Influence of pressure and density on adsorption equilibria from near and supercritical solutions - experimental determination and thermodynamic modeling

使用超临界流体的吸附过程越来越重要，颗粒直径达到纳米级。相应的吸附平衡的准确知识是绝对重要的设计这样的分离processingefficient.This建议申请资助，以进一步发展密度依赖吸附的热力学模型的基础上，可压缩的超临界溶液在色谱柱内的吸附平衡的实验测定。沿着这种柱的物理上必要的压降沿着是这种流体的吸附的动态测量中的主要误差源。到目前为止，还缺乏一个模型来描述吸附在这些列在理论上健全的方式。在该项目的实验部分中，研究了二元溶液（CO2 +非挥发性有机固体）的吸附。吸附测量将在分析色谱柱中的大压降下进行。通过使用第二个较短但在其他方面相同的柱，超临界流体的吸附将在其中密度可以假定为恒定的段内测量。随后，不同的热力学建模的可能性将进行评估，并在必要时进行扩展。目标是使用较长的色谱柱，从具有大压降的测量值中尽可能准确地计算出各段中的吸附。对于建模，将应用Peng-Robinson状态方程、SAFT和维里状态方程等模型。接下来的密度依赖性吸附的描述，所需的纯和混合化合物的数据的数量是该模型的性能的标准。在二元溶液吸附的基础上，将实验和计算推广到三元溶液（CO2 +有机改性剂+非挥发性有机固体）。此外，将测量溶解在正己烷中的非挥发性固体在相同吸附剂上的吸附，作为参考数据。任选地，建模也将应用于液体吸附，以测试非挥发性固体和吸附剂之间的相互作用参数到超临界吸附的建模的可转移性。

Adsorption processes using supercritical fluids are gaining increasing importance, with particle diameters reaching into the nanoscale. Exact knowledge of the corresponding adsorption equilibria is of utter importance to design such separation processes efficiently.This proposal applies for a grant to further develop the thermodynamic modeling of density dependent adsorption based on experimental determination of adsorption equilibria of compressible supercritical solutions within a chromatographic column. The physically necessary pressure drop along such a column is a major source of error within the dynamic measurement of adsorption of such fluids. So far, there is a lack of models to describe adsorption in these columns in a theoretically sound manner. In the experimental part of the project the adsorption of binary solutions (CO2 + non-volatile organic solid) is investigated. Adsorptions measurements will be carried out with a large pressure drop in an analytical chromatographic column. By using a second, shorter but otherwise identical column, the adsorption of the supercritical fluid is to be measured within segments in which the density can be assumed constant. Subsequently, different possibilities of thermodynamic modeling will be evaluated and extended if necessary. The goal is to calculate the adsorption in the segments as exactly as possible from the measurements with large pressure drop using the longer column. For modeling, models such as the Peng-Robinson equation of state, SAFT and the Virial equation of state are to be applied. Next to the description of the density dependent adsorption, the number of pure and mixed compound data needed is a criterion for the performance of the model. Based on the adsorption of binary solutions, the experiments and calculations are extended to ternary solutions (CO2 + organic modifier + non-volatile organic solid). Additionally, the adsorption of non-volatile solids dissolved in n-hexane on the same adsorbents is to be measured as reference data. Optionally, the modeling will also be applied to liquid adsorption to test the transferability of interaction parameters between non-volatile solid and adsorbent to the modeling of the supercritical adsorption.