Abstract:

To research the non-equilibrium sorption kinetic models of SrCl₂ compound sorbents-NH₃ working pairs, the sorption and desorption performance of SrCl₂-expanded natural graphite treated with sulfuric acid (ENG-TSA) composite sorbents with the ratio of 4:1 (SrCl₂:ENG-TSA) is tested and researched. Results show that the non-equilibrium sorption processes are controlled by two variables other than single variable. Then, the isobaric sorption/desorption processes and the hysteresis phenomena were analyzed, and the kinetic models were established. The refrigeration performance of composite sorbents is studied, and the corresponding COP and theoretical refrigerating capacity are analyzed by equilibrium data, experimental data, and modelling data, respectively. The results show that the established kinetic model fit the experimental data well. For instance, compared with the experimental data the error of COP by the established kinetic model is less than 1%, while that value by theoretical equilibrium data is 25.8% (under the condition of evaporating temperature of 0℃, environmental temperature of 25℃, and heating temperature higher than 90.5℃). The system refrigerating capacity obtained by theoretical equilibrium data is 188.1% higher than that gotten from the experimental data, while the value by kinetic model is just 2.1%.

Key words: solid sorption, sorbents, kinetic model, non-equilibrium, hysteresis

摘要：

为了研究氯化锶混合吸附剂-氨气工质对的非平衡吸附动力学模型，对混合比例为4：1（氯化锶：膨胀硫化石墨）的氯化锶-膨胀硫化石墨混合吸附剂的吸附与解吸性能进行了测试与研究。发现其非平衡吸附过程是双变量控制过程而不是单变量控制过程。通过对其等压吸附/解吸过程及解吸滞后现象进行进一步分析，建立了氯化锶混合吸附剂的动力学模型。分别用理论、实验及模型数据拟合吸附制冷过程的COP和制冷量，结果表明，所建立的非平衡动力学模型的拟合结果和实际结果吻合得很好。例如在蒸发温度为0℃、环境温度为25℃、热源温度为90.5℃以上时，拟合COP所带来的最大误差只有1.0%，而理论的平衡吸附性能计算所带来的最大误差为25.8%；理论得到的制冷量比实际值偏高188.1%，而拟合值只比实际值偏高2.1%。

关键词: 吸附, 吸附剂, 动力学模型, 非平衡, 滞后