Seeing Hydrogen

[robwaddell]

I want to know if there is a process out there to make a hydrogen flame more visible. Will bubbling it through salt water give it a color? Or is there somthing I can do at where the H2 is burning to give me a visible flame. Any help would be greatly appreciated. I'm pretty much ready to try anything. I just want a visible flame for the hydrogen I am making with my electrolyzers.

Thank you for your help
Robert

 

[kenvlach]

I don't think bubbling would do much. You could use a nebulizer to aspirate some saltwater into the H[sub]2[/sub] flow in order to get some color (greenish-yellow, if memory serves); but don't do this without an exhaust hood.

Or, position a piece of platinum wire in the flame, so you can see a glow. Put a loop in the hot end to increase the size.

 

[peebee]

Don't they inject something into natural gas to make the flame visible? Can you mix another gas into your hydrogen?

 

[IRstuff]

This linke doesn't help much, but Section 6 of the MSDS was very amusing:

http://www.eecs.umich.edu/ssel/MSDS/Hydrogen-Compressed_Gas.pdf

Basically, is says something to the effect of approaching the flame cautiously with a straw broom ;-)

The idea of the colorizer is pretty much it, short of getting a UV sensor, but I couldn't find any obvious about what would make a good colorizer and what your usage might limit that to.

TTFN

 

[peebee]

After a little websearching. . .

It appears they don't intentionally add anything to LNG to make it visible -- it (methane) is normally blue, but impurities such as benzine, etc., turn it orange occasionally.

The best source of information I could find on gas colorizers came, um, from the Anarchist's Home Companion of all places. . .

http://www.flashback.se/archive/AHC.TXT

. Nothing specific there. And I'd think twice before following any of their advice.

It seems like most any element that has an electron energy band in the visible spectrum would work. And that would seem to mean that most any impurity you introduced would likely have some effect. You'd just need to find something that wouldn't interfere with whatever reaction you're using the hydrogen for.

I'd suggest calling some bottled gas suppliers or manufacturers, they must deal with this all the time and probably offer some rather standard solutions.

 

[kenvlach]

Thanks, IRstuff,Air Products' official test for burning H[sub]2[/sub] is a straw broom!!!

robwaddell,
It should suffice to put a piece of alumina rod or refractory wire partly into the flame, to get a visible glowing indicator.
However, for a commercial project dealing with large quantities of H[sub]2[/sub], you need an IR sensor, such as the flame detectors used with boiler burners, which can automatically shut off the flow if the ignition fails on start-up or interrupted flow & restart. You will need this for UL/CSA approval if wish to sell units.

 

[negotiator]

Make a housing (stainless) to insert a carbon rod into the
flame. These are used to 'cut' steel and when joined with hydrogen and the ambient oxygen in the air, well, you can see it for miles. Non-corrosive, clean burn, and looks pretty trippy (do not stare at it).
Nothing less than a welding carbon arc...........
They are in mm. from 2-25, the larger used to cut up subs.
We start VW engines on fire with ours for the Fourth (MgAl)

............or are you looking for colors ?

thestocksguy@hotmail.com

 

[bobboyd]

The color in a natural gas flame is carbon. Natural gas is a mixture of hydrocarbons, primarily methane (CH4) but with variable (typically < 3%) levels of CO2, Nitrogen and whatever else they can stuff in while keeping the SG (specific gravity or density) inside a specification range as well as maintaining a heating value of about 1000 to 1050 Btu/scf. Additionally there is a Wobbe index spec that standardizes the fuel energy flowrate through a fixed orifice under standard conditions.

The smell in natural gas is a sulfur compound, (H2S, hydrogen sulfide is the rotten egg smell) Ethyl Mercaptan (Ethanethiol, C2H6S) is the typical odorant in Nat Gas. Sulfur compounds are found naturally in rotten eggs, onions, garlic, skunks, and, of course, bad breath.

Hydrogen is colorless and odorless and burns with an almost invisible flame Although hydrogen burns in air over a wide (4% to 75% ) range of mixtures with air, a small leak disperses rapidly and is surprisingly hard to ignite (particularly a small high velocity leak from a high pressure source) considering hydrogen’s very low ignition energy. A big potential problem is letting hydrogen gas collect at the top of an enclosure, and hydrogen detectors are used for most indoor industrial applications. With the advent of hydrogen fuel cell vehicles, low cost hydrogen detectors are being developed that will be positioned all over the vehicles to monitor leaks. Infrared or UV cameras or sensors can be used to detect hot (ignited) leaks.

Adding colorants or odorants is very problematic as the most valuable use for hydrogen may be with Fuel Cells and any CO or sulfur compounds will poison the platinum used in the Fuel Cell. The DOE is spending quite a bit of coin on Hydrogen right now and some of that is to find an acceptable odorant. So far, not much progress, and I am not too sure a good odorant for hydrogen will be found. (go ahead and please prove me wrong)

If you have a continuously venting hydrogen stream, add a twisted nickel-chrome wire to the vent stack and ignite the leak, The nichrome wire will glow a nice bright red-orange and if the flame gets blown out, the hot wire will re-ignite the venting hydrogen. For intermittent venting, I would suggest a pilot flame with a UV, IR or thermal sensor.

Approaching a suspected hydrogen leak with a straw broom or a loosely rolled up newspaper is an industry approved standard method of practical flame detection. Do not try to extinguish a hydrogen flame except by shutting off the source.

 

[peebee]

Cool info, Bobboyd.

Re, &quot;The DOE is spending quite a bit of coin on Hydrogen right now and some of that is to find an acceptable odorant. So far, not much progress, and I am not too sure a good odorant for hydrogen will be found. (go ahead and please prove me wrong)&quot;, maybe they should just throw in a free broom or newspaper subscription with every fuel cell . . . .

 

[DaveHasse]

depending on the application, you might be able to use a UV fluorescent material. H2 does produce UV, and there are any number of materials for a background that will convert this to visible light. (although walking around with a gin and tonic (an excellent UV fluorescent) might get you in hot water.

 

[robwaddell]

I just want to thank everyone for all the great ideas. I'll see if my boss will okay the purchase of gin, tonic, and a couple bags of ice (it probably won't work well if its warm).

Thank you