Gassifier shut down procedure

I built a gassifier and it produces a flammable gas. Once running I found myself embarrassed because I did not know what would be the best procedure to shut it down. Initially I thought I would shut down the blower and open the reactor assembly lid but that seems dangerous due to the extreme heat / gasses that would be escaping. Also by introducing air to the hearth would waste the remaining fuel in the hearth. I finally decided that after I shut off the blower, stuff a rag in the air inlet and close off the outlet not allowing any air into the system. To date I have not found a best practice method. I am sure there are experienced folks out there that maybe laughing at this. If you could stopping laughing for a minute maybe you could give me some advice.
Any Thoughts?
Thank You


What I consider proper method of shutdown is to close off your air intake before relieving vacuum. When you relieve vacuum pressure your hopper pulls both the intake air and also the raw fuel gases backwards into the combustion zone and can cause a flashback. Not a big deal for most of us but if you are looking to eliminate this possibility this how too. If you shut off the air supply you are only pulling the gases back but its void of oxygen so a flashback should not able to occur.

So first thing is shut off air supply to the gasifier and then close off and shut off the blower or shut down the gas supply to engine.


Hey Joseph,

Welcome to the site and be sure there will be no laughs from me .

When I shut down my gasifiers I seal the gas exit and the air intake . Usually right before shut down I will let it cool off just a little , maybe about a min . This is usually done by deceleration as I am coming into a parking area .

1 Like

Thank You so much Matt great advice. Makes sense.

1 Like

Hi Wayne Thank You for the welcome and not laughing. Makes good sense to allow a cool down a little.
Thank You for the advice. You guys make the a great site.


Welcome to the site, Joseph. You’ll find that no one makes fun or laughs at anyone’s efforts at gasification or building a gasifier. My unit may look advanced with a shiny paint job, but it took several years of some pretty crude arrangements to get here. You are doing and that’s what counts. You can also count on some pretty down to earth explanations from the great membership here. Everyone here wants everyone else to succeed.
My shutdown procedure is, close the air inlet first. In this old pic I clamped a gasketed plate over the inlet. I now have a hinged flap which flips down, a little faster. Then I immediately close the fuel shutoff valve on the filter unit to kill the engine(or if you’re just flaring for fun shut off the vacuum source) and let the whole unit cool down. Checkout “My first small engine run” in the small engine section here for a few smiles.


I shut down the engine, then the wood gas to engine supply valve. I then shut the gasifier air valve. I don’t get flash backs.

1 Like

Thank You Pepe2000
I love your gasifier. Really looks great. Also watched your video. Hope to be there some day.
Thanks for the great advice.

1 Like

Hi Tritowns
Thank You. I am not sure if I have a leak or just different internal design of my gasifier but when I do not shut off my inlet prior to the outlet I get a pop which I am assuming is a flash back.
Once again thank you for your help.

1 Like

Hello Joseph.

Below is a short clip of shutting down the truck gasifier .

From running 70 mph to parking and walking away from the truck is about a min .

There will be no signs of smoke or fire.