[Digestion] Dry fermentation in developing countries

David david at h4c.org
Thu Oct 28 13:07:30 PDT 2010


On 10/28/2010 11:48 AM, Markus Schlattmann wrote:
> HI David,
>> I would venture a guess that where the inlet air is being forced in 
>> [to the batch container] by bubbling through water, and the outlet 
>> air likewise is allowed to escape by bubbling through water, then 
>> the only place in the system where there would be both a 
>> potentially explosive gas mixture and the potential of a spark 
>> would be at the evacuation point of the exiting gas mixture. Where 
>> sufficient air is blown over the water through which the evacuating 
>> air is exiting, then the risk of any explosion would, I would 
>> think, be very close to zero.
> Just for some additional explaintation: Those garage systems have 
> just one door whichs seperates the digesting room from the 
> atmosphere. So you need to open the door to get the old material out 
> of the system and put in the new material. Existing methane from the 
> last digestion process may get in mixture of air oxygen during this 
> process. I think this is the problem Yvonne is wondering about.

Yes, as she said: like Bekon (http://www.bekon-energy.de/englisch.htm: 
see last picture on that page). Thus, I appreciate your clarification, 
but I am puzzled. The process I attempted to describe should be easy 
to implement whether in a situation where low cost is a primary 
consideration, or in a shiny packaged version for a high tech system. 
What have I missed here?

> For getting a better idea of such garage systems you may look at 
> this report (2003, an independent, scientific report about one of 
> the first BioFerm systems, german language, but there are also a lot 
> of pictures to look at).
> See page 24, upper image

Very clear, yes. I have seen other, similar drawings of Bekon and 
Bekon-type systems in the past (and in fact included them in 
presentations on biogas such as no doubt we all offer from time to 
time), but this is an excellent graphic. Since I am language 
impaired-- I do not speak German-- there is much which escapes me with 
regard to this report. I would think that the literature in German 
regarding biogas is very rich, based on what little I know.

David William House
"The Complete Biogas Handbook" |www.completebiogas.com|
/Vahid Biogas/, an alternative energy consultancy |www.vahidbiogas.com

"Make no search for water.       But find thirst,
And water from the very ground will burst."
(Rumi, a Persian mystic poet, quoted in /Delight of Hearts/, p. 77)

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