Julien,
Please describe with details the placement of the thermocouples in your measurements.
Inside the bed of fuel there are several “positions” where the temperature is or should be measured:
A. the gaps between the fuel pieces contain combustible gases that burn at high temperatures, but in very small amounts. It is easier to measure those temperatures if the gaps are relatively larger.
B. the surfaces and gradually thickening layer of char around each piece of raw fuel. THIS is where pyrolysis is occurring but the actual process of pyrolysis is gradually becoming further from the surface that could be measured by contact.
C. The inner core of each piece of fuel, where temperatures gradually rise from ambient (20 C??) to the maximum exposure (over 1000 C). And at some point along that continuum pyrolysis occurs. And after that, as the temperature continues to rise, the long-term-resident or fixed-carbon content of the charcoal continues to “develop” and the volatiles are progressively driven off.
Recently Hugh McLaughlin taught me about exothermic processes during pyrolysis. I do not remember the numbers (and Hugh can improve this statement), but there is a temperature (around 300 C ???) where the temperature within the fuel will rapidly rise (about 100 degrees C ???), and then it goes back to being endothermic. Somebody has measured that phenomenon which is so unique and critical to the process of making the resident carbon in charcoal. But that is not the measurement that Julien was making.
My point is that when we discuss charcoal that is “created at XXX degrees C” we are giving an estimate and we are not precise (unless in a carefully monitored steady temperature of a retort / heated screw environment). We have much work to do to determine which charcoals (created at which temperatures) have benefits (if any) for the numerous possible applications of biochar (to be sequestered in soil or roads, etc. and not burned).
Paul
Doc / Dr TLUD / Paul S. Anderson, PhD
Exec. Dir. of Juntos Energy Solutions NFP
Email: psanders@ilstu.edu<mailto:psanders@ilstu.edu> Skype: paultlud
Phone: Office: 309-452-7072 Mobile: 309-531-4434
Website: www.drtlud.com<www.drtlud.com>
From: Julien Winter <winter.julien@gmail.com>
Sent: Friday, August 9, 2019 6:49 AM
To: Anderson, Paul <psanders@ilstu.edu>
Cc: Dean Still <deankstill@gmail.com>; Harris, Kirk <gkharris316@comcast.net>; Vi Rapp <vhrapp@lbl.gov>; Ronal W. Larson <rongretlarson@comcast.net>; Norman Baker <ntbakerphd@gmail.com>; Larry Winiarski <larryw@gotsky.com>; Jock Gill <jg45@icloud.com>; Derby, Elisa <ederby@winrock.org>
Subject: Re: making charcoal to help control climate change
I am attaching some work I did a few years ago to give you an idea about may approach to building knowledge of TLUD operation. In 2015, there was no information on the kinds of temperatures that can develop in natural draft TLUDs, so I set out to measure it with some very basic tools; thermocouples and a balance.
I measured the maximum temperature in a TLUD burning at different rates (by controlling grate aperture), different fuels, and different moisture contents. I ran the TLUD with an open grate, right down to closing the primary air flow to the point where the gasification reaction failed.
The results are summarized in the 2-page flyer attached. Each point in Figure 2 represents a complete run of the TLUD; the primary pyrolysis of a batch of fuel from experiments represented in Figure 1.
In explaining the results, we start to build up theories about how ND-TLUDs work. We can now make predictions about other ND-TLUDs, and the properties of biochars that are made. (What would have been really good would have been to submitted the chars to laboratory analysis).
I have posted this document on the Stoves list a couple of times now.
Cheers,
Julien
On Thu, Aug 8, 2019 at 10:05 PM Anderson, Paul <psanders@ilstu.edu<mailto:psanders@ilstu.edu>> wrote:
I do not agree about waiting. And waiting. And waiting. And waiting ………….
I do agree that unjustifiable claims are to be avoided.
Additional public exposure about TLUD stoves would be good. I hope that Kirk is successful to get the topic onto Science Friday.
