大,分别为36.25%、35.36%、85.50%和68.97%,而基于的概念得到公用工程HU3、CU6、CU7的损率较大,分别为37.83%、17.98%和13.95%,则(火积)传递效率比效率分析换热网络的能量利用情况更加精确。选取最小传热温差ΔT_(min)=15 K后,(火积)传递效率从57.18%增加到76.45%,节约公用工程52.53%,效率从59.62%增加到83.31%,节约公用工程60.61%,进一步说明(火积)传递效率能够用来分析换热网络中的能量利用情况。

Analysis on the Energy Utilization Efficiency of Heat Exchange Network in SSOT Unit based on Entransy

The concept of entransy can be used to describe the ability of an object to transfer heat, and the energy utilization efficiency based on entransy theory can be used as a basis for the rational use of heat. In this paper, a mathematical model of energy utilization efficiency of heat exchange networks (HENs) based on entransy was established, and the corresponding calculation procedure was put forward. With the aim of the maximum energy recovery, the energy utilization efficiency of the HEN in a single-stage once through hydrocracker (SSOT) unit was studied, and the rationality of the entransy transfer efficiency was verified. When the original HEN of SSOT unit was analyzed, the entransy dissipation rate value of HU1, HU3, CU6 and CU7 of utilities was bigger, which was 36.25%, 35.36%, 85.50% and 68.97% respectively. Based on the concept of exergy, the exergy loss rate value of HU3, CU6, CU7 of utilities was bigger, 37.83%, 17.98% and 13.95% respectively, so the entransy transfer efficiency was more accurate than the exergy efficiency. After selecting the minimum heat transfer temperature difference?Tmin = 15 K, the entransy transfer efficiency increased from 57.18% to 76.45%, saving 52.53% of the utilities, the exergy efficiency increased from 59.62% to 83.31%, saving 60.61 % of the utilities. Thus, the entransy transfer efficiency can be used to analyze the energy utilization efficiency in the HENs.