Solar Energy and Hydrogen

dlzc wrote:


Now you're being ridiculous. Slow the speed down to .1 ft/s and how large a pipe will you need? Or going with 100 smaller pipes, to get a flow of 88.4 ft^3/s at a velocity of .1 ft/s, you need a total flow area of 884 ft^2. Using '100 outbound' pipes as you suggest below, those pipes are 3.35 ft across (larger than the 1 m pipe I posited).

Nope. Using several small pipes instead of one large one increases the friction losses. Slowing the flow to 1/100th what I posited saves you losses by reducing to 1/10000, but then increasing the number of pipes to 100 raises it back up to about 2/1000 of what I was assuming.
And now you need 100 pipes, about 3.35ft diameter, 250 miles long, able to contain 60,000 psi. Congratulation, your pipe costs are now 100 times what I suggested.

This is *MUCH* different than the drill pipe used on ocean platforms. For goodness sakes, the high pressure piping used in the highest steam pressure power plants is only about 3-inches wall thickness. Yours needs to be five times as thick as this. Drill pipe wall thickness is less than 1 inch.
Where did you ever get the idea that the pipe thickness of drill pipe was comparable to 15 inches?

And that was my point. Slow it down to your speed of 0.1 ft/s and your construction costs are incredible. You couldn't afford even the interest on the debt.

No high pressure steam pipe in the world operates at even 20,000 psi, much less your 60,000 psi. (P.S. I've actually found steam leaks using brooms, but it was only 600 psi. A high-pressure drain trap cap blew out flexa-tellic gasket)

I'd like to see the specs on a pump that can achieve 60,000 psi at more than a milliliter per minute.

Engineering can't fix a poorly conceived use for hydraulic power. (I 'kinna change the laws of physics captn) Hydrogen piping would be vastly cheaper than this hydraulic idea (not that I'm in favor of H2).
daestrom
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Dear daestrom:
I think we've beat this dead horse pretty well...

...
"Money is no object." I did say that electrical distribution is far superior...
...

I saw them in Mexico. They used them to sterilize orange juice (80,000 psi) and guacamole (100,000 psi). 250 hp (less losses) being sent through a 1/2" line (and no not any great distance). Seems like the manufacturer was Ingersoll-Rand.
Was a cool story about the guacamole. One time they did not purge all the air from the chamber (~3ft in dia x 8' high), before pressurization. Got it up to pressure, held if for <secret squirrel> minutes, slowly opened the chamber, and before they could start unloading it... the gas changed from whatever state it was in to the state of 'BOOM'. Guacamole on the ceiling. They said no one was hurt...
David A. Smith
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dlzc wrote:

That's cool. How does that 'sterilize' the juice? Pumping it through some sort of microsieve? Or is that pressure so high that bacteria are killed directly?

Yeah, at such pressures I can only imagine what the air in the chamber did. Probably dissolved into the guacamole fluids some how. Then release the pressure and it suddenly comes out of solution (like a scuba diver getting the bends). Or perhaps even a super-saturated state and one tiny disturbance caused it all at once like superheated water suddenly flashing to steam.
Later, daestrom
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Dear daestrom:

The latter. Life depends on a cell wall, and in humans (and simpler) we use a Na+/K+ ATPase "pump" to carry food and such across the membrane, and send wastes out. At those pressures, there is essentially *no* cell wall, no membrane, and the pump just shuts down. Everything diffuses everywhere. Means life is unlikely on massive planets...
Even short life with stubby legs.

The latter seems most likely. Glad I wasn't there when it happened. They'd've had some BROWN to clean up too.
Out.
David A. Smith
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dlzc wrote:

Hydraulic energy transmission suffers from losses. Anything over a few hundred feet becomes a waste of time. Fluid friction in the pipe is very real and lossy (depending on exactly what fluid you're pumping).
daestrom
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Dear daestrom:

Not saying you are wrong, but you could take it fully laminar, or take it very large diameter, and change that "equation". It is cost savings at some point.
Far superior would be direct electrical transmission (or even microwave), without a doubt.
But making hydrogen first, and pumping that, is a lose-lose proposition.
David A. Smith
PS: Thank heavens for some real engineering content on sci.engr.mech... Been nothing but spam for months.
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dlzc wrote:

Going to larger pipe for laminar raises the initial costs by more than a 100 times. Who wants to pay the interest on that debt?
daestrom
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Okay, let's build the complete system:
By international agreement, governments around the world contract to buy designated amounts of high-purity hydrogen produced by solar mirror powerplants.
The solar mirror powerplants for the production of high-purity hydrogen are built around the world in locations where solar mirror powerplants are effective and where port export is possible.
Fuel-cell fueling locations are put in place by governments near ports and along populated coastlines. Hydrogen delivery is from the port and by truck.
The car manufacturers seeing fuel-cell fueling locations in populated areas, begin making fuel-cell vehicles.
As lines back-up at the hydrogen fueling locations then private industry begins adding hydrogen fueling locations and pipelines.
But what is the advantage of fuel-cell vehicles over electric vehicles ?
Well, fuel-cell vehicles have quicker fueling, less weight, and a lower cost of battery replacement.
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Well, Honda has a fuel-cell car for the U.S. market and MB will have a fuel-cell car in the U.S. market in a few months.
I'm saying that the government could establish a market for Hydrogen produced from water and produced by solar mirror powerplants. If the governments will establish the market then the solar mirror powerplants will be built around the world and in the locations where they are most effective. Then the hydrogen can come into ports and fueling stations can be established within trucking distance of the ports.
The advantage of a fuel-cell vehicle over a plug-in electric vehicle is that the fuel-cell vehicle has quicker fueling, less vehicle weight, and a lower cost of battery replacement.
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The hydrogen produced by solar electrolysis only has to be pumped to the nearest port. At the port it can liquefied and loaded onto tankers for export. Then at the destination port the hydrogen fueling network can be limited to delivery trucking range. Fuel-cell vehicles can then be based within 50 miles of all ports worldwide.
Also, any hydrogen produced by solar electrolysis and not near a port can be pumped to the nearest major city and then fuel-cell vehicles can be based in that city.
Making the hydrogen may be an additional step beyond making the steam and electricity but fuel-cell vehicles have advantages over plug-in electric-vehicles. A fuel-cell vehicle has quicker fueling, a lower cost of battery replacement, less vehicle weight, and greater range than a plug-in electric vehicle.
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Now the hydrogen produced by solar electrolysis has consumed water at the production country and the fuel cell will output water at the country of use. That's a strange transfer of water. But also the solar electrolysis has produced oxygen at the production country and the fuel cell has consumed oxygen from air at the country of use. The question is, is the oxygen consumed by a large number of fuel cells a significant problem ? If so then the fuel cell needs to be fueled with both hydrogen and oxygen...otherwise oxygen has been gained at the Hydrogen production country and lost at the country of fuel-cell use.
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