Running the gasifier

It’s been about a month since my last video and I have been gone for most of that time on vacation. I did a quick run of the gasifier again tonight. I re-sized the charcoal to a more uniformed size. Last time I had some rather big lumps of charcoal in the gasifier and I think that was one of the reasons why it didn’t run that well. I also added a steel can to the outlet to make a simple burner(or to at least disperse the flow so it ignites better). It seems to work much better this time.

I’m having a hard time sourcing some decent hose or tubing to run to a filter and then to the engine. Once I find some, I will get that part going.

Here’s the latest vid.

Looks good Byran.
I think even if it was windy the flame would maintain now.

Hi Bryan, you have the basics down. Charcoal size is important as you found out. Too big and you get too much space between the particles where the carbon dioxide can avoid getting reduced. Try for a mix of sizes between 1/8 and 3/4". Bump up your outlet pipe to a 1" iron pipe and you can use 1 1/4" flexible exhaust hose to move the charcoal gas to your filter. This same pipe size fits nicely to sump pump hose to move the gas to your engine. Your next improvement will be a cyclone to trap the dust as it exits the generator. Reallya nice feature to have and makes your final filter last longer. Isn’t this fun?
Gary in PA

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Out of curiosity, if one were to make a charcoal gasifier, what would you use for a final filter and a cyclone? Are they different than used for a wood gas unit?

The same as far as what the engine wants NOT to see BIllS.
Simplistically a well designed, well fueled, well operated down draft raw fuel gasifier is a charcoal gasifier with a charcoal making thermal/chemical close coupled unit on top.
Of course a poorly designed, poorly fueled, poorly operated and a raw fueled gasifier IS a tars passing though machine.
So is a charcoal gasifer with poorly made up charcoal.

Anytime you are trying to filter/wash tars you are WRONG some where and should be backing up to re-do a lot to just not be making theses passed trough tars.

Here is where I may get controversial. But I now have lots of hours of on-hands using proof.
Cyclones work alright. BUT ONLY if propertly 2D/3D designed: IF you want to use them for more than just heavy out of the hearth sucked through heavy coarse ash separation.
Most raw fueled gasifiers are designed with an internal hearth ash grate separation ash holding area so within thier flows design ranges ashes for the most part are not out of the hearth flow pulled.
Most charcoal gasifiers it is intentional to flow draw out hearth ash to be out of the hearth separated out later downstream.
So different cyclones purposes and designs needed for charcoal/ash-out systems versus most raw wood gasifiers trying to SOOTS separate out too.
Raw wood fuelers do tend to be far more downstream sooty operating. These SOOTS mostly were blow away or absorbed in the separate charcoal making operation.

Here’s my most controversial assertion.

  1. It DOES take a mechanical energy input to pull/push hearth outputs flows through a cyclone. Blower; or engine piston made negative pressure suction take energy. FACTS.
  2. A cyclone, ANY cyclone will only have a narrow range of flow/velocity for effectiveness. Have to get the actual internal speeds up and kept up to get the weights flung separations to occur. FACTS.
  3. I have now been show and use much simpler settlement chamber systems that can ash/soots separate out as well as any cyclone. These take far less energy input to operate. Work effectively over a far wider very low gasees flow to a higher gasses flow range than a cyclone. Means engine idle to wide open fully loaded engine output.
    Wayne Keith does this. All true WK system builders use no cyclones but do use heat exhanger/soots droppers.
    Ben Peterson’s VictoryGW systems past the three different sizes of mid-production Victory model hearths, all HotWatts and VictoryGrid systems all doing this with settling chamber of some type.
    Vesa Mikkonen and any others using a HOT bag house “filtering” systems are doing this. Look at the settlement lower clean out chamber/doors/ports in these.
    All of these users have evoled past the use of cyclones.

PLUS to a cyclone, is size and weight. So what to go with for in a compact vehicle, a most compact mobile systems. Thats about it for pluses. Very difficult to make to work “quack” effectively beyond a “looks like a duck” cyclone.
For dedicated stationery systems jump past these very limiting “boxes” of un-needs and go directly to settlement chambers for either charcoal or raw fuel systems.
Go forward - not backwards.

