气体膜分离过程模拟中2种平均推动力模型的准确性验证

Two average models scope divided in gas membrane separation process simulation

在各种气体膜分离模型中,平均推动力模型以其计算简单、易于在商业流程模拟软中使用等优点,普遍应用于气体膜分离过程的工艺设计中。但随着膜分离技术的发展,膜的渗透率增大,分离过程中压力范围变广,需要重新判定平均推动力模型的准确性及适用范围。以计算比较准确的离散模型为标准,对比离散模型、对数平均推动力模型和算术平均推动力模型的计算方程,确定压降为影响平均推动力模型准确性的主要参数。分别用离散模型和平均推动力模型对H_2/N_2、CO_2/N_2、O_2/N_2 3种具有代表性的体系进行模拟计算。并分析在不同膜渗透率、操作压力、浓度条件下2种平均推动力模型准确性。结果表明,算术平均推动力模型在低压降体系中的准确性较好,对数平均推动力模型适用于高压降体系。

Average models are commonly applied in gas membrane separation process simulation, due to their simple calculation, and easy incorporation into commercial process simulation software. With the development of membrane technology, membrane permeability increases and operating pressure range becomes wider. Therefore, the accuracy of average models and applied conditions need to again be determined. The comparison between both of arithmetic model and logarithm model and precise discrete model demonstrates that pressure drop is the main factor which affects the accuracy of average models. The simulation of three typical gas separation systems including H2/N2, CO2/N2, O2/N2 is performed with discrete model and two average models. Moreover, the accuracy of two average models has been investigated at varying conditions, i.e., membrane permeability, operating pressure, and concentration. The simulation results show that the arithmetic average model exhibits a better accuracy in low pressure drop systems, whereas the logarithm average model is more suitable for high pressure drop systems.