Biogas - experimental scale Anaerobic Digestor and collector

[wooliver]

Encouraged by the ARTI digestor in India, i proceeded with the construction of the system. This project involves dealing with gaseous and chemical enginuity as well as a good deal of patience. Like the wind, you're dealing with naturally occuring phenomenon, and harnessing it. Like wind generation, it involves delving into essoteric knowledge. I feel just as strongly that this source of power has been overlooked by many by ignorance. This gas is as usable and is similar in make up to more widely used petroleum natural gas. I have already experimented with some success running an small engine on biogas. This technology is far from new as well. Subsequent entries will deal with quantities of feedstock vs. volume of gas, and consumption of gas at varing degrees by different engines.  

http://elwood.longlines.com/~jonz/AD/MM_03.jpg

[electrondady1]

hello

what sort of stuff are you going to use as a feed stock?

can you explain the use of a heating pad and what sort of temperatures /power requirements might be required?

[elvin1949]

   electrondady1

 Bio_gas_generator's produce there maximum at temperatures between 95 degrees and 105 degrees F.

 At lower temp's production and all but stops at about 55 degrees.

 At temp's of 115 degrees the bacteria that make the gas dies.

 For feedstock you can use any animal manure or vegetable matter. The ratio of one to the other matters,pure vegetable matter will make about 7 times as much gas as manure.

 But if mixed at the right ratio the production

will go up and last a whole lot longer.In small batches I/E 55 gal drum batch digester.about a 50/50 mix seems to work the best.A smaller digester needs more manure in the mix than a large digester.

 Temperature control is critical.There are so many way's to do that i won't go into that.

{electric_gas_solar_Greenhouse_hot water_i quite}. IT is simple but very complicated at the same time.

later

Elvin  

[spinningmagnets]

I recall a fscinating article where visitors described a very remote mountainous village in China that used Pig manure and farming left-over bio-mass in a digester to make methane.

Initially it was used for home heat and cooking, but eventually it was also used for a small generator to power a satellite dish. From stone-age tech to 100 channels.

Another recent story (Wired magazine?) had an ethanol pilot plant next to a cattle yard  (don't recall if it was dairy or beef) The cattle manure was used in a digester to make methane that was used cut evaporation heating costs for the distiller.

The left-over Dried Distillers Grain (DDG) was mostly high-protein corn with carbohydrates digested out to make ethanol, and was used to supplement the cattle feed. One corporation owned them both, and saved on the supplies and also supply transportation costs.

[Bruce S]

wooliver;

 Nice setup. While looking at the design; I didn't see a pressure relife valve.

Have you looked into adding one? With the water and bucket setup, you can get a failry descent mmHg and could , once the gas gets going build up a good haed of pressure.

Cheers

Bruce S

[elvin1949]

  Bruce

 Look again it is built in.The excess gas can come out at the bottom of the inverted bucket bubble out through the water to the atmosphere by the guide pipe.

later

Elvin  

[Bruce S]

Elvin;

   Took a re-look. I'm more worried about the amount of pressure it will take to get it to bubble past the inverted 5gal bucket.

Since the unit is sending the "gobar" off to the other inverted 5 gal bucket full of water( which is a good design) sitting in a 33 gal bucket and has a steel weight plus conduit on it. There's the ability to have a good amount of pressure to build up.

If the unit is as the drawn picture shows , then the pressure will back fill the to slurry before the bubbles come out from under the "storage" tank.

a very simple math, ( Finn can help better with this, he's got a real good grasp on math) Finn if you have the time can you correct this for me?

1 inch column of water is ~.44 psi, gravity pushes on us about 14lbs. A small steel plate say 4inches round 1/4inch thick plus condiut say 2lbs.

A 5 gal bucket is say 14 inches tall.

So 14 inches times .44= 6.16 + 14 +2 = ~~ 22psi. This is above the normal ~10 psi BBQ grills regulators run at.

So by the time the bubbles start to get out from under the 5 gal bucket it's already up to 22psi and will have back fed into slurry. Making big yucky mess :-)

I could be way wrong on this!!! don't take this as a slam or anything, just trying to keep anyone safe.

I could even be reading the drawing totaly wrong.

Cheers

Bruce S

[Tritium]

The problem is where the gas is introduced into the storage container. Its ok to take gas off the top to use but it should bubble in from the digester at the bottom of the inverted bucket used for pressurized storage not at the gas delivery port at the top.

That way no back pressure on the digester can occur

Thurmond

[elvin1949]

  Bruce,I went back and looked again[real slow eye's ain't what they used to be]

 You are right he needs 2 things.A pressure relief

valve and He needs to bubble the gas through the water.It will remove some of the impurities from the gas.

later

Elvin

[Bruce S]

Elvin;

  I know what you meam about the eyes ;-).

Cheers

Bruce S

[elvin1949]

   Bruce S

 What i would not give to be 25 again.

later

Elvin

[Darren73]

Bruce,

1 inch water column is 0.03613psi or the other way around 1 psi = 27.68 inches water column, therefore the 14 inch head is more like 0.5 psi.

Regards

Darren