[Gasification] Sail-cloth employed to concentrate hydrogen

[Art Krenzel]

Thank you Andy.  It was a real challenge for my first job out of college.

Hydrogen diffuses through polymers faster than Helium due to having a 
smaller molecular size.  We did not have an over concentration of hydrogen 
problem in our four stage process because the amount of hydrogen in the feed 
gas was extremely low.   I used special ultra high purity Helium reference 
gases in our GOW MAC analyzer to measure the final Helium concentrations. 
Had there been any significant amounts of hydrogen present, the detectors 
would have picked it up very quickly.

Temperature did have a significant effect on permeation rates.  We used a 
temperature controlled permeator bay with heaters in the trailer to keep the 
permeators at a constant temperature higher than room temperature.

The driving force for selective permeation of gases depends upon partial 
pressure of the selected gas on both sides of the polymer membrane.  We used 
vacuum pumps on the first stage to keep the partial pressure of Helium as 
low as possible on the shell side of the polymer fibers when the partial 
pressure of Helium was lowest.

I have not thought about this project for 42 years so some of the details 
might have some rough edges.

Art

----- Original Message ----- 
From: "andy schofield" <scothebuilder at hotmail.com>
To: <gasification at listserv.repp.org>
Sent: Monday, January 14, 2008 9:03 PM
Subject: [Gasification] Sail-cloth employed to concentrate hydrogen



Dear Art,

   Congratulations on your successful project.
Is a hydrogen particle smaller, or larger than a helium particle? Mark 
hinted at specific size as molecular radius.

   Besides surface area and pressure you indicated, would temperature 
increase up to and including maximum the membrane is able to withstand help 
kg gas "leaking" out alone/hr?


Andy