"George Smiley" wrote: >Trouble with methane - it's the lightest of all those 'anes' and the amount >you can put in a car tire will get you about as far as you walked with the >tire. Saw a picture of them cooking with biogas in Vietnam - stored in a >huge clear plastic bag suspended over the range and the gas came out when >they pulled a rope that squeezed the bag. If it ever lit up it would all be >gone before anybody could grab an extinguisher.
That's not how it's usually done with the polyethylene bag digesters. http://www.ias.unu.edu/proceedings/icibs/ibs/info/ecuador/install-polydig.htm How to install a polyethylene biogas plant http://www.fao.org/WAICENT/FAOINFO/AGRICULT/AGA/AGAP/FRG/Recycle/biodi g/manual.htm Biodigester installation manual http://www.husdyr.kvl.dk/htm/php/tune96/13An.htm The Introduction of Low-Cost Polyethylene Tube Biodigesters on Small-Scale Farms in Vietnam >Better to have a weight on >a diaphragm in the top of your digester kind of like the big natural gas >storage tanks they have all over London that slide up and down a tower like >a caisson into a water tank Different system. As ever, there's probably no "best" one-size-fits-all solution, but the polytubes have many advantages, one of them being that they float: "Among the polyethylene digesters installed, 5% of them were floated in ponds adding an innovative feature to the development. According to Khoi et al (1989), in the Mekong Delta where most land is low, the application of concrete digesters was very difficult especially when the water level went up. The floating digesters solved this problem and as they also required little space they were very well suited for low-lying areas. More than 90% of the plants were installed in rural areas indicating the good fit of the technology under these conditions." >But it is purely a stationary fuel. I don't think so. That might be its most efficient use, but it certainly can be used as a transport fuel. For instance: "Methane, the lightest organic gas, has two fundamental drawbacks to its use in heat engines: it has a relatively low fuel value (Table 7), and it takes nearly 5,000 psi to liquefy it for easy storage. (87.7 ft3 methane gas = 1 gallon of liquid methane or 1 ft3 methane gas = 9 tablespoons liquid methane.) So a great deal of storage is required of methane for a given amount of work. For comparison, propane liquefies around 250 psi. Consider the following example where methane is compressed to just 1,000 psi in a small bottle and used to power a rototiller of 6 brake horsepower: "Example [see website for data] "At 25% compressor efficiency it would take 0.52 hp-hr to compress the gas (1320 BTU). In other words, it would take 1320 BTU to compress 25,300 BTU worth of gas that provides 6,350 BTU worth of work. Clearly the system is not very "efficient" in the sense that 21% of the resulting work energy is needed for compression while 75% of the available energy is lost as heat. "Methane has been used in tractors (Ref. 49, 50) and automobiles (Ref. 51). The gas bottles carried by such vehicles are often about 5 ft long by 9 in diameter (1.9 ft3) charged to 2800 psi so that about 420 ft3 of methane is carried (about 3-1/2 gal. gasoline). However, it seems that the most efficient use of methane would be in stationary heat engines located near the digester (e.g., compressors and generators)." http://journeytoforever.org/biofuel_library/MethaneDigesters/MD4.html Methane Digesters for Fuel Gas and Fertilizer - Chapter 7-8 Refs.: 49. Schmidt, F. & Eggersgluess, W. 1954. Gas From Agricultural Waste. Gas Journal 279:2861. 50. Rosenberg, G. 1952. Methane Production from Farm Wastes as a Source of Tractor Fuel. J. Min. Agric. (England) 58:487-94. 51. Imhoff, K. & C. Keefer. 