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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US">Hi Crispin,<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US">
</span><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US">Another question:<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US">¿what is the benefit of injecting steam in a stove? What is the scientific reason?<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US">This is a cookstove example of Alexis Belonio:<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US"><a href="http://stoves.bioenergylists.org/stovesdoc/Belonio/rhstove/RICE_HUSK_QUASI_GASIFIER%20STOVE.pdf">http://stoves.bioenergylists.org/stovesdoc/Belonio/rhstove/RICE_HUSK_QUASI_GASIFIER%20STOVE.pdf</a><o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US">Another example of steam injection:<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US">http://stoves.bioenergylists.org/stovesdoc/Andreatta/Continuous_Flow_Steam_Generator.pdf<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US">Can a TLUD stove improve the combustion efficiency with the addition of this technology?<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US">Thanks, and greetings<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US">Roberto Poehlmann<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
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<p class="MsoNormal"><b><span lang="ES" style="font-size:11.0pt;font-family:"Calibri",sans-serif">De:</span></b><span lang="ES" style="font-size:11.0pt;font-family:"Calibri",sans-serif"> Crispin Pemberton-Pigott [mailto:crispinpigott@outlook.com]
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<b>Enviado el:</b> martes, 04 de agosto de 2015 20:57<br>
<b>Para:</b> Ronal W. Larson <rongretlarson@comcast.net>; Discussion of biomass <stoves@lists.bioenergylists.org><br>
<b>CC:</b> Rebecca A. Vermeer <ravermeer@telus.net>; Roberto Poehlmann Ramirez (Telsur) <Roberto.Poehlmann@grupogtd.com>; Paul Anderson <psanders@ilstu.edu><br>
<b>Asunto:</b> Re: [Stoves] Charcoal burning, secondary flame vs no flame<o:p></o:p></span></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal" style="background:white"><span lang="EN-GB" style="font-family:"Calibri",sans-serif;color:#1F497D">Dear Ron<o:p></o:p></span></p>
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<p class="MsoNormal" style="background:white"><span lang="EN-GB" style="font-family:"Calibri",sans-serif;color:#1F497D"><o:p> </o:p></span></p>
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<p class="MsoNormal" style="background:white"><span lang="EN-GB" style="font-family:"Calibri",sans-serif;color:#1F497D">I want to make sure you are aware of what the 9% number refers to. It is not the concentration of CO nor the CO/CO2 ratio. It is the energy
loss at a certain combustion inefficiency. <o:p></o:p></span></p>
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<p class="MsoNormal" style="background:white"><span lang="EN-GB" style="font-family:"Calibri",sans-serif;color:#1F497D"><o:p> </o:p></span></p>
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<p class="MsoNormal" style="background:white"><span lang="EN-GB" style="font-family:"Calibri",sans-serif;color:#1F497D">For gas stoves operating indoors in Germany in standard housing the permitted CO/CO2 performance is 2%, same as kerosene stoves in South
Africa. The energy loss is 1.5%. <o:p></o:p></span></p>
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<p class="MsoNormal" style="background:white"><span lang="EN-GB" style="font-family:"Calibri",sans-serif;color:#1F497D"><o:p> </o:p></span></p>
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<p class="MsoNormal" style="background:white"><span lang="EN-GB" style="font-family:"Calibri",sans-serif;color:#1F497D">The best available stove test is the CSI-WHT which is capable of making in the lab a prediction of future performance in the field. It also
uses valid metrics and correctly reports fuel consumption. <o:p></o:p></span></p>
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<p class="MsoNormal" style="background:white"><span lang="EN-GB" style="font-family:"Calibri",sans-serif;color:#1F497D"><o:p> </o:p></span></p>
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<p class="MsoNormal" style="background:white"><span lang="EN-GB" style="font-family:"Calibri",sans-serif;color:#1F497D">You will be pleased to know that the test also reports recoverable charcoal mass. <o:p></o:p></span></p>
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<p class="MsoNormal" style="background:white"><span lang="EN-GB" style="font-family:"Calibri",sans-serif;color:#1F497D"><o:p> </o:p></span></p>
