Hello Patrick, we talked about you on the topic of using wood gas in a diesel engine, I saw your shots and measurements. Do you think it works well?
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It can even be quite beneficial because clean woodgas will help reduce carbon deposits in precup diesel…
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Hi Robert
Thanks . Yes it’s been a while , traveling around Aus in a truck and 23 foot caravan . So internet access has been limited .
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Hi Wayne and Jo thanks .
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Hi TS
Yes for a generator or stationary it works very well and will save you 80-90% on diesel . My system is still running in South Africa at another saw mill . The only thing they have done as far as I know was add an additional baghouse filtration system.
Thanks
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Did you leave the Chevy in South Africa or manage to get it into Australia? Or am I mistaken and you converted the pickup when you relocated?
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Thank you Patrick, your words also confirm my tests. Can you remember how much compression ratio your diesel engine had, how you performed power control with wood gas, and what the power drop was compared to 100% diesel fuel? Sorry for the curiosity. 
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Compression ratio does not really matter.
The gas mixture should always be kept too lean to burn without diesel fuel.
Gas should not ignite under compression on its own.
The best analog for this is too look at propane or NG injection in diesel engines.
This fuel has 25% less BTU than diesel fuel and has similar auto ignition properties to woodgas.
In theory the power loss can be ZERO because you are going to reduce gas inflow beyond 40- 50% in peak load to prevent the engine from going anaerobic ( not burning fuel and smoking badly ).
Your ideal operating range will be between 50% and 75%.
There a mixture of wood gas is co fired with the fuel and this will give you best power, cleanest emissions and fewest injector temperature problems.
Bellow 50% is where you might get into trouble with injector tip over heating.
In this power range you can burn significantly more gas than than diesel fuel.
You lose the ability to cool your injector with fuel flow.
In this range you will need to carefully monitor how hot the injector gets and reduce gas input as needed.
Matching the load to the engine is pretty important because it will determine where your best at substitution of diesel…
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Back to the coke battery.
I never worked in Coke making dept so I never really got to know the process.
Actually I avoided the place because of the high cancer rates…
I think its obvious because of the scales we can match not all the process is of interest.
But the heat exchangers to preheat the air inlet and the methods used to heat cells in stages are.
Also fuel size.
They are using a fine;y crushed coal product so it stands to reason we should also emulate this and keep pour wood size small and uniform.
Why is any video on youtube thats technical and interesting done by a fellow in India?
I’ll tell you.
Those Indian fellows are working a lot harder trying to get better than we do over here.
I have watched this several times and i am thinking about the end product.
Hard coke.
I got some in my shop I will take a picture of later.
Hi Wallace
Thanks for the comments on the diesel system ,
I did not have any problems with the injectors , admittedly I only ran the engine for about a year -10 hr days and 4-5 days a week so maybe with long term use it may fail. But I think because the Woodgas is a lot cooler burning than diesel it may not affect the injector tips.
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Hi Tone
Sorry I did not dyno test the engine for performance .
It ran the generator without a problem .
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That sounds pretty long term.
AS long as your not overheating the tips of the injector you can add gas until the power drops off with a fixed pilot injection system ( sounds like what you did )
Wood gas has more inert gas in it so peak combustion temperature will be lower than diesel.
The longer burn rate of the fuel means more work for the cooling system because the block is absorbing more heat.
What kind of diesel and injector type?
W hat was your typical load range vs nameplate?
I’m thinking and reading a lot on the subject of coking.
Temperatures and residence times adjuncts ect to make the coke hard.
I stumbled upon some notes about an east German coke plant built and operated for about 30 years ( 1991 ) that was based on Lignite.
This is very interesting stuff because its much more like wood that coal
I think it worth further reading.
Coke production methods, like the beehive kiln were once common but abandoned for more efficient and higher quality products
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7+ years later, and I’m still imagining the ideal continuous retort… This original idea is far too complicated for too little production. However, I’m still intrigued with the idea of an auger—albeit a horizontal one.
The current idea is more like a brick-lined pit with sloping sides, and would operate like a kontiki kiln (open air). An auger would live at the bottom of the pit and “pull” charcoal into another (sealed) container.
I can imagine a grate of some sort above the auger that would serve as both a screening mechanism and some weight relief for the auger.
Of course branches and other wood products would continuously be fed from the top at the same rate as the auger pulls from the bottom.
Above the pit, I’d like to build a shallow vessel (same footprint as the pit) for heating water or air through a baffle (maybe 4’ x 8’ x 4"), and in the general shape of a twin-sized mattress. I’m especially keen on using hot air for food dehydration. To be clear, this would be a large, walk-in dehydrator.
The charcoal would still need to be sifted of fines, but the grate would ensure nothing bigger than an inch would make it through until reduced.
I really like the simplicity of open air kilns, and extremely large batches could be realized without needing to cut the wood… i.e. branches of similar size could be thrown on top and will shrink, crack, and split themselves in time.
The part that gives me the most satisfaction is in the heat exchange vessel. Most of the flame from pyrolysis would be used for “work,” and not just blown off to atmosphere.
