[Gasification] Biochar production by Amazonians - Was [biochar] Pine char gasification

[Kevin C]

Dear Jon

Thanks very much!! This looks like a very authoritative and  
comprehensive piece of work! It should add geatly to our understanding  
of Terra Preta.

Kevin



Quoting "rcwarship ." <rcwarship at gmail.com>:

> I just started reading MORGAN J. SCHMIDT's dissertation on the very subject
> of how the natives created terra preta.  I admit upfront that I won't be
> studying the whole document, just skimming/studying the pertinent
> sections.  It's been a very informative read so far.
> Best Regards To All,
> Jon
>
> http://marte.museu-goeldi.br/arqueologia/pdf/schmidt_m2.pdf
>
>
> "RECONSTRUCTING TROPICAL NATURE: PREHISTORIC AND MODERN ANTHROSOLS (TERRA
> PRETA) IN THE AMAZON RAINFOREST, UPPER XINGU RIVER, BRAZIL"
>
>
> On Thu, Dec 26, 2013 at 3:38 AM, Kevin C <kchisholm at ca.inter.net> wrote:
>
>> Dear Ron
>>
>> Quoting "Ronal W. Larson" <rongretlarson at comcast.net>:
>>
>>  Tom  - see notes below.  I have little time for a few more weeks, but
>>> will try to get back to this, if others haven?t already supplied enough of
>>> a response.
>>>
>>>
>>> On Dec 23, 2013, at 4:36 PM, Tom Miles <tmiles at trmiles.com> wrote:
>>>
>>>
>>>> Ron,
>>>>
>>>>
>>>>
>>>> I didn?t mean anything quite so personal. :-/
>>>>
>>>>       [RWL1:  See next response to Mark Ludlow.  I was mostly trying to
>>> get some humor injected - about my own ?cult?.
>>>
>>>>
>>>>
>>>> Most of the biochar research has focused on pyrolitic char and not on
>>>> combustion or gasification char. There is a clear bias toward  
>>>> pyrolysis, or
>>>> low temperature char. Can anyone really say this is the way that the
>>>> Amazonians, or anyone else, created the charcoal that we find in the terra
>>>> preta soils? Or was it smoldering combustion, staged combustion (a la Alex
>>>> English), or a combination of pyrolysis, gasification and combustion? I
>>>> know that I have had a lot of bad slash and straw burns that have left a
>>>> lot more char on the ground than ash. Are there ?signatures? in the terra
>>>> preta char that point specifically to pyrolysis, gasification or  
>>>> combustion?
>>>>
>>>>        [RWL2:  I just spent half an hour trying to find something
>>> definitive.  I found one Ppt by three friends on this topic,  but not
>>> enough words to go with the pictures.  I will check after Xmas.
>>>     I hope someone on this list has looked at efforts to mimic the Terra
>>> Preta soils.
>>>
>>
>> # KC: This seems to be "The Unspoken Elephant in the Room." Just how did
>> the Terrapretians actually make Terra Preta??? Did they actually make it on
>> purpose, OR did it just happen, when they disposed of wastes, either
>> ``jungle wastes`` or ``domestic wastes``? What is the difference between
>> making "Terra Preta" and the Milpa Agriculture, as practised in Belize?
>>
>>  It seems clear they did much more than just put
>>
>>> out ash - which seems to have been what the vast majority of aboriginal
>>> slash and burn cultures did.
>>>
>>
>> # KC: The inorganic fraction of the char remaining from "slash and burn"
>> could be one possible explanation for the presence of charcoal in the soil.
>>
>>   I favor an argument that the
>>
>>> char came from what happened during and after cooking (If wood is easy to
>>> come by, you can make a lot of char in a 3-stone arrangement.
>>>
>>
>> # KC: Certainly, there was an excess of wood available.... a "jungle full
>> of wood." However, it was certainly not easily available... there would be
>> an enormous labour content requirement to cut down trees and prepare the
>> wood for use as a fuel, with only "Stone Age Implements and Technology."
>> The ``Amazonian Terrapretians`were no doubt just as smart and just as lazy
>> as Modern Day Men. Those who have chopped down a hardwood tree with a sharp
>> axe can appreciate the difficulty of chopping down jungle trees with a
>> relatively blunt stone age axe.
>>
>>   I have seen one argument for an approach like HTC.