Paul
Doc / Dr TLUD / Paul S. Anderson, PhD
Exec. Dir. of Juntos Energy Solutions NFP
Email: psanders@ilstu.edu<mailto:psanders@ilstu.edu> Skype: paultlud
Phone: Office: 309-452-7072 Mobile: 309-531-4434
Website: www.drtlud.com<www.drtlud.com>
From: Julien Winter <winter.julien@gmail.com<mailto:winter.julien@gmail.com>>
Sent: Thursday, August 8, 2019 4:23 PM
To: Dean Still <deankstill@gmail.com<mailto:deankstill@gmail.com>>
Cc: Harris, Kirk <gkharris316@comcast.net<mailto:gkharris316@comcast.net>>; Vi Rapp <vhrapp@lbl.gov<mailto:vhrapp@lbl.gov>>; Ronal W. Larson <rongretlarson@comcast.net<mailto:rongretlarson@comcast.net>>; Anderson, Paul <psanders@ilstu.edu<mailto:psanders@ilstu.edu>>; Norman Baker <ntbakerphd@gmail.com<mailto:ntbakerphd@gmail.com>>; Larry Winiarski <larryw@gotsky.com<mailto:larryw@gotsky.com>>; Jock Gill <jg45@icloud.com<mailto:jg45@icloud.com>>; Derby, Elisa <ederby@winrock.org<mailto:ederby@winrock.org>>
Subject: Re: making charcoal to help control climate change
I agree with Dean. There is a lot of research yet to be done on TLUDs. There are several theoretical approaches and geometries possible with natural draft TLUD burner design. All this needs systematic testing of hypotheses by modifying one variable and holding many other variables constant. When more that one hypothesis is tested (e.g., concentrator diameter, riser height and specific gasification rate) then we need to test various combinations (a factorial design) … replicated.
Also into this mix are different types of fuel and fuel water content.
We need a big grant (that we don’t spend on mass spectrometers and lasers) to run 1000s tests measuring basic parameters such as excess air, CO, PM in the exhaust, and the superficial velocity of primary air.
In the meantime, we do what we can by trial and error on an ad hoc basis. The good thing about the informal burner trials is that they have generated hypotheses to be tested more rigorously.
Cheers,
Julien
On Thu, Aug 8, 2019 at 4:46 PM Dean Still <deankstill@gmail.com<mailto:deankstill@gmail.com>> wrote:
Dear Kirk,
I would wait until the bugs are worked out?
The stove community has hurt itself a lot by promoting stoves that do not work well yet.
I am laughed at by potential funders who have read the newspapers and blogs.
We are digging ourselves out of a hole that the stove community dug for itself.
Much better to downplay performance, never exaggerate.
All Best,
Dean
On Thu, Aug 8, 2019 at 12:25 PM Harris, Kirk <gkharris316@comcast.net<mailto:gkharris316@comcast.net>> wrote:
Dean,
Thank you for your considered response. I appreciate your expert input. Your concerns are an important part of what I was hoping could be brought into the public discussion on Science Friday. Dr. Anderson added some important input as well. Perhaps Julien, you would like to present your work on public radio, so the world can benefit from the knowledge of your efforts. I am not saying this system is perfect and is what we need to save the world (though it could help if we can stimulate politicians to be supportive). What I am asking is to bring this into the public discussion, instead of leaving it with a privileged few.
Kirk H.
On 8/8/2019 12:02 AM, Dean Still wrote:
Hi Kirk,
Remember that black smoke is about 700 times worse for climate change than CO2 by weight.
1.) The energy in the wood really has to be used for a good purpose so it’s not wasted and 2.) there needs to be no smoke or CO. And 3.the wood has to be sustainably harvested to be carbon neutral.
So far, I haven’t seen anyone meet these three criteria so when asked I can’t say that biochar is currently a supportable process.
Maybe a good idea but like other biomass schemes, such as cooking, needs a lot more R&D.
All Best,
Dean
On Wed, Aug 7, 2019 at 1:52 PM Harris, Kirk <gkharris316@comcast.net<mailto:gkharris316@comcast.net>> wrote:
All,
For the last few months I have been trying to get a public radio
program, Science Friday, which frequently has programs on climate change
to bring into the discussion biomass power plants, especially plants
that remove CO2 from the atmosphere by producing char. The program
always includes solar, wind, and mechanical CO2 extraction from the
atmosphere, but never includes the biomass options. I am hoping to get
the biomass options with their advantages, into the public discussion,
and this seems to me to be a good place to start. Could you contact the
program and ask them to include the biomass options in their
discussions. I understand this is not about TLUD cook stoves, but it is
a related topic. Perhaps TLUD principles can be scaled up to work for a
large scale power plant.
Go to “Science Friday” and scroll to the bottom of the home page and
click on “contact”
Attached is my last communication with the Science Friday people.
I have continued to experiment with stove concepts, with the goal of
burning clean at high power levels in the TLUD-ND, enhancing the older
designs and trying some new variations. I am focusing on increased
surface contact, and maximizing the use of the pressure difference,
between the air and wood gas.
Kirk H.
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Julien Winter
Cobourg, ON, CANADA
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Julien Winter
Cobourg, ON, CANADA