[Terrapreta] Strong warning against "simple" charcoal kilns
Kevin Chisholm
kchisholm at ca.inter.net
Mon Apr 28 08:45:48 CDT 2008
Dear Sean
There seems to be some lack of clarity in your explanation below...
Sean K. Barry wrote:
> Hi Max,
>
> Not necessarily. Methane-CH4 burns at a higher temperature than CO or H2.
What do you mean by "burns at a higher temperature"? Do you mean the
"end temperature" attained when these gases burn, or do you mean that
"CH4 requires a higher initial temperature to initiate combustion than
required for CO or H2"? If the latter, would you have a URL showing the
temperatures required for ignition of CH4, CO, and H2?
> Burning the (CO and H2) gases will use up the available oxygen
> before the Methane-CH4 will burn.
This is a surprising statement. In most chemical reactions, where there
is a mixture of reagents, there is also a "mixture of simultaneous
reactions." Certainly, some reactions will be favored more than others,
at a given stage of the reaction, but it is extremely unlikely that
"Reaction A" and "Reaction B" complete fully before "Reaction C" starts.
Would you have a URL for a paper showing that in a mixture of CO, H2,
and CH4, the CO and H2 burn to 100% completion before combustion of CH4
starts?
> There is almost 10 times as much CO and ten times as much H2 in
> "producer gas" as there is Methane-CH4 in producer gas.
Where does the producer gas come from? The product of pyrolysis is
pyrolysis gas, not producer gas. Could you post an analysis for a
typical pyrolysis gas?
> The heat of formation of Methane-CH4 (the energy needed to begin
> combustion)
The "Heat of Formation" is not the energy needed to begin combustion.
The Heat of Formation is the energy released or absorbed when a compound
if formed from its constituent elements.
> and the amount of oxygen needed to burn Methane-CH4 are both greater
> than either H2 or CO.
The amount of oxygen required for complete combustion is not important
at the start of combustion. What is important at the start and during a
reaction is the aggressiveness with which each reactant seeks out and
consumes the available oxygen.
> So, the H2 and CO content in the "producer gas"
Pyrolysis gas, not producer gas, in the case of Folke's Charcoal Retort URL
> start burning at lower temperatures and will use up most, if not all,
> of the oxygen before the Methane-CH4 can even begin to burn.
Would you have a URL that would show initial and final gas composition
when a pyrolysis gas is burned in ?
> To burn the Methane-CH4 would require injection of oxygen above what
> is needed to combust the CO and H2.
I would doubt very much that it is possible to take a mixture of CH4,
CO, and H2 and burn the CO and H2 to completion under sub-stoichiometric
condition without burning at least some of the CH4 present. Would you
have any URL's showing that this might be possible?
> The heat generated from H2 and CO burning may ignite the Methane-CH4,
> but without enough oxygen, it will more likely just just eject it from
> the reactor, un-burned, because there was not enough oxygen left.
Why do you assume there is "not enough oxygen left"? The pictures shown
in the URL referenced by Folke show clean combustion with no smoke, or
anything to suggest a "starved oxygen combustion" condition
It is hard to imagine any CH4 escaping this inferno. ;-)
Kevin
>
> Regards,
>
> SKB
>
> ----- Original Message -----
> *From:* MFH <mailto:mfh01 at bigpond.net.au>
> *To:* 'Sean K. Barry' <mailto:sean.barry at juno.com> ; 'Kurt
> Treutlein' <mailto:rukurt at westnet.com.au>
> *Cc:* terrapreta at bioenergylists.org
> <mailto:terrapreta at bioenergylists.org>
> *Sent:* Sunday, April 27, 2008 10:36 PM
> *Subject:* RE: [Terrapreta] Strong warning against "simple"
> charcoal kilns
>
> Sean
>
>
>
> Sorry if I'm being a little thick about this, but if the methane
> has to pass through the fire zone at the base of the inner drum,
> won't it burn?
>
>
>
> M
>
>
>
>
>
> ------------------------------------------------------------------------
>
> *From:* Sean K. Barry [mailto:sean.barry at juno.com]
> *Sent:* Monday, 28 April 2008 10:24 AM
> *To:* 'Kurt Treutlein'; MFH
> *Cc:* terrapreta at bioenergylists.org
> <mailto:terrapreta at bioenergylists.org>
> *Subject:* Re: [Terrapreta] Strong warning against "simple"
> charcoal kilns
>
>
>
> Hi Max,
>
>
>
> Try this? When carbonacious organic wastes (biomass?) are left to
> decay in open air, they decompose into CO2. When pushed
> underground into a landfill, some of the carbon molecules in the
> biomass decompose into Methane-CH4, which is also under the
> ground, and is often already being harvested. In fact it is
> illegal to allow Methane-CH4 emissions from landsfills. It can be
> economical to harvest the trapped Methane gas found in landfills.
