[Stoves] TLUD-ND transition from hydrocarbonflametocharcoalflame / Temperature gap between self incending charcoalandwoodgas

[Kirk H.]

All,

There were some excellent responses to my post concerning TLUD-ND transition from wood gas flame to char flame.  As I think through them I come to a hypothesis as to why the flare of wood gas occurs at the end of a burn.  I think the key is in Dr. Boll’s response, that char and wood gas have vastly different ignition points.  

As the migratory pyrolytic front reaches the grate, the heat begins radiating from the coals downward.  This lost heat brings the wood gas below its ignition temperature, and so the secondary flame cools and becomes less capable of burning the wood gas efficiently.  The char in the bottom solution put forward by Crispin and the perforated plate solution put forward by myself both keep the wood gas hotter so the secondary flame is not cooled.  The char on top solution put forward by Ray reheats the wood gas by adding heat above the char.  The igniter solution put forward by Frans would continuously reignite the lower temperature wood gas, so the gas does not need to be kept hot.

As a side benefit Dr. Anderson noted that the char in the bottom solution would also protect the stove materials for a longer stove life span.

Thank you for your contributions,

Kirk H.



Sent from Mail for Windows 10

From: Peeters Frans
Sent: Thursday, August 16, 2018 12:51 AM
To: Discussion of biomass cooking stoves
Subject: Re: [Stoves] TLUD-ND transition from hydrocarbonflametocharcoalflame / Temperature gap between self incending charcoalandwoodgas

         Dear  Martin ,Kirk and All,

To keep the flame on stoves and your enthousiasm……
Woodgas is hydrogen ,mol weight 2 versus CO molweght 28 ,so the escape speed is 14 times faster !
Looking years to the magic flames ,you see one day hydrogen flashes 40 cm higger then CO blue mini flames .
    A spark plug HELP- ignition may gain efficiency ……Over SELF ignition .
          Gas ignitors are easy to make with a car spark coil, tyristor,diac,diode and 2 capacitors,controled by light sensor .

     Mr Kirk,  wasted expansion vessels 35x45 cm scalped 20 cm are the best TLUD vessels/
2x30 air  holes of 8 mm.
Scrap price 3$   . Load 4Kg twigs /pineappels .

      Regards
F.





































gap between self incending charcoal and woodgas

Kirk, Crispin and all
























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