Dear all,
as asked above:
I'm dealing with a porous carbon based membrane for the separation of water vapour from a gas stream at elevated temperatures between 120 and 220 °C.
I'm conducting experiments (adsorption and permeation) in order to have a solid data base.
I think a good starting point for the modeling approach would be to use the solution diffusion approach of dense membranes. From my first trials it's becoming visible, that the capillary effect and surface adsorption in the capillaries plays an important role in the diffusion process.
Do you think this approach is worthwhile and physically sane?
Do you have a good starting point (e.g. papers, models, etc) for me at hand?
Thanks all for your thoughts and help
The given equations or functions (mathematical model) can be used to simulate the process but also to describe datapoints. As to the rationality of a given mathematical model, one can be sure after its verification on experimental data. However, I would not equate diffusion with capillary effects.
Thanks Dr. Grzesik for your answer and your thoughts.
I am not planning to use a diffusive approach for the capillary effect. The idea is to incorporate the capillary effect in the adsorption description in the model and then use surface diffusion coefficients for the diffusive part of the model.
My question was more about if this approach was tested for vapor transport in porous media before and if yes if it's still worthwhile.
Dear Matthis Kurth;
Interesting question. If you have a porous membrane system, I think you should start by considering a pore-flow model for assessing the separation of your components. After that, you could assess other transport mechanisms such as solution-diffusion through the membrane material. It may result that these effects are neglible compared with bulk-flow transport.
Here I attached a link to a work on mass transport mechanisms through organic solvent nanofitlration membranes in which both models were considered: solution-diffusion and pore-flow mechanisms. In such case, the membrane is considered a dense-layer membrane, so a solution-diffusion process appears as the main transport mechanism.
Article Solute molecular transport through polyimide asymmetric orga...
Hope this is useful for your research.
Regards.
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