I have a question concerning the transport of low concentration ammonia gas (balance nitrogen) through tubing. I have an application where I need to transport a very small quantity of 425 ppm ammonia in N2 over a distance of about 300 to 400 feet (at about 20 or so psi maximum). I would like to use unheated PTFE tubing (1/4 inch ID) for this application but have been told that the ammonia concentration will decrease in the passage of the gas through the tubing. A 5 or 10 ppm ammonia loss is not a problem, but reduction in the concentration by 20 or 30 ppm would be a problem. Is there any experience with a situation similar to the above? Is it necessary to use heated tubing (about 300 deg F) to eliminate the ammonia concentration change in the transport through the tubing? I understand that for very low ammonia concentration the line losses can be considerable but I have not heard of any applications with higher ammonia concentrations.
Thanks for any advice that can be provided on the above.