>>>
>>
>> # KC: The possibility of using the nutritious ``black goop`` from the
>> bottom of the Òxbow Lakes that are very common along the Amazon River has
>> been suggested as a source of fertiliing nutrients for Terra Preta on this
>> list in the past, and the concept was received with extreme disinterest. I
>> would suggest that the ``black goop``was made by the `LTAHTC Process``, ie,
>> the ``Low Temperature Anaerobic HydroThermal Carbon Process``
>>
>>>
>>>>
>>>> I see biochar production growing in stages. For the time being a large
>>>> quantity of char that is sold as Biochar is actually char from
>>>> gasification. As biochar markets grow we might expect to find more
>>>> pyrolytic char made ?for purpose? but now we have some pyrolitic char and
>>>> byproducts of gasification (including TLUDs) and combustion.
>>>>
>>>>     [RWL3:  I wouldn?t couple the words ?TLUDs? and ?gasification?.
>>>> TLUDs look like pyrolysis to me.
>>>>
>>>
>> # KC: Also in the past on one of these lists (Biochar...Gasification...
>> Stoves...) were extensive discussions on the subject of whether a TLUD was
>> a `Gasifier Stove`or not. The conclusion at the time seems to have been
>> that the TLUD was indeed a gasifier, that was close coupled to a stove .
>> Given that gases are produced in pyrolysis, it would seem fair to accept as
>> a fact that pyrolysis is a `gasification process.
>>
>>
>>
>>>> The ?high temperature? gasifier char performs very well and in some
>>>> applications better than pyrolytic char. Several studies (and some
>>>> commercial producers) have found that conditioning the char through
>>>> partially oxidation (to higher temperature) enhances nutrient retention.
>>>> These products are for improving soil fertility , not necessarily to
>>>> replace activated carbon. So why not consider CO2 gasification as a
>>>> possible process step?
>>>>
>>>>    [RWL4:   I need help on this.  I am assuming that adding CO2 to hot
>>>> char is designed to leave little char.   Doesn?t sound like a major help
>>>> for producing a biochar.
>>>>
>>>
>> # KC: The ``Pillar of Agricultural Biochar`` seems to be Terra Preta.
>> Perhaps someone could provide evidence of some sort showing how the
>> Amazonian Terrapretians controlled their char making temperatures.
>>
>>>
>>>> One major producer of char in California uses a downdraft gasifier. In a
>>>> downdraft gasifier wood devolatilizes at or above the oxidation zone.
>>>> Volatile carbon is oxidized by the air injected from nozzles to make CO2.
>>>> The hot CO2 reacts with the char to form CO and H2. This occurs in the
>>>> ?reduction zone?. The reduction zone is often shown as a deep bed  
>>>> of carbon
>>>> but in fact it is usually only a couple of inches thick. Large  
>>>> chips reduce
>>>> to powdered char in less than 2 inches where gas temperatures are  
>>>> 800-900C.
>>>> The resultant producer gas is a mixture of this CO from reducing char and
>>>> the devolatilized gas. Taking CO2 and reacting it with charcoal  
>>>> at 800-900C
>>>> as Purdue has done is not a lot different so the qualities of the char
>>>> should be similar.
>>>>
>>>>
>>>>
>>>>      [RWL5:   Still need help  (not knowing enough about the term
>>> ?gasification?).  In downdraft gasifiers, I have been assuming that the
>>> injected air was reacting mostly with the char, not with the already
>>> produced gases.  The intent was to get rid of as much char as possible (and
>>> I assume the same for the Purdue researchers).   I understand that Purdue
>>> is inputting CO2 and not air (in a second stage), but the intent in both
>>> cases is (I presume) to leave as little char as possible.   I just don?t
>>> see how that fits into this list - interested in getting a lot of char.   I
>>> understand that part of the processing is to maximize CO and H2.    I?ll
>>> try to get back to this.
>>>
>>
>> # KC: The problem seems to be when those interested in producing
>> ``Biochar`` for Agricultural Purposes get into conflict with those who want
>> to produce ``Biochar```for ``Climate Change Purposes``, or other purposes.
>> A clear definition of ``The Various Biochars`` would indeed be helpful
>>
>>>
>>>  I think we need to explore all avenues of producing char and energy
>>>>
>>>> 1.      Slow pyrolysis ? 25%-30% char; 30% oil+gas
>>>>
>>>> 2.      Fast pyrolysis ? 15% char; 60% oil
>>>>
>>>> 3.      Gasification ? 5%-25% char; 75%-95% energy
>>>>
>>>> 4.      Combustion ? 1-5% char; 95% heat
>>>>
>>>>
>>>     [RWL:  Tom - the bottom two total near 100%, but not the top two; can
>>> you add some more components?.  I am surprised also to see gasification
>>> char as high as 25%;  who is getting this high - and how?.
>>>
>>
>> # KC: There are indeed a lot of different kinds of chars that are produced
>> by various means, for various purposes, from various feedstocks, and at
>> various temperatures. It seems that there are still a lot of ``loose ends``
>> associated with ``Char``, ``Biochar``, etc.
>>
>>>
>>>     Adding to this list might be the work of Mike Antal (and Mantria)
>>> with added pressure.  Also Cool Planet uses pressure and catalysts with the
>>> term ?fractionator?.   Retort char (zero oxygen) could be a little
>>> different from your four - all of which involve some O2?.  Maybe same for
>>> char made with microwaves (heating from the inside of particles being
>>> different)?   Certainly HTC  (hydrothermal carbonization) is very
>>> different.  Is the approach by Alex English different from any of these  (I
>>> think it is close to slow pyrolysis).  Nat Mulcahy with World Stove has a
>>> different approach with no oxygen flowing through the fuel bed.  Jim
>>> Mason?s BEK will be called gasification?
>>>
>>
>> # KC: You make a very good case for the need for the IBI to clean up their
>> definition of ``Biochar``.
>>
>>>
>>>     I heat my home partly with wood (mostly solar (except when cold and
>>> cloudy), no gas) - and have pulled copious amounts of char out of my (open
>>> front) stove - a lot more than 5%.  I believe that has to be called
>>> interrupted combustion - just the same as the whiskey maker Jack Daniels
>>> does - combustion interrupted at the end of the pyrolysis stage and before
>>> much gasification can have occurred.  The difference seems to be whether an
>>> O2 molecule can reach a hot char surface or not - because of still-exiting
>>> pyrolysis gases getting oxidized first (mainly to CO and H2O).
>>>
>>
>> # KC: With all this char being available to you, it would be interesting
>> to see your comments on tests that you have probably done, using this kind
>> of char as a soil additive for improving plant growth.
>>
>>>
>>>
>>>      All in all I think it great that there are so many carbonization
>>> approaches - hopefully enough for every combination of soil and plant
>>> species.    The big divider will be process temperature, it seems.
>>>
>>
>>  # KC: It would be very interesting to see your comments on which kinds of
>> chars are best for the various end uses to which the various chars can be
>> put.
>>
>> Best wishes, for ``Biochar Clarification`in 2014``.
>>
>> Kevin
>>
>>  Ron
>>>
>>>>
>>>>
>>>> Tom
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>> From: biochar at yahoogroups.com [mailto:biochar at yahoogroups.com] On
>>>> Behalf Of Ronal W. Larson
>>>> Sent: Monday, December 23, 2013 2:53 PM
>>>> To: Biochar; Tom Miles
>>>> Cc: Crispin Pemberton-Pigott; Gasification-Request
>>>> Subject: Re: [biochar] Pine char gasification
>>>>
>>>>
>>>>
>>>>
>>>>
>>>> Tom etal:
>>>>
>>>>
>>>>
>>>>    1.   I?m not sure I want to accept the ?philia? part of this message
>>>>  (?philia? goes with ?abnormal? and pedophilia at one google site).  I
>>>> found the word agape - but that sounds presumptuous.  But I do admit to
>>>> being at the non-sensical end of the char spectrum.  Maybe charphilia is
>>>> apt.
>>>>
>>>>
>>>>
>>>>   2.  I know close to zero about any part of gasification, but I can
>>>> understand why one would promote the idea of recycling the CO2 to get more
>>>> gas (eventually the Purdue group wants liquid, it seems).  But that has to
>>>> result in less char - and apparently leaves much higher temperature char.
>>>>  Eventually it is almost all CO2, for gasification, but I worry that the
>>>> char produced this (high temperature) way might only be suited to replace
>>>> AC = activated carbon.
>>>>
>>>>
>>>>
>>>>   3.  Since Alex English name came up today, we should note that he also
>>>> recycles CO2.
>>>>
>>>>
>>>>
>>>>   4.  The dogma of the cult I am in says more char beats more heat, gas
>>>> or liquid, so I will look forward to some proof that is not correct.
>>>>
>>>>
>>>>
>>>>  Good luck to the Purdue folk.
>>>>
>>>>
>>>>
>>>> Ron
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>> On Dec 23, 2013, at 12:58 PM, Tom Miles <tmiles at trmiles.com> wrote:
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>> Ron,
>>>>
>>>>
>>>>
>>>> This work is very important for both the biochar and gasification lists.
>>>> Biochar will be produced at the large, or even small, scale as a  
>>>> co-product
>>>> of energy (liquid fuels and/or power). The most efficient way to generate
>>>> power from the gases and vapors from slow pyrolysis (50% of the energy) is
>>>> probably through charcoal gasification (e.g. run the pyrolysis gases
>>>> through a charcoal gasifier). There are commercial systems under
>>>> development to make char and power in this way. There are also commercial
>>>> systems under development to make liquid fuels through combinations of
>>>> pyrolysis and gasification. The char products from these and fast  
>>>> pyrolysis
>>>> processes run from 0% to about 15% of fuel input. I don?t know the fuel or
>>>> char yield for Cool Planet.
>>>>
>>>>
>>>>
>>>> This particular study prepared the char with high temperature (826 C)
>>>> nitrogen.  Wood particles (chips, sawdust) and resultant char particles in
>>>> this study are larger than for other char studies. Obs
>>>>
>>>>
>>>>
>>>>
>>>> ervations about BET surface area, particle size and the char morphology
>>>> are very interesting. The char morphology looks different than the SEM
>>>> images that we typically see. From gasification and pyrolysis we know that
>>>> pine carbonizes differently than hardwood so it is interesting to see the
>>>> shredded fibrous appearance of the pine char in this study compared to the
>>>> neat geometric structures that we often see, which is probably from
>>>> hardwood chars. The authors observe that the macropore volume is
>>>> significantly greater than the mesopore or micropore volume of the char.
>>>> They observe ?numerous wide tunnel protruding into the char particles. . .
>>>> [that] may provide pathways for bulk transport of CO2 into the particle.?
>>>>
>>>>
>>>>
>>>> Char conversion numbers are interesting. Only 10-12% of the char was
>>>> gasified at 726 C (BET 391 m3/g) while 98-100% was converted at 896 C.
>>>> Surface area increased with conversion but not much greater than  
>>>> the 35-47%
>>>> conversion at 776 C so CO2 gasification could be used to increase surface
>>>> area at the expense of half of char (660 m3/g). Meso and micro pore volume
>>>> doubles at the higher rate but stays pretty constant above 776 C.
>>>> Researchers conclude that a significant proportion of the pore volume is
>>>> within macro pores although the majority of the internal surface area is
>>>> within micro pores.  They point out that the mass loss with surface
>>>> gasification occurs within the smaller pores leading to pore widening.
>>>>
>>>>
>>>>
>>>> Researchers explain that the char gasification process involves three
>>>> steps: (1) adsorption of the gas-phase species to the char surface, (2)
>>>> surface reactions, and (3) desorption of the gasification  
>>>> products from the
>>>> surface. The latter is the rate limiting process.
>>>>
>>>>
>>>>
>>>> Recycling CO2 from gasification to gasify the char is an interesting
>>>> concept that may apply to modifying char properties (e.g. increase surface
>>>> area) from pyrolysis or recovering energy (heat, power, syngas) in an
>>>> industrial setting.
>>>>
>>>>
>>>>
>>>> There is very little information about gasification or combustion chars.
>>>> Sometimes it helps to step back from our char-philia (and gaso-phobia) to
>>>> see what products combined pyrolysis and gasification can produce.
>>>>
>>>>
>>>>
>>>> Tom
>>>>
>>>>
>>>>
>>>>
>>>>
>>>> RL> don?t see any relevance to the biochar list.  (Except if this work
>>>> shows that char is more valuable in the ground and/or that an  
>>>> approach like
>>>> Cool Planet?s is more efficient.)  On the biochar list, we should  
>>>> want BOTH
>>>> high value fuels and charcoal.
>>>>
>>>>      This Purdue work is all about gasification of char - not pyrolysis.
>>>>   I am not sure whether the topic is appropriate for  
>>>> ?gasification? either,
>>>> since that list seems to want gases for engines, not liquids.
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>
>>>
>>
>>
>> _______________________________________________
>> Gasification mailing list
>>
>> to Send a Message to the list, use the email address
>> Gasification at bioenergylists.org
>>
>> to UNSUBSCRIBE or Change your List Settings use the web page
>> http://lists.bioenergylists.org/mailman/listinfo/gasification_lists.
>> bioenergylists.org
>>
>> for more Gasifiers,  News and Information see our web site:
>> http://gasifiers.bioenergylists.org/
>>
>