Clinker will start to form about 750C. If you have local peaks of 1000c you'll see clinker.
Tom T R Miles Technical Consultants Inc. [email protected] Sent from mobile. On Oct 15, 2011, at 11:25 PM, Paul Olivier <[email protected]> wrote: > Tom, > > But the temperature in the reactor is much higher than 350 C. > I have seen a sort of clinker in the biochar if I do not turn the fan off at > the end of a batch. > At what temperature does the vaporization of K take place? > > Paul > > On Sun, Oct 16, 2011 at 12:33 PM, Tom Miles Easystreet <[email protected]> > wrote: > it exists in a form in which a portion will vaporize easily especially if > chlorine is present. But at 350c you won't lose much from the char. > > T R Miles Technical Consultants Inc. > [email protected] > Sent from mobile. > > On Oct 15, 2011, at 10:25 PM, Paul Olivier <[email protected]> wrote: > >> Tom, >> >> I am not sure if I understand all that you are saying here. >> I thought that the potassium compounds melt at 350 C and vaporize at >> substantially higher temperatures. >> If most of the K stays in the char, then it does not vaporize at 350 C. >> Is this correct? >> >> Paul >> >> On Sun, Oct 16, 2011 at 11:00 AM, Tom Miles <[email protected]> wrote: >> The actually exists as KOH and vaporize starting at about 350 and increasing >> in greater proportions as you increase temperature. Once it vaporizes it >> condenses quickly with chlorine or sulfur, if present. Only when it is hot >> enough (750 C or higher) will it begin to melt, especially If it is present >> with silica in a ratio of about 1:2. Husk silica is more resistant than >> straw silica to alkali silicate formation. I would think the most of the K >> will stay in the char. If you get K volatilization you will see it where you >> burn the gas. Over time you’ll get agglomeration of very fine (submicron >> like cigarette smoke) particles that we call an alkali fume. At such low >> fuel rates you’re not likely to see anything for some time. >> >> >> >> Using the rice husk as a pilot fuel for the coffee husk makes a lot of >> sense. You’ll get a clean gas and a rich husk char. >> >> >> >> Tom >> >> >> >> From: [email protected] >> [mailto:[email protected]] On Behalf Of Paul Olivier >> Sent: Saturday, October 15, 2011 5:17 PM >> To: Discussion of biomass cooking stoves >> Subject: Re: [Stoves] why does coffee husk biochar smell like urine? >> >> >> >> Frans, >> >> When subjected to temperatures greater than 350 C, >> are you saying that K2O melts but does not vaporize? >> Are you saying that we end up with melted K2O? >> If the original coffee husks contains 36% to 38% >> then the final biochar must contain at least twice that amount. >> If this is correct, then coffee husk biochar must be quite valuable, >> not only as a soil amendment but also as a fertilizer. >> Surely this cannot be right. >> >> The coffee husk contains some sort of oily substance >> that begins to volatilize at temperatures as low as 170 C. >> When gasified it produces a lot of black soot. >> I tried many burner designs in the last few weeks to get rid of the soot and >> to turn orange flames into blue. >> Supplying hot premixed secondary air does not effectively consume this soot. >> Sometimes it makes things worse. >> >> A few days ago I cheated. >> I mixed coffee husks and rice hulls in equal volumes. >> (Note that the coffee husk has a bulk density of 180 kg/m3, >> while the rice husk has a bulk density of about 100 kg/m3.) >> The flame at the base was blue and white. >> This is the first time I saw the color white in the gasification of coffee >> husks. >> As the flame rose, it split into two parts: >> one part vertical and the other part more horizontal. >> The vertical part was blue/white and the more horizontal part was orange. >> But there were no streaks of black within the orange part of the flame and >> no visible soot. >> >> The gasifier that I used looked like this: >> http://dl.dropbox.com/u/22013094/150%20Gasifier%20Drawings%20PDF/001%20-%20150%20Gasifier%20Assembly.pdf >> Note the burner design: >> it is a Belonio burner with two rings of burner holes, together with a >> burner housing. >> This burner design gives by far the best result. >> Secondary air is