Pellet gasifier

A friend of mine here owns a sawmill. He bought a big pellet mill and makes pellets for the Forestry Dept. Last week when I dropped off a pint of syrup for him he asked about my gasifier and if I could run pellets in it. I explained to him how it’s not an ideal material and why. Needless to say, I walked out of there with two 6 gallon buckets filled with pellets.
So for a week this has been gnawing at me. From my understanding the pellets that remain after the gasifier is shut downturn soggy unless it has already turn to charcoal? The pellets that are affected are going to be directly above the firetube? If that’s the case, what if I make a 4" firetube with an 8" or bigger hopper? If I were to secure a 4" metal tube in the center of the hopper, the moist steam can go straight up and then to the walls of the monorator to condense, would that work? My guess is I would need holes in the 8" hopper at the bottom for air flow? The pellets would be filled between the 4" and 8" tubes and fall in just above the firetube.
I can’t give a picture right now because my camera decided to now work anymore.

Interesting concept, try it all ready!!

If you burn down the pellets every time you wont have an issue when you mix in the fresh new pellets for the next run they will fire right up. Even with a full hopper that moisture will only affect the fuel closure to the bottom and then again you poke down in there mix in the unaffected pellets down in there. Generally at shutdown you will create a small void in your combustion zone. So when you fire up again you poke that down and the good pellets can be mixed down in there. If you have a machine optimized for pellets they are the best fuel you can possibly get this mho and based on my own experiences with comparing them to chips. . They flow well, make tons of gas, offer 2 1/2 times wieght density as chips and are easy to manage, the only issue with pellets is your grate needs more attention, this is where people get in trouble with grate clogging crashing the machine and with pellets this get very bad as the tars created from the crash will lock up your char bed with solid tar. In order to make pellets work its all about flow, no flow no go.

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one other thing, pellets are dense all around so when you process them they also make more gas and your char bed has to deal with this. So your charbed needs to be sized big enough to process the created gases. Or you need to choke down your oxidation zone so you are over producing gas beyond what your char bed can process and manage.

Thanks Matt.
I bought some needed stuff for the build. I also stopped in the well company and picked up more pressure tanks for the build. I should have enough stuff to get started.
Suggestions for me on the grate?

get a cast iron floor drain grate. 3/8" spacing will work just fine.

Edit never, drill or modify one of these in anyway. it wil break with 100% certainty. Simple make a bolt on attachment on a shaft coming up from the bottom of the unit. Easy to put a shaker handle on it this we too.

You can see exactly how I do this in the TOG open source build I did on Youtube

One of the things that attracted me to wood chunk gasifiers is my ability to make my own fuel. Pellets are easy to handle and probably are a good fuel source but I can’t make it so I’m stick’in to sticks.


I agree Don. Myself included.
I think what this guy wants is to see if his pellets have another useful purpose. I will probably give it to him if it works. I may ask for some lumber in return. :slight_smile:


l have run pellets in a normal wood chunk gasifier. No special modification. Simply put, its easyaly the best fuel one can burn. Matt allready wrote down why, but after tar problems that MAY (it is possible but not sure) have happent from burning pellets, l decided not to use them any more unless absolutely nessesery.
Compared to chunks, pellets gave me about 20% batter performance!

The easy flow of pellets can sometimes be a problem. At lightup, the cavity in the oxy zone may get filled with raw pellets, l had them fallen past the restriction in some occasions, this is a recepie for tar.

Allso, if building a pellet gasifier, l wuld make a stratified auguer fed gasifier, or a normal lmbert with a small oxy zone and a HOT HOPPER. The last is most important!

In my previous build, l had a hot insulated hopper. At no point it was possible to get any liquids in the hopper, so the pellets stayed dry eaven after cooldown and l had no problems relighting a hopper full of previously cooled charge.
On my new system, l have a cold condensing hopper. Putting pellets in here wuld be nothing short of a disaster. The top of the wood in the hopper is allways moist. Pellets wuld turn to sawdust after minutes!


Sophistication in observations/experiences; lessons learned; advices given.
J-I-C Steve unruh