Barry, you have integrated the system beautifully on the motorcycle, it fits nicely, well, I don’t have much experience with charcoal gasifiers either, my friend Giorgio is an expert in making such gasifiers, but the closest thing to your gasifier is made by Matt’s units.
Your design where the air is fed through a “Christian flute” with holes on the top, and the gases are sucked down through a grate, frankly, is not the best. Why? A hot zone will form above and around the flute, it will be exposed to very high temperatures, and it will dissipate energy, and the walls are also close, here you will also lose energy, which is necessary for the formation of good gas. The ideal charcoal gasifier is a container, where superheated air is fed somewhere in the middle, here a glowing zone in the shape of a ball is formed, surrounded and insulated by charcoal. The air inlet nozzle is best placed at the bottom and insulated with ash (this is how Kristjan installed the flute) so that it is not exposed to heat and you do not lose valuable high temperatures. Another way is to install the nozzle sideways, as Matt does, and the gas is sucked out on the opposite side, and the ash falls down through the grate. What would I do if I were you? I would remove the flute, on one side I would install a nozzle of about 12 mm, and on the other side the gas outlet would be protected by a grate or mesh, the hot area will spread longitudinally.
Barry, Isn’t this DOW forum great? Hopefully with the help of Dave, Cody, Giorgio and Tone you are now getting the principles that will give you a go at a working gasifier. Remember Dave’s original advice. After a good leak test, change only one thing between tests so you will know which change is making a significant difference.
Before I forget, AFTER you feel that you have optimized your geometry and have a good chargas flare then think about a water drip for another big boost.
Bruce and Tone,
Wow, I really appreciate both of your responses and welcome your idea, as well as any criticism. This forum is great indeed!
I am, for sure, willing to change the nozzle configuration, whether it be plugging some holes, raising it higher or cutting it down into a shorter version, where air enters horizontally on one end, like Matt’s designs. Elements of Matt’s, among others, have been influential in my design. I could even change it altogether into an updraft.
As already mentioned, I’ve incorporated several good ideas (obtained from reading this forum), but I’m was never sure that the components I put together would work appropriately together. Compactness and reversibility was my main goal.
I hope to leak test the reactor in the next couple hours, then try to leak test other areas.
If everything checks out, I’ll start by tapping and plugging three holes in my nozzle pipe (maybe even just weld them shut).
I’ll try getting a flare again.
Finally, I may cut the nozzle pipe so that it only protrudes from the rear where those rear fins are-(This is actually the level of the current nozzle pipe anyway.). So that would end up being the new air inlet. I’ll just use the current air inlet as a second lighting port, or a place that Ash can be vacuumed out. There is already a SS grate built into the gas outlet just before the valve.
Thanks again, Dave Cody, Giorgio, Bruce and Tone for your suggestions.
And yes, Bruce, I am all about doing the water drip! You may have noticed the canteen above the dropbox. That will be connected to an IV drip chamber. Below that, copper tubing is to come down the frame down tube and coil around the left exhaust pipe where it will be tapped into the air inlet.
I didn’t want to spend a lot of time doing that, or some of my charcoal storage ideas, until I actually got the thing running.
Thanks, everyone
Regarding nozzle hole size, my charcoal gasifier uses a single nozzle with a 3/8" hole to run a Honda GX-340 engine at 3000 rpm. Its displacement is 337 cc’s, about half of your engine. Doubling the area would give a 1/2" nozzle. I think like others have said, you need to cut down on nozzle area. Really nice workmanship BTW.
I agree with the suggestions so far about nozzle area. Air velocity is important in charcoal gasifiers. Too much nozzle area will slow the velocity. High velocity makes the char glow deep red like when you blow on charcoal and that is when gasification takes place. Just my 2/100ths of a dollars worth.
Martin and Don,
thanks for the confirmation from both of you, This seems to be the general consensus. I guess my just under half inch hole size was about right, I just didn’t need four of them.
In the meanwhile, I have found some leaks and I think I’m going to have to redesign my spring loaded lid. This may take a while because I’m leaving town for a couple weeks, in a few days.
But with the information everyone’s given, I’m sure I’ll get this beast running— it just may take some time
modifications and time.
Hi Barry. Matt, on Thrive Off Grid here on DOW site has been working with a water to steam loop in his gasifier. Check It out. I have a double flute gasifier that I want to incorporate the steam loop into to super heat the steam intake air. This will help absorb the waste heat above the flute nozzles holes. He is getting some great results from it, with a better quality gases by turning of more water into H2 gases.
barry, also your hopper design is very nice, but not ideal, because you loose hopper space over the nozzle in the down sloped part of the hopper…therefore, think about , when you make a crossdraft design, that you have the nozzle in the part where the hopper is high, because there takes place the most consumption of coal…further, when it runs, is to think about filtering…with charcoal you have a lot of dust in the system…so best is when you can bring some umidity in to keep the filter medium in a certain umidity state, this binds the dust to the filter medium… Motorcycles with gasifiers - History - Drive On Wood!
meanwhile in the link some history in way you loose not the courage, i hope to see soon your motorcycle also in this topic…your yamaha is very nice vintage motorcycle…in summer riding with the motorcycle on country roads is really refreshing, and making a stop in some country pub for a ice cream…
Hey Bob,
I remember seeing the flute nozzle in my study, and yes, I do want to incorporate the steam — for sure! I’ve seen several of Matt’s builds. I might have to revisit what he has lately. Thanks for chiming in.
Giorgio
I was pretty fond of the saddlebag look, but it does have a few leaks (mostly because of that curvature at the filler opening).
Sadly, rebuilding the reactor might be the solution to several of my issues.
It’s probably really only a been about three months of part-time building to get to this point, and I knew it may not run right out of the gate.
I’ll be going away for a little while to be with kids/grandkids out of state, so I’m not sure when I can do the rebuild, but I’ll be chewing on these ideas. Maybe in several weeks (or even months) I’ll have a running bike to present. That’s the goal.
Thanks
Don, great reminder about air velocity. Somewhere in my pile of gasification documents I have a research paper analyzing the critical role of "superficial velocity.’
Robert, Please keep us informed about your steam loop mods. I bought a piece of that yellow SS flex gas pipe ( HIGHCRAFT 36 Inch Gas Connector with Fittings, Yellow Coated Gas Connector, 1/2" OD, 1/2” FIP x 1/2” MIP Connection - Amazon.com $7.33 for 36 inches. Also got the peristaltic pump and silicone hoses that Matt mentioned. I hope to incorporate into my Simplicity Baron. I could use some guidance.
Barry, You have got the old charcoal juices flowing around here. Enjoy the kids and let us know when you get back.
Will do Bruce, thanks again