Steve Unruh

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Steve and group;
I hear this term “settlement chamber” and I think other terms that mean the same thing. I understand you are calling Mr. Wayne’s heat exchanger a SC. If I wanted to build a dedicated SC what would it look like? Round- rectangle; long - short and squatty; pipe coming in the bottom and leaving the top or come in through the side ( top or bottom) and out the top or side. I get quite a bit of dust out of my cyclone but I also get a build up on my throtte body. oh this is for a wood gasifier in my truck.TomC

Good Morning Brian White
Good job getting that nice energetic flare.
Good job for not falling into the “perfect blue flame” crap-trap jabber and wanting to now go as directly as possible onto engine running.
Three hours to find a bread crumb trial to finally get your nice short compact video to load up. Good job there too.
Now seeing your system, yep, GaryG is correct you will want to hot cyclone out first as you will need to have all of the consumed char released ASH pulled and produced gasses swept out all along too.
Depending on your wood base you have made your char from, this ash by weight, will be a min of 1% to as high as ~8% of the char weight you put in and consume. Don’t get it out, ongoing all along and you will char particle gases exchanges flow clogging and even get very undesirable char particle heat insulate.
With the temps in your base next to the nozzle end you will even ash melt and clinker clog if you do not flow sweep it out as released.

Anyone else having problem downloading this new video go to his memebers page and look up his previous posts.
He has a video link on this previously that will load fine for me. That gives access to his youtube’s members channel and then this new video links from there, easy.

Hey TomC most of the three hours tring to find away for me to view BrianW’s video I was hopping, skipping around looking at other gasifier system video’s that would link and download tring to get an alternative link to his to side-bar pop-up.
Settlement chambers/heat exchangers visibly used on some APL’s works, some VictoryGas works, Vesa Mikkonens works, Ray Risslers works (Missouri gasifier), and others.
Seen all types. Round and rectagular upright the most prevelent. Mid IN to HIGH outs always. Don’t want to stir up and recirculate lower settlements. But a few as flat-ish, shallow, wide/long deep rectangles too. IN one end HIGH; Out the opposite also High.

Your big 4.3L V-6 truck as a raw wood fueler is far different than these small charcoal gasifiers.
Getting soots out before your throttle body is not your problem.
Most of your problem is your big high flow American positive crankcase ventilation system filling your intake system. This is filling from just behind your throttle plate(s) the whole intake with crankcase oil vapors. Be much worse on a worn engine with lots of piston rings blow by crankcase pressurizing and needing ventilating out. This wet oil acting as a adhesion magnet for any soots passed through; or just after the trottle plates being formed. Leaking/worn valve oil seals a problem for this too filling the negative pressure intake with oil mist.
You cannot effectivley eliminate the low pressure and temperature dropping area just after your trottle plates on your big engine. Too much you be be at just cracked open throttle creating a turbulance point low pressure point. Small engine/gen-set kept highly loaded with an always near wide open throttle is the trick way to reduce this.
You can eliminate routing your PCV oil vapors into your intake. Just go old school natural draft crankcase vented and expect to have to change your oil for contaminates building up more often.
Ha! With wood/char gas fueling you should be doing more often oil changes anyhow. Oil is a soots sponge.
ALL WOOD/CHAR gas SUCTION engines should do this out of the more higher forced vacuum intake eliminating of crankcase ventilation anyhow. Some of the 80’s 90’s Briggs and Strattons switched to air cleaner crank case ventilating with even a simple clogged air filter are notorious for sucking out all of the crakncase oil through the caburetors! Air cooled, oil low then, overheat, seizing. Air cooled, engine oil cooling is a significant factor.

Sorry for the topic drift GaryG. I was tring to clarify to BillS and others who would read why smaller heads need smaller hats, and larger heads need larger hats. One-size-fits-all solutions (like just throwing on somewhere a looks like a cyclone); fits most poorly.

Back to ON sub-forum CHARCOAL topic. On BrianW’s char screening and sizing discovery that you and other experenced advocate. As an apology, let me point out found in my three hours of videos struggling Doug Brethowers newest almost no fines, and no large’s needing grinding in his pellet charcoal engine running gasifier works.
“Missouri Gasification Systems S-80 Powering a Tractor on Charcoal”
“Refueling a Tractor on Charcoal”
“Charcoal Powered Wood Chunker”
These are now up and all on his on his name youtube channel. Let you all find you own links. Mine end up being convoluted back doors.
These deserve to be set up and viewed here in Charcoal Gasifiers on their own topic.
And he has even converted a sawdust intened raw fueler to work with his charred converted pellets using engine exhaust recirculation for heat moderation.