1952. Sludge Gas as Fuel for Motor Vehicles. Wat. Sewage Wks. 99:284. There'll be many more than that now. You didn't check those refs I supplied it seems. Eg.: Put a chicken in your tank -- Eccentric British inventor Harold Bate found a way of converting chicken droppings to gas -- and runs his car on it. He claims chicken power will run a car faster, cleaner, and better than gasoline. Bate says he has driven his 1953 Hillman at speeds up to 75 mph without the use of gasoline. http://journeytoforever.org/biofuel_library/methane_bate.html "Bate's invention is simple, it's incredibly inexpensive... and it works. Hundreds of people, who are now driving chicken-powered cars the world over after contacting Mr. Bate directly, can vouch for that." http://ww2.green-trust.org:8383/2000/biofuel/batesmethane.htm Bate's Methane Car Best Keith > >----- Original Message ----- >From: "Keith Addison" <[EMAIL PROTECTED]> >To: <biofuel@yahoogroups.com> >Sent: Saturday, June 12, 2004 3:02 AM >Subject: Re: [biofuel] Ice Age bolthole > > > > Greetings Bob > > > > Fancy meeting you here! LOL! What a world, eh? It sure does have its > > brighter moments. > > > > Folks, this young feller Bob Molloy and I worked together at the Cape > > Times in Cape Town 27 years ago just before I left South Africa, and > > it was a real delight to get an email from him a few days ago, after > > all this time. He used to live in a cottage all by itself on one of > > the more beautiful beaches in the world. Four years ago when we > > started this project we were living on another of the more beautiful > > beaches in the world. > > http://journeytoforever.org/about.html > > > > (But Hout Bay's better! And so was your cottage - the Beach House on > > Lantau was a ramshackle old wreck.) > > > > >Jumping in here as a total newbie (and in reply to the Kim and Garth >Travis > > >on the best bolthole during the coming Ice Age) why not think of New > > >Zealand? The world's best kept secret is an English-speaking high-tech > > >liberal democracy located on a group of three major islands in the >Pacific, > > >with a population of four million in a land area the size of the British > > >Isles (pop. 60m). Green, clean and pristine, with scenery to die for - >Lord > > >of the Rings was shot here - the climate ranges from semi-tropical to > > >temperate. > > > > You're right, by all accounts. That movie had Americans calling their > > travel agencies trying to book a holiday in Rivendell. And now you've > > gone and told them where it is! > > > > >Bob. > > >PS: forget bio-diesel, look at methane gas. A clean burning fuel that >runs > > >any petrol engine with but minor modifications, easily transported in old > > >rubber car tubes, is available free from any city garbage dump (and your >own > > >household septic tank if you have one) and can be generated in your own > > >backyard by digging a large hole and filling it with animal/human faeces > > >and/or green vegetation. For more information try Brian at >[EMAIL PROTECTED] > > > > Or here: > > > > Put a chicken in your tank > > http://journeytoforever.org/biofuel_library.html#bate > > > > Methane Digesters For Fuel Gas and Fertilizer -- With Complete > > Instructions For Two Working Models > > http://journeytoforever.org/biofuel_library.html#methanefry > > > > Nepal Biogas Plant -- Construction Manual > > http://journeytoforever.org/biofuel_library.html#nepgas > > > > Jean Pain: France's King of Green Gold > > http://journeytoforever.org/biofuel_library.html#pain > > > > And loads more to come. > > > > But you don't see people doing it, do you? Lots of people visit those > > pages, lots of inquiries all the time about Bate's chicken car, but > > it never seems to go any further. > > > > Same with woodgas: > > http://journeytoforever.org/at_woodfire.html#woodgas > > > > Millions of vehicles used woodgas in Europe and elsewhere in WW2, but > > now? A few demos, that's all. > > > > Anyway, don't forget biodiesel, nor any of these technologies - it's > > often said here that there's no one-size-fits-all solution for > > biofuels, bio-energy or alternative/renewable energy, a rational > > energy future will need them all, in whatever combinations best fit > > the circumstances. I'm sure that's right. > > > > Regards > > > > Keith ------------------------ Yahoo! Groups Sponsor --------------------~--> Make a clean sweep of pop-up ads. Yahoo! Companion Toolbar. Now with Pop-Up Blocker. Get it for free! http://us.click.yahoo.com/L5YrjA/eSIIAA/yQLSAA/FGYolB/TM --------------------------------------------------------------------~-> Biofuel at Journey to Forever: http://journeytoforever.org/biofuel.html Biofuels list archives: http://infoarchive.net/sgroup/biofuel/ Please do NOT send Unsubscribe messages to the list address. To unsubscribe, send an email to: [EMAIL PROTECTED] Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/biofuel/ <*> To unsubscribe from this group, send an email to: [EMAIL PROTECTED] <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
