Hydrogen Generators

[Patrick Figgis]

Dear All,

We have an application that requires hydrogen with a flow of circa 800ml/minute.

Previously we have relied on cylinders of hydrogen but we are now thinking of using a hydrogen generator.

I think my maths is correct in that a large cylinder of hydrogen (7.2 cubic metres) if the whole thing leaked into the room which has a volume of circa 110 cubic metres this would give a % of hydrogen in the room of 6.5% which is above the explosion threshold of 4% ( LEL). If we switched dot a hydrogen generator at 800mls/min even if we left that running to atmosphere for 24 hours we would only manage to reach 1% volume in the room.

So unless anyone can see anything wrong with my logic a hydrogen generator is a very good idea?

I wonder if anyone is using a generator and what make etc. I see them available from China for around £2000

PF

[Consumer Products Guy]

We bought a hydrogen generator for our GC room, to save on labor of changing out tanks and for safety. The engineer for the company did calculations, and felt that the regular room exhaust would be way more than needed to prevent any potential leaks from reaching danger levels.

But the pointy-haired boss decided to route the split vent flows to the fume hood anyway, I had no issues with that. He ordered 20-foot long straight stainless steel tubing sections because he didn't want to use roll of tubing, and "only he" could make the bends and install the SwageLok unions. Plus, we then had to run leak check every time we changed the septum (which we did every day of use) and record the leak check in a log book. So overkill.

We actually saw an Agilent-made video of their engineers trying to get a 5890 GC to explode, and they couldn't until they artificially induced both hydrogen excess and spark. And the door didn't even open !

[osp001]

The Chinese-made ones likely won't reach the pressures you need unless you're doing pretty bland GC stuff, so that's one thing to watch for. Note that you'll also need to get super-high purity water, so you'll either need to buy it in, or purchase an ultrapure water system.

Proton is the big name in non-Chinese hydrogen generators. Pricey.

[James_Ball]

If it is just carrier and FID then most hydrogen generators can work well, if you are doing something sensitive to water such as ECD or MS, you definitely want the higher end model that uses the Palladium membrane. Even with the molecular sieve traps in the lower priced units we had a lot of trouble with moisture in the lines when running ECDs and MSs on hydrogen carrier.

The best we used was the Parker Balston Pd membrane one rated for 1200ml/min but it was quite expensive, on the other hand it made excellent quality gas and we did not even have to run any gas filters on the instrument with that one, though I usually put a small indicating oxygen trap at the instrument just to alert if there might be a small leak somewhere.

Most of the generators will shut down if they sense a pressure drop indicating a large leak, so it is doubtful they would produce enough hydrogen to make even small rooms dangerous.

[aldehyde]

Parker and Peak also make good H2 generators.


I always recommend having a moisture filter installed if using an H2 generator: the primary "bad thing that happens" if you don't do maintenance or a problem occurs is moist hydrogen is generated. For GCs, this means potentially damaging the electronic pressure controller that the H2 is plumbed to. Annoying but not the end of the world.

And as was said, if it detects a leak it will shut down. This is the other "bad thing that happens" with generators lol.

A good moisture trap and regular maintenance to the generator and you should be good. Better and safer than a tank IMO.