Asteroid Mining - Gas Storage Question

>
> > Is it possible to pump the hydrogen gas back into the water
tank? Is
> > there a limit to how much hydrogen can co-exist with the water?
> >
> It is impossible to store pure hydrogen for more than a few days,
> period.
>
> It really makes no difference how much H2 you try to pump in, it
will
> rapidly leak out through the seals.

Is that always the case. No matter how well engineered the seals?

>
> If you try to store it in gaseous form you will need to raise it
to a
> high pressure, it therwise occupies many times more volume than the
> water from which it was produced. At higher pressure the leak
rate
> increases.
>
Ok, this is what I'm curious about. If the gas is pumped back into
the tank with the millions of liters of water (ice) and we start
increasing the pressure, what effect takes place. Here's a thought.
What if the seal is under water, so the hydrogen is pumped into the
tank and directly into the water. Eventually it'll separate, but
won't the water act as a barrier or seal to prevent the gas from
leaking. Also, what happens to the whole system (water/ice/gas as
the pressure of the hydrogen starts to increase?

> You can try to store it as a liquid, but that requires very low
> cryogenic temperaeutres and you will not be able to sustain it
that way,
> it will boil off rapidly, then leak out through the seals.

I'd prefer to steer clear of a cryogenic solution. Adds more
complexity to the system.
>
> Fortunately the quantity of hydrogen liberated by electrolyusing
the
> water si relatively small. The cheapest solution would be to
simply
> vent it off into space. The amount of hydrogen you lose will be
only a
> relatively small percentage of the overall payload mass.

True, but I haven't gotten around to the rocket equation yet and I
haven't finalized the volume and mass of the system. So I don't
really know yet how much water would have to be split in order to
ferry this package back home to luna/LEO
>
> However, if the value of the hydrogen is high enough it might be
worth
> trying to combine it with N2 to make Ammonia, or Carboin to make
> methane. That way it will be alot easier to store. Maybe you
can
> extract the N2 or C from the asteroid itself.

Thanks for introducing this complication. I haven't thought this
completely through yet. Where to store the N2 and other gases. I was
going to look up data for how common an occurance, and how
pure "Snowball" NEO are. Can they be pure ice? I don't know. I
suspect that you comment may be closer to the truth, and it would be
a dirty "snowball"

So, what would be the simplest way to extract water and the other
gases? Could one furnace do the trick? Could one storage tank do the
trick?