【作者】 吴芹；

【导师】 周理；

【作者基本信息】 天津大学 ， 化学工程， 2003， 博士

【摘要】 多组分超临界吸附平衡是多组分吸附平衡目前亟待解决的问题，是吸附领域内一个明显的薄弱环节，很少有相关的实验和理论研究报道。多组分超临界吸附平衡的研究对多组分吸附平衡理论的发展和工业化生产的需要具有重要的理论意义和工业应用价值。因此本文重点研究了多组分超临界吸附平衡。首先系统评述了多组分气体吸附平衡的实验和理论研究现状，并采用JX-101椰壳活性炭为吸附剂，用静态容积法测定了纯CH4、N2和H2的吸附等温线，温度范围283K～298K，压力范围0～10105Pa，以此作为预测多组分吸附平衡的基础。然后采用动态法测定了超临界组分CH4－N2－H2混合物在JX-101活性炭上不同浓度、不同温度条件下的吸附平衡数据，实验温度范围283～313K，压力范围0～6105Pa。利用实验测得的多组分超临界吸附平衡数据，检验了各种已有模型的适用性，包括EL、LRC、G－M、IAST、FHVSM、MPSD和MISC七种模型，对各个模型的优缺点进行了分析比较。通过对现有模型的比较，发现FHVSM 模型和本实验室前期提出的MISC模型对超临界多组分CH4—N2—H2吸附平衡的预测精度最高。但是，现有模型的共同缺点是把吸附相看作为饱和液体，这种处理方法对超临界多组分吸附平衡是不合理的。本文基于超临界气体吸附的基本特性，把吸附相看成吸附质分子在吸附剂表面形成的非理想的单分子层混合二维压缩气体，用二维维里方程描述吸附相行为，同时用孔径分布函数描述吸附剂表面的不均一性，由此提出一个新的预测多组分超临界吸附平衡的理论模型—SAEM。通过实验数据对此模型进行了全面考核，结果表明SAEM模型整体表现优于现有其它模型。为充分检验SAEM模型的可靠性，亦采用文献发表的其它多组分吸附平衡数据对此模型做了进一步考查，发现SAEM模型对超临界多组分吸附平衡的预测表现最优，对既含超临界组分也含亚临界组分吸附平衡的预测能力仅次于MISC模型。由此证明了SAEM模型预测超临界多组分吸附平衡的方法是合理且可靠的。更多还原

【Abstract】 Knowledge of multicomponent supercritical adsorption equilibrium is important to the design of separation processes and the progress of theory. However, only few research had been done on multicomponent supercritical adsorption equilibrium. Therefore, multicomponent supercritical adsorption equilibrium was studied systematically. The research progress in the experiments and theories of multicomponent adsorption equilibria was reviewed in detail. Pure component adsorption isotherms of methane, nitrogen, and hydrogen on JX-101 activated carbon were measured by the volumetric method and acted as basic data for predicting multicomponent adsorption equilibrium. The experiment condition covered the range 283-313K and pressures 0-10(105Pa. In addition, the adsorption equilibrium data of the CH4-N2-H2 mixtures of various composition on JX-101 activated carbon were measured by the dynamic method in the range of 283K(313K, 0(6(105Pa.Several well-known models to predict multicomponent adsorption equilibrium were tested by experimental data presently. The models tested include (1) the extended Langmuir model (EL); (2) the laden ratio correlation (LRC); (3) the ideal adsorption solution theory (IAST); (4) the Flory-Huggins vacancy solution theory (FHVSM); (5) the model basing on micropore size distribution and the extended Langmuir equation (MPSD-EL); and (6) the model for mixture including supercritical component (MISC). Performance of multicomponent adsorption equilibrium models is compared with experimental data. It was found that the FHVSM model and the MISC model can give better predictions for the experimental data in the classical models. However, the adsorption equilibrium is treated as a gas-liquid equilibrium between the gas phase and the adsorbed phase in these models. But it is not correct that the adsorbed phase is considered as saturated liquid for multicomponent supercritical adsorption equilibrium. A new model, SAEM, to predict multicomponent adsorption was proposed assuming (1) The energetic heterogeneity of adsorbent surface can be described by micropore size distribution; (2) The adsorbed phase is visualized as a two-dimensional non-ideal compressed gas, whose state can be described by two-dimensional virial equation. The new model was applied to the experimental data measured. It is found <WP=4>that the SAEM model predicted much better than all classical models. In addition to our own data, the SAEM model was applied to the data published by other researchers, which are widely used in the testing of adsorption models. The results showed that the SAEM model gave the best predictions for multicomponent supercritical adsorption equilibrium and was only inferior to the MISC model for the gas mixture including supercritical and sub-critical component. Therefore, it was proved that the SAEM model was reasonable and reliable.更多还原