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<p class="MsoNormal" style="background:white"><span lang="EN-GB" style="font-family:"Calibri",sans-serif;color:#1F497D">Regards <o:p></o:p></span></p>
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<p class="MsoNormal" style="background:white"><span lang="EN-GB" style="font-family:"Calibri",sans-serif;color:#1F497D">Crispin <o:p></o:p></span></p>
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<p class="MsoNormal" style="background:white"><span lang="EN-GB" style="font-family:"Calibri",sans-serif;color:#1F497D"><o:p> </o:p></span></p>
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<p class="MsoNormal"><span lang="EN-GB"><o:p> </o:p></span></p>
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<p class="MsoNormal"><span lang="EN-GB">List and ccs<o:p></o:p></span></p>
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<p class="MsoNormal"><span lang="EN-GB"><o:p> </o:p></span></p>
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<p class="MsoNormal"><span lang="EN-GB">1. I think we should first try to answer the original question from Mr. Poehlmann - which I take to be whether it is better to burn char in the TLUD or in another device. I think the exchanges below say clearly that
the answer is the latter.<o:p></o:p></span></p>
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<p class="MsoNormal"><span lang="EN-GB"><o:p> </o:p></span></p>
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<p class="MsoNormal"><span lang="EN-GB">But I would urge also taking a look at doing neither - but rather placing the produced char into soil. You have a char product that is clearly worth something in any/every market. If you care about climate change, placing
this char in the ground (then can be called biochar) will be worth more than dollars.<o:p></o:p></span></p>
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<p class="MsoNormal"><span lang="EN-GB"><o:p> </o:p></span></p>
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<p class="MsoNormal"><span lang="EN-GB"><o:p> </o:p></span></p>
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<p class="MsoNormal"><span lang="EN-GB">2. I suggest that we follow the available stove testing literature - with the best I know of being that from a webinar given by EPA’s Jim Jetter.<o:p></o:p></span></p>
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<p class="MsoNormal"><span lang="EN-GB"><a href="http://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=307494">http://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=307494</a><o:p></o:p></span></p>
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<p class="MsoNormal"><span lang="EN-GB"><o:p> </o:p></span></p>
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<p class="MsoNormal"><span lang="EN-GB">Slide 22 shows total CO output by weight of less than 1% in an apparently well done test<o:p></o:p></span></p>
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<p class="MsoNormal"><span lang="EN-GB"><o:p> </o:p></span></p>
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<p class="MsoNormal"><span lang="EN-GB">3. I am not up to date on CO mortality figures, but would personally be very scared of the 9% value offered as an average by Crispin. The values at one or two sigma away must have lethal potential many places and we
certainly hear of CO-caused deaths. Anyone following this closely?<o:p></o:p></span></p>
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<p class="MsoNormal"><span lang="EN-GB"><o:p> </o:p></span></p>
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<p class="MsoNormal"><span lang="EN-GB">Ron<o:p></o:p></span></p>
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<p class="MsoNormal"><span lang="EN-GB"><o:p> </o:p></span></p>
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<p class="MsoNormal"><span lang="EN-GB"><o:p> </o:p></span></p>
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<p class="MsoNormal"><span lang="EN-GB">On Aug 4, 2015, at 9:40 AM, Crispin Pemberton-Pigott <<a href="mailto:crispinpigott@outlook.com">crispinpigott@outlook.com</a>> wrote:<o:p></o:p></span></p>
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<p class="MsoNormal"><span lang="EN-GB"><br>
<br>
<o:p></o:p></span></p>
<blockquote style="margin-top:5.0pt;margin-bottom:5.0pt">
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<p class="MsoNormal"><span lang="EN-CA" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">Dear Rebecca and Paul</span><span lang="EN-CA"><o:p></o:p></span></p>
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<p class="MsoNormal"><span lang="EN-CA" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"> </span><span lang="EN-CA"><o:p></o:p></span></p>
