[Terrapreta] Folke's retort kiln

[Sean K. Barry]

Hi Folke, Bakary,

Fischer-Tropsch processing of is not a technically incorrect suggestion, but it is very likely an unreasonably expensive one (how very Northern European of a suggestion, too).  FT catalysts of iron-cobalt compounds for instance and other more esoteric metals tend to be quite expensive, and are easily "poisoned" and made useless by gas compositions containing any Methane-CH4.  "Synthesis gas" (mostly H2 and CO, some CO2) is the usual required feed gas for FT processing.  It can be made readily from reformation of natural gas and by gasification of coal, but it can only be produced from biomass with an "oxygen-only" blown gasifier and some "water-shift" processing of the output gas (to increase H2 and CO content).

"Syngas" is like "producer gas", which is normally what comes from conventional "air-blown" biomass gasifiers, but it is not diluted with Nitrogen gas-N2, like producer gas is.  Producer gas will not work in FT processing.  Folke's kiln is not "blown" at all, is very small, and so it likely does not produce much syngas or producer gas at all.  That which it might burp out under the inner barrel lip is burned, by all accounts, anyway. I do not think the complete combustion is entirely clear, though, because it does depend highly on gas composition, temperature, pressure, and the availability of oxygen.

Probably the simplest way to determine whether complete combustion of these "off-gases" is occurring is to mount an oxygen (or lambda sensor) at the top of the outer barrel (another inexpensive and useless retrofit for Bakary's purposes).  If there is not any oxygen in the exhaust stream, then it is likely that complete combustion of all of the gases is not occurring. 

FT processing is not KISS KISS either.

Regards,

SKB
  ----- Original Message ----- 
  From: folke Günther<mailto:folkeg at gmail.com> 
  To: bakaryjatta<mailto:bakaryj at gamtel.gm> 
  Cc: terrapreta at bioenergylists.org<mailto:terrapreta at bioenergylists.org> 
  Sent: Thursday, May 29, 2008 3:02 AM
  Subject: Re: [Terrapreta] Folke's retort kiln





    My 200 l drum retort is too big for cooking. Really, I would like to find
    out how to control the process and store the extra gas for other purposes.
  Perhaps it would help if you lead the gasses through a Fishcer -Tropsch catalyst<http://en.wikipedia.org/wiki/Fischer-Tropsch_process>? (Mainly consisting of iron fillings)



    Someone told me once not to complicate subjects when talking to simple
    folks. KISS, KISS ( Keep It Simple Stupid)

    We have no choice in audience on internet, but if we want to influence large
    numbers to become of active participants in applying TP for its many
    benefits, perhaps the experts should try hard to introduce KISS KISS
    technology and use KISS KISS communication. And a drum equals a bag of rice
    in cost here. That's a big investment when many earn less than that per
    month.

    Kind regards,

    Bakary Jatta



    Francoise Precy <f.precy at hotmail.co.uk<mailto:f.precy at hotmail.co.uk> wrote:
    >
    >

    > Hi everyone,
    >
    > http://www.holon.se/folke/carbon/simplechar/simplechar.shtml<http://www.holon.se/folke/carbon/simplechar/simplechar.shtml>
    > Trying to piece things together and clear up my understanding. What got
    > said so far:
    >
    > On 27 May 2008 22:51:33 -0700 "Philip Small" wrote:
    > ?when the pyrolysis front advances "upwind", against the draft, and that
    > draft comes from below, it corresponds to the same principles as both top
    > lit updraft pyrolysis and reverse downdraft pyrolysis. The draft carries
    > smoke, generated between the pyrolysis front and the charcoal, across the
    > hot char to the flame.? This device is top-lit so we ?get some of this
    > effect.? ?The more he controls his Superficial Velocity (Source - PDF
    > http://www.woodgas.com/Superficial%20Velocity.pdf<http://www.woodgas.com/Superficial%20Velocity.pdf>), the more benefit he
    > can get from this effect.? ?Only a toplit "stage 1" is a candidate (for
    > that effect).
    > ?after the initial batch burns down, (...) the retort is still putting out
    > woodgas?. When the fuel (is topped up), (the pyrolizing) does ?not conform
    > to the same effect.?  ?Superficial Velocity effects (affects?) the
    > pyrolysis gas temp as it closes in on the charcoal. ie slower SV cracks
    > more CO2, until it's too slow to keep the flame above the charcoal burning
    > red hot enough to radiate down (so as) to push the pyrolysis front
    > (advancing upwind, away from the charcoal). OK my head hurts now. -philip
    >

    > This gets me confused b/c I imagine the draft going down (towards the only
    > way out, so there is a downdraft inside that inner barrel), and the
    > flame(s) being mostly up albeit outside. Assuming that the pyrolysis
    > starts within at the top, is the pyrolysis front on top of the layer of
    > charcoal or underneath it?
    > If it's underneath, then the gases get 'filtered' mostly by the biomass /
    > wood etc, not by the charcoal. If the pyrolysis front is on top, which
    > doesn't make much sense to me so far, then the gases get filtered both by

    > charcoal and by biomass. Was seeing it underneath but Philip ain't the
    > only one who gets a headache from it, so by now I just can't work out
    > anything further
    > The only sort of sensible thing I can think of is a system of 3 barrels of
    > progressive sizes, the smallest (with a few small vents at the bottom
    > maybe) filled with wood / biomass, sitting upstraight inside the largest;
    > with the intermediary barrel turned over (bottom up) coming on top of the
    > smallest barrel. So the smoke would have to go through the charcoal, come
    > out by the top, go down the inner side of the intermediate barrel, and get
    > burnt on the outside of it.
    > One notable advantage as far as I am concerned: saves lugging full barrels
    > about (can't see myself lifting ? not dragging ? on my own 2 metal bins
    > with the smaller one full of wood). So allows for bigger batches than a
    > poxy 20 litres-sized one. Don't know about any advantage re. elimination
    > of gases.
    > Serious potential downfall: it'll probably take longer to heat up as the
    > fire is not in direct contact with the container that holds the wood.
    > Wonder if anyone's got any more precise idea on that point?
    >
    > ?Wok pan?:
    > 2008/5/27 Ron Larson wrote: ?enjira. This is a (delicious) thin sourdough
    > flat bread cooked on a homemade thick ceramic disk (a "magogo"), of about
    > 60 cm diameter.... this plate (disc) maybe sitting on top of the interior
    > can (barrel).?
    > Folke answers: ?when putting something flat on the stove, it easily starts
    > smoking (=incomplete burning of the gasses).? So it's not the
    > wok-pan-shape that's necessarily needed: if the 'plate / disc' is sitting
    > on top of the inner barrel without overlapping (too much) the gap between
    > the inner and outer barrel, the combustion of gases should still be
    > effective. May also raise the disc on 3 stones so it leaves a gap between
    > itself and the outer barrel's rim.
    > _________________________________________________________________
    > Great deals on almost anything at eBay.co.uk<http://ebay.co.uk/>. Search, bid, find and win on
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    >

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  ----------------------------------------
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  URL: http://www.holon.se/folke<http://www.holon.se/folke>
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