[Gasification] [Stoves] Thickness of flame front

[Kevin Chisholm]

Dear Das

aguadas at onebox.com wrote:
>
> Char starts to give offf volatiles at the peak temperature of the 
> charring process for that particular char.

Thanks, but in Antal's case, I believe he chars under pressure. It would 
be very interesting to see what the "gas evolution temperature is when 
the char is heated at atmospheric pressure.

Best wishes,

Kevin
>  
> Das
>
>
> -----Original Message-----
> From: Kevin Chisholm
> Sent: Tue, 22 Jan 2008 16:38:26 -0400
> To: Discussion of biomass cooking stoves
> Cc: "'Thomas Reed'" ;"'GASIFICATION'" ;"'Jim Fournier'" ;"'agua Das'"
> Subject: Re: [Stoves] Thickness of flame front
>
> Dear Michael
>
> Michael Antal wrote:
> > Although I always admire Tom's postings, they occasionally contain
> > typographical errors. We recover about 70% of the energy content of 
> biomass
> > in the energy content of charcoal. This is well documented in a long 
> series
> > of papers. Regards, Michael.
> >
>
> If that char was slowly heated at atmospheric pressure, at what
> temperature would it start to give off volatiles?
>
> Thanks.
>
> Kevin
> >
> >
> > Michael J. Antal, Jr.
> >
> > Coral Industries Distinguished Professor of Renewable Energy Resources
> >
> > Hawaii Natural Energy Institute
> >
> > POST 109, 1680 East-West Rd.
> >
> > Honolulu, HI 96822
> >
> >
> >
> > phone: 808/956-7267
> >
> > fax: 808/956-2336
> >
> > www.hnei.hawaii.edu
> >
> > _____
> >
> > From: Thomas Reed [mailto:tombreed at comcast.net]
> > Sent: Tuesday, January 22, 2008 6:55 AM
> > To: Discussion of biomass cooking stoves; GASIFICATION; Michael 
> Antal; Jim
> > Fournier; agua Das
> > Subject: Re: [Stoves] Thickness of flame front
> >
> >
> >
> > Dear Andrew and All:
> >
> > I was involved with diamond synthesis at Union Carbide and have 
> converted a
> > few diamonds to graphite.
> >
> > At 1000 C diamonds are pretty stable in a hard vacuum or argon at 1 
> atm.
> >
> > At 1100C they begin to decompose slowly.
> >
> > At 1200 C they pop like popcorn....
> >
> > What a fascinating element. And to think that the hydrogen people detest
> > it.
> >
> > Biocarbon or biocoal is carbon neutral and leaves the atmosphere as 
> it is.
> > It can be called "Green Carbon" or "Green Coal". So after we have 
> stopped
> > our dependence on fossil fuels it will be the preferred energy form. 
> It is
> > a better way to convert biomass to energy which can then be stored, 
> shipped
> > and burned carbon neutral.
> >
> > Mike Antal has developed a process that recovers > 30% or 40% of the 
> energy
> > in biomass as biocoal with 12-13000 Btu/lb.
> >
> > Hydrogen is NOT neutral - it removes O2 from the atmosphere without
> > replacing it.
> >
> > Your biomass curmudgeon,
> >
> > TOM REED
> > BEF
> > BEC
> > WoodGas.com
> >
> >
> >
> >
> >
> > ÐÏࡱá
> >
> >
> >
> > AJH wrote:
> >
> > On Fri, 18 Jan 2008 21:54:46 +0200, IPC wrote:
> >
> >
> >
> > "Some carbon-carbon bonds are so strong the carbon won't burn, diamond
> > decomposes to graphite at 1200C but it doesn't burn."
> >
> > Really?
> >
> >
> >
> > I think so, as I said the diamond first graphitises and then further
> > heating will burn the graphite, I think this is how it was proved
> > diamonds were carbon in the 18th century but a solar concentrator had
> > to be used to get the temperature high enough.
> >
> >
> >
> >
> > The only diamond I ever found was identified by a mineralogist.
> > When I doubted his identification, he said "Watch!", lit a bunsen 
> burner,
> > put my stone on the end of a spatula and - Poof!
> >
> >
> >
> > I heard a similar story about a researcher at a university that was
> > "loaned" a diamond to do experiments on the vibrations of the bonds.
> > To excite the diamond he placed it on a stainless steel ultrasonic
> > transducer and proceeded to heat it up, being careful to keep below
> > the transition temperature, it too disappeared and the physics
> > department had to explain to De Beers how their diamond was now a
> > small piece of cast iron (or more correctly cementite) in the middle
> > of a stainless steel platter, search on cast iron eutectic mixture.
> >
> >
> >
> >
> > Don't leave your wife's jewels around in a fire.
> >
> >
> >
> > And this story featured in a novel about a girl casting her diamond
> > engagement ring into the coal fire, regretting it but only finding a
> > blob of gold in the ashes next morning, a young lecturer wanted to
> > test this but De Beers wouldn't co operate!
> >
> > IIRC diamond auto ignition point in pure oxygen is ~700C and someone I
> > trust implicitly has told me he has preheated a diamond to ~400C and
> > burned it by dropping it in liquid oxygen, he, like Tom Miles, has
> > money to burn ;-).
> >
> > AJH
> >
> >
> >
>
>
>
>
>
>
>