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</o:shapelayout></xml><![endif]--></head><body lang=EN-US link="#0563C1" vlink="#954F72"><div class=WordSection1><p class=MsoNormal><b><span style='font-size:14.0pt;color:#7030A0'>Dear Crispin,<o:p></o:p></span></b></p><p class=MsoNormal><b><span style='font-size:14.0pt;color:#7030A0'><o:p> </o:p></span></b></p><p class=MsoNormal><b><span style='font-size:14.0pt;color:#7030A0'><snip><o:p></o:p></span></b></p><p class=MsoNormal><span style='font-size:14.0pt;color:#1F497D'>></span><span style='font-size:14.0pt;color:#7030A0'>Is the height where the inside-outside heat standard or site specific? </span><span style='font-size:14.0pt;color:#1F497D'><o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>It is site-specific but as the intended audience is in gers (yurts) the height is very constant. It is about 2.7 metres from the floor. The chimney is typically 3 metres long and sits on the top of the stove so depending on the stove height, the amount of chimney poking into the sky is about 1 metre. Generally speaking all stoves have chimneys that are too large in diameter. That is interesting.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:14.0pt;color:#7030A0'><o:p> </o:p></span></p><p class=MsoNormal><b><span style='font-size:14.0pt;color:#7030A0'>You say to large in diameter. Based on the need for faster gas flow?<o:p></o:p></span></b></p><p class=MsoNormal><b><span style='font-size:14.0pt;color:#7030A0'><o:p> </o:p></span></b></p><p class=MsoNormal><b><span style='font-size:14.0pt;color:#7030A0'><o:p> </o:p></span></b></p><p class=MsoNormal><span style='font-size:14.0pt;color:#1F497D'>></span><span style='font-size:14.0pt;color:#7030A0'>The compressor taking in CO2 free air is making the dilution? </span><span style='font-size:14.0pt;color:#1F497D'><o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>The compressor compresses air. It is filtered to 0.01 µm and put through a CO2 and water vapour adsorber, filtered again and then sued in the diluter. It is very simple and effective. The dew point is -100 F. The CO2 is <1 ppm. The O2 is much higher, about 33% which was interesting to see.<o:p></o:p></span></p><p class=MsoNormal><span style='color:#7030A0'><o:p> </o:p></span></p><p class=MsoNormal><b><span style='font-size:14.0pt;color:#7030A0'>All this seems unnecessary to me. The amount of CO2 in the room air must be insignificant to what is going up the stack. Same as to moisture. Perhaps particles are a problem so in-air should be filtered. <o:p></o:p></span></b></p><p class=MsoNormal><b><span style='font-size:14.0pt;color:#7030A0'><o:p> </o:p></span></b></p><p class=MsoNormal><span style='font-size:14.0pt;color:#1F497D'>></span><span style='font-size:14.0pt;color:#7030A0'>What is used to scrub the CO2 from the air? </span><span style='font-size:14.0pt;color:#1F497D'><o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>I think it is a metal matrix of some kind. It does not get used up. There are two units and they are cycled. One breathes with ‘wash air’ or ‘sweep gas’ as it is termed. The other is under pressure for 30 seconds.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:14.0pt;color:#7030A0'>Very interesting. I am thinking it may be a Teflon membrane where when the gas is pressurized the CO2 goes through the membrane more than the O2 or N2(?) and swept away on the other side. It would be interesting to know how this works.</span><span style='color:#7030A0'> <o:p></o:p></span></p><p class=MsoNormal><b><span style='font-size:14.0pt;color:#7030A0'><o:p> </o:p></span></b></p><p class=MsoNormal><span style='font-size:14.0pt;color:#7030A0'>The CO2 produced is measured real time(?) using IR detection? <o:p></o:p></span></p><p class=MsoNormal><span style='font-size:14.0pt;color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>Yes. Two channels in parallel, one for the stack and one for the diluter.<o:p></o:p></span></p><p class=MsoNormal><span style='color:#7030A0'><o:p> </o:p></span></p><p class=MsoNormal><b><span style='font-size:14.0pt;color:#7030A0'>Don’t see how this can work. Measure the CO2 before diluter in the stack and after the diluter in the stack and you can get the dilution (mixing required I would think). The CO2 concentration from combustion goes up and down a lot so the two measurements before and after must be synchronized perfectly to determine the dilution rate. Then we have the constant changing in gas flow up the stack would vary enough to make this synchronizing a problem. As I have mentioned in the past we need some type of segregate standard gas to introduce into the primary dilution air at a constant rate to do this. Mercury is the only one I can think of and that is very toxic. But it