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<p class="MsoNormal"><span lang="EN-CA" style="color:#1F497D">RAV>…</span><span lang="EN-CA">I have always been worried about the CO level that is produced in wood burning stoves (3-stones, traditional and improved) that become charcoal burning at the end stage
of cooking. I am specifically referring to the traditional way rice is cooked in the Philippines to prevent it from burning at the bottom of the pot. First, the water is brought to boil at high power; then rice is added and stirred until most of the water
is absorbed; and then any remaining unburned wood is removed and the rice, in the covered pot above the stove, continues to cook to perfection the "palangay" way -- i.e., with the heat from the glowing embers of the charcoal remains. Alternatively, rice and
water are brought to boil together and then cooked the "palangay" way.<o:p></o:p></span></p>
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<p class="MsoNormal"><span lang="EN-CA"> <o:p></o:p></span></p>
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<p class="MsoNormal"><span lang="EN-CA" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">Understood.</span><span lang="EN-CA"><o:p></o:p></span></p>
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<p class="MsoNormal"><span lang="EN-CA" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"> </span><span lang="EN-CA"><o:p></o:p></span></p>
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<p class="MsoNormal"><span lang="EN-CA">Have you or anyone else taken CO/CO2 measurements under the above described cooking conditions, both indoor and outdoor?<o:p></o:p></span></p>
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<p class="MsoNormal"><span lang="EN-CA" style="color:#1F497D"> </span><span lang="EN-CA"><o:p></o:p></span></p>
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<p class="MsoNormal"><span lang="EN-CA" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">I have taken many measurement of CO/CO2 at various stages and what I see is that in the late burning stage the CO/CO2 ratio is not as bad as many
assume – even in a poorly sheltered fire. The combustion of char tends to stabilise at 12-16% CO/CO2 with 14% being common in a ‘cold fire’. It is not true at all that the carbon mostly emerges as CO.</span><span lang="EN-CA"><o:p></o:p></span></p>
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<p class="MsoNormal"><span lang="EN-CA" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"> </span><span lang="EN-CA"><o:p></o:p></span></p>
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<p class="MsoNormal"><span lang="EN-CA" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">To get high CO one has to ‘force’ the production of it such as in a hot, choked, air-inadequate fire. Then one can see the CO/CO2 reach 30% or more.
It is not uncommon to see 25% in poorly constructed stoves, but not at the end. Little well-aerated char fires stabilise in that 12-16% range.</span><span lang="EN-CA"><o:p></o:p></span></p>
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<p class="MsoNormal"><span lang="EN-CA" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"> </span><span lang="EN-CA"><o:p></o:p></span></p>
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<p class="MsoNormal"><span lang="EN-CA" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">It is often said that “the CO is really high”. That is relative true compared with a really good fire, but CO is highest in hot, bad fires where
there is enough energy to create a high burn rate and poor mixing or poor combustion.</span><span lang="EN-CA"><o:p></o:p></span></p>
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<p class="MsoNormal"><span lang="EN-CA" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"> </span><span lang="EN-CA"><o:p></o:p></span></p>
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<p class="MsoNormal"><span lang="EN-CA" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">Let’s use the example of 14.28% CO/CO2. I choose that because the CO as a fraction of C is 1/8<sup>th</sup>. The ratio of CO to CO2 is then 1:7 which
is 14.28%. So we are burning char with 1/8<sup>th</sup><span class="xapple-converted-space"> </span>of the carbon emerging as CO and 7/8 as CO2, OK?</span><span lang="EN-CA"><o:p></o:p></span></p>
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<p class="MsoNormal"><span lang="EN-CA" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"> </span><span lang="EN-CA"><o:p></o:p></span></p>
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<p class="MsoNormal"><span lang="EN-CA" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">If the char is 85% carbon (realistically, this is a reasonable guess) then the heat available is about 29.5 MJ/kg. We lose about 75% of heat for
