Here’s the deal Steve. I just get off on building crap. I still have sex even though I haven’t procreated anyone in 40 years. I just like doing it.
Not to worry though. I worked on this project for about half the day today. Should be making fuel by late next week. Right now I’ll have to hook it to my Generac generator. It’s set up to run on gas or propane and I saw someone with wood gas pumped into a port on the propane regulator that by passes the regulator itself. I hate that generator. Takes about a dozen pulls to get it started on gas after it’s been sitting overnight. I’m never getting another one without electric start. Should be able to start it on gas and then feed the wood gas to it and close off the gas petcock. At least that’s my hope.
Tom , just an idea if you take the pull start enclosure off and use a cordless drill or even an electric one with a socket and then place on the center nut to spin the engine over , its the easiest way starting a charcoal fueled engine for me when there is no electric start .
Dave
Thanks. I didn’t know if that was possible and still be able to pull the drill off when it starts running but I’ll definitely be trying that tomorrow.
I have a question before I start my day and work on the new unit. In a design like Don Mannes would it work to pressurize the plenum below the hearth. If the whole system were sealed then wouldn’t that provide the same draft as a vacuum past the filters. Just thinking about the discussion about cyclones and there not being enough gas velocity to allow them to function fully.
In my experience, the startup is the only time I need the vacuum blowers. Once the system is making good gas, the engine vacuum is the only thing needed to keep the the gasifier making gas. I have a 5500 watt generac generator that runs well on it. I do have a pressure blower blowing in to the ammo box under the nozzle but never had as much luck starting with pressure as I do with suction.
I tried to understand sizing cyclones from the PDF download in the library section. About all I got out of it was that most cyclones are to large to operate efficiently. I know that you are using a pair of them on the gasifier you posted pictures of. I have a tank from a dual tank air compressor I was planning to use to build a cyclone. It’s six inches in diameter and 18 inches long. I would roll a cone to slide into the cylinder like Gary G. showed on one of his videos. Is it the inlet piping that is usually to large or is the diameter of the cyclone body and length of the cone the main design issue.
I was planning on using the second tank as a water tank. It’s 2.2 gallons. How many gallons is the tank for your set up and how much run time does it provide.
Tom, I have referred to this link before for info about cyclone sizing. It might be of some help.
I believe a more detailed chart of cyclone dimensions exists somewhere on DOW. Perhaps someone remembers where that is located.
Tom, I don’t know if you have seen my walk around video of the charcoal gasifier I have on my Geo Tracker that I posted somewhere here before but I think it may answer some of your questions so here goes :
https://www.youtube.com/watch?v=BvRtMk_huHM&t=20s
Thanks Steve. At least I can understand the dimensions on that chart. Apparently the six inch diameter container I am planning to start with is good for 30 wood gas HP. I don’t know how wide that range may be or if you need to up size a cyclone for larger engines. For starters I’m just wanting to run a 6500 watt generator. Probably seven/eight HP. I’m not sure. The next application will be the engine from a 1980’s Honda Civic I have laying around. The units in the link you posted do not use a cone. All the info I’ve found seem to say that the cone is necessary to increase velocity to draw out smaller particles. I don’t know. Not that hard to make a cone if it doesn’t have a sealed seam.
I didn’t know you had a channel Don. Probably could have saved you answering a lot of questions. I subscribed. You Geo looks great. The video’s are from a while back. I’m guessing it’s still working fine. If I steal some extra hours I should be able to get my gasifier working by the week end. I’ll probably just cobble some kind of filter together until I have time to make a proper one. Thanks to both of you for the help. Pretty sure I know enough now to finish this without fifty more questions. Then I’ll get the saw mill set back up and start on building a chunker. Time is zipping by. Winter time will be here before I know it. Hard to get much done outside here in the winter because we average 13 feet of snow.
Good Morning TomH.
For pictured small generator cyclones look here:
open up the Micro Gasifiers button.
Scroll down the right hand side pictures to ones all painted green.
Open those up to full size.
