Kristijan, I cannot disagree with you. If you will notice, I didn’t put an $800 nozzle in a simple fire. I priced one. When I learned what it cost, I ruled it out.
Someone else is trying the titanium nozzle (Bruce, I think). So, I am interested in how it works out for him. Scrap titanium is actually not all that expensive, if it holds up.
My point here is that the simple fire design is probably the cheapest and easiest way to get started in gasification. For those who like to learn by doing, or don’t have the patience or money or skills to construct a more sophisticated gasifier as their first project, I think it is a great option. And, it is entirely practical to run a generator from it, provide you come up with some reasonable solution to the “nozzle problem.” Based on what I have seen, Dave’s solution is reasonable and cost effective, and transforms the simple fire into a basic gasifier that is real world usable at low cost.
However, as a second or third project, I would heartily recommend and endorse some of the more sophisticated designs that can be seen on this website, including yours. And, for wood gasification, I would definitely recommend Mr. Wayne’s design (working on one of those, myself).
In fact, of the designs being discussed, the only one I would categorically rule out would be the FEMA design, due to the very high probability that it will make tar and gunk up your engine.
Joshua - I am no expert. But from what I have picked up so far, it is virtually impossible to “filter out” tar. The whole trick is not sending any to the engine in the first place. There are two ways to do that. (1) Make a charcoal gasifier, since the tar is already removed or (2) go with a design that can “crack” the tar by suitably high temperatures, such as the WK design.
I’m gonna probably go with kyle on this. I will continue my research. I have loads of free time and little money so: research research research until I find the most ideal cost effective solution.
Black iron pipe is fairly cheap. Out of 50 bucks worth (10 feet) and 6 inches of it at a time I should have more than 2000 hours worth of run time. That comes down to 2 cents an hour of run time.
A washable filter would reduce the run cost even further. I did look into the prices of tungsten and tantalum or even titanium. I don’t think the cost per pound is that high, its just its not a common material so the few that carry them online charge a ton to process it and make what you want. Some refractory brick could also extend it but i never had a lot of luck with stove brick. a year later it tends to break but it might just be what i get is low quality. I’ll give the simple fire a shot. Might buy a cheap harbor freight engine or the smallest champion generator i can find and just see how long it lasts.
I tried looking back on the nozzle thread last night to see if I could find any results on Bruce’s nozzle. Either I couldn’t find them, or he hasn’t reported them yet.
My best guess is that titanium won’t be much better than steel. But, you never know until somebody tries it.
l cant remember either. l know there was a discusion.
l work with titanium and l can tell you this. Not nozzle material. Althugh it has amazing chemical inertnes, it loves to oxidise at high temp. We have filters for wery strong acids made out of titanium but when you just scratch it with a metal object it sparks like a firecracker.
It was me… I chickened out and threaded the titanium tube to take a tig cup in front of it… Only 2 hours on it so no test results worth talking about yet. it seems intact so far. Busy working these days, sorry
David
My nozzle is 4 vertical holes in thick-walled copper tube passing through the reactor and sucking air from both ends. Copper because it has been used successfully for crude iron smelting.
“A suggestion by Dr. K. Smith on the possible use of copper tuyeres historically led to some experimentation with this material. Several tuyeres were forged from differing thickness of scrap copper plate and tested at a workshop in February 2005. … During this workshop, Sauder, Williams and McCarthy worked with a tuyere forged from 1/4 inch thick (about 7 mm) plate. The forming process created a conical shape that varied in thickness from roughly 3 mm at the air supply end to about 7 mm thick at the smelter end. … The interior diameter was approximately 20 cm in the smelter. This copper tuyere proved extremely durable. the high conductivity of the copper allows it to radiate away the heat its working tip is exposed to.”
I hope to have my MG running on this nozzle by the end of August. Don’t hold your breath, I previously thought I would have it going by the end of May. I fear that there may be a good reason that we have not seen copper nozzles in gasifiers (other than war-time scarcity). Time will tell.
Joshua - So far, my experience is limited. However, based on what I have observed, the rest of the system would last indefinitely (with the possible exception of the blower - others report failure at some point, and recommend having a dual gas path so that gasses only pass through it for start up, but not for running). With that said, this assumes that you don’t let the ambient temperature of the exiting gas rise too much beyond 120 F. I usually shut mine down when the lid gets 150 F. Using a grease barrel for the main reactor, I am getting about 1 hour of run time before that happens.
But that limitation is just because of the cheap plastic sump pump hose that is used to conduct the gas from the reactor to the filter. If you did that through some sort of metal pipe or flex pipe (or through a cyclone), then the radiative cooling would extend your run time significantly. If the entire setup was metal rather than low melting point plastic, I am not sure how far you could push it before the engine would start complaining.
Certainly, you wouldn’t want to push it beyond the auto-ignition temperature of CO (1128 F).
As a practical matter, I imagine you would want to stop around 500F.
At this time, I can’t give you a good estimate of how long it would take to get there, but I would imagine it is at least 2 or 3 hours. Maybe more. After that, it would be time to refuel, in any event.
An automotive radiator or the backside (condenser? Evaporator?) of an air conditioner with a strong 12 volt blower on it could cool it down real quick. I guess its just a matter of more heatsink surface area. I dont mind using electric to cool it. Especially DC. A nice K&N washable air filter would be a nice last line of dust filtering. A cyclone would be a first start to cool it down. Wouldn’t want to burn my filters. hmm. I will look into this some more tonight and start drawing out some plans. So as long as i can keep it cool and I have a big enough reactor I can get long run times? Really I would like to see if i can get 14 hours unattended. I know that will have some design hurdles alone but it would be very sweet to run the air conditioner for once.
From what I gather, these cause WAY too much restriction/friction losses to be useful on even the smallest of engines. I once suggested an intercooler like used for turbo induction applications in racing, which should give proper flow-through, but they’re expensive, and woodgas might cause corrosion in aluminum.
hmmm i guess I could always make my own. Use thicker steel pipes and fins or better yet, a long steel box with pieces of angled steel zig zag inside it to make it cross it a lot (not to small so you dont get the said restrictions) and some form of heatsink like a large aluminum one and a strong 12 volt fan.
Hi Joshua , if you are low on funds and have plenty of free time I would defiantly try a charcoal simple fire design for your first attempt at running a engine for generating power , if you can get your hands on just a few everyday items from a local scrap yard you could be up and running very quickly indeed .
Don’t worry about buying lots of black iron pipe you wont need much at all if you go with Kristijans nozzle design as I think that seems to work very well .
Intercooler works great for that application. Had it on my wood powered moped but havent run it long enough to see how long it wuld last. Made it charcoal powerd later.
ln a good system you can theoreticaly run your geny for days. This is the buty of charcoal. Set and forget. But keep in mind you will burn lots of charcoal, and you have to make it first.
Yeah thats what I am looking into now. Trying to figure out how long a smaller generator will run. Like a 5 hp engine or so.
Pretty sure a 55 gallon drum would get around 5-6 hour of run time.
I have been on the dow quite a bit talking about engine fails, and so far it has been failure after failure, and all on motors i have tryed too rebuild, allthough none of my motors have ever ben run on wood gas yet.And the motors i have installed without rebuilding lost bearings oil PSI from petro gasoline washing out the bearings from some of my past carb motors years ago. have fun building lots of good quallity experianced wood gas design builders of the WK design And some of the imbert type design builders have drove on pure dry wood for years, by knowing the signs of the 75% leaning part. That all comes with the have wood will travel quallity book.
Joshua if your engine can still run on gasoline figure out consumption that way. How much run time does a gallon of gasoline give you while under load? Now figure on anywhere from 11 to 14 lbs of charcoal to replace that gasoline. Volume will depend on species of wood you used for your charcoal. Best I’ve got to offer…
David Baillie