Did another test today. Change the shape of the combustion zone and reduction zone. Ran the 14 and a half horsepower engine for 1 hour and 20 minutes on 7 lb. The engine was at full throttle although it is governed and is not under a load. You could rev the engine and it held up. The throttle on the engine was very responsive. It took about 5 to 6 minutes to get the gas fire up to temperature. And the engine ran the whole time without having to touch the gas fire. It needed no poking or prodding it just worked continuously until it ran out of pellets.
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Congrats on your run. Yes what the others have said everyone here wants the best for the ones building and operating gasifiers safely. Before you know it you will be understanding the other 75% of gasification.
You are well on your way of that. Keep It Super Simple. KISS
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Hello Darren, I also once thought about gasifying wood in an upward process in a narrow layer of the glowing zone, but there are several factors that made me abandon this method.
Assuming that a layer of glowing charcoal is created above, which is covered and insulated with ash on top, it can quite effectively convert gases into relatively clean gas, I imagine that at some optimal load this works well, but when the gas consumption is increased, a large gas flow raises this fluffy glowing layer and suddenly we are left without gas. However, if the gas flow is reduced too much, we again lose high temperature over the entire surface - the cross-section of the glowing layer and along the wall, where it is colder, tar gases can escape conversion,…
I drew a sketch of how I imagine such a gasifier,…
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You are spot on man. That’s exactly what I’m doing but I’m also applying a method to keep the combustion zone and reduction zone contained and it’s a perfect concentration. I can put a very large load on it and it holds up. It’s amazing. Thanks for your input.
It has no problem running the 14.5 horsepower Briggs & Stratton at full throttle. I can even rev the engine and it responds great. I’ve made some more changes to the reduction zone and combustion zone containment and it just keeps getting better. I can run it hotter now and I can tell that it’s much lower moisture. Not getting any tar that I can see. No tar residue anywhere in the system.
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If you can keep the reduction zone and combustion zone contained it’s no longer narrow, it gets rather thick but it doesn’t stop up
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This is how our friend Joni explained the gasification process in a narrow zone, well, my way is a downward process with a large supply of charcoal.
If we look at a wood gasifier from a distance, I can easily tell how efficiently it works based on the heat losses that occur when converting wood to gas, the narrow hot layer really represents a small heat loss, which we try to approach with good air preheating and heating the storage tank in a “classical gasifier”
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Hi Tone, Darren,
If this is the basic of the working principle build, then it is actual an inverted (upside down) fema style gasifier.
Ad some restriction plates and some other basic stuff, then you still have an inverted gasifier…
in some shape and form it might perform similar as an normal imbert style, but more fema as the air comes thru the fuel un regulated.
Difficult to manage consistency in fuel behavior as the gravity is opposing the fuel transition from zone to zone.
Any idea on how to do the refilling ?
Thoughts about a bottom feeder ?
I have build something similar, but with air intake nozzles and bottom feed.
Wil look up in my older postings. Also have a big version in my patent design papers.
In my case it was to directly feed a burner into a boiler to avoid heat losses.
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Yes I’m planning on a bottom feeding auger. The burn tube would not have to be near as long as it is now. All the problems you guys talk about our problems that I have had in the past especially the narrow glowing carbon layer. It’s no longer narrow it’s about 3 to 3 and 1/2 in thick. And it maintains that if there’s enough load on it. It seems like the more load the thicker the glowing carbon layer will get
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At one point I was thinking larger diameter tube. Yes that would increase gas production but it would just be more heat mass but not that hot. So I thought how can I stay with the smaller diameter tube and manipulate the glowing carbon zone into being much thicker.
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Currently I’m using a 4.25-in ID pipe. I’m only using 19 in of that for pellets. I figure it will run the 5500 w generator for about an hour and a half. So a 60-in tube should be good for about four and a half hours. It’s so simple you could have a second tube. It lights really quick and is ready for use after about 5 to 8 minutes. So reloading isn’t that big of a problem. And if you want to go all out you could use an auger
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I was once sent a link by a European friend about a German designer who was augur forced up from the bottom feeding. Mainly as was explanded to reverse the zones; then removing produced fuel gases from the top. It was to be “more natural heat rising sensible.”
My friend wanted my input before investing into it.
Told him to ask for the means of ash removal. Running system removal? System shut down; cooled; opened up and all dumped out for ash removal?
All solid wood based fuels you will have remaining cell walls mineral ash remaining after all of the volatiles and char carbons are gasses made, removed.
This freed up ash will always be at least 1% up 11-13% of the weight/volume of the fed in solid fuel.
In my mind natural ash flowing downward for separation and removal is the reason for in continuous long hours operated systems to all evolve to downwards flowing of the fuel; the char; the gases.
They could not answer him. He did not invest. The designer and his system disappeared.
So DarronB. how do you propose to remove the ends results mineral ash so the system does not choke out and gasses flow clog?
These ashes if allowed to accumulated will separate and smother your fuel particles. And even insulate them from being able to be heat activated.
