[Stoves] Emissions issues (A) with Flame Cap and TLUD char-making devices FW: follow-on to today's biochar emissions call

[Anderson, Paul]

Dear Stovers and Charists,   This is message    (A)

I am sending TWO messages (A & B with this same introductory comment) about emissions from char-making devices, specifically Flame Cap (FC) and TLUD.  The messages are long and unfortunately were not on any Listservs, and were with Paul Taylor (Paul T, not to be confused with Paul A.).   Paul T. is today on his way back to Australia.   We spoke before he left.   Here are the main issues:

1.  Paul  T. is working with several co-authors (Hans-Peter Schmidt and others) to finalize a paper about emissions from char-making devices.  They would like some additional data (probably already collected, but not in their hands yet, so please consider sharing, with appropriate recognition for your work.)

2.  A major issue is the emission of methane from FC and TLUD char-making devices.  Paul T. is mentioning how important methane emissions are.   And I was saying that stove testing has NOT been measuring methane.  Who has measured it?   (Jim Jetter????)  Is methane release from FC devices so high (when new fuel is added, there are spikes of emissions) that it virtually negates the carbon-negative advantages of sequestering biochar that is made by FC devices.   And by inference, does  that also apply to biochar made by TLUD devices, noting that new fuel is NOT added and the spikes do not occur in the batch process of TLUD devices larger or small.

Comments are welcome on each separate Listservs, with appreciation of efforts to share as private forwards to  those who are on only one or neither of the Listservs.  Please distinguish between Paul T. and Paul A when making statements.  Paul A. is assisting.   Paul T. is the main person raising the issues.

Paul A.


Doc / Dr TLUD / Paul S. Anderson, PhD
Exec. Dir. of Juntos Energy Solutions NFP
Email:  psanders at ilstu.edu<mailto:psanders at ilstu.edu>       Skype:   paultlud
Phone:  Office: 309-452-7072    Mobile: 309-531-4434
Website:   www.drtlud.com<http://www.drtlud.com>

From: Paul Taylor <potaylor at bigpond.com>
Sent: Friday, December 21, 2018 8:12 PM
To: Anderson, Paul <psanders at ilstu.edu>
Subject: Re: follow-on to today's biochar emissions call

Email thread with Norm Baker re operations and emissions from TLUDs, Flame cap and hybrid kilns
Flow is from bottom email initiated by Paul Anderson.

Hi Norm: I am a proponent of running kilns cleanly.  That is the focus of the Kon-Tiki and the Ring of Fire kilns.  A 200L drum can be made to run cleanly, as alluded to in my recent emails.  Its easy to run any device NOT cleanly, and that is what is mostly done.  To a large extent a quick and dirty kiln is not so much about the quick production of a simple drum device;  it's about the dirty operation of it. To run cleanly requires some understanding of combustion and its relationship to the environment; proper design (which can be simple, as illustrated by the Kon-Tiki); how to properly use the device; feedstock preparation and management; and perhaps most importantly a real concern and respect for well managing the material world.

The sequestration potential of non-commercial machines is so marginal that they can easily be of no value at all, or a substantial menace if multiplied massively.  Net sequestration requires managing the whole cycle of C and pollution from feedstock acquisition, transport,  production, application, to new biomass and remediated soil management.  This stewardship will be an exemplification of our maturity.  Even well designed commercial systems in some circumstance only gain their net sequestration potential out of storage in increased biomass C in plant and soil.  As an extension of the Kon-Tiki emission studies, a new paper is underway to quantify the sequestration actuality of small scale devices.

I think it more likely that if dirty operation of simple devices proliferates enough they will be regulated, and not allowed.  There is the also likely alternate scenario that our present social forms are overwhelmed by the looming perfect storm of environmental crises, and society disintegrates and simplifies, in which case the environment will still be stressed beyond survival, for the reason that globally more billions of people will be back to pure survival, and everything will be unregulated - everything will be eaten and consumed, like now but with even less chance to control.

In meantime I would look to how the simple devices can be tweaked and used best, and put a lot of focus on guiding and spreading the behavioral changes needed to run them properly.  It may turn out that its too much to expect that people in field and forest will consistently run the simple biochar devices optimally and the C management by biochar systems will need to be on a regulated commercial basis with high tech machines.   The Kon-Tiki and simple flame cap devices can run fairly cleanly, with better emissions than TLUDs in the literature.  The methane and particulate emissions mainly occur in feedstock entry, so could be less still with care, but greatly worsened with lack of care.  Can we incorporate design features and processes to control this? We will be considering this.

Paul

On 12/5/18, 7:08 AM, "Norman Baker" <ntbakerphd at gmail.com> wrote:
Paul;

I agree almost completely in your interpretation of a combination flame cap TLUD. Over the next few weeks I will be building a few ideas to test a few hypotheses. These will all be built in preparation for the TLUD Summit where we can measure emissions. As you know, Ryan Thompson and I are collaborating on measuring emissions. Going to be very interesting getting a few large TLUDs to ethos and then to Aprovecho. Seems to me you should attend if at all possible. You and I and the rest of this group have a lot to talk about.

Ever since the publication of your Kon-Tiki article and the explanation for its physics and combustion and especially its emission measurements, I have been a proponent of the Kon-Tiki. Unfortunately, many local people here on the Olympic Peninsula are taking any number of large drums 55 gal. up to 500 gal. drums, cutting them in half longitudinally or horizontally, and burning a lot of wood to make biochar. No one has had any qualitative tests on the quality of the biochar, but the biochar seems to be working when incorporated into the soil. I have been a vocal critic of these "aftermarket designs" because, every one that I have seen operate has an unacceptable level of smoke coming from it. Amongst my local biochar community who are interested in progress and science, I freely label these things "quick and dirty biochar kilns" because they are done too quickly and have dirty particulate emissions.

