Slashdot Mirror
Creating Hydrogen With (Very) Hot Water
carbonman writes "NYTimes is reporting that a public-private research team will announce on Monday that they have discovered a new technique to produce pure hydrogen that is far more efficient than conventional methods. The advance could be a significant development in attempts to realize the dream of the hydrogen economy in taking gasoline-powered vehicles off the road, and without releasing carbon dioxide emissions that are linked to climate change. It does, however, require the use of advanced high-temperature nuclear reactors, none of which have been built on a production scale before."
swiftstream adds a link to the same story at the no-reg Indianapolis Star, and summarizes the method as "electrolysis of very, very hot water."
Is it just me or water can't be very very hot? At about 100 degrees Celcius, it vaporize...
Yes it does at standard temperature and pressure. If you were to increase the pressure it would require a higher temperature to vaporize, just as lower pressures require lower temperatures.
Water can be superheated as much as you please, it simply has to be at a high enough pressure. Past water's critical point (about 650 K and 22 MPa), it becomes a supercritical vapor, indistinguishable from liquid or vapor. Additionally, the boundary between liquid and gas dissapears, and the properties of the substance are somewhat different.
Already invented:
Mini nuclear reactor could power apartment blocks
A nuclear reactor designed to generate power in the basement of an apartment block is being developed in Japan
Generation IV Nuclear Reactors
Very high-temperature gas reactors. These are graphite-moderated, helium-cooled reactors, based on substantial experience . The core can be built of prismatic blocks such as the Japanese HTTR and the GTMHR under development by General Atomics and others in Russia, or it may be pebble bed such as the Chinese HTR-10 and the PBMR under development in South Africa, with international partners. Outlet temperature of 1000C enables thermochemical hydrogen production via an intermediate heat exchanger, with electricity cogeneration, or direct high-efficiency driving of a gas turbine (Brayton cycle). There is some flexibility in fuels, but no recycle. Modules of 600 MW thermal are envisaged
This isn't really correct - although pretty much all the power reactors in the USA are water cooled (primarily due to the Navy's interest is nuclear propulsion), there are plenty of gas cooled reactors elsewhere. Most of our (Britain's) nuclear generating capacity is from either AGR (Advanced Gas-cooled Reactors) or Magnox (named after the Mg-alloy fuel can) reactors, both of which use carbon dioxide as the coolant.
So, the technology may be new to the USA, but there's are wealth of knowledge on designing and running these reactors elsewhere in the world.
Oh yes, they're arguably quite a bit safer than PWRs as well!
There were interstate oil pipelines completed or under construction before World War II. U-Boat attacks on coastal tankers accelerated the process. Today, there are 200,000 miles of oil pipelines and 2/3 of US oil is transported by pipeline. Houston to New York, the cost is about $1 a barrel, or 2 1/2 cents a gallon at retail. Association of Oil Pipelines
I don't think it's that hard actually.
While I can't verify the temperature that the water was at, I had an incident this weekend that indicates this super-heating is not too difficult.
I put a 2 cup pyrex measuring cup in a microwave for about 2.5 minutes. The water appeared very calm and didn't have any bubbles. But as soon as I dropped my tea-bag into the cup, the water flared up and began to boil very vigorously for a few seconds.
The water was filtered drinking water from Walmart, and the pyrex was only cleaned with tap-water (rather "hard" water) and soap.
polar h20 molecules are flipped or spun as the microwave passes by them. because the em field emparts energy into the molecules, they can contain enough energy to phase shift. Think about covering a gym floor with basket balls so that none are touching. Then somehow make every ball spin at 10000 rpm. At first the balls would continue to sit on the floor spinning really fast. They have a ton of energy, but are still floor balls. Then a single ball is nudged into it's neighbor. Suddenly a chain reaction would happen with basketballs flying everywhere as the spin energy is converted into movement energy.
same thing happens in a microwave to h20, or any other free floating polar molecule. h20 just happen to absorb the microwave em very efficiently.