# Clathrates as fuel source

Discussion in 'Chemistry' started by fishtail, Jun 29, 2007.

1. ### fishtailRegistered Senior Member

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Methane is the main component of natural gas. There are quite a few vehicles already that use compressed natural gas or LNG (liquefied natural gas). The conversion from gasoline isn't difficult nor terribly expensive.

But the problem here would be in extraction. I suppose you noticed where the stuff is (bottom of the ocean - and that's NOT continental shelf, either, which is all we can manage right now.) There aren't any open ocean oil wells and this material would require a quite different approach than ordinary well drilling and extraction anyway. It would require a tremendous amount of technology development (you can read that as \$.)

By comparison, oil shale and tar sands would be a much more economical source of energy.

5. ### Captain KremmenAll aboard, me Hearties!Valued Senior Member

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It would replace gas. Most of the stuff is made out of water. For anyone who doesn't know, its a kind of ice which traps gases. Mainly Methane.
Yield is about 160 cubic metres of Methane per Tonne. The stuff will naturally yield up the methane if it is raised, there being less pressure. Some people fear that as sea temperatures increase, it will start bubbling up and add to global warming. Considering the problems we would have raising even a small amount of matter from the ocean depths, say the Titanic, I don't think it would be viable at the moment. By the way, manure yields 80 metres per tonne. That's easy to get.

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Just for the benefit of the reader that may not be aware of it, this material is more commonly called "methane hydrate."

8. ### Captain KremmenAll aboard, me Hearties!Valued Senior Member

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It would make a good engineering project. I think that raising the mass is out of the question, but the two other methods would be raising temperature in situ, or lowering pressure. Both would be made difficult by the sheer volume of water as opposed to the amount of gas. Another consideration would be energy input versus energy gained.

9. ### Captain KremmenAll aboard, me Hearties!Valued Senior Member

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There is a large amount of the hydrate locked up in the permafrost of Siberia, which is easier to get at. It is a strange material, when pure, it looks like a snowball, but will light if you put a match to it.

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11. ### Walter L. WagnerCosmic Truth SeekerValued Senior Member

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BillyT has weighed in on this topic. He's quite concerned about the undersea methane hydrates, having seen bubbles rising from some of the deposits in a TV documentary.

While I do not know if we'll be experiencing runaway hydrate release as early as 2012 [five years from now], it is known that the Arctic is getting warmer. If we do have a runaway release of methane, things on planet Earth won't quite be the same for a long time to come. All governmental efforts should be towards nuclear energy, solar energy, wind energy, tide energy, biomass energy, and any other energy that does not dump fossil carbon into the atmosphere.

Last edited: Jul 4, 2007
12. ### Captain KremmenAll aboard, me Hearties!Valued Senior Member

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Yes Walter, the topic is a serious one. It's not helped by fanatics shouting "the sky is falling", but the subject does attract them. Have done a search through the forums, and it does not look as if this subject, as opposed to Global warming in general, has been discussed in detail.

13. ### Captain KremmenAll aboard, me Hearties!Valued Senior Member

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Fishtail. A vital topic, but attracting no attention as a chemistry subject, and I feel as if I'm talking to myself. I think Earth science is a better place for it. I'll post something there shortly unless you want to.

Last edited: Jul 5, 2007
14. ### Captain KremmenAll aboard, me Hearties!Valued Senior Member

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Cummon, someone talk about Clathrates. Pleeees.
They could end the World!

15. ### Billy TUse Sugar Cane Alcohol car FuelValued Senior Member

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You are correct and I have talked about it. Here is part of my post in "The age of perspective" thread:

I have mentioned one possibility (unlikely I think, and certainly hope, but impossible to be sure about) for man to make the Earth uninhabitable for any form of life. I will try to find my post with more details, but the current RAPID* addition of CO2 and other gases much more effective at retaining heat (CH4, etc) per molecule to the atmosphere may cause the ocean floor methane hydrates to decompose in a positive feedback system with initially greater than unity gain. This system, like all instabilities, will eventually "saturate" but when it does so, the Earth will be a "Cooler version of Venus." (Lead on surface of Venus is liquid. I.e. there may be "lead lakes" on Venus. Earth´s "hot stable state" has a lower temperature but it is several 100 degrees C. I.e. There is a stable state of Earth with very high pressure very hot steam, greater than any steam boiler, at the surface, at least until the oceans boil off into space.)
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*There have been warmer times and probably times with higher CO2 concentrations in Earth´s long history, but unfortunately this does not reduce the chance that Earth is now on its way to becoming a "Cooler version of Venus" to zero. "This time" may be different because of the speed with which the CO2 (from fossil fuels) is being released. If the methane of the hydrates (CH4) were released slowly, it would have time to decompose as it is destroyed by oxidation into water and CO2. Replacing a molecule of CH4 with one of CO2 and two H2O molecules is a way to keep the gain of the positive feedback system less than unity (avoid the conversion of Earth into the "Cooler version of Venus") because the concentration of CH4 can only increases slightly IF there is time for decomposition into H2O & CO2. Then the water molecules will fall out as rain and two CO2 molecules are much less effective greenhouse gas than one CH4 molecule. These CO2 molecules will also have time to be absorbed by the oceans, made into carbonate sea shells etc.