 I will freely admit drying a lot of feedstock in an environment is wet is the Olympic Peninsula can be difficult. But with enough time and preparation up front it can be done. Unfortunately very few people actually take the time and adequate preparation to have adequately dry feedstock. Almost no one tries to have appropriately sized feedstock - they use whatever they have available - usually in order to clean up on their landscape waste.  Consequently, as the time approaches to make biochar, a lot of wet wood in varying sizes and shapes is applied to a large fire in a drum or trough. The argument made for the proponents of these quick and dirty biochar kilns is that the need for carbon sequestration is so great, that we must make biochar for carbon sequestration by any means available. That said, recently our Olympic Region Clean Air Agency (ORCAA) shut down two biochar workshops where everything but our ring of fire TLUD and the Japanese Cone were prevented from being used to make biochar. I personally worked with one of the decision-makers at ORCAA and they told me in terms of their regulations, that what they saw was a burn barrel which has long since been outlawed inside cities. In rural communities, burn barrels are in common use because of enforcement problems. In fact, I can show you several neighbors who simply build a fire to burn all of their residential waste simply to avoid  transportation costs and disposal fees at our local transfer station.

Frankly, I am concerned the use of the quick and dirty biochar kilns will become so prevalent, that it will be extremely difficult for clean air agencies to regulate them for health reasons. More and more data says ultrafine particulate emissions are linked to an incredible array of human diseases and health consequences. With the need to sequester as much carbon into the soils as global warming suggests, it will be incredibly difficult to prevent mankind from endangering itself with a health consequences of particulate emissions.

With your experience on these quick and dirty flame cap kilns, what is your "sense of appreciation" for them.

Norm

On Tue, Dec 4, 2018 at 5:07 PM Paul Taylor <potaylor at bigpond.com> wrote:
With a vortexing flame cap mode and incremental fuel feed at the completion of TLUD mode there is no need for other primary air entering from the bottom.  Unless some further oxidation is desired for enhanced functional groups on the char, open PA at the bottom presents the insecurity of losing some char.  If a portion of the flame cap exits the down-drafting vortexing mode, or the TLUD develops common internal convection loops (such as up the center and down the colder walls), easily enhanced by chaotic pressure variations communicated from the flame cap, then an updraft in the TLUD may occur, oxidizing more char higher up.

The primary air only needs to be open long enough to get to peak natural pyrolysis temperature, around 400-450C, at the bottom of the TLUD, then carbonization in that charring material will coast from there provided there is not too much heat loss.  There will be no smoke because pyrogas that continues to evolve from the TLUD is consumed in the flame cap.  The top of the TLUD char will be kept at pyrolysis temperature (above 300C) for some time by heat transfer from the accumulating flame cap char.

TLUD mode is a great way to start and prep a bed of embers for flame cap operation, the following flame cap mode is a great way to finish the carbonization in the TLUD, smoke is avoided, and twice as much char is obtained from the device. Perhaps a diversity microorganisms/plants can be made happier because of the variations in base char characteristics.

Paul


On 12/4/18, 12:00 PM, "Norman Baker" <ntbakerphd at gmail.com <http://ntbakerphd@gmail.com> > wrote:
Paul;

Your explanation of turning a TLUD into the operation of a flame cap is exactly what I am about to build to test some ideas.  That is the first step for version 19. What really surprised me was that there was no need to close off the primary air before going to flame cap mode. There was no smoke and no evolution of pyrogasses at the end of the burn. It simply went out or extinguished and started to cool (while burning a bit of BC). I want to get a video of the event. Bought a new camera so I should be able to get a decent video. Still, I will include a closable primary air to test the need for a TLUD being converted into a flame cap.

Norm

On Mon, Dec 3, 2018 at 11:23 PM Paul Taylor <potaylor at bigpond.com <http://potaylor@bigpond.com> > wrote:
Running a TLUD to completion, then closing off the primary air and converting to flame cap mode can preserve the TLUD char and continue to make biochar until the reaction vessel is filled.  This maximizes use of the volume of the vessel, and its heat shield if any, makes the device easy to start in the TLUD mode (primary air supply) and easy to continue in the flame cap mode (a nice base of coals and heat).  The vessel-shield-combustor-chimney arrangement of the hybrid can be optimized for the duel use, to exploit the natural convection flows that are exemplified in the Kon-Tiki, and to allow access to load fuel.  We discussed this while developing the ring of fire.  Those convection dynamics in fact provide insight to optimize some aspects of secondary air supply and mixing in a straight TLUD.

Paul


On 12/3/18, 9:40 AM, "Anderson, Paul" <psanders at ilstu.edu <http://psanders@ilstu.edu>  <http://psanders@ilstu.edu> > wrote:


Norm, at another meeting last week (at Univ of Dayton), the presence of a flame cap in a TLUD stove was mentioned.   I see the two as being distinctly separate.   The presence of a flame above some biomass (sometimes a goodly distance above a layer of charcoal that covers the lower biomass) does not function in the same was as a flame cap in the sense that it is used (by Kelpie Wilson and others).    You may present your reasoning, but expect at least me to challenge that usage of the flame cap explanatory name.

Paul

Doc / Dr TLUD / Paul S. Anderson, PhD
Exec. Dir. of Juntos Energy Solutions NFP
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