Dutch Johns’ three cyclones are pictured there with the collection cans at their bottom ends. I had earlier posted they were 1/2" (13mm) ID. I was remembering wrong. Looks like 1" (27mm) inside ID’s.
You may have to manually re-type in his sites address. I do not easy button cutn’past link to give cookies isolation. His site IS still open, and accessible.
Oh. All of his systems are raw wood gasifers. The cyclones will be the same.
Regards
Steve Unruh
Got the charcoal gasifier about done. Just need to get the filter done and a few odds and ends. One concern is whether a grate shaker is required or not. I’m talking about something that runs on a timer. This is a design very similar to Don Mannes but it is stationary, not in a vehicle. I’m thinking that if I connected it to the frame of the generator the vibration from the running engine would be enough to keep the grate unclogged. Anyone have experience with something like this. Also too busy to want to try and make a barrel of charcoal right now. I do have a couple of bags of Kingsford brickettes. Can they be used as fuel? Not concerned with hooking it to the engine right now.
Tom,
My thought is that some type of cleaning between runs is sufficient–like poking through the nozzle hole, or in Don’s case, flipping the pulley. Poking down the charcoal before refueling is necessary to keep the charcoal down at the nozzle.
Kingsford briquettes are not refined (burned) enough to be used as engine fuel—too many volatiles. Also, binders are used to hold the briquettes together which may increase the amount of clinker produced. I suppose they would be fine for trial purposes, not running an engine. The “regulation” size for engine grade charcoal is 1/8" to 3/4" or so.
Thanks Steve.
Don’t want to sound like too much of a dumb ass or make it too obvious how anal I get about these things but just a few more things since I don’t want to have to go back and cut stuff up after I get it painted. Should the lighting port extend into the area just above the hearth or is just an opening at the surface of the hopper good enough? Is there any advantage to pumping exhaust gas back into the area above the hearth like Gary G shows into his nozzle. I’m thinking that if it didn’t do any harm, at least it would act as a muffler for the engine. I’m linking thermocouples on Amazon I want to order them today. Which would be the best for this application. Amazon.com : K Thermocouple Sensors.
Don. The cleanout port you said you added in your video. Is that to clean the charcoal out of the hopper if needed or is there another reason for it?
For the quickest light up, the closer to the nozzle the better but not so close as to melt the pipe.
I put that in there to be able to clean out the clinkers without having to come in from the top.
As far as thermocouples go, I like the ones that look like this
They have the threaded connector for an airtight fit. Make sure you get them with a high enough temp rating but still keep them out of the hottest area or they will still melt. Thermocouples are fun to have for a reference against overheating but I’m not convinced they are a necessity in a charcoal gasifier if you keep an eye on things. If you lived a little closer, I have extra bags of charcoal I’d give to you so you could get yours running 
Thanks. If we lived a little closer I wouldn’t have to ask all these questions here. I have about half a 30 gallon trash can of char I made for the garden and didn’t use. I think that would fill my hopper up about half way. I can just go to Menards and get a few bags of hardwood charcoal to fill it. What was your opinion about the generator vibration being enough to keep the grate clean? It vibrates enough that anything you lay on top of it while it’s running ends up rattling off.
Grilling charcoal from the store is not generally cooked to completion - it will still have some volatiles in there. Probably will not be enough to generate tar, but might make it tough to grind it up. You want the pieces to all pass through 1/2" hardware cloth, and then be screened over 1/8" to remove the dust and fines. Char size is very important to get dialed in. Too big and the reaction gets spread out and makes weak gas - too small and the hopper will plug, or char will get sucked into your filter. Larger engines can probably handle slightly larger pieces, but you want the full range of sizes.
Is your summer climate over there a no-go for making charcoal this time of year? We are expecting a couple of days with 90 degree heat, 15-20% humidity, and 20 mph wind. I dont think I will even dare light the bbq.
Looking forward to seeing some pictures of your setup!
Engine vibration should be enough to get rid of ash.
Hey Don, what do you use for readouts for those thermocouples?
Don, do you have a link so I can purchase?