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

[Ronal W. Larson]

List, Crispin, Drs.  Zhang and Zhou (the first and corresponding authors on the paper that Crispin forwarded a few days ago)

	RWL1:  Hopefully, Crispin intended to send this to the full list.  I see no reason to have sent it only to me, and he made no request for privacy.

	RWL2:  This is to ask Drs. Zhang and Zhou for their comments on anything in the following several exchanges, but especially on RWL13 below.  This I feel is the crux of this dialog and to which Crispin again did not respond:  the team rationale for the exceptionally large value for peanut hull energy density.   To repeat:  I believe this value to be in error by about 25-30% (should be closer to 16 MJ/kg than 21 MJ/kg).

Ron 




> Begin forwarded message:
> 
> From: Crispin Pemberton-Pigott <crispinpigott at gmail.com>
> Subject: RE: [Stoves] Effects of biomass pellet composition on the thermal and emissions performances of a TLUD cooking stove
> Date: August 20, 2018 at 8:48:20 AM MDT
> To: "Ronal W. Larson" <rongretlarson at comcast.net>
> 
> Dear Ron
>  
> >>I am glad that the research was done and that the report was published.  If Crispin knows the researcher(s) or their host institution, perhaps we might get some clarification.
>                 >[RWL2:   Crispin's response a few hours ago to this last sentence might not have been understood by some.  Crispin IS a co-author.  Quite possible that he never read it - being given a thank-you cite.
> 
> Ron, stop making things up, again. Your hostility and bias are showing.
> >>I am disappointed that you are disappointed. These fuels are proposed as
> substitutes for wood to the extent that are available. Very little work has been
> done investigating emissions from any small stoves. Or at all.
>                 >[RWL4:   This is a strange comment.  I like the work of Jim Jetter in this regard.  On this list,  Kirk Harris has reported a lot.    I liked the doctoral thesis of Jessica Tryner (CSU) on TLUDs specifically.  There are emission reports on small stoves in all 14 of the ETHOS conferences (see http://www.ethoscon.com/proceedings-archive/ <https://nam01.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww.ethoscon.com%2Fproceedings-archive%2F&data=02%7C01%7C%7Cf845dde907b6469bff3908d606a688be%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C636703709655479358&sdata=eoj6%2FG5o%2F%2BSEE8hAEm2AJdJdvo7KbzZqoYxa7cVroJo%3D&reserved=0>).
>  
> Ron, you do understand the difference between testing the emissions of different fuels in a stove v.s. testing a number of stoves using the same fuel, right?
> 
> >>That depends on the culture. Apparently in your culture they measure char.
> Why do you think there was any char at all? The purpose of the stove is to burn
> the fuel and cook, not produce char..
>                 >[RWL5.   Nope.  In this paper the intent was to study 3 specific types of fuel in apparently identical pellets.  No cooking involved.  And a cooking test procedure was and is inappropriate.  For one thing, the tests would have been conducted more than once each.
>  
> They are not identical if they are made from different materials. There was a test of the “cooking power” (the missing chart). The numbers are in the text of you bother to read it.
> 
> 
>                 >[RWL6.  If a stove that makes char is reported to have 15% efficiency, I think most on this list would like to know more on the char production.    Even more so when the result is so out of balance with any other ever.
> 
> The paper was not written “for most of this list”. Surprisingly, there are many other interested parties wanting to know how fuel composition affects emissions. The thing that is out of balance is the fanatical insistence that everyone should worry about char production when cooking.  
>  
>                 >[RWL7.  I asked in hope of finding out both why the performance was so poor - and if that could have caused the strange result.  
> 
> Poor in what respect? Most TLUD’s have quite a low thermal efficiency if they make a lot of char. We can assume that this stove did, because it delivered only 15% of the fuel energy to the pot. As it is a cooking stove, that is the appropriate number to report. If people have free fuel, or at very low cost, then fuel efficiency doesn’t matter, as Nikhil has repeatedly pointed out.
> 
>                 >[RWL8:  Again - the tier level or efficiency could have something to do with you report (which would lead to the conclusion  peanut shell pellets should be banned).
> 
> One might consider other options, such as a stove specifically designed to burn peanut shell pellets. You don’t ban an entire class of fuel because one on stove’s inability to burn it well.
> 
> >>I think that is an omission that could have been filled: first the density of the
> pellets, and then the bulk density.
>                 >[RWL9:  Agreed - but I doubt that either density is the cause of this very curious report on peanut shells.  I'll bet that if the test is repeated, that either density will be much different from the other two stocks.  The test results are very similar, except for the reported efficiency.
> 
> You are welcome to investigate and find out. That way you will not be reduced to speculation and guessing. It is called “science” and the result should be reported faithfully.
