Downdraft Gasifier Part 8 - Gas Composition

In essence, the CO2 formed in the upper portion of the gasifier is suctioned down through glowing coals who convert it to carbon monoxide. The hydrocarbons outgassed are cracked to hydrogen and carbon monoxide, as well.

After starting the fire, and letting it become hot, you might want to add a substantial quantity of fuel to it, maybe even a couple of feet of fuel to it; then, you can put the lid on. You also might want to reduce the speed of that blower that you have attached to it.

There is some good literature on gasifiers. Try a google book search for "producer gas"; this was popular with coal back in the early 1900s; plus books from back then are out of copyright, so you can download them in full.

My suggestions: CO, which burns, is formed from incomplete combustion (2C + O2 = 2CO), complete combustion makes CO2 (C + O2 = CO2). You might have too much airflow and not enough fuel. You need a bed of hot fuel to reduce CO2 to CO (CO2 + C = 2CO) and form combustible gas.

first you have a flame in your firebox and the flame will burn up the gas. second you have to have a base in the bottom charcoal to start the operation so it can't flame out the bottom where you can't see it and add more chips.

Maybe you have too much moisture (steam) in your gas. I saw another gasifier video that said this was a problem for lighting flare. Try bubbling gas through water to condense steam. If this works you will need to improve your cooler.