[Stoves] Mercury in leafy biomass ... cont

mtrevor at mail.mh mtrevor at mail.mh
Tue Feb 10 16:06:22 CST 2015


It might be a case of perspective but from the sand pile in the Pacific.
With the only TLUD stove in the country I am not too concerned about the amount
of Hg I release into the atmosphere.  However I suspect the amount of coal being burned
in Asia maybe releasing slightly more than I produce.  Other references suspect the upswing
in Hg maybe an effect of atmospheric Hg getting “rained” into the ocean. 

Michael
Marshall Islands





u source suspect From: Paul Anderson 
Sent: Wednesday, February 11, 2015 9:17 AM
To: Discussion of biomass cooking stoves 
Subject: [Stoves] Mercury in leafy biomass ... Was Re: Fly ash cement and of levels of radioactivity?

Crispin,

Under the old subject line about fly ash and radioactivity, perhaps people missed your message (which is intact below) about mercury in leafy biomass.

I inquire about the reasoning and the results related to your message.   I am supporting NONE of the statements, nor denying any of them.   Just trying to see the reasoning.

1.  Mercury (Hg) is more concentrated in leafy biomass than in woody biomass.   (Unstated about whether the Hg gets to the leaves from the air or from the soil.)

2.  Leafy biomass into briquettes is more likely to be burned in TLUD stoves than in other stoves.

3.  Letting the leaves decay on the ground lets the Hg go into the ground.

4.  Burning the leafy biomass releases the Hg (95%) into the atmosphere.

5.  Is there a statement that Hg in the atmosphere is worse than Hg into the soil (and ground water)?   I leaf that to the experts to discuss.   (pun intended)

6.  Because TLUDs make char (and char does not hold back the Hg), therefore TLUDs release more Hg into the atmosphere PER UNIT OF AVAILABLE ENERGY than do stoves that do not make charcoal.

7.  And is the above situation being declared to be important enough to be a negative aspect of TLUD stoves?

Maybe I missed something.   

It is interesting that the topic of Mercury related to stoves has created so much interest for Listserv discussion, but has not been a topic at stoves meetings.   Granted that Hg is bad.   But in the grand scheme of things, are there any proposals that should be considered for implementation about Hg and biomass and stoves?

Paul

Doc  /  Dr TLUD  /  Prof. Paul S. Anderson, PhD  
Email:  psanders at ilstu.edu   
Skype: paultlud      Phone: +1-309-452-7072
Website:  www.drtlud.comOn 2/10/2015 2:45 PM, Crispin Pemberton-Pigott wrote:

  Dear Biomass burners

   

  There is a good article from sensible researchers  here

  http://www.mindfully.org/Air/Mercury-Smoke-Biomass.htm

   

  Now consider this and see how it affects your understanding of mercury in the environment (it is literally everywhere so pay attention).

   

  Mercury is released disproportionally from biomass relative to the mass percent burned. In other words, operating a TLUD gasifier releases the mercury in largely gaseous form (95%) and the rest in particulate form. It is easily evaporated going from Hg+2 to Hgo. 

   

  So should we worry about TLUD’s releasing, proportionally, about double the amount of Hg per useful MegaJoule of heat?

   

  Hg is concentrated in the leaves, especially deciduous tree leaves. There are being processed into briquettes on an increasing scale. Basically all the Hg is released when they are burned even if there is char powder in the ash at the end.  Should we worry Richard and his alternative fuels promotion?

   

  The most ‘toxic, mercury laden’ smoke in the stove community would come from a TLUD burning leaves from a deciduous tree while making biochar: full release, maximum concentration, least dilution during combustion.

   

  Is everyone automatically alarmed? But TLUD’s and gasification and biochar and burning non-woody biomass are four of the darlings of the improved stove community. What now?

   

  The answer is obviously to calculate what the emission rates are and the exposure level and the effect of such exposure before jumping to any conclusions about wood or leaves or coal or anything else.  Data matters. Coal is just old wood.  

   

  Burn hot, maintain a cool head.

  Crispin

   

  ++++++

   

  One sandwich a week?

   

  Who told you that?

   

  Good grief. There is lots of mercury in the environment including in sea air, and there are completely unknown biological pathways metabolising it as was shown by the atmospheric research station at Cape Point. The general idea is that mercury is well "mixed in the atmosphere". Not so. Sometimes it drops to zero in the air blowing from Antarctica for hours at a time. There is no known process that can do this. Most atmospheric mercury is from the sea. 

   

  I am amazed that these coal memes survive for so long. There is a really good lab at Clarkson Univ in Potsdam‎ NY that researches Hg in fish in the Great Lakes. Fantastically small quantities can be detected. One sandwich a week?  

   

  Argh

  Crispin 

   

   

  Frans and Crispin,

  Thanks for putting dimensions on the issue. I know that coal ash is the bad actor. 

  I'm still perturbed that I can only eat one tuna fish sandwich a week because of the Mercury from coal. 


   

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