Your process will compete with "wet-gas" CO2 removal processes like the Benfield process and other amine based CO2 scrubbing processes. That means removal may need to be very good (

Thank you sir for your interest.

According to your information, which types of membranes are most used in the separation processes in the industrial units. And what are the factors on which the membrane is selected.

There a lot of information available online if you look for it. Here are a few links I found:

https://www.newpointgas.com/services/carbon-dioxide-co2-removal/

https://www.sciencedaily.com/releases/2017/10/171018090158.htm

Figures:

https://images.search.yahoo.com/search/images?p=Membrane+for+CO2&fr=mcafee&imgurl=https%3A%2F%2Fsc02.alicdn.com%2Fkf%2FUT87i1PXyRaXXagOFbX1%2Fco2-removal-membrane-for-natural-gas-separation.jpg#id=4&iurl=https%3A%2F%2Fsc02.alicdn.com%2Fkf%2FUT87i1PXyRaXXagOFbX1%2Fco2-removal-membrane-for-natural-gas-separation.jpg&action=click

Here is a description o the Benfield process normally used to remove CO2 from H2 rich streams at comercial H2 plants.

https://www.bre.com/PDF/Simulation-of-the-Benfield-HiPure-Process-of-Natural-Gas-Sweetening-for-LNG-Production-and-Evaluation-of-Alternatives.pdf

Thank you sir

You are welcome sir

Dear Dhyaa,

Some time back I was part of a team that was retrofitting a CO2 plant for a local manufacturer in Uganda and we found out that carbon membranes gave better results on industrial applications as compared to membrane contactor's or polymeric membranes. We developed our techniques on the background provided by SINTEF which you can search online.

Unfortunately I can't share much as I am bound by legal agreements however look up SINTEFs work on this.

thank you sir

There are several factors influencing selection of CO2 removal technology. Aqueous amine absorption usually wins, but membranes can be preferable for some offshore applications and some cases where CO2 content is very high, but usually only when H2S does not have to be removed as well (membranes can usually achieve the low % levels required for CO2 in product gas, but not the low-ppm levels of H2S that are also required). It also helps if the raw gas is at high pressure, or if it needs to be compressed to a high pressure as a product, since membranes are more dependent of gas pressure as a driving force than amine absorbers are.

On page 12 of this document (https://www.netl.doe.gov/sites/default/files/netl-file/Carbon-Dioxide-Capture-Handbook-2015.pdf ), at the beginning of Section 1.1 is a chart showing technology selection guidelines for CO2 removal. This chart does not include membranes at all, and it is only relevant for streams where H2S removal is not an option, but it is a good example showing how different technologies win out under different conditions. Membranes are discussed in Chapter 3, but this reference is directed more at CO2 capture from flue gas.

There are similar studies in the natural gas processing literature, and membranes have gradually moved from being absent there as well to carving out a niche of their own. "Membranes for Gas Separations: (Carreon, 2018) is an up-to-date resource. "Handbook of Natural Gas Transmission and Processing: Principles and Practices" (Mokhatab, et al., 2015 )is another, also "Natural Gas Processing: Technology and Engineering Design" (Bahadori, 2014) and "Natural Gas Processing from Midstream to Downstream (El-Halwagi, et al. (Eds), 2019). If you can't access any of these, let me know and I'll see if I can share a relevant excerpt or two (see recent LinkedIn invite).

When the great American chemist Carothers was trying with his Anglo-American team of researchers (at DuPont) to prepare artificial silk, they started with polyesters but that didn't work after many trials so he decided to change the direction of research into polyamides and obtained exceptional results which gave the important family of NYLON "NY stands for New York & LON stands for London".

I do not see why a membrane must be used if the main aim is to separate CO2 from a mixture of gases "Natural Gas". Industrial chemists know that ethanolamine is efficient in dissolving CO2 and aqueous K2CO3 can also dissolve CO2 so there may be a room to try gas-liquid absorption using a small packed tower absorber or scrubber in a pilot plant study. Solvents, that can dissolve CO2, are well-known & they are tabulated in many references. Washing this gas more than once with a proper selective solvent may prove to be highly efficient as is done in separating CO2 during the production of hydrogen by steam reforming of natural gas.