This is my first post to this forum, please be easy on me!
Unfortunately my first real attempt at a gasifier was fueled by a (i hate to
say it) MrTeslonian YT video - the one about making a gasifier out of two
propane tanks. I won’t post a link as I am unsure if it is against the forum
rules. In anycase, I have built the gasifier EXACTLY as he shows in his video
and I am having some strange problems. (Yes yes I know, everyone will say
Ofcourse I am having problems, its a mrteslonian style gasifier)
Some specifications:
‘firetube’ is 8" in diameter, and 4" deep.
there are two 1" air inlets on opposite sides of the firetube, extending roughly
3/4" into the firetube at maybe 30-40deg angles inward.
I am using small chunked pieces of hardwood and softwood - standing dead that is bone dry.
Questions:
What kind of gasifier is this thing!? I assume an imbert style because of
the air intake, however the hearth is not like any I have read about for imberts. Seems almost like a modified FEMA? Idk…
If this is an imbert, are the air inputs correctly dimensioned for the hearth?
What kind of blower should I use? I tried a cheapo hair dryer, which creates draw but I still have issues - see below.
Problems:
Starting the gasifier, things start OK… I have smoke out of the output pipe,
however the hotter things get the more the air flow reverses! The point where
I shut it down there are flames (more like torches) shooting out of the air inlet pipes and smoke leaking out of the top of the gasifier.
I do get flammable gas out of the output, and I can flair the gas however the long the gasifier runs (matter of several seconds or a couple minutes) as flames start coming out of the inlets the flair on the output starts to die.
I am really hoping I can salvage this gasifier even though I am sure I will get a lot of criticism for actually building a mrteslonian gasifier…
Thanks in advance, any advise or help is greatly appreciated. I can provide pictures and maybe even a video tonight if it helps.
Welcome to DOW Chad. I know you’ve came to the right forum. A lot of do’ers here. If you haven’t became a member I would suggest you do. Although it’s not necessary in order to come up with a working design.
First of all, if it were me, I would like a 4" diameter fire tube 8" long. Spreading out the air inlets with smaller diameter holes was more effective for my first gasifier.
Realistically, one should build the gasifier to the engine they want to run. Also to consider in your build is the type of fuel you have on hand. Flaring a gasifier is different than running an engine. Running an engine on wood gas is different from running a loaded engine.
Just a warning for you, just as I completed each level of success, it becomes more addictive.
I dubt anyone will ever critisize you here, we all started at the enthusiastic video or other wood gas rumour some time in the past.
But unlike most other “free power” crap out there, woodgas is a real thing.
Like Bill said. More smaller nozzles (look at this sites library for “imbert dimensions”) and a suitible restriction, plus a good grate and you are preety much ready to make engine grade gas.
You shuld see my first engine ruined with a similar gasifier. But in a few years l came from that to a dayly woodgas driver.
Yes warm welcome and congratulations on a very descriptive beginning project post.
Please, please DO NOT SCRAP out this your first attempt. let us help you to make it a more effective learners machine.
In the Library button on the top bar here open up and read my short engine gasification explain. Then read Jim Masons much more detailed out descriptive explanation.
BillS’s and KristijanL’s advice’s are all valid, and take to heart.
My going forward advice is to garage-sale, thrift-store find an old Kerby, Rainbow, or FilterQueen vacuum cleaner. These can all be made into very good suck through pullers.
You want to flow suck up your system good and hot quickly. And kept flows HOT continuously.
You can blow through with a much more common plastic body shop vacs if you are always OUTSIDE and very well ventilated for carbon monoxide safety.
NOT how for safety you will want to engine woodgas fuel a system except just on cold gasifier system starting/heating up.
You will want to engine suck it.
Best to just suck-flow from the get-go for sealing and design purposes in my opinion.
Regards
tree-farmer Steve unruh
Added missing “NOT” word above. Please re-read. S.U.
Bill, kristijan, steve, thank you all for the kind words and suggestions. I will start digging through the library tonight with a fresh pot of coffee. I will revert back with the current design pics (as soon as I fix some air leaks). I will keep the topic updated as I progress in my redesign.
