[Digestion] The relatively high cost of digesters.

[Hoysall Chanakya]

Dear Paul (high digester costs),
Thanks for bringing it out succinctly - our narrow-focused obsession for
yields seen as gas production rate (m3 gas /m3 reactor /d) has led us to
this predicament of "sophisticated" and large digesters almost having
reached a point of no-return.  As we climb the yleld-rate ladder the
tolerance falls rapidly so the process can only be run with sophisticated
controls.  Loading so much controls makes it viable only at a large scale
- a catch-22 situation.

Many of us on this list have now moved towards a utility focused approach
- and in effect sacrificing a small bit on the "volumetric efficiency". 
What is interesting is in this exercise it also seems one could expand on
the feedstock variety - a vital requirement in tropical areas.  I am sure
like Dr.Karve, there are many more who have experimented and prioritized
with feedstock flexibility (especially agro-residues) with amazing
results.  IT would be nice to exchange more on this experience
best wishes
chanakya





  be "measured"
> G'day All,
>
> One reason for the "high" cost of digesters is that "Westerners" seem to
> have a preoccupation with complexity and large, centralised facilities -
> which "we" expect to inflict on the rest of the world.
>
> The small, simple, decentralised systems used extensively in China, India
> and more recently Columbia, Vietnam, Cambodia and Bolivia and reported by
> some members of this discussion group are making a big improvement to the
> environment by providing convenient, clean fuel without deforestation or
> fossil fuel depletion. They may not win on "biogas per unit digester
> volume"
> or "throughput per day" and will not make corporate profits but they do
> lift
> people from poverty, ease the grind of daily life and may well get more
> biogas per unit of VS/COD, compared to "our" large units.
>
> I agree you get what you pay for and there are bound to be improvements
> that
> may need to be done, but it's also "horses for courses".
>
> Happy digesting,
> HOOROO
>
> Mr. Paul Harris, Room S116b, Waite Main Building Faculty of Sciences, The 
> University of Adelaide, Waite Campus, PMB 1, Glen Osmond SA 5064 Ph    :
> +61
> 8 8303 7880      Fax   : +61 8 8303 4386
> mailto:paul.harris at adelaide.edu.au  
> http://www.adelaide.edu.au/directory/paul.harris
>
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> -----Original Message-----
> From: digestion-bounces at lists.bioenergylists.org
> [mailto:digestion-bounces at lists.bioenergylists.org] On Behalf Of Edgar
> Blanco-Madrigal
> Sent: Tuesday, 7 December 2010 10:51 PM
> To: For Discussion of Anaerobic Digestion
> Cc: digestion
> Subject: Re: [Digestion] The relatively high cost of digesters.
>
> In AD the universal principle applies:
> "You get what you pay for"
>
> You can build a cheap digester, and produce gas, etc. But you should not
> pretend this in any way will be helping the environment, because to do
> that
> money has to be committed in the whole operation.
>
> SNIP
>
> Please, do not peddle technology on the basis of its low cost, do it on
> the
> basis of quality!
>
>
>
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> for more information about digestion, see
> Beginner's Guide to Biogas
> http://www.adelaide.edu.au/biogas/
> and the Biogas Wiki http://biogas.wikispaces.com/
>
>
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-- 
Dr. Hoysall Chanakya
Centre for Sustainable Technologies
(Assoc. Faculty at Centre for Infrastructure, Sustainable Transport and
Urban Planning (CiSTUP) and Centre for Contemporary Studies)
Indian Institute of Science, Bangalore 560 012
ph 91-80-2293 3046; fax-91 80 2360 0683


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