[Stoves] Effects of biomass pellet composition on the thermal and emissions performances of a TLUD cooking stove

[Crispin Pemberton-Pigott]

Dear Paul



I can try to answer:



>1.  The physical characteristics of the stove are highly important because TLUD stoves can be made in so many ways.   Therefore, the name of that specific stove is important if we are to be able to replicate or improve or comment about the stove.



It is not a report about the stove. It is about fuels in a "constant stove".



>2.  Does this TLUD stove make char?  If it is a TLUD stove, it DOES make char.



All biomass stoves :create char". Some consume it, some consume some if it, some consume only a little. As we have heard before, the moisture content changes the equation.



>But the user might choose to consume the char inside the stove by continuing to cook after the pyrolytic front reaches the bottom of the batch of fuel.



I think you are assuming something there:  not all TLUD stove "wait" until the whole batch is pyrolysed.



>If that is done, that needs to be clearly indicated in the report.



Why? It is a report on fuel properties, but combustion systems.



>And such cooking with char is unlikely to be at the typical high power used for Chinese cooking, so is something else different?



Well, we can't know that by guessing. Char burning might be very powerful - and the heat transfer efficiency might be higher too. Who knows?



>Unanswered questions mean that a more complete report would have helped.



The report delivers the result of the investigation. It is not about the stove. All you questions are about the stove, right?



>3.  ... energy density >21 MJ/kg... is indeed unusual.



I find it odd that you guys think so. Would you be surprised to know that there are biomass fuels with 22 MJ/kg? Cashew nut shells - good TLUD fuel - are 25-28<https://energypedia.info/wiki/Cashew_Nut_Shells_as_Fuel> MJ/kg.



>Expecting about 16 MJ/kg, means 5/16 = 30% increase.   Such a difference should have received a sentence or two of comment.



I don't agree. It is the result of the bomb calorimeter test. It is not noteworthy. It is on the higher end of the biomass range. What should the student do, report a number different from that which he obtained? We are free to speculate about why it is so high, but not about the result. We can have our own ideas, but not our own facts.



>I am glad that the research was done and that the report was published.



So am I. The reason (which is not obvious) is that it gave me a good opportunity to emphasize that one cannot 'test a fuel for emissions" which is a misconception so widespread that it has infected the hallowed halls of the UNEP. WHO, Berkeley, and numerous other noteworthy institutions which ought to know better. Fuels have inherent emissions, but accidental emissions are reported as being inherent. That is where all this "solid fuels are dirty, we have to switch away from them as a mark of progress" (see MDG 7).

>If Crispin knows the researcher(s) or their host institution, perhaps we might get some clarification.



All that is at the top of the paper.



Regards

Crispin
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