Regards
Steve Unruh
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I have not had that problem. Tube size will dictate velocity. So far everything has been burning up into ash and blowing out into the ash collection barrel. After each burn there’s maybe just a small handful of gritty/sandy ash that drops through the lower grate but there’s lots of room there and you can do several runs before it needs removed. Almost everything burns up and is carried away. I’m only burning wood pellets and I plan to experiment with wood chips. That’s the only material that I will be burning in this setup. So far have not had any clogging issues. And I’ve probably burnt at least 200 lb of pellets so far. Lol. Everything burns up into a fine ash. One thing you must consider is that the glowing carbon is not compacted as with a downdraft. Now if you used an auger that could become a problem over time. Heavier grit / fly Ash would possibly begin to cause problems to the auger system. But without the auger there are no problems so far. I’ll look into that more and see what I can find out.
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I call it the floating grate. It’s not too heavy and it’s not too light. The grid holes are just the right size. It drops as the pellets burn. Underneath is a fairly thick but non-compacted glowing carbon layer. It’s not compacted so air can pass through quite easily without boring large passages. It gets very hot. The floating grate keeps the glowing carbon contained until it starts to burn up into ash. It then passes through and out of the system. I have had no clogging issues and this floating grate has made a huge difference in performance. This is just a crude test model. I will be welding up a 100% stainless version in the next couple of days. The wire I’m using is stainless currently.
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I’m using this to intentionally cause some clogging so that the glowing carbon layer can heat creep downward and become quite thicker. Due to the tube size and the amount of draw the velocity is just right to keep it from completely clogging
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It is the way updrafts -should- work. 
One issue especially with vehicles is the ability to keep the velocity up because of the variance in engine rpm from idle to acceleration to stop. thus most here are using downdrafts. The efficiency with updrafts is slightly higher but it adds complexity to the filtration as well since you have to collect all the ash in the filters rather then it just mainly falling out of the grate. Tar can also be a larger issue which you seemingly have also avoided
There is more then one way to gasify. I am happy you are doing so well!
I look forward to seeing more pictures of your system and hearing about your successes and failures.
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I guess it’s all about trade-offs. But so far Ash has not been an issue. I just like trying different approaches. It’s just a hobby. Thanks for your comment. I’m going to be trying a larger engine tomorrow. Fingers crossed 
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It is all about trade offs. It sounds good enough to run a generator. If it is mostly a hobby, then have (mostly*) fun with it. I love to see new ideas in action.
*something they can be very frustrating as well and working through the issues makes it rewarding.
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Burning Pellets vs. Wood chips is a very big difference. You are right about wood pellets not having much ash when burning them especially in a pellet stove because the way they are made at the factory. A lot of ash seems to fly up the shove pipe and out. But wood chips are very different. Specifically on what kind or type of wood you are using for the wood chips. Some wood chip types produce more tar in them because of the chopped up bark. Wood chips very a lot in size and in shapes from very small like wood pellets to much larger, and they are not uniform in shape like the wood pellets. Wood chips like to stick together and clump up because of their irregular shapes and with a little moisture and tar vapor that is coming out of the chips as they start to pyrolysis down to charcoal .
If you have this system working with wood pellets, I wood stay with the wood pellets or move on to engine grade charcoal where there is no tar in the charcoal to be formed in the wood gasses.
I am looking forward to your work in the world of gasification.
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Good. I was hoping someone else would bring up commercial wood pellet characteristics.
I did not want to come off as too critical.
DarrenB. be sure and run out all loaded in wood pellets to the point of only leaving those that have been heat browned then surface torrified sealed.
Any out of the bag wood pellets left inside at shut down sealed; and the gasifer will turn them into sawdust mush from the trapped internal combustion moisture.
On wood chips as BobMac says; it can be done alright with chips sizing and form classifying. @spaco Pete Stanaitis has some very good topics and experiences to be able to use wood chips in his Chineses JXQ-10 gasifer system.
Another small system that was instead specifically designed from the get-go to use wood chips to fuel operate electrical generators were @sabbadessa Stephen Abbadessa’s.
A starting relevant topic of his on the DOW was his “Victoria’s Corner” set up in the Small Engines Category back in Oct 2014.
I’ll try to direct link to that:
A relevance test of a gasifier systems design is if others can build and operate them.
Arvid Olsen @tritowns consulted with StephenA. and made up many different sized and applications-use gasifiers used wood chips.
You system Darron Booth may be useable with wood chips directly. Or could be internally modified for them.
The chip sourcing/making clues any of these fellows and others would say is make the wood chips from hardwood stocks when the trees and bushes are in winter sap down.
Making your chips if you stip back to not putting into the chipper twiggy stems; whisker branches; leaves &needles; and thick barks you will be far ahead for direct using of the chips made.
Regards
Steve Unruh
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Well, my power just went out and I’m not prepared. Lol 
I got to go get some gasoline.
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