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Gas Goes Solid
Roland Piquepaille writes "This innovation from Japanese researchers can potentially revolutionize the energy distribution sector. Instead of transporting liquid gas, they changed gas into a solid material which is easier, safer and cheaper to distribute. Technology Review has the story. "Rather than extracting methane from hydrates, they want to turn methane into hydrates -- essentially, transforming the colorless and odorless gas into small pellets that can be easily stored, transported, and eventually turned back into natural gas. A few months ago Mitsui, in partnership with Osaka University, opened a demonstration plant near Tokyo to promote the concept and show that it works." Check this column for an analysis."
Gas Goes Solid
Japanese researchers may have found the secret to exploiting the world's untapped natural gas reserves.
By David Wolman
April 11, 2003
Nearly 95 percent of the known gas fields in the world are too small to justify the costs required pipe the gas to a plant, turn it into a liquid, and then transport it on specially equipped tankers.
But a handful of researchers have an idea that could make these fields worth mining: rather than figure out cheaper ways to transport this cleaner-burning energy source from point A to point B as a liquid, why not change natural gas into a solid substance that's easier and cheaper to transport?
Japanese researchers Hajime Kanda and Yasuhara Nakajima at Mitsui Engineering and Shipbuilding in Tokyo think they've found a solution with the aid of hydrates, solid crystals in which natural gas--composed chiefly of methane--is caged inside of water molecules.
For decades, researchers have been looking for ways to gather these crystals from their deep-ocean deposits and reap what they expect could be a natural gas harvest. Kanda and Nakajima are taking an opposite approach. Rather than extracting methane from hydrates, they want to turn methane into hydrates--essentially, transforming the colorless and odorless gas into small pellets that can be easily stored, transported, and eventually turned back into natural gas. A few months ago Mitsui, in partnership with Osaka University, opened a demonstration plant near Tokyo to promote the concept and show that it works. If the Mitsui's process proves feasible and economical, many untapped natural gas deposits could become vital energy sources.
Changing natural gas into a hydrate form for cheaper transport gained attention in the early 1990s. Norwegian petroleum engineers first proposed the idea after comparing the transport economics of liquid natural gas to natural gas hydrates, knowing that hydrates could store large amounts of natural gas in a small space. "More than 180 standard cubic feet of gas can be stored in one cubic foot of hydrate," says Rudy Rogers, professor of chemical engineering at Mississippi State University, and an authority on industrial use of gas hydrates.
Another major advantage: "transporting natural gas as hydrates can be done at lower temperature and pressure than liquid natural gas, and the risk of ignition in transport is much lower," explains Hugh Guthrie, who studies natural gas at the U.S. Department of Energy's National Energy Technology Laboratory in Morgantown, WV. Much of the high cost of liquid natural gas comes from temperature and pressure demands on piping, shipping, and storage facilities.
Producing the hydrates requires mixing natural gas with water in a continuously stirred tank reactor. When gas is piped into the water from the bottom, hydrates form on the surface of the gas bubbles. Removing the residual water leaves behind a residue of hydrate powder. Kanda and Nakajima envision a hydrate-pellet production plant close to gas fields in Southeast Asia. From there, a pellet carrier would transport the hydrate load to plants where the pellets would be turned back into gas and piped to market.
The company's demonstration plant produces as much as 600 kilograms of hydrates per day, moving the methane through all the necessary phases: hydrate formation, storage, pelletizing, and "controlled dissociation," or separation of the gas and water. Whereas a liquid natural gas facility requires temperatures of -162 C, Mitsui's plant operates at -10 C, which means huge savings in cooling costs. Kanda says the project, which is co-sponsored by the government's New Energy and Industrial Technology Development Organization, demonstrates that hydrates can be a successful vector for gas transport.
Mitsui's only significant competition in gas hydrate technology comes from another Japanese company, Mitsubishi. Mitsubishi is pursuing its own gas-to-solid technology based on a hydrate-oil slurry, a process whose main drawback is that i
Ugh. First off, they are talking about natural gas, not gasoline.
Secondly, they arent expecting the consumer to recieve these pellets, the pellets are just a intermediary to ship and store the gas easier before it gets to the customer. This should have been EXETREMELY obvious since it specifically states that the pellets are harder to ignite then regular gas, you shouldnt have even had to RTFA for this one.
And thirdly, you wouldnt convert all the cars on the road to a new fuel source, you would just produce new cars, and eventually phase the current ones out.
When the temperature of your freezer goes up by even a fraction of a degree (and it need not go anywhere near as high as 0 degrees celsius), some of the ice melts. When the temperature drops again, it re-freezes, but in a slightly different location.
Bzzt. No. But thanks for playing.
Whether a liquid or a solid, water is has a vapor pressure. If a system of ice and air is at the same temperature, there will be water vapor in the the air. The system will be (once there is enought water vapor in the air) in equilibrium - there will be no net movment of water from its ice form to its vapor form. But this is dynamic equilibrium, ice will be moving to vapor at the same rate that vapor is moving to ice. (Both processes - solid to gas and gas to solid - are called sublimation.)
If there is a temperature difference in your freezer, the ice will move from the (even slightly) warmer spot to a colder one. However, the process, for instance, of having all your ice cubes smoothing their edges and attaching themselves to each other would occur even if the contents of the freezer were all at the same temperature. The ice is trying to get itself into its minimum energy configuration, where it would be one big sphere.
If the top of the ice cream container is cooler than the rest of it, water will migrate to the top. The migration just requires a spatial temperature gradient, not a temporal temperature change.
The BBC also have a story including a picture from Geomar showing "burning ice" resulting in water dripping in some brave soles hands. As the Beeb's website says "Don't try this at home!"
wot no sig