Air question HP5890/FID - zero air vs pure O2?

Discussions about GC and other "gas phase" separation techniques.

6 posts Page 1 of 1
I'm setting up a HP 5890 II - the setup manual states it needs "air" for the FID. However when they refer to "air" are they referring to pure oxygen or regular air?

My guess is that it needs "zero air" which I can easily get from my gas supplier (perhaps even in a disposable tank) - but I just wanted confirm here.

FYI - the hydrogen will be provided onsite by a generator while my carrier gas will be He.
lespaul wrote:
I'm setting up a HP 5890 II - the setup manual states it needs "air" for the FID. However when they refer to "air" are they referring to pure oxygen or regular air?


The GC needs zero air. This can be from a cylinder, or we used oil-free "house" (lab) air that passed through a Balston zero air purifier, not expensive.


Don't use air from an oil-lubed compressor, our St. Louis production facility did this, and oil got into the FID plumbing and even overflowed into the oven insulation (that was on a 5890).


Since you have a hydrogen generator, consider using hydrogen as carrier gas; you'd still need helium or nitrogen as FID make up gas however.
Consumer Products Guy wrote:
lespaul wrote:
I'm setting up a HP 5890 II - the setup manual states it needs "air" for the FID. However when they refer to "air" are they referring to pure oxygen or regular air?


The GC needs zero air. This can be from a cylinder, or we used oil-free "house" (lab) air that passed through a Balston zero air purifier, not expensive.


Don't use air from an oil-lubed compressor, our St. Louis production facility did this, and oil got into the FID plumbing and even overflowed into the oven insulation (that was on a 5890).


Since you have a hydrogen generator, consider using hydrogen as carrier gas; you'd still need helium or nitrogen as FID make up gas however.


Yes, Zero Air is what you need.

We use a oil lubed compressor that has about 100 gallons of storage tank on it, and it is filtered several times, lastly through a hospital grade chilled condenser to remove the last water and oil and it is over 100 feet from the zero air generator so we haven't had any oil problems. This air also feeds a Parker-Balston nitrogen generator for ECD makup gas which is also used on the FIDs.

With a good compressor and a Zero Air and Nitrogen generator you could go completely tankless.
The past is there to guide us into the future, not to dwell in.
Thanks Consumer Products Guy and James_Ball for the help!

Not sure I'll have space for a air generator so I'll likely just purchase the zero air. Thanks again!
James_Ball wrote:
We use a oil lubed compressor that has about 100 gallons of storage tank on it, and it is filtered several times, lastly through a hospital grade chilled condenser to remove the last water and oil and it is over 100 feet from the zero air generator so we haven't had any oil problems.


At R&D, the original house oil-less compressor was eventually replaced with an oil-lubed one (for cost savings), with "controls" like you detailed. The maintenance/shop guys had the responsibility to maintain and drain that, and want to guess what happened? Basically the entire first floor of the laboratory had oil-contaminated air. The analytical chemistry department was fortunate that by chance I had mounted the zero air purifier high up on the wall, so the oil never reached it, and our GCs were not damaged.

We later used cotton-filled see-through filters so we could monitor and trap any oil contamination for the air used for regular lab tasks.

So - as Yogi Berra said - cost savings ain't always a savings !
Consumer Products Guy wrote:
James_Ball wrote:
We use a oil lubed compressor that has about 100 gallons of storage tank on it, and it is filtered several times, lastly through a hospital grade chilled condenser to remove the last water and oil and it is over 100 feet from the zero air generator so we haven't had any oil problems.


At R&D, the original house oil-less compressor was eventually replaced with an oil-lubed one (for cost savings), with "controls" like you detailed. The maintenance/shop guys had the responsibility to maintain and drain that, and want to guess what happened? Basically the entire first floor of the laboratory had oil-contaminated air. The analytical chemistry department was fortunate that by chance I had mounted the zero air purifier high up on the wall, so the oil never reached it, and our GCs were not damaged.

We later used cotton-filled see-through filters so we could monitor and trap any oil contamination for the air used for regular lab tasks.

So - as Yogi Berra said - cost savings ain't always a savings !


Yea, they first tried it here without the filtering. We began using the nitrogen generator with desiccant traps in front of it(the large see through tubes you can refill) and we had them on a switching manifold so we could service one while the other was in line. Well we were changing out wet desiccant almost ever day. We finally bought the refrigerated dryer and when we went to the lowest point in the air lines we remove almost 10 gallons of water. Since then though we have not had problems. We have someone in charge of opening and venting the tank bottom valve plumbed into the floor drain every morning.

Hydrocarbons can be a problem with oiled compressors, but water condensation is a problem with all of them unfortunately. I would prefer a dry scroll compressor but there just isn't enough space to fit one in the utility room and it would not last long if mounted outside. It was a tight squeeze to fit in the 7hp dual stage compressor we have now.
The past is there to guide us into the future, not to dwell in.
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