Slashdot Mirror
Undersea Deposits of Frozen Methane Found
geoswan writes "The CBC is running a story about large deposits of
Frozen methane off the
coast of Vancouver Island .
The deposits may be 850 meters deep. The story doesn't say how the methane came to be a
solid. Pressure? The story doesn't address what technology could be used to mine these deposits,
if the decision is made to develop these resources. The CBC showed pictures taken of the methane
hydrate. Sure enough, it looked like a big snowbank. It is an environmentally sensitive area. So, how about it, should it be exploited?"
It's not actually frozen methane as such. The freezing point of methane is much too cold for that. It's a clathrate essentially a form of ice with methane molecules trapped among the water molecules. It's stable at temperatures just above the normal freezing point of water, and high pressures. If the pressure is released (for example by bringing it to the surface) it decomposes into water and methane gas.
Most living things produce some methane. At depth, the pressure is high, the temp is about 4 degrees and methane will freeze solid just by the water pressure since its on the solid side of the triple point .
There is a huge amount of frozen methane over most of the ocean but only where its about 1000m deep. If you can find a way to get it out at lower cost than oil, you can put opec out of business.
With ships it is a little different. The gas bubbles decrease the density of the water and therefore decrease the buoyancy of the ship. If there is enough gas bubbles in the water the ship does no longer swim and simply sinks.
Yes this a major concern in case of global warming, trapped methane can buble to the surface and cause a major disater, and even further enhance greenhouse effect. There is a lot of this methane all around the ocean.
Just to be clear, the article states that the methane deposits are under 850 metres of water, not that the deposits themselves are 850 metres thick.
Can't believe it'll happen? It already did, in the Northwest Passage some decades back. That's Canadian territory, but Canada had always permitted sea traffic through it as long as you called it in.
One year, the US decided "fsck you, these aren't your waters" and refused to check in anymore. Canada protested strongly but of course there was nothing they could do.
And people wonder why we get hated. Remember, this is the way we treat our "friends".
It doesn't matter who owns it right now...because with current mining and salvage technology, that deposit of hydrates is a liability and nothing more. Right now, there's no way of safely and efficiently getting all that gas from the bottom of the ocean. If you went down there and hit a big chunk of that stuff with a pick axe, you'd risk setting off a chain reaction that could lead to a catastrophic explosion (no kidding...I wrote a research paper on methane hydrates for my degree) that could spell disaster for the whole world...(methane is about 50 times more potent as a greenhouse gas than CO2)...or at the very least kill everyone at the site either by suffocation or fireball. Even if you gently try to scoop the stuff up and bring it to the surface, it will decompose on the way up and either suffocate everyone at the site or ignite and burn everyone to death. There's been several times already where an oil derrick was engulfed in flames because the hydrates around the site became unstable, bubbled to the surface and met up with a happy spark.
The point of all this informative rant: hydrates hold the world's most ginourmous amount of natural gas--but if you mess with it with current technology, you can release it all at once and really screw the earth up.
More information can be found under methane hydrate in google or:
article
among other. It's really an interesting compound and future power source.
Actually, the gas molecules get trapped within a cage of water molecules. Depending on pressure, this can happen above the usual temperature where water freezes. In deep sea drilling, this can cause things to ice up, even in fairly warm water, if the pressure is high enough.
The result can be costly in terms of money (processing equipment not working or hydrates clogging up pipelines, for example), or costly in terms of human lives. Blow-out preventer valves can freeze in the "open" position, giving a false sense of security, or hydrate plugs can clog up pipes, until they shoot off down the pipe as the pressure builds up on one side, eventually arriving like a projectile at the other end. The Piper Alpha fire in the North Sea was caused partially by gas hydrates preventing safety valves from closing.
Gas hydrates can be very problematic, and chemicals such as methanol (called inhibitors) are routinely added to the oil/water/gas mix that is pumped up to prevent the buildup of gas hydrates.
On the other hand, they can also be used to store gas. One volume unit of gas hydrate can be separated into 179 volume units of gas and 0.8 volume units of water.
Gas hydrates are fairly common in the ocean floor. In fact, the largest land/mud/ocean floor slide known to man, off the coast of Norway about 7000 years ago, is suspected to have been caused by melting gas hydrates releasing their "grip" on the sand.
Besides the article it has also been broadcasted in BBC series on global warming. Few notes: 1. It is not frozen - it is gaz-hidrate. Which is natural under the pressure+temperature conditions in question. It is though that there is a humongous quantity of methane tied in gas-hidrate on the ocean floor especially where rivers bring out organic matter into the ocean. 2. If you look into the global warming models - half of them do not account for this methane and methane has higher greenhouse effect than carbon dioxide. The ones that take into account this methane in general predict hell on earth. Basically once the ocean has warmed up enough the methane starts to come out which speeds up global warming and more methane comes out. Classic chain reaction. 3. There is some geological evidence that these methane eruption global warming events have happened in the past. It was presented on the BBC program in question. 4. Forgot how the show was called but it is possible that you may find some of the data on bbc web site (not news, the proper www.bbc.co.uk).
Baker's Law: Misery no longer loves company. Nowadays it insists on it
http://www.sigsegv.cx/
...it is methane hydrate. That is methane associated with water; the water and methane molecules are entangled in a weird fashion, but it's solid and stable under conditions that are not quite exotic.
I don't watch the Discovery Channel, but if they didn't have anyone on staff with enough knowledge to rule out such obviously impossible failure modes you should not be using them as a source of information (at least not on a more trusted level than the National Enquirer).
Unfortunately, a pilot in the midst of a huge bubble of methane might not be able to manage that, plus the engine quitting or backfiring (and if the methane was mixed with enough air to be flammable, BOOM!), and even if neither of those things happened the pilot would be breathing toxic amounts of methane and might not be able to control the aircraft.
Scientists restrict study to entire physical universe; creationist