Char producing stoves are ok if the user does not mind having to refill now and then and the after cooking mess to be cleaned up. After cooking mess also includes ash content. We can not escape the ash for as long as we are talking about biomass power. Farmers and those who want cheap source of power for ic engines should not mind the char producing stove even though it does produce ash. Another stove option is that which has the capacity to cook for long hours and has ash content too. The degree of ash content is a function of biomass type. Yet a third option is char production industrial scale. This kind of stove can be used to generate electricity as well as been of benefit to the soil. The design as well as biomass type should take care of smoke. Clem. Nigeria.
On Sat Sep 25th, 2010 8:37 PM Etc/GMT+12 paal wendelbo wrote: >Lloyd > >Crispin is right this time. We used grass (Hyperrenia rufa) as fuel in the >Adjumani refuge camp in North of Uganda in the early 90ties tree times per day >for about two years into TLUDs PekoPe and had no problem rather opposite. The >advantage by using grass as fuel into a TLUD is the simmering effect caused by >the fact the glowing mass, after the flame is over, doesn't collapse like wood >fuel and by that it will be giving good simmering temperature close under the >pot for quite a long time. > >.Paal W [email protected] > > > >----- Original Message ----- From: "Lloyd Helferty" <[email protected]> >To: "Discussion of biomass cooking stoves" <[email protected]> >Cc: "Crispin Pemberton-Pigott" <[email protected]> >Sent: Sunday, September 26, 2010 4:10 AM >Subject: Re: [Stoves] The Biochar myth..another stovers myth > > >> Crispin, >> >> You say right at the end that "Pelletized grass can be used in >> /*any*/ pellet stove or furnace." >> >> I do not believe that this is generally true. High ash grass pellets >> could be a big problem. Many stoves cannot handle high ash content >> fuels, and more ash means much more maintenance**. >> >> Clinkers are where the combustion temperature of the fire exceeds the >> melting point of the ash in the fuel pellet (esp. with chlorine and >> potassium), and the silicates within the ash will bind together to form >> a glass like mass. >> When ash melts it forms a glob of sticky material that cools hard. If >> a fuel has a lot of ash with a low melting point a clinker will form, >> and this will have to be manually removed, which increases >> maintenance**. ("Slag" is the name used for a similar material which >> collects around the heat exchanger pipes, and reduces heat exchange, and >> thus performance.) >> >> **You might end up having to give it a serious cleaning every 6 hours or >> so, in order for the stove to continue functioning. >> >> Ash clinker formations are usually associated with biomass pellet >> fuels such as grass and straw pellets. If the ash content of these >> pellets is too high and the ash melts and form clinkers you could be >> looking at a big loss on fuel -- as well as a big mess inside your >> stove. Clinkers can end up blocking the air holes of the incoming air >> which can upset the mixture of air and fuel. Incorrect adjustment of the >> air to fuel ratio can then greatly increase the likelihood of more >> clinker formation. This is due to the stoves inability to adequately >> burn the excess fuel and remove the excess ash that is building up in >> the burn pot. >> >> Not very many simple stoves that I know of that can correctly handle >> very high ash fuel pellets. Even most of the more expensive commercially >> available pellet stoves in North America and Europe (designed to burn >> wood pellets) have no means of dealing with high ash content (except >> Perhaps a for Harman corn stoves, Dell-Point Industries Europa stoves or >> the Country Flame Technologies Harvester stoves). >> >> A simple TLUD with its "flaming pyrolysis" should not create clinkers >> and will result in a biochar residue that should also not be too >> alkaline (and so hopefully can be placed directly into soil or compost >> without worrying too much about changes to the pH). >> >> Lloyd Helferty, Engineering Technologist >> Principal, Biochar Consulting (Canada) >> www.biochar-consulting.ca >> 603-48 Suncrest Blvd, Thornhill, ON, Canada >> 905-707-8754; 647-886-8754 (cell) >> Skype: lloyd.helferty >> Steering Committee member, Canadian Biochar Initiative >> President, Co-founder& CBI Liaison, Biochar-Ontario >> Advisory Committee Member, IBI >> http://www.linkedin.com/groups?gid=1404717 >> http://www.facebook.com/group.php?gid=42237506675 >> http://groups.google.com/group/biochar-ontario >> http://www.meetup.com/biocharontario/ >> http://grassrootsintelligence.blogspot.com >> www.biochar.ca >> >> Biochar Offsets Group: http://www.linkedin.com/groups?home=&gid=2446475 >> >> >> On 9/15/2010 6:32 PM, Crispin Pemberton-Pigott wrote: >>> Dear Friends >>> >>> First a tip of the hat to Dean for pointing out that stoves can be designed >>> to produce char or not. >>> >>> I remind everyone to please look at the whole equation of a problem , not >>> just a part and then make claims. In some cases one might want to create >>> char and some not, for example when cooking at a low heat for a long time. >>> >>>> RWL - Crispin, being a climate denier, should not be taken as the final >>>> word on these issues. Biochar in many places is giving a doubling of soil >>>> productivity for centuries not just the first year, when there is a need >>>> for twice as much fuel. >>> I agree with Ron on this: there is a lot of support for the idea that char >>> increases growth of plants. Alex English and I had a long conversation a >>> couple of weeks ago and he report that some plant diseases are limited by >>> an increased ability of the plant to cope with infections if there is char >>> in the soil. Personally I think it has to be in the form of char, not >>> carbon in general. I know some Permaculture stalwarts who think the answer >>> lies in composting done correctly. >>> >>> The point I was making is that claims are being made for char making stoves >>> to simultaneously save fuel, save trees and produce significant amounts of >>> char. The energy and efficiency math does not support this, interesting as >>> char is as a soil amendment. >>> >>> I have already pointed out that in order to get 'meaningful' (as promoted >>> in the literature) quantities of char from a stove means fertilising a >>> potted plant, not a field. >>> >>>> But as Nathan Mulcahy has been emphasizing, the fuels for pyrolyzing >>>> stoves need not be wood at all. And for charcoal consuming stoves - >>>> almost certainly obtained from wood, the gain of pyrolyzing stoves is >>>> even greater. >>> As AD Karve has shown, charcoal fuels can easily be made from agricultural >>> waste and the whole system creates employment as well - basically out of >>> nothing. Let us not toss that system aside too easily. >>> >>>> RWL The last part is indeed true - but I am pretty sure that trees >>>> generally produce more than grasses on an annual basis. >>> It is Roger who has conclusively shown that grasses significantly >>> outperform trees. >>> >>> Melting permafrost allows for a huge increase in biomass per sq metre and >>> the tree line used to be much farther north than it is now only 6000 years >>> ago. One expects that this can also grow grasses for biofuel. Right Roger?? >>> >>>> But grasses are pretty hard to use in all but pyrolyzing stoves. >>> Pelletized grass can be used in any pellet stove or furnace. It is also >>> worth the energy to create the pellets which is harder to say about wood. >>> >>> Regards >>> Crispin >>> >>> >>> >>> _______________________________________________ >>> Stoves mailing list >>> [email protected] >>> http://listserv.repp.org/mailman/listinfo/stoves_listserv.repp.org >>> http://stoves.bioenergylists.org >>> http://info.bioenergylists.org >>> >>> UNSUBSCRIBE HERE; >>> http://listserv.repp.org/mailman/listinfo/stoves_listserv.repp.org >>> >>> >> > > >-------------------------------------------------------------------------------- > > >> _______________________________________________ >> Stoves mailing list >> [email protected] >> http://listserv.repp.org/mailman/listinfo/stoves_listserv.repp.org >> http://stoves.bioenergylists.org >> http://info.bioenergylists.org >> >> UNSUBSCRIBE HERE; >> http://listserv.repp.org/mailman/listinfo/stoves_listserv.repp.org >> > > > >_______________________________________________ >Stoves mailing list >[email protected] >http://listserv.repp.org/mailman/listinfo/stoves_listserv.repp.org >http://stoves.bioenergylists.org >http://info.bioenergylists.org > >UNSUBSCRIBE HERE; >http://listserv.repp.org/mailman/listinfo/stoves_listserv.repp.org _______________________________________________ Stoves mailing list [email protected] http://listserv.repp.org/mailman/listinfo/stoves_listserv.repp.org http://stoves.bioenergylists.org http://info.bioenergylists.org UNSUBSCRIBE HERE; http://listserv.repp.org/mailman/listinfo/stoves_listserv.repp.org
