[Digestion] Electricite generation

[adkarve]

If you just want heat to poduce steam for running a steam turbine, you can
as well burn the biomass directly, without converting it into biogas. A kg
of dry dung, burned in the form of dung cakes, would yield 2200 kcal energy.
The same amount of dung would yield only 660 kcal energy, if it were
converted into biogas and burned.
Yours
A.D.Karve
----- Original Message -----
From: Bruno M. <brunoM1 at telenet.be>
To: <Digestion at listserv.repp.org>
Sent: Monday, September 03, 2007 10:09 PM
Subject: Re: [Digestion] Electricite generation


Maybe you need ( already) to rethink your endeavor,

If I understand it correctly you have biogas from a digester( CH4 + CO2 )
you like to blow that in a boiler to produce steam,
then you gonna blow that steam into a expensive turbine,
that drives a generator that makes electricity

for your own use or selling to the grid).
And you think blowing the rest steam of the
turbine back into the boiler will help?

To expensive and to complex i believe, on every
conversion you gonna loose energy.
so leave out the boiler and the expensive turbine and blow your biogas
into an adapted motor ( ICE), that is coupled to a generator,
find a use for the waste heat from the ICE, e.g. heating a greenhouse
( than you can also use the CO2 containing exaust gas as fertilizer),
or heating your digester.

Also, in your proposed setup there will be no
real gain by blowing the turbine exit steam
back into the boiler.
Why?
Let say you make 10 bar wet steam ( = 184°C ) you blow that steam
in the turbine, you will get energy out as
rotation of the shaft to run your generator,
what comes out of your turbine is steam ( and
water droplets) with a temp lower than
184° C. How you gonna heat your boiler who needs to get above 184°C
with steam that is colder? ( wile your boiler is
working the water will be constant on 184°C,
and al heat input will then be used to convert
water from 184°C to steam (-vapor)
of the same temp; so there will be no real use
(gain) for a fluidum with a temp below 184°C
to help (pre-)heat the boiler.

Maybe you can start with telling us about your system you already have
( how much gas a day you produce now, and whats the quality) ,
and what your future needs are ( electricity and heat ).


grts
Bruno M.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
At 12:22 3/09/2007, Francois wrote:
>Hi all,
>
>I am looking for a system to produce electricite out
>of biogaz - most likely a cogeneration steam turbine
>that reuses the exhaust to preheat the boiler for max
>energy efficiency.
>Does anyone know of trade marks, sellers etc.
>Cheers and thanks
>Francois
>==================================================================


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