Thanks again for the motivation, long term goal obviously driving on wood (which I am sure will be several gasifiers from now)
Welcome Chad, all of us here have traveled the road you are now on, but if you want to save yourself a lot of time, aggravation, and money buy Wayne’s book, read all the builds and updates on the premium side, build it once and drive. His system is hands down best for every day driving.
Thanks Al, next week I am going to make the purchase. I’m the meantime I am playing with this one… Quick question, pulling a vacuum through a shop vac - any idea? I am worried about flammable gas being drawn through the shop vac which likely has sparks from the motor…
How do you guys use a shop vac as a blower/suction?
Please forgive the crudity of the build it was very much more of a test. I did not want to put too much into this build for fear of it not producing gas. I added rtv “just in case” however all seals are fully welded except the middle joining the two tanks. There I used stove sealing rope and hose clamps, and I am worried about air leaks there… I guess it’s a limitation of the mrteslonian gasifier…
Welcome Chad,
What Bill and Kristijan said about the air nozzles.
May I also suggest an air mattress blower. My gasifier is about your dimentions and I use one for lightup every day. It’s cheap and it actually pulls 3-4 times more vacuum than my 4 cyl engine at high idle.
Very good idea, thanks! Forgive my ignorance but do you put the mattress blower right inline with your output?
Do you ever have any heat/melting issues if it is inline?
To answer your blower concerns, yes the blower goes inline, this we usually call a “suction blower”. You should be OK using the suggestions given (Kirby, shop-vac, mattress blower), yes the gas passes through the motor area but many heavy duty vacuum cleaners are explosion resistant, ie designed not to make sparks into the airstream. In addition, the gas passing through the blower should be pure, ie no oxygen. If this is the case, it cannot burn because of the lack of oxygen. Make sure you have no air leaks prior to the blower!
The melting concern is justified however. You need to cool the gas before the blower. Some long metal tubes or pipes, any configuration, will do fine for this experimental build. If you go to any kind of trouble to build one, make the tubes run in parallel not in series.
Just a side note, there are also “pusher blowers” and “reverse blowers” but that’s not necessary (or even desirable) on this build.
From your description of the gasifier, it is definitely possible to make good gas with it. You need a lot more flow to keep it hot. Keep an eye on the output temps as you ramp things up, at some point it will dramatically spike and you’ll know you’ve reached the limit of your char bed.
Speaking of char, you should be using homemade charcoal in small pieces. If you don’t have any yet, you can use the gasifier itself to make some. I have a couple videos on this:
For testing i temporarily used 5ft of flex exhaust tubing running down in some water and 2 10ft sections of PVC… needless to say that shop vac sure did pull a vacuum and things got a little too hot and I had to shut it down. I’ll have to build the heat exchanger before testing again. I plan on using 25ft of flex exhaust tubing wound inside of a metal garbage can with air inlets at the bottom and a blower on top to blow hot air (eventually ) into the house to supplement out winter heating. Not sure how sufficient this will be for cooling purposes but id hate to waste all that heat - especially when it’s -30degf here in the winter…
Has anyone ever done this before? It must sound crude compared to all the fancy radiator style coolers I’ve seen pictures of.
I will try to upload some video and pics - again this is a test and not pretty! Beware
Whats the best way to check, should I remove wood from the hopper and look down, or dump my grate? If I dump it I assume I would want to sift and put back afterward?
For throttling, hmm yes i will work on that… maybe a variac
Yep, you can take the wood out one layer at a time, and get a good visual of what’s happening in there. Ideally you’d have raw wood at the top, black wood above the nozzles, charcoal at the nozzles and below, finer and finer down to the grate, where there should be some char dust and pieces about 1/2 to 3/4". You can save the various layers into different containers and put it back together again in order, it will work more or less the same.
Should look something like this:
I suspect your char is gone, or never existed. If you reassemble the charbed better/deeper than you found it, it will run better. You will likely need more charcoal.