all CO produced instead of CO2. Therefore we get as a loss:</span><span lang="EN-CA"><o:p></o:p></span></p>
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<p class="MsoNormal"><span lang="EN-CA" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"> </span><span lang="EN-CA"><o:p></o:p></span></p>
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<p class="MsoNormal"><span lang="EN-CA" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">0.75 x 1/8 x 29.5 = 2.765 MJ</span><span lang="EN-CA"><o:p></o:p></span></p>
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<p class="MsoNormal"><span lang="EN-CA" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"> </span><span lang="EN-CA"><o:p></o:p></span></p>
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<p class="MsoNormal"><span lang="EN-CA" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">So instead of getting 29.5 we get 26.73 MJ/kg, which is a loss of 9.375% or 9-3/8<sup>ths</sup><span class="xapple-converted-space"> </span>per cent
at 14,28% CO/CO2.</span><span lang="EN-CA"><o:p></o:p></span></p>
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<p class="MsoNormal"><span lang="EN-CA" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"> </span><span lang="EN-CA"><o:p></o:p></span></p>
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<p class="MsoNormal"><span lang="EN-CA" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">So in round numbers it is reasonable to assume you are losing 10% of the heat energy in the form of uncombusted carbon.</span><span lang="EN-CA"><o:p></o:p></span></p>
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<p class="MsoNormal"><sub><span lang="EN-CA" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"> </span></sub><span lang="EN-CA"><o:p></o:p></span></p>
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<p class="MsoNormal"><span lang="EN-CA"> <o:p></o:p></span></p>
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<span style="color:#1F497D">PSA></span>Concerning the issue of what is the heat lost (not liberated) if CO from charcoal escapes instead of being burned, you have illuminated my (our) understanding.</span><span lang="EN-CA"><o:p></o:p></span></p>
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<span lang="EN-CA" style="font-family:"Helvetica",sans-serif;color:#1F497D">></span><span lang="EN-CA" style="font-family:"Helvetica",sans-serif">In a "typical" charcoal stove that is generating dangerous amounts of CO, what percentage of the consumed carbon
is "well burned" (and becomes CO2) versus the carbon that is only transformed into CO? </span><span lang="EN-CA"><o:p></o:p></span></p>
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<span lang="EN-CA" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">It is highly dependent on the kitchen conditions. In a well-ventilated kitchen CO is not an issue, first because low level CO is not all that dangerous, and second because
one doesn’t have to breathe the CO or the smoke, just because it comes out of the stove. In a real kitchen the smoke rises strongly to the top and most leaves by way of ventilation holes or gaps. In other words a ‘single box model’ of kitchen emissions being
spread evenly around the room at all times is unreasonable. Kitchens don’t work like that. There is some advanced mathematical modelling done by KK Prasad at Eindhoven University in the 80’s on this matter. CO and PM are strongly concentrated above the stove,
and are not spread around the room. Thus the exposure is affected much more by the kitchen than the actual emitted mass.</span><span lang="EN-CA"><o:p></o:p></span></p>
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<span lang="EN-CA" style="font-family:"Helvetica",sans-serif;color:#1F497D">></span><span lang="EN-CA" style="font-family:"Helvetica",sans-serif">The reply might need to give some range of values or qualify the responses relating to a "high heat" charcoal fire
versus a "low heat" charcoal fire, probably with the latter being proportionately much more of the carbon ending up as CO, with a corresponding 75% loss of the heat value for that amount of charcoal.</span><span lang="EN-CA"><o:p></o:p></span></p>
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<span lang="EN-CA" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">The CO emitted by a charcoal stove on high power is usually more than the same stove at low power even if the combustion conditions at the end are poor. However, modern
charcoal stoves are far better at combusting the fuel than the old and new ‘Jikos’. I am hoping to be able to point to a new charcoal stove product soon that has been waiting in the wings for launch. It has greatly reduced CO production throughout the burn.
