Bladder material for containing ammonia

[RandomGuy88]

For my job I want to design a system that will have a bladder for containing and dispensing liquid ammonia, and I am trying to determine the ideal material/product that I could use. It will be fairly small, holding approximately 100g of liquid ammonia.

I am envisioning a bag/pouch with a tube attached for dispensing liquid. The bag/pouch expands when filled with liquid and compresses to near zero internal volume when all liquid is expelled.

Note that my company has plenty of experience handling ammonia and all proper safety precautions will be taken. This is not a DIY project being done at home. Because of the design of the system the external pressure will always be greater than the internal pressure so the bag/pouch material will not be under tension.

My first thought was a polyethylene bag, but my concern is the potential for the ammonia to permeate through the thin layer or polyethylene over a long time. Is this a valid concern?

We are in the prototyping stage right now and if anyone has suggestions for material or an off the shelf product that might work, as well as a method of attaching a tube to the bag/pouch that would be appreciated.

 

[berkeman]

How much do you dispense at a time? How precisely does the dispensed amount have to be? Will the operator use bare hands, or medical gloves or work gloves when doing the dispensing? How often will the dispenser need to be refilled?

Maybe something like a 100mL syringe (no needle) with a cap?

https://www.amazon.com/dp/B07DXS7ZTV/?tag=pfamazon01-20

 

[Baluncore]

There is little data available. Google ' Ammonia permeability'
This abstract from 2011 says little is known ...
"Ammonia gas permeability of meat packaging materials".
https://pubmed.ncbi.nlm.nih.gov/21535796/

 

[RandomGuy88]

Thanks for the replies. To answer berkeman's questions:

The pouch will be compressed by a pressurized gas and a valve will be used to release small amounts at a time. This will be done automatically so no one is handling it and it will be in a sealed container. Refilling will take place through a series of valves so again no one has to handle the bag once it is sealed in the pressurized container.

Baluncore, thanks for the link. Will the permeation rate of liquid through a polymer film be less than that of vapor?

 

[phyzguy]

When you say "liquid ammonia", do you mean NH3 gas dissolved in water (household ammonia), or liquified NH3 gas?

 

[Baluncore]

Will the permeation rate of liquid through a polymer film be less than that of vapor?

I do not think it will make a difference if the ammonia is gas, liquid or disolved in water.
Molecules passing through the film will pass as individual gas molecules, not as the liquid.
Molecules disolved in water will pass through the film as a gas, independent of the solvent.

 

[RandomGuy88]

When you say "liquid ammonia", do you mean NH3 gas dissolved in water (household ammonia), or liquified NH3 gas?

I mean liquified NH3 gas.

 

[hutchphd]

All I know is that the mylar balloon from the dollar store holds Helium far better than anything else in my experience. Far better. I don't know the physics

 

[Baluncore]

Ammonia permeation in semi-welded plate heat exchangers
https://www.hvacrsearch.com.au/arti...i-weldedplateheatexchangers_Whitepaper_EN.pdf

Transport Properties of Gases in Polymers: Bibliographic Review
https://ogst.ifpenergiesnouvelles.fr/articles/ogst/pdf/2001/03/klopffer_v56n3.pdf

Permeability of silicone polymers to ammonia and hydrogen sulfide
https://onlinelibrary.wiley.com/doi/abs/10.1002/app.1989.070381114

The Permeability of Polyethylene to Ammonia
https://onlinelibrary.wiley.com/doi/pdfdirect/10.1002/app.1980.070250522