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Author: Subject: Hydrogen Generator
VSEPR_VOID
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[*] posted on 29-11-2017 at 11:33


I think someone already solved this problem in 1844.
https://en.wikipedia.org/wiki/Kipp%27s_apparatus

[Edited on 29-11-2017 by VSEPR_VOID]

Kipps_apparatus_diagram.jpg - 53kB




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[*] posted on 29-11-2017 at 12:48


Quote: Originally posted by VSEPR_VOID  
I think someone already solved this problem in 1844.
https://en.wikipedia.org/wiki/Kipp%27s_apparatus

I bet it was expensive to acquire one in 1844 too.




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aga
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[*] posted on 29-11-2017 at 12:58


Kipp's apparatus is very clever, however it doesn't guarantee a constant gas flow rate, which is kinda needed in a GC column.

Another problem with it is Leaks or Blockages.

A blockage is kinda fine, but a leak would prevent it from working to stop the gas production.





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[*] posted on 29-11-2017 at 13:27


Quote: Originally posted by aga  
What reaction conditions did you use ?
Al powder, chips, solid chunks ?
What NaOH did you use ? Solution or dry NaOH on the metal with water dripped on ?
Science doesn't happen by vagueness.
Details and data or it's like a fart in the breeze,
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1: I wasn't doing science, I was making floaty balloons for my kids
2: NaOH solution (somewhere around 100g to a litre of water - it wasn't for science), Al chunks - usually long pieces of scrap extrusion.
3: Surely any observations about the reaction are useful in designing a method to overcome potential problems?

Personally I think you have been too quick to abandon electrolysis, given the ease of control, and low cost of consumables.

Quote:

Hydrogen will also be needed in much higher quantities to produce the flame for the FID

and this is where electrolysis wins. Its used to produce H2 fast enough for welding torches.




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aga
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[*] posted on 29-11-2017 at 14:48


If you do the maths, the energy required to make enough hydrogen for those torches is enormous.

Water really likes to be water, so it takes a LOT of energy to break those H-O bonds.

Others have also said it would be cheaper/easier to buy a second-hand GC, and it would.

What would be the point though ?

Personally i would like to know how one works from the ground up and make one.




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[*] posted on 29-11-2017 at 15:41


I build a homemade Kipp apparatus for chlorine. here link of model

https://makezine.com/projects/on-demand-benchtop-gas-generat...


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[*] posted on 29-11-2017 at 16:19


Nice design !



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[*] posted on 29-11-2017 at 21:19


I produced hydrogen gas by slowly dripping NaOH solution on aluminum foil balls in water and the vessel in an ice bath. The gas produced was passed through a drying tube with calcium chloride. You could fill up balloons but if you need to hydrogenate something I found it more effective to fill a jimmy rigged beach ball (that was completely evacuated with a vacuum aspirator) and use that to fill balloons. Did not collect the initial gas produced and waited until it lit a flame consistently to collect.

Indeed you gotta make sure you keep temperature under control or things can runaway very fast, which actually happened the first time lol. Also I think it's best to go with an excess of aluminum because when I went with molar equivalents I ended up having leftover NaOH, so the foil may of been impure or some other factor.

I noticed the hydrogen produced had this faint smokeyness to it. Not exactly sure what that byproduct was because it should've been colorless and undetectable. If anyone has a guess let me know because the following hydrogenation did work.

Have also attempted to produce via electrolysis but ended up with severe corrosion of the copper cable leading to the carbon electrodes, and very slow rate of hydrogen production.

Calcium hydride apparently isn't that easy to source (cheaply) these days for the amateur. Even the chinese want an arm and a leg, mostly on shipping.




[Edited on 30-11-2017 by Leafs]
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