Crispin Pemberton-Pigott and Roger Samson, January 2010


Roger Samson was here tonight and we made and tested a Grasifier: a Switchgrass burning stove based on the dimensions of the Vesto adapted to make a lower cost pellet burning stove for Haiti.

Power, 2.5 kw
Burn rate 8-10 g/min
Mass 550 g
Fuel load 600 g though it can hold 750

Lighted with two caps of paint thinners
The flame went completely blue (just before the end) then wobbled a lot and went out.
When it went out there was no smoke indicating there were no volatiles left.

Time to fabricate, about 30 minutes.

I see this as a burner that can be attached to the centre of a Haitian charcoal stove to convert it into very clean burning a pellet stove.

Char yield: 25% of the initial dry mass.
Moisture content of the initial fuel, about 7%

Ash: nearly none.


Jeffrey R. Davis



Fuelage is a fuel and construction material made from grass or possibly other plant material. After the grass or other plant material has properly retted it is wet extruded in the form of a pellet and allowed to dry.


In the fall of 2007 I was experimenting with composting as a source of space heating. This is called the Thermo-Biopile [2] and can be seen in photo 17. The plant material used was switch grass and wood chips. Photo 15 is the grass field before harvesting and photo 16 is the harvest photo. During the summer of 2008 I noticed a black material when the Thermo-Biopile was disassembled. I saved some of this material to test as a feed stock for Fireballs.

You can refer to my other article in order to understand the Fireballing process [5]. The first step was to place this material in a rotating drum with rocks and then after a period of ball milling the rocks were removed and the feedstock was left in the drum to see if it would agglomerate into balls. The consistency of the material would not allow this but it might be possible if another material was added.

It became obvious that this feedstock would be best used in an extruder so I modified a meat grinder that can be viewed in photo 1. The Fuelage is drying in photo 2 and 3. I'm not sure if this material needs to be milled (in this case ball milled) some before before extruding. An extruder could be designed to dewater and maybe mill this material, thus possibly a higher density particle and shorter drying period. Photo 4 is a picture of a dried particle.

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