sucked up between the housing and the burner. >> It then moves from vertical to horizontal, >> and from here it hits the two rings of holes that are offset from one >> another. >> >> The best result, of course, is with 100% rice husks. >> With the current burner design, the flame is totally blue right from the >> very beginning. >> >> When I mixed rice hulls with coffee husks (half/half by volume), >> not only does most of the soot disappear, >> but the burn is quite consistent and steady from beginning to end. >> >> Paul >> >> >> On Sun, Oct 16, 2011 at 5:35 AM, Frans Peeters <[email protected]> >> wrote: >> >> Dear Paul , >> >> >> >> I did many times fusions with pure KOH . >> >> At 350° C it melts and is very aggesive to dissolve ceramics Al2O3 and SiC >> powders . (Diamond recup. ) >> >> It is verry verry hygroscopic and the hydroxyde airosols with water in the >> air gives your nose sense alcalic . >> >> Your brain makes the link to urine . but not the real potasium make it . >> >> It goes not into gas but sputers airosols has a special creep effect out of >> a creuset .! Even after cooling . >> >> Also a battery and fuel cel with KOH . It creeps in a isolated conductor >> for 20 cm after years ,and destroys manny apparati . >> >> KOH Is colourless but Nickel gives yellow.salts . >> >> It does not become K2O2 becouse to destroy SiC we must ad Na2O2 to oxydize >> the carbide . >> >> Potasium is to measure with flame spectro 440 um purple colour in a hydrogen >> flame . (Sodium =yellow . Cupper =green Sr =red >> >> Sorry ,I drink no coffe ! But have a friend who drinks pee …. >> >> >> >> Regards >> >> Frans >> >> >> >> >> >> Van: [email protected] >> [mailto:[email protected]] Namens Paul Olivier >> Verzonden: zaterdag 15 oktober 2011 9:07 >> Aan: Discussion of biomass cooking stoves >> CC: Will Rutherford; loren cardeli; CHRISTA ROTH >> Onderwerp: [Stoves] why does coffee husk biochar smell like urine? >> >> >> >> Christa, >> >> Do you have any idea why coffee husk biochar smells like urine? >> >> I just read that coffee husks contain 36% to 38% K2O. >> This supposedly accounts for the low melting point of its ash. >> That its ash has a low melting point makes sense to me, >> since, if I leave the fan on a bit too long after the gasification cycle is >> finished, >> I see a stony yellowish/white ash at the bottom of the reactor. >> >> How is this possible that coffee husks could have so much K2O? >> What happens to the K2O when it is subjected to heat? >> I see that K2O has a melting point > 350C. >> If subjected to heat does it turn into K2O2 or even KO2? >> At what point does it turn into a gas? >> >> Does the presence of K2O account for its urine smell? >> What does this urine smell mean with regard to the value of coffee husk >> biochar? >> Would coffee husk biochar be rich in potassium? >> >> Paul >> -- >> Paul A. Olivier >> 27C Pham Hong Thai Street >> Dalat >> Vietnam >> >> >> _______________________________________________ >> 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/ >> >> >> >> >> >> -- >> Paul A. Olivier PhD >> 27C Pham Hong Thai Street >> Dalat >> Vietnam >> >> Louisiana telephone: 1-337-447-4124 (rings Vietnam) >> Mobile: 090-694-1573 (in Vietnam) >> Skype address: Xpolivier >> http://www.esrla.com/ >> >> >> _______________________________________________ >> 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/ >> >> >> >> >> >> -- >> Paul A. Olivier PhD >> 27C Pham Hong Thai Street >> Dalat >> Vietnam >> >> Louisiana telephone: 1-337-447-4124 (rings Vietnam) >> Mobile: 090-694-1573 (in Vietnam) >> Skype address: Xpolivier >> http://www.esrla.com/ >> _______________________________________________ >> 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/ >> > > _______________________________________________ > 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/ > > > > > > -- > Paul A. Olivier PhD > 27C Pham Hong Thai Street > Dalat > Vietnam > > Louisiana telephone: 1-337-447-4124 (rings Vietnam) > Mobile: 090-694-1573 (in Vietnam) > Skype address: Xpolivier > http://www.esrla.com/ > _______________________________________________ > 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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