I was thinking more of a gasometer type of thing made from a 44gallon
(220L) drum - or two.
I'm not sure what pressure it would be OK for but I'd imagine it would
be fine in the gasometer type situation.
1. invert drum
2. seal bottom with lid - this only needs to be watertight
3. arrange a water pipe from the bottom of the drum tto another one,
water filled & slightly elevated - open to atmosphere at its top.
4. Prime the lower drum by opening the gas feed pipe at its top (Allow
to fill with water from the top drum)
5 feed & retreive the hydrogen into the top space of the lower drum

By adjusting the height of the upper drum the pressure could be
increased (or by sealing its top the trapped air would balance the
hydrogen pressure and allow higher pressure operation - otherwise 10
metres of height would be required for every atmosphere of pressure..
I don't thisng a 44gallon drum would withstand too much pressure
anyway.
Might have fun getting a good seal in the first place?

RP

On 08/09/06, Russell McMahon <apptech@paradise.net.nz> wrote:
> > Pressure and air are definite issues. The real problem with hydrogen
> > storage
> > is how to safely store it in a KISS fashion. It seems at first
> > glance that
> > storing hydrogen on top of water would be the cheapest and simplest
> > way to
> > manage both keeping air out and pressure reasonable.
>
> Generating it en situ in an old water filled Propane tank would allow
> it to self pressurise. Mount tank vertically. Initially allow water to
> expel out bottom vent as a gas head builds. Then close valve and allow
> pressure to build to target maximum. Then incrementally release water
> as gas increases to maintain required pressure. Pressure will drop
> when you use gas but you will likely want exit gas at not much above
> atmospheric for burning. Getting more water into tank will require
> pumping against gas head unless you are prepared to allow tank to
> depressurise to below mains water pressure and then use that to refill
> the tank with water. You could use a header tank and use some gas
> pressure each time to vent water to the header tank and thereby have
> some local filling pressure. Not much though.
>
> A CNG (compressed natural gas) tank or Aqualung tank will be rated to
> far higher pressures. A CO2 tank is good for around 800 psi working.
>
> *******BUT********** at high pressures beware Hydrogen embrittlement
> of metals - this occurs as the H2 diffuses through the metal.
>
> A gasometer has its disadvantages but may be less dangerous overall.
>
> Re the idea of folding seams - coal gas can have substantial Hydrogen
> content so gasometers have to be rated for Hydrogen. When air is blown
> over coke you get CO (too much and you get CO2). This is exothermic
> and bed heats up nicely. You then blow in water (steam) and this is
> cracked to H2 and O2 The O2 makes more CO and the H2 joins the output
> too. Output gas calorific value rises due to H2 but this process is
> endothermic (no surprise) and bed cools until another air cycle is
> needed.
>
>
>
>
>        Russell
>
>
>
> --
> http://www.piclist.com PIC/SX FAQ & list archive
> View/change your membership options at
> http://mailman.mit.edu/mailman/listinfo/piclist
>
-- 
http://www.piclist.com PIC/SX FAQ & list archive
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist