Fuel Purification Plant

[Icosahedron]

Originally posted by Supplement Four:

I wonder why hydrogen gas isn't used? In an internal combustion engine, the process is that gasoline is turned to vapor, and that's what really drives our cars.

Why not store LHyd as a gas? It seems it would a heck of a lot lighter.

EDIT: Help me with my science here. (Not my best subject.) I know that hydrogen is one of the lightest gases known, but would the same volume of liquid hydrogen weigh the same as that of hydrogen gas? Need help with basic science...

The energy is related to the mass of fuel. 1kg of liquid provides the same energy as 1kg of gas - but you need MUCH bigger tanks to hold the gas...

 

[Icosahedron]

Originally posted by Supplement Four:

I wonder why hydrogen gas isn't used? In an internal combustion engine, the process is that gasoline is turned to vapor, and that's what really drives our cars.

Why not store LHyd as a gas? It seems it would a heck of a lot lighter.

EDIT: Help me with my science here. (Not my best subject.) I know that hydrogen is one of the lightest gases known, but would the same volume of liquid hydrogen weigh the same as that of hydrogen gas? Need help with basic science...

The energy is related to the mass of fuel. 1kg of liquid provides the same energy as 1kg of gas - but you need MUCH bigger tanks to hold the gas...

 

[JustinInOz]

I wonder why hydrogen gas isn't used? In an internal combustion engine, the process is that gasoline is turned to vapor, and that's what really drives our cars.

Why not store LHyd as a gas? It seems it would a heck of a lot lighter.

EDIT: Help me with my science here. (Not my best subject.) I know that hydrogen is one of the lightest gases known, but would the same volume of liquid hydrogen weigh the same as that of hydrogen gas? Need help with basic science... [/QB]

With respect to the volumes of gases and volumes of liquids. If a kilo of mass of liquid is converted by any process into the same number of molecules of gas. (What I am specifying here is that there is no chemical process changing the liquid into a gas. For example burning the liquid.) The gas takes up approximately 1700 times the volume.

If you want to see more of the science, check out this page: http://hyperphysics.phy-astr.gsu.edu/hbase/thermo/phase2.html#c3

Look under heat of vaporization.

From that I would say that when you skim a gas giant, your ship would have to be converting the gass into a liquid that would be stored in the fuel tanks. If the ship was only storing the gas, even at very high pressure, the amount stored would be insubstantial. It would have to be converted to a liquid.

Your purification plants would have to be pretty neat to concentrate the gas from a big gas giant into LH2, split water into 02 and LH2. I reckon they could do something similar with methane CH4. I am just supposing on the last one.

 

[JustinInOz]

I wonder why hydrogen gas isn't used? In an internal combustion engine, the process is that gasoline is turned to vapor, and that's what really drives our cars.

Why not store LHyd as a gas? It seems it would a heck of a lot lighter.

EDIT: Help me with my science here. (Not my best subject.) I know that hydrogen is one of the lightest gases known, but would the same volume of liquid hydrogen weigh the same as that of hydrogen gas? Need help with basic science... [/QB]

With respect to the volumes of gases and volumes of liquids. If a kilo of mass of liquid is converted by any process into the same number of molecules of gas. (What I am specifying here is that there is no chemical process changing the liquid into a gas. For example burning the liquid.) The gas takes up approximately 1700 times the volume.

If you want to see more of the science, check out this page: http://hyperphysics.phy-astr.gsu.edu/hbase/thermo/phase2.html#c3

Look under heat of vaporization.

From that I would say that when you skim a gas giant, your ship would have to be converting the gass into a liquid that would be stored in the fuel tanks. If the ship was only storing the gas, even at very high pressure, the amount stored would be insubstantial. It would have to be converted to a liquid.

Your purification plants would have to be pretty neat to concentrate the gas from a big gas giant into LH2, split water into 02 and LH2. I reckon they could do something similar with methane CH4. I am just supposing on the last one.