[Stoves] Use of furnace emissions testing equipment

[Ron Larson]

Sent from my iPad

On Feb 2, 2011, at 11:17 AM, "Crispin Pemberton-Pigott" <crispinpigott at gmail.com> wrote:

> Dear Paul'n'All
> 
> Sorry not to be able to get to ETHOS - it was my intention to get here this
> year but things in Ulaanbaatar are moving fast than expected and several
> major advances in products, understanding and financing have popped. That's
> life, at least some of the time. What this space because it is going to have
> effects beyond UB.
> 
>> 2.  To the best of my knowledge, neither Aprovecho nor any  
>> installation of the PEMS equipment does not have TSI or Testo testing  
>> equipment, so no correlations have been made between the results of  
>> these different types of equipment.
> 
> There are two approaches used to defining combustion efficiency: the
> CO/Total Carbon method and the CO/CO2 method. Both use only a portion of
> actual combustion efficiency and this is done because they are easy to
> measure and/or calculate.
> 
> CO/CO2 is a measure of combustion IN-efficiency.
> 
> Measures of combustion inefficiencies include:
> CO/Carbon and CO/CO2
> H2/H2O
> H2S/S and H2S/SO2
> 
> I am hoping that Steve Garrett will come up with a way of measuring H2O at
> high temperatures (700) using an inexpensive thermoacoustice device. He is
> optimistic.
> 
> The direct measure of combustion efficiency is often written as:
> 
> CO2/(CO2+CO)
> 
> That is the ratio of CO2 (proper combustion) to the sum of CO and CO2 (total
> carbon-containing gases measured). The higher the number, the more complete
> the burn. 
> 
> Examples are: smouldering dung in an Indian open fire might be 85% (reported
> by K Smith), and burning lignite in a Mongolian GTZ 7.5 stove averages
> 99.44% (reported by SEET Lab).
> 
> Legislation is rarely written this way. It is not written with a high
> combustion efficiency in mind, it is written with a permitted 'inefficiency'
> in mind, meaning emissions of something we don't want.
> 
> So the most commonly used measure of combustion is CO/CO2. It is also common
> to have 2% as the target value for combustion because it has been shown that
> in a normally ventilated house, the CO level does not build up to dangerous
> levels if the burner is working well enough to keep the CO below that level.
> 
> 98% combustion efficiency is NOT the same as CO/CO2=2%. The latter means 1
> molecule of CO per 50 molecules of CO2. 98% means a ratio of 1/48.  Thus it
> is technically to refer to the CO2/(CO2+CO) as an efficiency, and CO/CO2 as
> a ratio. It is often referred to as COr (the CO ratio) because it is easier
> to say. We ask, 'What is the combustion efficiency?' and get the answer,
> 'The COr is 3.51%.'
> 
> Combustion analysers often give the COr as a % or as a fraction. My TSI
> reports the fraction in decimal form: 0.0200 is 2%. Testo reports 2% on the
> screen.
> 
> The reason they do not report the combustion efficiency is the technician is
> testing a burner like an apartment building furnace and has been told to
> tune the air supply until the number is 'below xx%' so that it is operating
> within the manufacturer's stated range.
> 
> Lab results sometimes report the CO2/Total Carbon = CO2/(CO2+CO) =
> combustion efficiency.
> 
> Russian republics (incl former USSR) normally have different COr values
> permitted for different fuels. Examples are:
> Wood 4%
> Coal 2%
> Anthracite 0.5%
> 
> There is an article on the use of a combustion analyser to test and develop
> stoves here:
> 
> http://www.hedon.info/docs/BP55-PembertonPigott.pdf
> 
> The upcoming Domestic Use of Energy (DUE) Conference in Cape Town in April
> will have three papers on the test lab use of combustion analysis to develop
> stoves in Ulaanbaatar. One is on the problem analysis (air quality and
> particle analysis to attribute the problem to domestic coal combustion).
> Another is on the test protocol used to make measurements and process them.
> The third is on the use of the measurements to adapt the product to minimise
> the PM produced. Over a period of 6 months, these methods were applied to
> reduce emissions by a factor of 1000 (99.9%). The baseline and improved
> stove PM measurements are attached. The black lines are real time emissions
> of PM2.5.
> 
> Key to this result was the use of real time calculations to discover when
> things were working well and expand that zone of perfection until it covered
> nearly the entire burn period. 
> 
> The stove development was not actually guided by the PM numbers, but by the
> CO/CO2 ratio. As the ratio goes very low when there are still volatiles
> present in the fuel, the PM disappears as a matter of course. You don't have
> a CO/CO2 ratio of 0.02% (1/100th of the permitted ratio) and still have lots
> of PM.  The reverse is not true. If the PM is absent, it doesn't mean the CO
> is gone. A coke fire can produce no PM and vast quantities of CO.
> 
> PM emissions are often expressed in g/kg of fuel burned which can be very
> inconvenient when making comparisons between stoves and fuels.
> Labs/engineering facilities usually express it in g or mg per MJ or per
> useful MJ (MJ absorbed, work done, used etc).
> 
> Stove rating involves testing the whole system, as used, so it should be
> mg/MJ absorbed (in the pot, if it is a cooking test). A stove with worse
> combustion but better heat transfer will rate better in terms of emissions
> per task accomplished. 
> 
> Regards
> Crispin
> 
> <081.10.4.1 PM 2.5+Mass Burned Traditional Baseline 2010-08-22 v2.58.JPG>
> <117.10.4 PARTICLES GTZ 7.5 2010-12-18.JPG>
> _______________________________________________
> Stoves mailing list
> 
> to Send a Message to the list, use the email address
> Stoves mailing list
> 
> to UNSUBSCRIBE or Change your List Settings use the web page
> http://lists.bioenergylists.org/mailman/listinfo/stoves_lists.bioenergylists.org
> 
> for more Biomass Cooking Stoves,  News and Information see our web site:
> http://www.bioenergylists.org/
> Stoves at lists.bioenergylists.org
> http://lists.bioenergylists.org/mailman/listinfo/stoves_lists.bioenergylists.org