So those three hole are the total intake air going into the gasifier or is there another intake for more air?
I like it Matt great thinking on the water intake nozzle and auto drain water out.
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Nope the old version had four holes and that was plenty for the engine range the gasifier is designed to run. Having the 3 instead just turns up the volocity it will probably work better at atomizing the air with the water and do a better job at breaking the surface tension. I doupt the engine is going to care. But Ive been wrong before lol
If not then you can always punch more holes in the 3/4 inch nipple.
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The only thing that I think that matters is the total combined area of the intake holes needs to match or be greater than the ID of the nozzle. I think these 5/16 holes are about the same area or a little more the ID of the 1/2 pipe nozzle. I have not done the math as I can just look at it.
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I admittedly haven’t read all of both parts to this topic, but I’ve been thinking of another nozzle idea. Not sure how well it would hold up in the long run.
Imagine a water jacketed nozzle, but instead of the jacket always filled with water you have a water drip. At the 12 o’clock position in the nozzle wall you have a small hole for the steam to escape into the nozzle and go into the reaction.
The jacket is essentially there just to hold in the water drips and allow it to boil away, and the vent being at the 12 o’clock position in the nozzle wall is so only steam is injected. My line of thinking is instead of worrying about cooling the water for the jacket and metering any steam generated, you just meter the amount of water added. Since there’s always a vent it shouldn’t run the risk of overpressure.
Just an idea that’s been rattling around in my head.
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Yup thought of this too and would like to experiment someday with it. The only reason I have not tried is simply the complexity of it verses the simplicity of current design. But yeah the more steam we can inject while sustaining temp parameters for reaction = more powerful / reliable gas output. I really think we can push water injection much farther than any current system. Based on what I have learned from this years CFX I think we can achieve 50/50 gas energy density. (50% from water and 50% from charcoal) If that can be achieved charcoal will be hands down more efficeint than a direct wood fueled gasifier.
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I think it will self regulate too. You just dump the water in full bore after the nozzle is up to temp. The water jacket will need to be sized correctly so its not over absorbing heat and cooling too much. Then it will sort of perkulate like a coffea pot.
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Or you just make the outlet hole small enough where surface tension is now our friend :). The steam isnt going to care how big that hole is as long as it can escape and not back feed the water tank.
Dang you!! now I got to build it!! lol
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I figure if you begin the drip when starting up you’ll have a good prime inside the jacket, and the drip will just ensure it won’t overfill. It would take maybe 5 minutes from light for the water to begin boiling I’d assume.
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You know I wonder if we were to use the ceramic gasket material inside that chamber it would act as a wick. Then it would surely self regulate plus it would make building it easier. Think of the kerosene heaters with the wicks. I might be overthinking but this maybe a plan B if flows are difficult to control without a wick inside.
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Either the gasket or maybe fiberglass wool or rockwool?
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Yup might be over kill and over thinking though. But yeah anything that will hold in there should work.
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It seems like something to experiment with. One of my worries would be the nozzle acting as a Venturi and sucking water through the vent hole. Especially if it’s overfull. A wick would help I think.
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Sounds like a feature, not a problem 
. Call it a “main metering jet” and you’re off to the races. Add a needle valve to regulate the self-regulating. I should go look for a small-engine carb that wouldn’t rust (unlikely as that sounds).
edit: Oh, and put it outside the nozzle shut off valve, so water doesn’t get sucked in (or smoke blown out) at shut down.
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That wont happen though. That is one of the challenges for me at least is getting a stable flow. Water tension is preventing that is more of an issue. A wick also solves that as well.
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Another thing too is when this is running its going to be a little engine. Steam expands pushing water back while exhausting then it will suck water in, then water hits hot surface, then flashes to steam and repeat.
If water is able to make it out the hole. This goes back to my earlier comment where that chamber needs to be sized so that water dont stand a chance making it out.
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I ordered parts to build a direct fit in my 2024 CFX. I think I am goingt to add the wick too. But will terminate the top side. So the bottom 2/3 will have the wick and the top 1/3 will be vacant to allow the steam to escape.
I ordered a 1 inch to 1 1/4 pipe bushing. With a little lathing I can bore that out to fit a 1 inch pipe and weld to it. Then I ordered a 1/2 inch pipe for the nozzle pipe section. This will extend one end to the other and Ill put a cap with the holes so it will have a flash back arrestor. Ill drill and tap a hole in the 1 inch pipe on the outside of the bushing adapter to fit a compresion fitting the water inlet. Then Ill probably punch a few 1/8 inch holes along the top of the nozzle at the 12 oclock possition for the steam exhaust.
I at least know already what the current nozzle can crack / or water cunumption rate is per hopper fill. So I will know right away if this improves anything.
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Kind of weird this discussion should pop up when I was thinking of doing something very similar for my saw mill gasifier. I’m thinking about a three quarter nipple inside a square tube The tube would be cut along it’s top and welded to the nipple water tight and then a slit the width of a cut off disk in the nipple. I was concerned that the water in the square tube would build pressure and over-dampen the reaction but the rockwool should prevent it from geysering. If it doesn’t work I will just screw in a nipple with a hexaloy tip.
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I think that this boil-off idea will work well, since gasifiers like the Pederick Plate used a similar idea. The water drip would hit the plate instead of trickling out.
Same for the Flutes some of us have made. Only issue with the Flutes is the water drops skate across the hot steel and are likely to slip out.
I do think this “Drip-Jacket” nozzle idea would be a bit quicker to generate the steam. It’ll be buried in the heat of the reaction.
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Yup this is why I think the CFX is doing so well this year. Since we changed the drip tube to the center and how the air flows over the tube. Also I extended the nozzle jet a bit so its longer. So all together the water is spread out and better atomized but also has a longer travel so it can evaporate fasterand fuller allowing more water flow; all while without it over running directly into the reactor over cooling it. Im hoping this boiler jet will produce more steam and displace the oxygen more. So instead of just using the water to cool we are actually cutting down the amount of oxygen instead. This means less oxydation consuming charcoal while boosting the H2 output and CO production from this reaction instead of the Co2 conversion from oxydation.
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Hi Matt, All
To give some helpful understanding…
The added water / steam should be balanced towards a stable reduction temperature to avoid melting the nozzle or clinker forming from exceeding the ash melting point. (which is different for each kind of feedstock )
The only thing you are replacing is the amount of nitrogen from the air, passing thru towards the final gas content.
A “perfect” gasifier gas content would be between 30-33% CO gas if it would be carbon only.
The oxygen of the air is needed for the oxidation carbon to CO , to generate sufficient heat for the process.
Now, if you could preheat the water/steam , by any means other than the oxidation temperature required, the moment it touches the glowing carbon, then it would produce H2 and O molecules, where as the H2 passes thru, enriching the gas with hydrogen, and the O would combine with C to form CO.
Coz i play a lot with different setting / many types of gasification, i found that its possible to preheat the water to steam with the exhaust heat and the surface heat around my nozzle.
With this you can reach gas contents , in the simple form, up to 40% CO and 25% Hydrogen. reducing the amount of nitrogen in the gas content.
To cool the gas down, as much as possible, i use an intercooler system, wetted outside , where as the water from the wetted outside is used to go into the nozzle thru the heating / steaming cycle…
Many things can be done playing around with those different functional cycles.
Hopeful this is in someway helpful for your future designs
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