Physico-chemical Principles of Supercritical Fluid Separation Processes

Author(s):  
Gerhard M. Schneider
2021 ◽  
Author(s):  
Fabian Jirasek ◽  
Jakob Burger ◽  
Hans Hasse

The conceptual design of fluid separation processes is particularly challenging if the considered mixtures are poorly specified, since classical thermodynamic models cannot be applied when the composition is unknown. We have recently developed a method (NEAT) to predict activity coefficients in such mixtures. It combines the thermodynamic group contribution concept with the ability of NMR spectroscopy to quantify chemical groups. In the present work, we describe how NEAT can be applied to equilibrium stage simulations of liquid–liquid extraction processes with poorly specified feeds. Only a single 13C NMR spectrum of the feed is needed for predicting the distribution of a target component for different process parameters, such as temperature or extracting agent. The predictions from several test cases are compared to results that are obtained using the full knowledge on the composition of the feed and surprisingly good agreement is found.


2016 ◽  
Vol 18 (1) ◽  
pp. 21-46 ◽  
Author(s):  
Darya Radziuk ◽  
Helmuth Möhwald

Cleaning and separation processes of liquids can be advanced by acoustic cavitation through bubbles with unique physico-chemical properties.


2009 ◽  
Vol 4 (5) ◽  
Author(s):  
Eugeny Y. Kenig

Modern fluid separation processes occur under very complex conditions. As a result, their modeling is usually based on severe assumptions and experimentally estimated gross parameters. On the other hand, the process optimization can only be achieved with reasonable model accuracy, whereas the process rates should be considered in a rigorous way, with respect to both transport phenomena and chemistry.Depending on the complexity of process fluid dynamics, different modeling ways can be applied, their rigor and complexity stretching over a wide range. Among these ways are a direct application of the equations of fluid dynamics, the hydrodynamic analogy method and the rate-based approach. These methods are complementary in the sense that, together, they are able to govern both simple and very complex process fluid dynamic conditions. Moreover, there is also another complementarity between the different approaches, namely, they can be applied in combination, for instance, by estimating process parameters by a more rigorous method and delivering them to the less rigorous one. In this contribution, the complementary modeling is discussed in detail and illustrated with case studies.


2020 ◽  
Vol 30 (2) ◽  
pp. 92-104
Author(s):  
Rafał Nowak ◽  
Maria Włodarczyk-Makuła

AbstractThe purpose of the paper was to assess the effectiveness of selected physico-chemical processes to improve the quality of retentates/concentrates obtained during the treatment of landfill leachates using membrane separation. Among the physico-chemical methods, Advanced Oxidation Process (AOP) and electrocoagulation were analysed. Landfill leachate resulting from the infiltration of waste mass by atmospheric precipitation as well as the dissolution and leaching of waste components are most often subjected to membrane separation. Permeate is usually discharged to the receiver, while the concentrate is recirculated and sprinkled on a waste pile. However, such action is only the retention of impurities in the body of the landfill and has an impact on the chemistry of raw leachates. Due to the very high concentrations of organic and inorganic compounds identified in the retentate, it is necessary to treat it, which will effectively reduce the amount of impurities in the leachate. Economic use seems to be another solution. An example would be growing energy crops but such application requires additional research.


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