[Stoves] Lots of smoke after a few minutes of clean burning

[Mangolazi]

Hi Paul and Julien, 

Thank you for your replies. I set the mailing list to digest mode so I couldn't reply to your messages. It's been a while since I've used a mailing list. 

I used dried grass as tinder, with a few drops of hot candle wax as accelerant. Maybe flaming embers could have fallen downwards. But I checked the can contents after the smoke started and the bottom twigs weren't burnt, so I doubt it was a bottom fire that caused the smoke. 

What's curious is that I first had a clean burn with a meter-high flame coming out of the chimney. Then the flame dropped until it was barely out of the chimney and the smoke started. There's already a huge hole at the bottom for primary air; maybe that's too much. I've heard of a 2:1 secondary:primary air ratio for a clean burn.

I'll try packing twigs in tighter with thicker ones at the bottom. I'll also reduce primary air and increase the air gap between the can and concentrator lid for more secondary air. 

I'm traveling around Southeast Asia at the moment. I see huge opportunities for small gasifiers but turning this into viable local ventures is always an issue, especially when LPG is cheap and easily available.

Just curious, have TLUD stoves been tested at high altitude, say 4000-5000 m? 

Thanks again!