Quoting Frank Shields <[email protected]>:
> Alex,
>
> Its the H/C ratio that has been considered.
>
> I like the term Fixed Carbon when we actually measure the carbon content in
> the left overs.
>
> Regards
>
> Frank
>
> Frank Shields
>
> Control Laboratories, Inc.
>
> 42 Hangar Way
>
> Watsonville, CA 95076
>
> (831) 724-5422 tel
>
> (831) 724-3188 fax
>
> www.biocharlab[1].com
>
> FROM: Alex English [mailto:[email protected]]
> SENT: Tuesday, February 05, 2013 3:36 PM
> TO: Discussion of biomass cooking stoves
> CC: Frank Shields; 'Crispin Pemberton-Pigott'; [email protected]; 'Hugh
> McLaughlin'; 'Ron Larson'; 'Thomas Reed'
> SUBJECT: Re: [Stoves] Characteristics of biochar was Re: [biochar] grassifier
> & cedar chip char
>
> Perhaps it should be called fixed-up carbon, its whats left after getting rid
> of the rif-raf that can['t tough it out in the kitchen when thing get hot.
>
> What other tests are there that would give a better representation of the
> biological recalcitrance of char?
>
> Alex
>
> On 05/02/2013 5:33 PM, Frank Shields wrote:
>
> Paul,
>
> My biggest problem with the term fixed carbon is that it is not a
> measurement of the carbon at all. Just the stuff left over after heating that
> can contain Oxygen and hydrogen.
>
> Frank
>
> FROM: Stoves [mailto:[email protected]] ON BEHALF OF
> Paul Anderson
> SENT: Tuesday, February 05, 2013 1:17 PM
> TO: Crispin Pemberton-Pigott; Discussion of biomass cooking stoves;
> [email protected]; Hugh McLaughlin; Ron Larson; Thomas Reed
> SUBJECT: Re: [Stoves] Characteristics of biochar was Re: [biochar] grassifier
> & cedar chip char
>
> Crispin,
>
> The influence of the coal industry on the testing is not a perfect match for
> what biomass gasification is all about and the testing of biomass and biochar.
>
> Biomass can be 50% carbon, but with decay it will all go to CO2. Fixed
> carbon must be created in the carbonization process.
>
> In Atlanta airport about to fly to Uganda for 3 weeks. I hope that others
> will comment, and not rely on me to reply.
>
> Paul
>
> Paul S. Anderson, PhD aka "Dr TLUD"
>
> Email: [email protected] Skype: paultlud Phone: +1-309-452-7072
>
> Website: www.drtlud.com[2]
>
> On 2/5/2013 10:09 AM, Crispin Pemberton-Pigott wrote:
>
> Dear Paul
>
> 1. As far as I know, there is no "fixed carbon" in the biomass. It is fixed
> during the process of carbonization/pyrolysis.
>
> That is the problem it you give a sample of wood to a lab and they perform
> a coal analysis test on it you will get a report on the amount of fixed
> carbon. The point I was making is that it is a metric of convenience arising
> from the test procedure, not a reference to a material property.
>
> 2. Some biomass such as seeds have "oils" that vaporize or are volatile.
> They are generally not pyrolyzed. However, the lignin and other "stuff" in
> biomass is what is pyrolyzed and gives off pyrolytic gases that are volatile.
> At low temperatures, the future volatiles are not yet in a form that can be
> called volatile. But they will volatize when subjected to higher
> temperatures.
>
> I will accept what the chemist eventually clarify for us.
>
> The % Volatiles are defined as that fraction that will boil (literally) at a
> given temperature. Choose you temperature. So when using a defined method,
> the result changes with the temperature your use.
>
> See for example http://www.sigmatest.org/Coal-Testing-India.html
>
> PROXIMATE ANALYSIS - MOISTURE, VOLATILE MATTER, ASH AND FIXED CARBON:
>
> Proximate analysis indicates the percentage by weight of the Fixed Carbon,
> Volatiles, Ash, and Moisture Content in coal. The amounts of fixed carbon and
> volatile combustible matter directly contribute to the heating value of coal.
> Fixed carbon acts as a main heat generator during burning. High volatile
> matter content indicates easy ignition of fuel. The ash content is important
> in the design of the furnace grate, combustion volume, pollution control
> equipment and ash handling systems of a furnace.
>
> This week we tried to get some tests of fuel content and were offered coal
> analysis tests. It all sounds good but if you look into the procedure, you
> are not getting what you think i.e. it is not an analysis of the elements
> that we are used to talking about in the biomass fuel biz.
>
> Getting a lab test result of this type using an instrument designed to do
> ANSI/ASTM D3172 tests http://www.marsap.com/anamedinstru.com/coal.shtml and
> turning it into a standard analysis is quite messy and I have a spreadsheet
> for doing that if you need it. It was necessary for the Asian Dev Bank (which
> built the SEET Lab) to do this because all that is available is standard coal
> analyses, but the HTP test method is more scientific in the sense that it
> uses the chemical composition of the fuel, not an approximation of it. It is
> also necessary to get the as received, ash-free heat content. Coal analysis
> methods gives AR (as received moisture), AD (after drying but not actually
> dry) and FC (fixed carbon, but not actual carbon content). It also view
> some of the moisture as inherent.
>
> There are two things which come back wrong: the moisture content and the
> carbon content. Finding out what the carbon content of the volatiles was is
> nearly impossible. The right approach is XRD and XRF.
>
> To give you an idea of how far wrong the method is for determining Carbon,
> here is a standard test result of some coals and sawdust briquette. It is
> well known that the sawdust contains about 50% Carbon. It was rated as having
> 16% fixed carbon. In other words it is basically a useless measurement when
> it comes to biochar (or anything else).
>
> Regards
>
> Crispin
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