We need some examples like this to stimulate the industry. We have been setting targets too low.</span><span lang="EN-CA"><o:p></o:p></span></p>
<p class="xmsonormal" style="mso-margin-top-alt:0cm;margin-right:0cm;margin-bottom:12.0pt;margin-left:0cm">
<span lang="EN-CA" style="font-family:"Helvetica",sans-serif;color:#1F497D">></span><span lang="EN-CA" style="font-family:"Helvetica",sans-serif">There is a big difference between (hypothetical numbers follow) 50% of carbon going to CO instead of CO2 (with
the loss of 75% of the heat value of half of the carbon [75% of 50% = 38% lost heat) versus only 5% of carbon going to CO (75% of 5 % = 4% lost heat). Of course, it is the CO that can kill you that is more important than some amount of lost heat.</span><span lang="EN-CA"><o:p></o:p></span></p>
<p class="xmsonormal" style="mso-margin-top-alt:0cm;margin-right:0cm;margin-bottom:12.0pt;margin-left:0cm">
<span lang="EN-CA" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">CO as a hazard is always going to be a hazard. On the other hand don’t over-sell a danger. If the 2-hr exposure limit is met, that’s OK. Remember that we have emission
targets, it is not a contest/race (though we love those too). Having no CO at all is great – better efficiency, no health risk. In practice however, people produce CO all the time and we don’t die from exhaling our own air. People have a CO/CO2 ratio of about
1.6%.</span><span lang="EN-CA"><o:p></o:p></span></p>
<p class="xmsonormal" style="mso-margin-top-alt:0cm;margin-right:0cm;margin-bottom:12.0pt;margin-left:0cm">
<span lang="EN-CA" style="font-family:"Helvetica",sans-serif">Comment: We are discussing "char-gasification", the oxidation of solid carbon (but as charcoal it is not necessarily pure) into either CO or CO2. The O2 that enters as primary air can result in
either CO or CO2. The role of secondary air is a very different story for char-gasification than it is for the combustion of pyrolytic gases as in the context of TLUD micro-gasifiers.</span><span lang="EN-CA"><o:p></o:p></span></p>
<p class="xmsonormal" style="mso-margin-top-alt:0cm;margin-right:0cm;margin-bottom:12.0pt;margin-left:0cm">
<span lang="EN-CA" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">I don’t have much add to that. It is important to recognise that CO2 produces at the pyrolysis front is often converted to CO endothermically in the char bed above it.
CO<sub>2</sub><span class="xapple-converted-space"> </span>happily goes back and forth several times to CO in a fire, or even to C<sup>++</sup>. It is not simple and direct. Similarly water in the fuel can be split into H<sub>2</sub><span class="xapple-converted-space"> </span>and
O. When measuring the content of unburned gases from a gasifier, you can find all sorts of strange totals of C and O<sub>2</sub><span class="xapple-converted-space"> </span>and water vapour and H<sub>2</sub>. Wouldn’t you be surprised to find that the total
of the O in the gas is CO, CO<sub>2</sub>, H<sub>2</sub>O, NO, NO<sub>2</sub>, SO, SO<sub>2</sub>, and O<sub>2</sub><span class="xapple-converted-space"> </span>is higher than the concentration in air?</span><span lang="EN-CA"><o:p></o:p></span></p>
<p class="xmsonormal" style="mso-margin-top-alt:0cm;margin-right:0cm;margin-bottom:12.0pt;margin-left:0cm">
<span lang="EN-CA" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">Regards</span><span lang="EN-CA"><o:p></o:p></span></p>
<p class="xmsonormal" style="mso-margin-top-alt:0cm;margin-right:0cm;margin-bottom:12.0pt;margin-left:0cm">
<span lang="EN-CA" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">Crispin</span><span lang="EN-CA"><o:p></o:p></span></p>
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