Biogas

[Guest guest]

In a message dated 2/14/2004 5:05:00 AM Eastern Standard Time,

gourdmad (AT) ovnet (DOT) com writes:

 

> For the process to work it has to be fairly warm.

 

---

This is not entirely true. I was researching this with a conference in Europe

in 1999 - 2000. And a group in Norway was doing this on their dairy. They said

only a minimal amount was used to heat the chamber as the chamber was actually

a concrete tube burried in the ground below the freeze line laterally. The

slurry would go in one end, and come out the other (down hill) so most of the

culvert tube was underground. Only some externatl fixtures were heated in the

dead of winter. The slurry generated a lot of its own heat (you can imagine).

 

 

I've seen several designs for lateral (tube) digesters. They are fairly simple

and can be assembled with commonly available parts.

 

YS - Gopal

[Guest guest]

> Only some externatl fixtures were heated in the

> dead of winter. The slurry generated a lot of its own heat (you can

imagine).

 

 

What was the volume. Or an easier question - how many cows were contributing

to the digester? It may take larger numbers to have a digester that

generated enough heat to sustain itself.

>

> I've seen several designs for lateral (tube) digesters. They are fairly

simple

> and can be assembled with commonly available parts.

 

Burying anything underground starts to move away from "simple" IMHO. I

suspect it was also an insulated installation as the upper portions of the

ground can and does freeze in Northern latitudes.

 

It is much simpler where you can dig a well and put a collector dome on top

and burn directly as you produce.

[Guest guest]

-

Mark Middle Mountain <gourdmad (AT) ovnet (DOT) com>

Saturday, February 14, 2004 2:10 pm

Re: Biogas

 

> > Only some externatl fixtures were heated in the

> > dead of winter. The slurry generated a lot of its own heat (you can

> imagine).

>

>

> What was the volume. Or an easier question - how many cows were

> contributingto the digester? It may take larger numbers to have a

> digester that

> generated enough heat to sustain itself.

 

Hmm... I remember a publication from some years ago when my son did a school

project on methane digesters. I think it was called "The Four Cow Methane Gase

Digester." I believe it was from Vermont or someplace.

 

As for simplicity, I don't think it was as simple as you describe the design

for a warmer zone. Probably keeping it warm in a cold climate did ads a layer

of complexity to it.

 

ys

 

hkdd

> >

> > I've seen several designs for lateral (tube) digesters. They are

> fairlysimple

> > and can be assembled with commonly available parts.

>

> Burying anything underground starts to move away from "simple"

> IMHO. I

> suspect it was also an insulated installation as the upper

> portions of the

> ground can and does freeze in Northern latitudes.

>

> It is much simpler where you can dig a well and put a collector

> dome on top

> and burn directly as you produce.

>

>

> -----------------------

> To from this mailing list, send an email to:

> Cow-Owner (AT) pamho (DOT) net

>

[Guest guest]

On these lines, I have found sources with as few as 6 - 10 to 600+ for

verious sized digesters. The tube ones can be 10ft long and 2 ft round or 5ft

diamiter concrete culvert pipe 25ft long.

 

The simplest digesters seem to be the tube ones as extracting the digested

slurry is the "work" involved and with this sort of project with a gravity fed

"in-one-side/out-the-other" unit the work is made easier than powering a pump

to pump it out of a well.

 

The ones I've seen with capped wells or ponds (like at the NV old goshalla)

usualy have high pressure water lines and have to be pumped out if burried, or

heated in the north if not burried.

 

Here is a link for a little warm weather tube unit. You can see how simple

the design is: it is a polyethylene (plastic bag-like) tube inflated with air

then filled with slurry. This is a do-it-yourself item using an old car for the

 

initial inflation.

 

http://www.royagcol.ac.uk/~francisco_aguilar/Slide-show1/sld001.htm

 

I don't mean simple as in growing your own polyethylene; I mean these can be

made with resources that are commonly available to most people.

 

This would have to be underground in a hard tube/culvert pipe thing for

northern climate. You could also use a thick diameter PVC culvert pipe as long

as

it can be tapped from above.

 

As far as underground not being simple, it is as simple as a digging a well

or burrying a cistern. It is work indeed but not complex. It also decreased the

 

amount of additional insulation and aids gravity flow if burried on a slope.

 

 

--------------------------

In a message dated 2/14/2004 1:00:26 PM Central Standard Time,

gourdmad (AT) ovnet (DOT) com writes:

> Only some externatl fixtures were heated in the

> dead of winter. The slurry generated a lot of its own heat (you can

imagine).

 

 

What was the volume. Or an easier question - how many cows were contributing

to the digester? It may take larger numbers to have a digester that

generated enough heat to sustain itself.

>

> I've seen several designs for lateral (tube) digesters. They are fairly

simple

> and can be assembled with commonly available parts.

 

Burying anything underground starts to move away from "simple" IMHO. I

suspect it was also an insulated installation as the upper portions of the

ground can and does freeze in Northern latitudes.

 

It is much simpler where you can dig a well and put a collector dome on top

and burn directly as you produce.