not only they have been tried but are used from many many years ago your numbers are real but as you point it these kind of digester are of bigger costs because of the technology involved
the most important point is the insulation used, bigger insulation thickness demands less energy but costs are higher... you can heat it with solar heater and the reminder energy if needed with biogas but you cannot provide this kind of digester to a small farm house without electric supply, for example for control and mixing porpuses..... these "high tech" digester are suitable for certain houses /locations/ with all basic requirement satisfied....... i work with these kind of digesters ..... if i can help you contact me SKYPE manuel.jimenezt Manuel 2012/10/3 Takamoto <k...@takamotobiogas.com>: > Dear Biogas List, > > I have been thinking about the biggest hurdles to producing more gas from > small scale biogas systems (4 cubic meters to 12 cubic meters) and by far > the biggest barrier is heat. From the literature I have read it seems that > if you increase the temperature of the digester from about 18C (the > temperature of our digesters) to 37C you can nearly double the gas yield per > unit of input and nearly halve the retention time which would reduce the > capital costs. > > Does anyone know of tests that have been done or ideas that have been put > forth to heat small scale digesters in a controlled manner? (For the moment > assume that such a process could be managed on many disparate, small scale > biogas systems. That is the next challenge.) The processes I was thinking of > were 1.) to heat the biogas system with biogas from the system itself or 2.) > to bubble a very slight amount of air through the digester so that there was > a slight anaerobic reaction that would produce heat and warm the digester. > Or 3.) you could use sunlight to warm the digester if you can warm the > digester and not the gas holder as warming the gas holder will only cause > the gas to expand and no heat will be transferred to the slurry. > > These methods are probably most applicable to fixed dome and floating drum. > > Have either of these ideas been tried? Are there other ideas out there? > > Cheers, > Kyle > > > > > _______________________________________________ > Digestion mailing list > > to Send a Message to the list, use the email address > digest...@bioenergylists.org > > to UNSUBSCRIBE or Change your List Settings use the web page > http://lists.bioenergylists.org/mailman/listinfo/digestion_lists.bioenergylists.org > > 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/ > > _______________________________________________ Digestion mailing list to Send a Message to the list, use the email address digest...@bioenergylists.org to UNSUBSCRIBE or Change your List Settings use the web page http://lists.bioenergylists.org/mailman/listinfo/digestion_lists.bioenergylists.org 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/