Again, I think and hope that the positive loop gain will not reach unity even with the current RAPID unprecedented release of CO2, but I AM SURE no one can compute something as complex as this. MANKIND MAY BE MAKING THE EARTH TRANSITION TO THE OTHER STABLE STATE: a COOLER VERSION OF VENUS.

I.e. this >1 gain instability may cause surface temperatures to exceed 100 degrees C and as the ocean surfaces boils, the atmosphere at ground level will be very high pressure hot steam. It will take hundreds of thousands of years before all the oceans are converted to steam and then the surface pressure will be 100s of times greater and the surface temperature >200 degrees C. - A very sterile Earth or a "Cooler version of Venus."
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The above is a rational consideration of a real (I hope unlikely) possibility. I resent the dismissal of any consideration of this physics with the accusation the one need not pay attention to "sky is falling” posts. In many cases that is a correct POV, but not when the mechanism is explained that indeed may make the sky fall. To do so then is a Head in the Sand" position. Because the potential danger damage to Earth is greater than any other man can make, this possibility needs to be seriously considered, and anal sized, not head in the sand ignored.

One can be certain, that there exists a very hot stable state for Earth, quite similar to the sate Venus is in now. If earth converts to this stable sate it will be sterile!

Last edited by a moderator: Jul 15, 2007
16. ### MetaKronRegistered Senior Member

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If it takes that long for the oceans to boil, then they will release the excess heat into the atmosphere plus a LOT of cloud cover. Nuclear winter, remember? Sunlight doesn't get anywhere on Venus that allows for a "greenhouse effect." It penetrates a short distance into the clouds and it is re-radiated and reflected from the clouds. Unless of course the simplest laws of physics are different there, but that would be a crackpot argument.

Anything that causes the oceans to release moisture, and that would be HEAT, will cause cloud cover that will cause cooling, thus keeping the temperatures in balance. Water vapor releases its heat when it freezes in the upper atmosphere.

17. ### fishtailRegistered Senior Member

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Please do, i seem to have less time these days.

18. ### Captain KremmenAll aboard, me Hearties!Valued Senior Member

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Doesn't cloud cover add to the greenhouse effect? I'm fairly sure the nuclear winter was caused by dust particles.

19. ### Captain KremmenAll aboard, me Hearties!Valued Senior Member

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Thanks Fishtail. Input from a chemistry angle would be welcome, so I won't start a new thread at the moment. It shouldn't really need to be moved.

20. ### MetaKronRegistered Senior Member

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Look at what happens when cloud cover forms on a hot day. Insolation to the ground decreases. More of it may be conserved but there is less of it to begin with. If you wind up with a cooler day because of cloud cover, and you do, there is no greenhouse effect because of that cloud cover.

Storm cells have their weird ways of releasing heat but that's a different story.

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There are two VERY important effects that you're overlooking here. The first is that water vapor produces a huge greenhouse effect which traps heat (far, far more than CO2 or CH4). The second is that cloud cover that does reflect some of the incoming heat in the daytime negates those losses by acting as a thermal blanket at night and retains a tremendous amount that otherwise would have been re-radiated back into space. The net effect would be an overall increase in temperature. Look at the planet Venus - considered to be Earth's twin except for being a little closer to the Sun AND it's thick cloud cover.

22. ### Billy TUse Sugar Cane Alcohol car FuelValued Senior Member

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You are a little confused here. the nuclear winter effect is due to the particulates (dust) that would be thrown high up and fine particles take a long time to fall out. these particals at high altitude are very good radiators and hence cool the Earth.

The presence of molecules, especially those with three or more atoms, like CO2, H2O and especially NH4 absorb radiation trying to leave the Earth - greenhouse effect. They are why Venus is so hot even though it is true that essentially no sunlight reaches the surface. Some heat is generated inside Venus, just as it is inside Earth and some sunlight is absorbed high up in the atmosphere. These heat sources, combined with the fact that the IR is trapped by the green house effect is why the surface is so hot.

Summary do not confuse the enhanced radiation of particles (nuclear winter) with the supressed radiation of molecular gases (greenhouse effect.)

I assure you, that unfortunately the Earth, like Venus, does have a hot stable state with hot high-pressure steam at the surface, at least for millions of years until the oceans have boiled off into space.

23. ### MetaKronRegistered Senior Member

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Suppressed radiation? You're kidding me, right?