> >>That is an important observation - more important than the density. Some
> pellets do not absorb water easily.
>                 >[RWL10:  I raised it because the anomalous result came from the pellets with the highest moisture content (and still having an amazing energy content).
> 
> I presume you read that the energy content is “dry”. The moisture content is also reported. The calculations determine the heat available from the fuel as burned. I am sure the other readers understood this. If you look in the back of the beloved WBT spreadsheet there are energy values for 86 or so fuels. They are also given “dry”.
> 
>                 >[RWL11:   The report on energy content should ALWAYS be on the pellets as being used - not as if they were dried.
>  
> That that up with the Custodians of the WBT and have then change the list at the back.
>  
>                 >Perhaps there is vegetable oil in it?  I look forward to hearing if that is the case.  The other figures in the paper show these peanut hell pellets were essentially identical to the other two types.
> 
> I don’t know. Anything I add will be speculation.
>  
>                 >[RWL12:   It is clear that Figure 5 is most unusual.  
>  
> In what way? 
>  
> >I have no idea what to expect for #6.  
>  
> You could get an idea by reading the numbers in the text. It is just a plot of those numbers.
>  
> >I think it will become clear soon that the fault is in the reported high energy density.  
>  
> There may be no fault at all.  Don’t assume, measure.
>  
> >Probably not even the fault of the first author.   I doubt this is the first time someone has reported an energy density number inaccurately.  It wouldn't surprise me that the right number was found and another used.  What would greatly surprise me is if that number was correct.
>  
> Like I said, learn something every day. If you were the repository of all knowledge of fuels, I would assign your comments more gravitas.  Whining because you don’t like the authors and don’t understand the purpose of the experiment nor the obligation to report what was found instead of what was desired doesn’t lead us to new knowledge.
>  
> I congratulate the first author, Dr Zongxi Zhang of the Ministry of Agriculture’s Key Lab of Clean Production and Utilization of Renewable Energy at China Agriculture University, Beijing, on receiving his PhD in June 2018. He researched and wrote on the topic of emissions from domestic combustors and vehicle engines. He is a joyful and methodical researcher and has gone directly to industry. Another member of the same team who investigated the emissions profile from different coal products in a crossdraft coal gasifier is Altanzul Jargalsaikhan who obtained her Masters in Engineering last year.
>  
> Taken together they show that change the fuel often requires changing the architecture of the stove if extremely low PM emission rates are to be achieved.  This work has been useful in developing a series of products now reaching the market in Central Asia.
>  
> For the interest of Ron and Paul, the metric “char mass produced” was used during the development of the dung-burning space heating and cooking stoves known as the Model 2.5 (various prefixes). The greater the char mass produced, the worse the performance. Eventually an architecture was found that reduces the char mass to the size of a peanut from 5 kg of fuel, with a thermal efficiency over 80%. The stoves costs about $110-130.
>  
> Oh – there is more!
>  
>                 >[RWL13:  You didn't address my main point - no explanation or rationale in this paper for the huge differences.  
>  
> Huge differences in what? When did J Jetter write about emissions and cooking power using non-woody biomass pellet fuels in Chinese TLUD stoves?
>  
> >>If correct, any such paper has an obligation to address them.  This paper would not have been printed with what could be legal difficulties (from the peanut industry) if some thought and print went into the meaning of the results.
> 
> Stop making things up. Again.
>  
>                 >I suggest that the wisest course for your team is to talk this over - with emphasis on other explanations (than hypothetical added oil) for this 30% high number.  
>  
> I suggest you read and understand the paper before deigning to speculate about things.
>  
>                 >Mistakes happen - they should be admitted.
>  
> I agree. And if there was no mistake, the mistake will be yours for challenging the work without cause. Will you admit it? Your claim that the energy content is 30% “high” is unsustainable. Do you admit that? The reported figure is 10.5% above the norm, and recall that this is a fuel pellet. What was the binder used?  You have no idea, yet you feel free to speculate that the energy content cannot be that high. Yet it was.
>  
> >One presumably young, probably very bright, first author is the one who is going to be hurt, if a correction is not made soon.
>  
> It seems someone has an interest in hurting some authors and boosting others. Perhaps the best course of action is to stop. No one is interested in your dark hints, obfuscations and aspersions.  
>  
> Crispin

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