Regards to All
Steve Unruh

Thanks to everyone for the input and advice. I think what I am going to do for a sizer/sifter is use two Weber grill grates perpendicular to each other to create a grid. It creates a grid of about 3/4 inch squares. Beneath that I will have another grill grate which has about 1/4 inch squares. That should give me some good sizes and let the fines fall through. I also bought some more plumbing and am working on a cyclone filer.

I’ve already gotten a lot of comments and inquiries from posting my latest video on Facebook.


Well I finished my basic filter. It consists of two steel coffee cans. The top can is filled with aluminum foil balls and the bottom one is filled with open cell foam. It seemed to work well on my trial run. I then tried to feed my lawnmower some of the gas, but I couldn’t figure out the air/fuel mixture. I didn’t fully take the carburetor off so that probably didn’t help, but I really don’t feel like disassembling the lawnmower since it’s my only small engine. I will probably try to find another engine to use in my experiments.

I think your engine will work. Can you post some pictures to show us what you tried? It will be the best way to get some feedback of what you can do to adjust, or just get some tips from the veteran gassers here. They were very helpful in getting my engine running.

Hi Bryan, Just out of curiosity, when you hook up the woodgas plumbing to your lawn mower engine, do you turn off the start up fan before trying to start the engine? On the off chance you are trying to blow wood gas into your engine, it will not work. You need the engine to suck the woodgas in. I’,m also curious about the aluminum balls. I’ve got the feeling this is something discussed earlier that I missed. heavy wool fabric makes a great dust filter and is easily cleaned.
Don’t take the carb off. Your engine will run just fine with the carb on once you figure out the current problem.
Gary in PA

HI Tom, I too am wondering about Steve’s comment about moving beyond the cyclone and has me curious too. His comments are “Seen all types. Round and rectagular upright the most prevelent. Mid IN to HIGH outs always. Don’t want to stir up and recirculate lower settlements. But a few as flat-ish, shallow, wide/long deep rectangles too. IN one end HIGH; Out the opposite also High.”
What I get from this is a container with a gas inlet coming into an air tight container in a relatively mid position with the gas exiting the container on the opposite side but at the highest point in the “settlement chamber”. The linear distance between the inlet and outlet will help determine the “settlement time” of the dust. Are there any pictures dedicated to this design so I can get a visual? Forgive me if this has already been gone over.and if so, can someone point me to the discussion.
Gary in Pa

I actually didn’t take any pictures this time. I was going to afterward, but I was too worn out from trying to pull start my mower and had some pretty serious blisters on my hand from the pull start handle. In all my excitement to try to get the thing running, I didn’t test my new filter for leaks. I just got finished testing it and noticed a leak around the pipe coming off the bottom of the filter. On the plus side, there was no charcoal dust at the outlet of the filter so it seems to be filtering the gas just fine. It did flare off fairly well at the end of the pipe. I think tomorrow, I am going to do another leak test on the whole setup and make sure things are tight.

One question I have is what is the recommended way to get woodgas/charcoal gas into the engine. I have seen videos with the gas piped in to the air filter box and I have seen the air filter and carb removed and plumbing hooked directly into the engine. Again, I would like to not have to remove the carb if possible.



While I was taking a long time to post my last reply, you posted your replies. I did make sure to turn off the starting blower. I am using sump pump hose to carry the gas from the filter outlet, although I didn’t cut it down in size so it was about 20 feet long. I think maybe if it was shorter, that would help too.

The aluminum balls on top of the foam seemed to work pretty well. There was no noticeable charcoal dust on the outlet pipe. I used the aluminum to catch any embers before they hit the foam. Seems to work.

I have plumbed it both ways, with and without a carburetor. One was a 12hp and the other a 15hp engine.
The 12 hp was a Honda and started on the first pull or two without a carb. That was a 1" gas inlet and a 3/4" air inlet and I ran it on wood chips.
The 15 hp with a carb was a little more touchy, but I used wood chunks. This brings other varibles into play for for me, wood size, density, restriction size, etc.
I’m not sure about the variables with charcoal. I’m going to guess it depends on your valve sizes and their position. Unless someone else that knows can chime in, I would probably start with 1/2" valves for a smaller engine?

