Crispin Pete et al. , Several in Malawi were dipping the agro residue based briquette in said veggie oils. Kobus experimented with same too. As I recall, It provided a quick start and readily efficient self-consuming/ hcleaning/ wicking system for the oil during combustion. Very little is needed something like 1 or 2 ccs per a 10cm ΓΈ x 7.4cm tall, hollow core (~ 550 cc/~140 gram) briquette.
Richard Stanley On Nov 28, 2011, at 9:00 PM, Crispin Pemberton-Pigott wrote: > Dear Peter > > Good to hear from you, I was thinking of you last week testing a downdraft > stove using chunks of wood the same size you use on your DD BBQ (barbie). The > chunks of wood provide quite a bit of excess air so the way the heat transfer > takes place it affected a lot. > > >As far as I know the difference between kerosene (paraffin) and higher > >hydrocarbon fractions, including vegetable oils is the fact that they are > >not distillable under atmospheric pressure. > The stove must work then by boiling something in the veggie oil that boils at > a temperature achievable in the evaporator tube. Perhaps that is why there is > so much gunk left behind. A completely different approach (and an old one) is > dripping oil onto a flat plate that is completely contained inside the > combustion chamber. People burn old engine oil that way, and for similar > reasons. > >Undistillable hydrocarbons are fed into the fire as a spray of very fine > >droplets that burn completely. > With the residence time in the flame matching the burnabilty of the droplet, > right? When a droplet of diesel burns, has it been evaporated by radiant heat > under that increasing pressure of the pressure wave? > The same could be done with vegetable oils at the combustor end. However, > most vegetable oils tend to react slowly with oxygen to form gunk which > eventually blocks the passages it has to flow through. > Is this process dramatically accelerated by heating the oil? In other words, > is the depositing cause by O2 already in the fuel? That bodes badly for the > future of burning raw oil. > So for a stove that burns vegetable oil, the piping from the storage to the > burner should be of very simple shape and easy to clean. > Daily, as I understand it. > Realising that producing a spray of fine droplets is out of the question for > domestic stoves, we have to find something that feeds the oil to the > combustion zone where the carbon, resulting from the decomposition of the oil > is burnt as well. > How about using one of those spinning disks with a spiky periphery that are > used in greenhouses to make as fine a mist as possible? They are very small > (50-75mm) and use only a small amount of power. It is conceivable they could > be driven by electricity, heat or draft. > Possibly something like a perforated disk where the oil burns in updraft mode > and where the holes occupy a sufficient part of the disk area that all the > char comes in contact with air. > Good idea. A variation on the drop-onto-plate idea might do. > Does the Protos stove have any relation to Siemens. > Yes it is a Bosch-Siemens product. > Regards > Crispin > > _______________________________________________ > Stoves mailing list > > to Send a Message to the list, use the email address > [email protected] > > to UNSUBSCRIBE or Change your List Settings use the web page > http://lists.bioenergylists.org/mailman/listinfo/stoves_lists.bioenergylists.org > > for more Biomass Cooking Stoves, News and Information see our web site: > http://www.bioenergylists.org/ >
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