can be detected at very low concentrations and scrubbed using S-treated activated carbon so not as toxic as one would seem when used in lab conditions (but I would not want to use it). If we can come up with a segregate standard we can come up with a very accurate means of gas analysis. Without it I see problems. <o:p></o:p></span></b></p><p class=MsoNormal><b><span style='font-size:14.0pt;color:#7030A0'><o:p> </o:p></span></b></p><p class=MsoNormal><b><span style='font-size:14.0pt;color:#7030A0'><o:p> </o:p></span></b></p><p class=MsoNormal><span style='font-size:14.0pt;color:#7030A0'>If CO2 is produced at varying concentrations as the fuel combusts how is it used as a measure of air dilution? <o:p></o:p></span></p><p class=MsoNormal><span style='font-size:14.0pt;color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>The CO2 in the stack is measured. Whatever the CO2 in the diluter is at the time is compared with the stack concentration and a mathematical correction is made to consider that some of the stack CO2 (and therefore a % of the diluter CO2) came from the ambient air. Stack/Diluter = dilution factor.</span><span lang=EN-CA style='color:#1F497D'><o:p></o:p></span></p><p class=MsoNormal><span lang=EN-CA style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-CA style='color:#1F497D'>We run the dilution between 4 and 300 with 10 being typical.<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-CA style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-CA style='color:#1F497D'>It has to be high enough (using dry air) to prevent condensation (formation of fog) in the sample so the particle does not think it is PM. This is calculated based on the moisture content of the fuel and the hydrogen content that forms moisture when burned. The system can deal with 140 gm of water vapour per cubic metre of gases. That is a humidity ratio (by mass) of about 13%.<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-CA style='color:#7030A0'><o:p> </o:p></span></p><p class=MsoNormal><b><span lang=EN-CA style='font-size:14.0pt;color:#7030A0'>It would seem that there is enough moisture in the outside air and the combustion gas to create the fog. That it is more the change in temperature (lowering) that creates the fog than the moisture in the gas. Pre-heating the dilution air is the answer to preventing fog and not dry air. <o:p></o:p></span></b></p><p class=MsoNormal><b><span lang=EN-CA style='font-size:14.0pt;color:#7030A0'><o:p> </o:p></span></b></p><p class=MsoNormal><b><span lang=EN-CA style='font-size:14.0pt;color:#7030A0'>Thanks<o:p></o:p></span></b></p><p class=MsoNormal><b><span lang=EN-CA style='font-size:14.0pt;color:#7030A0'><o:p> </o:p></span></b></p><p class=MsoNormal><b><span lang=EN-CA style='font-size:14.0pt;color:#7030A0'>Frank<o:p></o:p></span></b></p><p class=MsoNormal><b><span style='font-size:14.0pt;color:#7030A0'><o:p> </o:p></span></b></p><p class=MsoNormal><span style='font-size:12.0pt;color:#7030A0'>Thanks <o:p></o:p></span></p><p class=MsoNormal><span style='font-size:12.0pt;color:#7030A0'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:12.0pt;color:#7030A0'>Frank Shields<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:12.0pt;color:#7030A0'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:12.0pt;color:#7030A0'>BioChar Division<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:12.0pt;color:#7030A0'>Control Laboratories, Inc. <o:p></o:p></span></p><p class=MsoNormal><span style='font-size:12.0pt;color:#7030A0'>42 Hangar Way<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:12.0pt;color:#7030A0'>Watsonville, CE 95076<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:12.0pt;color:#7030A0'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:12.0pt;color:#7030A0'>(831) 724-5422 tel<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:12.0pt;color:#7030A0'>(81) 724-3188 fax<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:12.0pt;color:#7030A0'><a href="mailto:frank@biocharlab.com"><span style='color:blue'>frank@biocharlab.com</span></a><o:p></o:p></span></p><p class=MsoNormal><span style='font-size:12.0pt;color:#7030A0'>www.controllabs.com<o:p></o:p></span></p><p class=MsoNormal><b><span style='font-size:14.0pt;color:#7030A0'><o:p> </o:p></span></b></p><p class=MsoNormal><b><span lang=EN-CA style='font-size:14.0pt;color:#7030A0'><o:p> </o:p></span></b></p><p class=MsoNormal><b><span lang=EN-CA style='font-size:14.0pt;color:#7030A0'><o:p> </o:p></span></b></p><p class=MsoNormal><span lang=EN-CA style='color:#1F497D'>Regards<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-CA style='color:#1F497D'>Crispin<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-CA style='color:#1F497D'><o:p> </o:p></span></p></div></body></html>