Metal Hydride storage

[rinku]

Hmm... it shouldn't take that long to just fill up with water.

Using a hose to fill tanks that are at a minimum 20 tons, can easily take a couple of hours. Using hoses is described in more than one place.

It can easily take a couple of hours, but it can easily take less, too. Depends on how many hoses, how much pumping is being done and the cross section of the hoses in question. 20 tons is 280 kilolitres. Just having a quick look at commercial pumps, I found a 4 cylinder deisel engine one that pumps 6000 litres per minute using 6" ports. That would fill 20 dtons in about 45 minutes. Run two of them and the job's finished in less than half an hour. The pump costs about US$25,000 for what that's worth, but that does include the deisel engine.

http://www.aussiepumps.com.au/fire-fighting-pumps/fire-fighting-pumps.html

My main objection remains that pumping raw seawater into tanks designed to hold liquid hydogen makes no sense. Logic says to pump the seawater into an electrolysis chamber, zap some of it to get H2, and pump it back out, or something similar. The electrolysed H2 will have gas impurities, so will be "unrefined". Or are you saying that the unrefined fuel that you buy at a class C starport on a desert world is seawater?

 

[rust]

My main objection remains that pumping raw seawater into tanks designed to hold liquid hydogen makes no sense. Logic says to pump the seawater into an electrolysis chamber, zap some of it to get H2, and pump it back out, or something similar. The electrolysed H2 will have gas impurities, so will be "unrefined". Or are you saying that the unrefined fuel that you buy at a class C starport on a desert world is seawater?

According to my notes for my setting, an electrolysis system cracks 1 gal-
lon of water into 1.58 gallons of liquid hydrogen and 0.76 gallons of liquid
oxygen (no idea where I copied that).

And according to the rules a fuel processor turns an amount of unrefined
fuel into the same amount of refined fuel.

Unless I am missing something, this makes only sense if the unrefined fu-
el is indeed liquid hydrogen, not water, because with water as unrefined
fuel the amounts before and after the processing would have to be diffe-
rent.

 

[Captain Jonah]

True but once you remove the salt, water plants, passing fish, disovled metals, floating bits of plastic etc you probably end up with about the right volume

According to the rules as is you can scoop your fuel in 1-6 hours which is either a gas giant skim or pumping out a handy body of water. You then purify/refine that at 20 Dtons per day per unit into useable fuel.

So as long as whatever you scoop contains enough H you simply dump the rest as you refine it. Unrefined fuel at a starport could be impure H from the gasgiant bought in by large tankers or it could be piped in from a nearby river or lake and left for you to crack the H. As you can also refuel for Ice asteroids you must be able to crack water onboard as part of the refine/purify process.

All of this has to run around and through the holes in Traveller as regards to fuel anyway

 

[rinku]

No, Jonah. You're missing the difference between unrefined fuel and refined fuel. Both can be used directly to run the plant and power the jump, but the unrefined fuel increases the chance of a misjump. Read pp.140-141 agan carefully - scooping takes 1-6 hours and results in tanks full of unrefined *fuel* - the same stuff you buy at a C or D starport. This can be processed to produce refined fuel if you have a plant - the same stuff you can buy at a starport A or B.

At no point does the text imply anything other than extraction of hydrogen from water or atmosphere by scooping.

Electrolysis is very efficient at producing quite pure hydrogen gas. Likewise you would easily be able to scoop very pure hydrogen by using a series of molecular filters - H2 is the smallest molecule. You may get elemental He in the mix, but there'd be a secondary process as part of the scooping to seperate that (the liquification process will likely take care of most of this either way).

"Unrefined" fuel is still highly pure hydrogen - it just isn't *as* pure as refined fuel. We're probably talking about the difference between 99% and 99.9% here. And getting that last 0.9% purity *is* going to take a specialist purification plant and time.

 

[DFW]

"Unrefined" fuel is still highly pure hydrogen - it just isn't *as* pure as refined fuel. We're probably talking about the difference between 99% and 99.9% here. And getting that last 0.9% purity *is* going to take a specialist purification plant and time.

I get it now. That last part takes the expensive purif plant gear.

 

[rust]

Electrolysis is very efficient at producing quite pure hydrogen gas.
(...)
"Unrefined" fuel is still highly pure hydrogen - it just isn't *as* pure as refined fuel. We're probably talking about the difference between 99% and 99.9% here. And getting that last 0.9% purity *is* going to take a specialist purification plant and time.

This is how I treat it in my setting, where settlements and starports usu-
ally are built near a coastline and have fuel processors, as a combination
of electrolysis unit and "refinery", to produce hydrogen from seawater for
the local power plant, the hydrogen fuel cells and hydrogen combustion
engines of the local vehicles and for visiting starships.