The very long torch flame with NO part blue at all! Not even in the root!
It has a foggy core!
Is it air-ejector driven, in the video a typical air hose is attatched to the rising tube of the torch?
Have you pressure – leak tested your air mantel between the nozzle tubes and the inlet for pressurized air?
(your video shows an air pressure and air valve attatched to the top of the silo!)
This could burn part of the gas around the airmantel… if it leaks.
Both with overpressure and underpressure! In fact, this mantel has always overpressure compared to the surrounding mantel…
If you have large nozzle tubes without outer threads for screwing on hats,
you can plug in copper tube-bits, less than 2X the diameter long.
Don’t plug in them completely, so you can “wrench” them out and change them for another hole diameter!
Once more: Floppy air beams with too large air-flow will just push the oxidation process down into the designated reduction area!
You will not reach the “white-glow” temperatures just before the restriction…
By the way, have you filled the reduction area well abowe the restriction plane in the big cylinder with clean charcoal?
If not, do it straight away!