[Stoves] The Art of Using Grass Bundles in TLUD Stoves

[Julien Winter]

Dear Martin, Anand, and stovers;

Thank you for reporting on trials with crop residues and leaves, and
introducing grinding as a possible solution.   It is not surprising to
hear of this research from India, where much work has been done.

One of the readers of this topic sent me an excellent paper on burning
sawdust in a stove with a vertical hole ("port") down the middle of
the fuel bed, and lighting the fuel from the bottom.  Multiple "ports"
worked even better.

The reference and abstract are below.  Searching in the Web of
Science, I don't find that anyone has published any advances on their
technique; work has continued using pelleted fuel.

Regards,
Julien

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Dixit, CS Bhaskar; Paul, PJ; Mukunda, HS. 2006.  Part I: Experimental
studies on a pulverized fuel stove.  Biomass and Bioenergy 30:
673-683.

ABSTRACT: This paper is concerned with development of a pulverised
fuel stove with improved conversion efficiency and minimal emissions
at near
constant power level without the use of external power. The design
originates from a cylindrical sawdust stove with a central porthole
being lit from the bottom. Such a stove will have a flame in port with
enhanced sooting tendency. For similar configuration, stable
premixed combustion behaviour of the combustible gases from the port
of the fuel block (known as the gasification mode) has been
achieved by use of air supply through a thin slot at the bottom, for
at least 30 min of stove operation. In order to ensure stable
combustion of the gases at exit, a metal device is used. In an attempt
to extend gasification duration, studies are conducted in single port
configuration having air entry from the bottom with a horizontal
baffle to control the flow rate. This configuration worked in
gasification
mode for about 20 min but there have been problems of flame
extinction. To overcome these drawbacks multi-port design with
vertical
air entry is employed with success.

The stove has exhibited conversion efficiency in excess of 37% due to
well focused nature of flame at exit. CO emission factors are
about 12 g / kg fuel, a performance superior to conventional biomass
stoves (ca. 45 g / kg
). NOx emission factors are about 1 g / kg

fuel
which falls in the range of reported data for NOx. Studies with
different pulverised leafy fuels have indicated these fuels have lower
volatile release rates and therefore exhibit lower power level
operation for a given port configuration compared to sawdust fuel.

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-- 
Julien Winter
Cobourg, ON, CANADA