> There is quickly growing industry in harvesting ""landfill" gas.
> Fecal wastes from animal feed lots is also are left mostly, to
> decay in open air, producing both CO2 and CH4. Anearobic Digester
> systems can harvest the Methane from animal waste pools.
>
>
>
> Now, the "charcoal-in-a-barrel" kiln? Well, when biomass if
> pyrolyzed in open air (or limited amounts of air). This pyrolysis
> reaction generates "producer gas" (H2:~20~, CO:~20%, CO2:~10-15%,
> H2O:~5%, Methane-CH4:~2-3%, and Nitrogen gas-N2:~40-45%)
>
>
>
> Air is 19% Oxygen, 78% Nitrogen, Argon is next, and some other
> trace gases (like CO2 @ 383 parts per million).
>
>
>
> The release of just the 2-3% Methane-CH4 content does more damage
> to the atmosphere than is ALL of the carbon were released as CO2.
> This is because Methane-CH4 is a long-lived and far more
> potent contributor to the green house warming effect than is CO2
> (23-62 times more potent, depending on how long of a time frame
> you consider). The production of large amounts of charcoal using
> "charcoal-in-a-barrel' kilns (and the release of any substantial
> portion of the Methane-CH4 from the process would undermine Terra
> Preta Nova in a profound way. Here we would be trying to mitigate
> climate and improve growing conditions, but while we tried we shot
> ourselves in the foot and advanced the speed of increase in the
> GHG warming effect.
>
>
>
> This doesn't even mention other pollutants possible from charcoal
> production in cheap simple "charcoal-in-a-barrel" kilns. These
> include particulates (carciniogens) and other toxic , air borne
> compounds. Who ever "sits" sucking in smoke form a camp fire? It
> also does not mention that there is an enormous waste of usable
> energy, due to the inefficiencies of this type of design.
>
>
>
> See http://en.wikipedia.org/wiki/Methane
>
>
>
> There are some who will dispute this claim. I know that there are
> more who would support this. If you must learn about charcoal in
> soil, then make some charcoal by any means, if you cannot get it
> from someone who can make it right, but advocating "millions" of
> these typoes of kilns is a bad idea. Advocate "millions" of
> "Clean Charcoal Kilns" instead.
>
>
>
> Regards,
>
>
>
> SKB
>
> ----- Original Message -----
>
> *From:* MFH <mailto:mfh01 at bigpond.net.au>
>
> *To:* 'Kurt Treutlein' <mailto:rukurt at westnet.com.au>
>
> *Cc:* terrapreta at bioenergylists.org
> <mailto:terrapreta at bioenergylists.org>
>
> *Sent:* Sunday, April 27, 2008 6:28 PM
>
> *Subject:* Re: [Terrapreta] Strong warning against "simple"
> charcoal kilns
>
>
>
> I'm struggling to understand why "millions" of back-yard
> simple kilns
> producing char to be buried in gardens aren't better than not
> having any at
> all. More particularly if they are consuming household scraps
> and garbage
> that would otherwise find its way to landfill.
>
> Sit on our hands and wait for big business to develop
> squillion dollar char
> factories, or do something positive at a personal level?
>
> Max H
>
>
> -----Original Message-----
> From: terrapreta-bounces at bioenergylists.org
> <mailto:terrapreta-bounces at bioenergylists.org>
> [mailto:terrapreta-bounces at bioenergylists.org] On Behalf Of
> Kurt Treutlein
> Sent: Monday, 28 April 2008 9:21 AM
> Cc: terrapreta at bioenergylists.org
> <mailto:terrapreta at bioenergylists.org>
> Subject: Re: [Terrapreta] Strong warning against "simple"
> charcoal kilns
>
> Hi folkes,
>
> Hands up all those who have "Strongly warned" against Folkes
> simple kiln
> concept, who are NOT working on developing a sophisticated highly
> efficient pyrolises system with the idea of marketing it to
> the world to
> make the gigatons of bio-char we will need to reverse GW.
>
> Anybody???
>
> Kurt
>
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> ------------------------------------------------------------------------
>
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