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

压力和密度对近临界和超临界溶液吸附平衡的影响 - 实验测定和热力学建模

基本信息

批准号：
260851204
负责人：
Privatdozentin Dr. Monika Johannsen
金额：
--
依托单位：
Institut für Thermische Verfahrenstechnik V-8
依托单位国家：
德国
项目类别：
Research Grants
财政年份：
2014
资助国家：
德国
起止时间：
2013-12-31 至 2016-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/260851204?language=en
关键词：
Influence pressure density adsorption equilibria

项目摘要

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.

使用超临界流体的吸附过程变得越来越重要，其颗粒直径达到纳米级。准确了解相应的吸附平衡对于有效设计此类分离过程至关重要。本提案申请拨款，以根据色谱柱内可压缩超临界溶液吸附平衡的实验测定，进一步开发密度依赖性吸附的热力学模型。沿着这种柱的物理上必要的压降是这种流体吸附的动态测量中的主要误差源。到目前为止，还缺乏以理论上合理的方式描述这些柱中吸附的模型。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以大压降进行。通过使用第二个较短但其他方面相同的柱，超临界流体的吸附将在密度可以假定恒定的区段内测量。随后，如有必要，将评估和扩展热力学建模的不同可能性。目标是根据使用较长色谱柱的大压降测量结果尽可能准确地计算各段中的吸附量。建模时采用 Peng-Robinson 状态方程、SAFT 和 Virial 状态方程等模型。除了密度依赖性吸附的描述之外，所需的纯化合物和混合化合物数据的数量是模型性能的标准。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+不挥发有机固体）。此外，还应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。或者，该模型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模型的可转移性。