[Digestion] compressing biogas

[adkarve]

Scrubbing and compressing biogas makes sense only if you want to use it as
fuel in an internal combustion engine. If you want fuel just for heating,
burn the biomass as it is, and make use of its full calorific value. When
you convert biomass into biogas, you lose at least 75% of the energy in the
process of conversion.
Yours
A.D.Karve
----- Original Message -----
From: Ken Calvert <renertech at xtra.co.nz>
To: <digestion at listserv.repp.org>
Sent: Monday, September 03, 2007 4:36 AM
Subject: Re: [Digestion] compressing biogas


> Dear Michael etal,  I think you have found the figures for LNG not CNG.
The
> only way to liquify Methane is at a very low temperature.  If you strip
the
> CO2 and H2S out of biogas then to all intents you have Natural Gas, and
CNG
> or compressed natural gas equipment operates at around 3,500psi, but it is
> still a gas.   If you are going to compress biogas at all,  then it is
best
> to stick to the usual figures and then you can run you car  cook your food
> and warm your house with standard mass produced Global standard equipment
> from off the shelf of any hardware/heating store.  If you, and anyone else
> wants some plans as to how to do it as economically as possible then send
me
> a private email and I will return mail you some  brochures put out by our
> Ministry of Agriculture  for  small  farm and hobby farm Biogas plant.
>     In brief, you collect the gas in a plastic bag, and monitor the
pressure
> with the filler guage out of a auto washing machine. The pressure switches
> on a  two cylinder air compressor which sucks the gas through one of a
pair
> of barrels filed with rusty bashed up tin cans which are alternated one in
> line and the other left open to the air. The Iron sulphide in air then
> reverts to iron metal for reuse of the barrel, and the sulfur is left as
> elemental flowers of sulfur which is useful stuff. (beware heat problems)
> At around 150psi  the gas is bubbled through a vertical water column
> consisting of a six meter length of 6" 150mil  plastic pipe.  2metres as
> someone suggested is not enough.  Natural gas at 150psi can then be used
in
> liu of LPG  if  it is metered through an LPG reduction valve and the jets
in
> LPG stuff are opened out a smidgeon.  Storing a reasonable volume of
methane
> at this pressure takes some ingenuity  but  it can be done.  To drive your
> car on CNG requires a pair of old double acting hydraulic cylinders off a
> bulldozer or some such. You can't  use one cylinder with a floating
piston,
> because as already mentioned lubricating oil will take up methane under
> pressure   and hydraulic pumps don't work too well with oil foaming out
the
> tank.   A single 3 ft stroke will take you up to 3000psi +  in one stroke,
> and normal DIY hydraulic equipment from  Northern Tool or other DIY stores
> operate at just the right pressures to make a  rather neat setup.
However,
> let me say it again  spending the money to go this far is crazy if you do
> not clean up your gas first and  convert it into the Natural Gas which is
a
> world wide commodity with so many appliances and equipment  matched to its
> use.
> Ken C.
>
>
> ----- Original Message -----
> From: "Michael Smith" <michael_1234 at msn.com>
> To: "digestion" <digestion at listserv.repp.org>
> Sent: Monday, September 03, 2007 8:31 AM
> Subject: [Digestion] compressing biogas
>
>
> > If the methane in pressurization is liquefied @ approx. 1100 psi what
are
> > the consequences of the CO2 and Nitrogen at these pressures? I expect
more
> > than enough electricity from wind power at various times to
pressurize...2
> > to 4 cu. ft. per minute.
> > _______________________________________________
> > Digestion mailing list
> > Digestion at listserv.repp.org
> > http://listserv.repp.org/mailman/listinfo/digestion_listserv.repp.org
> > Beginner's Guide to Biogas
> > http://www.adelaide.edu.au/biogas/
> > http://info.bioenergylists.org
> >
>
>
>
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> Beginner's Guide to Biogas
> http://www.adelaide.edu.au/biogas/
> http://info.bioenergylists.org