The great and upsetting thing about YouTube videos is that they don’t go away! A lot of this old video now seems incomplete:
Our understanding of how to come closer to complete combustion has changed and includes details missing before. The following describes a hopefully less wrong set of design principles. David Evitt is currently deep diving into clean combustion and who knows what details will be added in the next few years?
Nine years ago, we thought that close to complete combustion could be achieved by forcing all gases and smoke into flame for a sufficiently long amount of time.
- Today we add that the air/fuel ratio in the combustion zone needs to be air rich.
- We add that the flame/gas/smoke/air mixture needs to be thoroughly mixed.
- We add that the temperature in the combustion zone needs to be above 850°C to allow short residence times to become effective.
- We add that at a minimum of 850°C the residence time needs to be more than 0.2 seconds. Longer is better.
- Wet wood, un-preheated air jets, and mass tend to reduce temperatures to below 850°C.
- Optimized heat transfer efficiency helps to reduce harmful emissions since less fuel accomplishes tasks.