DIY vortex gasifier cookstove from coffee cans

This is the latest version of my pyrolyzing gasifier stove made from two sizes of coffee cans and a piece of stovepipe. I used a junked computer fan powered by a 9-volt battery to provide the forced draft. This is not a TLUD stove since after it's lit and burning on the top it gradually turns into a down-draft gasifier, with the gas leaving the bottom of the combustion cans by venturi action, mixing with the secondary air, then exiting at the top in a vortex forming a hot flame cap over the fuel. I'm calling it a TLOD-FC, top-lit other-draft forced-convection. The primary combustion air has almost no oxygen in it since it comes down from the top where the flame is. The secondary air is pre-heated by passing between the can layers in a spiral flow pattern.

1 kg. of oak pellets burn for approx. 1 hour and in that time are able to bring at least 2 gallons of water to a rolling boil. [Update: 37 min. for 9 liters to rolling boil from 56 deg.F] The stove burns very clean with NO detectable smoke after lighting until the very end when it gives a slight puff before going out, and leaving only a very small deposit of tar on the pot bottom.

About 12-15% of the original weight and 50% of the volume of pellets is left as biochar, which is a good additive for soil to increase its fertility and water-holding capacity. NO unburned pellets remained at the end, only 100% biochar.

The triple-wall design keeps the cans from getting very hot so I expect a long life from them. The lower outer can is always cool and can be handled without danger. [Note: since the hot gas coming down from the flame cap to pyrolyze the pellets is mostly hot nitrogen almost devoid of oxygen, there is very little oxidation of the pellets OR the cans.]

While I did this test using oak pellets ($3.99/40 lb. bag at Lowes) other biomass fuels, of course, could also be used.

This technology is important because an estimated 2 million people die each year from indoor air pollution (smoke from wood stoves). I'd like to eventually get away from the battery and fan and go with just natural convection, a la Everything Nice stove by WorldStove.

Видео DIY vortex gasifier cookstove from coffee cans канала Approtechie