Biogas IE: methane from organic matter

[Smertrios]

In the Harold Bate article about using methane to power a car he say 1100 PSI to liquefy the methane. What I am reading from google searching says methane will not liquefy at room temperature no matter what amount of pressure is used *but* the CO2 will liquefy and then the methane will dissolve into the liquid CO2. The Harold Bate article says its "pure" methane but thats obviously not so.

[Smertrios]

6 cubic feet per pound of chicken manure across 30 days... thats 14.4 cubic inches per hour. I have had just over 1/2 pound of frass in a 2-liter bottle for 24 hours now and it has built up pressure but I am not getting anywhere near 14.4 cubic inches. I used aquarium water thinking that would eliminate any delay in gas generation but I may be expecting to much.

[Smertrios]

geof;

Would you know about the efficiency of storing methane disolved in liquid CO2? Still very high pressure but I'm thinking that this must be how Harold Bate was getting "liquid methane". I am assuming a large quantity of methane will disolve into liquid CO2.

[Geof]

Originally Posted by Smertrios geof; Would you know about the efficiency of storing methane disolved in liquid CO2? Still very high pressure but I'm thinking that this must be how Harold Bate was getting "liquid methane". I am assuming a large quantity of methane will disolve into liquid CO2.

I cannot give you a good answer; I also do not understand how he got 'liquid methane' at only 1100psi.

You are correct that methane cannot be liquified no matter what the pressure at normal temperatures; it has to be cooled and kept at a low temperature but still under some pressure.

Carbon dioxide can be liquified and at around 20 degrees C the pressure needed is about 1800psi.

In other words Bates was not even at the pressure to liquefy CO2 so I do not know what he can have been getting.

I cannot give a definite answer about methane dissolving into liquid CO2 but my feeling is that it would not be a very efficient method for storage.

I Googled "methane solubility in liquid carbon dioxide" and did not get any hits with the quotes but with them removed there were a lot but non specifically dealing with methan dissolving into liquid CO2.

I do not expect that methane will mix very well in liquid CO2 because the two molecules are very different. Methane is somewhat similar to gasoline (petrol) being composed of only carbon and hydrogen while CO2 is somewhat similar to water; in chemical terms methane is non-polar while CO2 is polar. You probably know that petrol does not mix very well with water and I think your 'large quantity' may be 'very small quantity'.

The second problem I see is that when you try to extract the methane you are going to get it mixed with CO2.

I suspect that if methane would dissolve efficiently in liquid CO2 it would already be in use for the transport of methane by ship; this is done on a large scale, Google 'LNG tankers' and if it could be done more efficiently using liquid CO2 I don't think the high pressure refigerated tanks would be used.

[m.marino]

IF you go looking up work done by the Chinese in the 1960's on Methane generation you can see that it does have it's uses but there is a demand limit as well as a having to deal with changing tanks and cleaning a tank out to re seed it and keep methane production going. There are generators out there that do run on methane and some cities are force seeding the bacteria into landfills as it does speed up decomp' of the land fill and produce a usable by product. Most systems that work worth a darn are buried as that helps with the heat issue to a degree (54°F below the frost line) so good luck and best wishes.

[Smertrios]

My 2 liter bottle test was semi-successful. It did generate methane but I put too much frass in the bottle and the small bubbles that would form on the frass would not pop and instead lifted the frass to the top and eventually out the tube I had in the top of the bottle. I emptied some out and refilled the remainder of the bottle with tap water and this was a mistake as the chemicals in tap water completely shut down the generator.

I tried again using a 1 gallon milk jug but again I used too much frass and had a similar problem with the frass. This time I dumped out the bottle and just rinsed off the top before refilling with aquarium water... the small amount of tap water that got in the bottle seems to have been sufficient to kill off the bacteria =/

The bubbling off the gallon jug with 1 pound of frass in it was sort of impressive. After 2-1/2 days it would release a bubble of gas about 2-3 times a second from a 3/16" rigid aquarium tube. A very tiny amount of gas but I keep thinking "its only 1 pound" and I have at least 200 pounds of frass in a 55 gallon trash can =P. If that rate of fermentation kept up for a month or more and was 200x faster it would run a heater full blast quite easily!

[rugcleener]

I am interested in making methane gas as did Harold Bates and run an automobile on it.If you have any experience and know how I would appreciate advice and results you may have.

[mactec54]

Smertrios

This link may help with how they liquefy the methane gas

http://www.acrion.com/LNG%20from%20LFG.htm

Here is another good link

http://extension.missouri.edu/public...b.aspx?P=G1881

[insanedragons]

Well Dave, our families have been there a whole lot longer than 9 years, can we approach the municipality about this ? Where did you hear this?

[BigKiwi]

Hi
Which part of the process are you looking for comment on. The making methane part or the compressing it part. I have a bit of experience in the making it part.

Big Kiwi