Bryan, I have found that for the really small engines without a starter positioning the blower fan inline and after the engine works well. The idea is to make sure the gas line that feeds the engine is saturated right to the carb at the get go. The displacement is so small with the pull start you will pull for some time before you move enough volume of gas to get a start otherwise. Nice looking toy… David Baillie

Hi GaryG
I do not want to take this too far off of BryanW’s project AGAIN. Ha! Now fascinated with his (I assume) wrinkly surfaced wadded up aluminum balls. Fascinating.

But a picture of my horizontal settlement chamber. The whole lower chamber is continious to the double side walls. In this case IN high on one side. And OUT high out the other side. Note clean out lower door. Designed and made by Ben Perterson. Used as a heat fuel conditioning system too in this case. Yes. Some patent passive and active enhancements detailing inside that I cannot picture. 1st-ish generation ideas.
I’m look for an owners youtube put up representing round/tall 2nd generation ideas. Still notebook looking.
Really Mr Waynes heat exchanger/soot droppers represent this well. Catching any ash system pulled out too. Helps MUCH for soot dropping out to rapidly de-heat the produced gasses.
Settlement chambers can be tricky on raw wood gasifiers with the added system could go boom volume.
How to design for minimal internal volume, yet have time, space, duration to allow for settlement and NOT restir up. Really I think thse are best used with gasifier hearths WITH separation grates and in hearth primary ash removal systems.

Many charcoal and some raw wood fuel gasifers (3G-I and I think StephenA’s) I think are intentionally to be gas flow ALL ash swept out of hearth and so a cyclone would be best. Once I saw BrainW’s actual hearth tube his would defiantly have to be an all ashes swept out type.

One size fits all solutions fits most poorly.

Well, the gasifier build got the better of me today. I ran a leak test and found that there were leaks around every joint. I originally used furnace cement as a bond/sealant around the inlet and outlet pipes, but it must have shrunk because it was letting air by. Today, I decided that I was going to weld the pipes at the inlet and outlet. I am a very novice welder and I don’t get to do it very often, but I figured I would give it a whirl. I also had one other hole that I had drilled in the wrong spot and filled with furnace cement and so I needed to weld a bolt head into that hole to fill it.

I successfully welded the outlet pipe and a bolt into the “spare” hole. Then, in my attempt to weld the inlet pipe to the gasifier, I burned a hole through the gasifier body(the tube). I don’t quite know how it happened as the other welds went without a hitch. I tried to fix it, but the hole just kept getting bigger and bigger. I couldn’t reach it from the inside, so I decided to cut the tube about 2 inches above the hole I burned. I cut the tube all the way around and now I have access to the burn hole from the inside. So, if I can patch the hole and weld the two halves of the tube back together, I should be back on track. I do have another one of the 155mm tubes and could use that to start over. I’ll decide on that later as I think I am done for the day.

On the plus side, I got to practice my welding. What’s the old saying? “A bad day building a gasifier is still better than a good day at work”.(or something like that)


Bryan: I tried using furnace cement on a few projects involving highish heat (well within rated limits) now and so far my experience shows that it is good for much other than furnaces.

Anything with higher temperature expansion rates (thinner/non-cast metals), quick temperature raises, any flexing, or any vibrations will cause it to crumble quickly. Almost any point on a gasifier system will have at least 2 of these factors going on at any given moment during operation.

I also haven’t gotten it to really “adhere” to most metal surfaces very well. Even at it’s strongest, after curing but before any firing/engine starts, I’ve been able to chip/peel it off with my finger nails with ease.

To help prevent welder burn-through, try to get a decent sized chunk of aluminum (I used a heatsink from an old computer with a sturdy wire handle once), and brace/hold (NOT WITH YOUR HANDS!) it to either the back of the thin piece or right next to your weld area. This will help control excess heat buildup in your stock and steel won’t really stick to aluminum so it won’t get spot-welded to your work like other metals.


Thanks for that. I figured I would try the furnace cement because I just wanted to slap a gasifier together with what i had on hand. I thought that if I was to do something more permanent, I would weld it.

I have been looking into using copper sheet/plate in the same way you use aluminum.