Anyway, that’s the current vision…
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I have a bunch of charcoal retort ideas banging around in my head as well. I think half the fun is solving all the imaginary issues. I know in my heart that an actual build would uncover no end of problems but that doesn’t stop the fun of running “Head CAD” designs to ever more complex ends.
I like a sluice gate (gravity fed one way valve kind of thing) to seal in the gases while allowing fresh material to enter the processer without too much mixing. A little air gets in and out but not that much and the mechanism is dead simple.
Bulk solids have always been tough to move through a process flow, even for the “big guys”. I like “pushers” over augers and conveyers. Imagine those arcade/carnival style coin pusher bar games but for wood/charcoal. When the pusher bar retracts, new material falls into the newly created void. The next cycle the bar pushes the new material forward which in turn pushes against the prior cycle’s material, etc, keeping it all flowing through the system without too much fuss. A little slope helps reduce back pressure but of course there is a limit to much material the bar will want to push.
My “Head CAD” design uses indirect heat from below applied to metal roofing panel. Troy, your “mattress” scale heating area is exactly what I had in mind, maybe even three mattresses worth in a line. This means the wood can be spread across a big surface area of panels, IE wide and long but with the wood kept shallow versus deeply piled for best heat transfer. Indirect heating allows the cooking chamber to be sealed so that volatiles can be captured for reuse as fuel.
If I’m really going for efficiency I’d counter-flow the heating exhaust with the combustion air. And of course the whole charcoaling unit would be insulated. In my head I’d use cheap perlite with a binder and/or surface dub.
Another sluice at the exit dumps the hot charcoal into a large sealed barrel to allow freshly made material to cool and/or be quenched. The pusher bar would be on the front end where things are still cool so the mechanics wouldn’t need to be heat tolerant. The pusher would need to generate a good amount of force but not with any speed. A windshield wiper gear motor would be plenty of oomph and is cheap/easy to source.
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If you are going to look at the horizontal auger idea. I don’t know if this is the same airlock system that was patented (but now in the public domain) or not.
http://wiki.gekgasifier.com/w/page/6123753/Horizontal%20fuel%20feed%20auger%20add-on
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Hi Troy on your idea of a kiln , mine is a approx. 30in square stainless steel box on legs with a sloping ledge inside to allow build up on sides to flow onto a auger ,no need for a grate as i start off by covering the auger with a mixture of charcoal and ash just a few inches will do and then i fire up the small sticks on top and once alight follow on with larger size wood and allow to get to around half way full before turning the auger to empty a little of the charcoal so as not to lower the height of charcoal too much inside that way allowing the charcoal below to cool off so when it comes out it fill into a open air container that i then empty into a sealed drum , on a much larger scale i am sure it would work great this is just a fire pit size really sort of proof of concept , i did post pics of it somewhere on another post i think .
Dave
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In case my description of “coin pusher” wasn’t landing. I’m thinking like this picture but with the system filling the pushed void with wood versus enticing nice people to drop a bunch of quarters to no end.
Augers can end up crushing the material to be conveyed and the spiral shape is complex to DIY. Pusher bars are dead simple and the mechanism stays at the cool end of the process.
Also if you want to heat a six foot wide swath of wood… it’ll take a lot of augers. Pushers are as happy with a two foot bar as six. For indirect heating you want surface area and I think pusher bars shine in that role.
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I was thinking about a pushing kind of like that but a rod of flaps from the top that stopped at 90 degrees.
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But this isn’t gasification, it doesn’t need to be as hot, and a conveyor chain with paddles on it might work.
I think the first continuous flow charcoal production machine was a vertical auger tower that flowed down.
I was just going to push from one side and keep adding material so that it came out of the other side. The pusher bar can’t clear all the material from the retort at the end of the process, but that is fine. It’ll be there for the next firing and already partially processed.
I don’t know if the back pressure will be an issue at five feet or fifty but there is obviously some limit before the material wants to back up and press hard against the top/sides/etc versus progress through the chute. I think I can get ten feet with a little downward slope to the chute and that would be enough. I can go wider or cascade two pusher bars if the dwell time needs to be extended or throughput increased.
The idea of a chain of pusher bars / flaps driven from a cooler or protected part of the retort is an interesting idea. I think just pushing from one end is that much simpler but I see the appeal of your system.
Stranded steel cable might work better than chain for your flappers because it doesn’t need lubrication and even charcoaling heat may challenge grease? Cable is cheap too vs bike chain or whatever. You also mention using a rod so maybe it may be you are thinking a “chain” in the sense of a sequence of flaps rather than using actual chain… in any case - I like cables in a hot zone.
Heat-wise, yea. I’m not looking for super hard charcoal. A gasifier will make short work of some residuals so ~600F brown charcoal is fine. I’d like to experiment with torrefied wood even. Solar dried wood (~150F+ and bone dry) plus some finishing with generator exhaust heating (800F+ EGT?) might get enough conversion to skip true charcoaling all together. I know about the water issue in exhaust - it may need to be indirect heating but maybe not.
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