From: Spudboy100@aol.com
Date: Fri Apr 11 2003 - 14:04:49 MDT
<A HREF="http://www.technologyreview.com/articles/wo_wolman041103.asp">http://www.technologyreview.com/articles/wo_wolman041103.asp>
Gas Goes Solid
By David Wolman
Nearly 95 percent of the known gas fields in the world are too small to
But a handful of researchers have an idea that could make these fields worth
Japanese researchers Hajime Kanda and Yasuhara Nakajima at Mitsui Engineering
For decades, researchers have been looking for ways to gather these crystals
Changing natural gas into a hydrate form for cheaper transport gained
Another major advantage: “transporting natural gas as hydrates can be done at
Producing the hydrates requires mixing natural gas with water in a
The company’s demonstration plant produces as much as 600 kilograms of
Mitsui’s only significant competition in gas hydrate technology comes from
Because hydrates are still a mysterious substance, there are many scientific
This archive was generated by hypermail 2.1.5
: Fri Apr 11 2003 - 14:12:43 MDT
Japanese researchers may have found the secret to exploiting the world’s
untapped natural gas reserves.
April 11, 2003
justify the costs required pipe the gas to a plant, turn it into a liquid,
and then transport it on specially equipped tankers.
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?
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.
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.
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.
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.
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.
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 ºC, Mitsui’s plant operates at -10 ºC, 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.
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 it produces thousands of tons of excess water that need to
be removed.
and engineering obstacles that could make the process cost prohibitive. But
Kanda and his colleagues are optimistic. Japan, the world’s number two energy
consumer, is investing heavily in hydrate research, especially as public
opinion turns increasingly against nuclear energy as a crude-oil alternative.
Mitsui researchers hope their tiny white pellets will be just what their
country needs.