Hi everyone, I have toyed with the idea of building a gasifier for several years now after seeing one for the first time on an episode of “Mountain Men” several years ago but finally decided to do it with the high cost of gas.
The primary reason I wanted to build a gasifier was to run a couple generators if my power ever goes out since I live rural and when it goes out it has been known to stay out for a few days. However when considering size and horsepower requirements, I decided I wanted to go bigger in case I ever wanted to power a vehicle with it. I figured a bigger gasifier should be able to meet the power needs of a smaller engine, but a smaller gasifier could not meet the needs of a larger engine if needed.
Plus, I had a lot of big “junk” lying around to use (55 gallon drums and larger metal canisters to start out with. I watched a ton of Youtube videos which made it look so very basic and I did a lot of research and reading online, but there were so many variations and options. I wanted to stay basic so I was aiming for a simple downdraft gasifier.
I started out with a 55 gallon drum and an old craftsman air compressor tank which became the fuel hopper and beginning stage of the fire tube. The tank is about a 12’ diameter. I reduced it to a 10” diameter by 4” drop, which is where I put my ignition port and eventually a couple of air nozzles thinking this would help my situation (it didn’t) I also added another reduction zone going down to 6” diameter by 2” drop. Shaker grate about 1/2” below that.
Leaving the reactor I have 2 1/4” pipe welded to the 55 gallon drum going into a cyclone filter, then passing into a radiator, finally going from the radiator into a filter medium box inlet of 2” and then output to 3/4’ pipe 12 volt air mattress pump is plumbed inline in the 3/4” pipe to create the suction to draw through the system.
Airflow/suction seems great, and everything is airtight - I’m not the best welder, but anywhere I had doubts I coated with high temp stove cement,
I started with lump charcoal and my fuel has been wood chips and chunks, these are admittedly irregular sizes because I have a lot of it from my wood splitting for house firewood and this was another big attraction to me is that I ave plenty of wood scraps to use.
No matter what I try all I produce is a bunch of smoke that will not ignite at all past the blower. I am getting something because occasionally the hopper will “burp” with a little backfire, but nothing I can ignite that is useable,
Any tips from anyone or something I can check into ?
I am thinking that it could be one of 3 things
- FUEL - I see a lot of people using wood pellets, but if I have to go out and buy wood pellets I might as well keep buying gas, I was under the impression I could throw any kind of dry wood or biomass in the hopper and like I said I have plenty of it, although it is not all a uniform size - so I hope its not my fuel.
- BLOWER FAN - maybe I need something bigger? Or maybe it is blowing too powerfully and making too great a draw? I couldn’t find a lot of direction on this subject so I not sure. -or- finally…
- MY REDUCTION ZONE
I feel pretty confident in my cyclone filter, radiator and medium filter, but the reactor is a different story. Like I mentioned there are so many different variations I wonder if my problem lies within the reactor and or the reduction zone - I’m just struggling to figure out what the “secret sauce” is.
This seemed like such a basic project, but after 3 or 4 attempts I’m not getting anything usable - also as a side note - how long should it typically take for a warm up, start up before you convert from smoke to useable syngas - I know there is a warm up period necessary, but I have gone 1/2 hour without anything useable and I’m thinking that by 30 minutes I should have gone from smoke to syngas.
I appreciate anyone who looks this over and can offer me some tips and get me pointed in the right direction again.