I have never burned pure hydrogen, so I may be way off here, but I seem to recall reading that it will burn with a nearly invisile/blue color, is that not the case?
I am maybe further muddying the water here, but I have also noticed that when you burn a propane torch at low pressure you get a really nice billowy yellow flame, but once you crank it up so that you have some velocity, it turns blue. Obviously the composition of the fuel is not changing, but clearly there is some factor -oxygen availabilty, dwell time in the reaction, temperature? - that is somehow changing the outcome. Anyone have a plausible theory that could tie all that together?
Billy, yes that’s what l am saying. That’s part of the reason why l put air preheat even on a charcoal gasifier. Kind a controversial since everyone tryes to keep the temp down in a char gasifier.
Carl, it gets tacky when we talk flame colour. You mentioned some examples.
You can kinda distinguish the woodgas flame colour from the video.
This is a video of the gas my current Mercedes gasifier makes. Its just char and water so no methane or tar in the gas, just H2 and CO. Should it be just charcoal, the flame would have no orange top, just that deep blue CO colour.
Regarding: sealing the leak between the grate assemble and the bottom of the reactor - The only fiberglass gasket I had was for a wood stove window, so I tried using that, with black rtv around the holes and tape joins, making sure it didn’t bunch up around the curve, but it still leaked air. I was afraid to tighten the nuts too much, as I had already stripped threads on one of them, so the nuts being too loose might have been the cause of the leak.
Anyway I took it all off and started over using the same product Ben pictured in the book, “Rutland fiberglass stove gasket cement”. I put lots of it on in between the two metal faces, and around the bolts and after it dried it didn’t leak.
I had fixed several leaks (I thought I had them all) and then I added 15% by weight of water to my 1/8’ - 1" charcoal (when mixing, much less dust with the water) and lit the reactor. The video shows the best results edited together. It seems like there is not enough suction from the engine to get rich enough gas to keep it going. There was a lot of condensation in the condensate collection shell. I have discovered one more leak just before the carb to fix before my next try. I’m wondering if I could improve the gas by plugging 3 of the 6 nozzles, which would make the reactor air speed faster, and thereby increase the gas quality. Another thing you have suggested, which I will try, is to have it running on propane (which it does well) and then slowly transitioning to chargas. I will post the results.
Hi Greg, reading your post, all signs point to a restriction. This will cause leaks to show up, more than normal condensate dropping, blower seemingly not able to pull hard enough and of coarse weak gas. If the gasifier can not breath, it will become a vicious cycle very quickly. As it becomes restricted and the blower or engine can no longer draft it; the processes will crash creating more tars and moisture, causing things to bind up even more, the gas can back draft through the hearth, causing tar from unprocessed gas to condense in the jets and else where.
So you are running a small engine in the 400-450 cc range?
Im going to assume the restriction is roughly 2"?
If this is the case Id leave the 6 jets, They should be somewhere around 0.28" tier opening or maybe slightly smaller as there are 6 and not the typical five as specked in the Imbert charts. If you do not have a restriction, check those jets and make sure they are not tar plugged. It sounds to me like you are having a clog some where.
Ok watched the video. Man it looks to me like that thing want to go!!
Looking at your valve set up, it looks like it is the same size as your gas going in? So generally it should be around 40-50% open. It looks to me you have 1 inch NPT fittings? If so 40% should be ball park.
It looked to me in the video it was on the rich side, when you bumped it up, it sounded like it want to take off. Sometimes when the machine is cold it will take time for everything to adjust as the gasifier is still warming up.
If you can replicate what you had there, try just bumping the valve open very slightly then do nothing. Listen observe. Did it ramp up or down? Then make another adjustment, stop, listen observe. As you are able to open the valve and engine starts to take off, it will pull harder on the gasifier, making better more potent gas as it warms up. As you are doing this it will reach a threshold and the engine will take right off.
Hi Matt, I have a 200cc engine. Gasifier has 6 jets, each is 19/64" (.3") diameter. Choke (restriction) is 2.4".
I’m wondering if the straw in the filter might be too dense. I used animal bedding straw which is chopped up quite a bit, maybe too fine. The pressure I measured after the filter is about -6.1"wc and the pressure in the hopper is about -2.2"wc, so there is quite a drop due to the filter and charcoal. The filter is designed for wood gas and since I am using charcoal (for the time being) maybe I can do with less filter media. Maybe less than the 4 layers of fine and coarse open foam and the chopped straw. I’ll check the jets for blockage, but I don’t anticipate any because there was no sign of it after the last attempt.
Yes, it is 1 inch NPT going into and out of the T with the valve. But the opening seems closer to 15%, where it performed best. Maybe on my next run, after I fix that last leak just before the carb, the valve opening will be closer to your 40% ballpark. I’ll try bumping the valve open slightly and then watching, and report back here. I appreciate your experience.
Ok yeah that engine maybe to small. I have ran the predator 212cc engines but they just dont pull hard enough and if you go any smaller on the gasifier things become very limited and its much more difficult. 200 cc is a bit small for this size gasifier. In my experience the Utility Gasifier had very close specs to your machine and 420 cc was the minimum engine it could run and marginal at that. I think you are going to need to get a larger engine in order for it to work. At least on wood, you may be okay and better off with charcoal with the lower volume. It is for this reason I have abandoned media filters, in my experience they do more harm than good. They just cause power robbing restrictions and as soon as they become even slightly restricted they can run away as they restrict the gasifier and it produces lesser quality gas. The only thing you can filter is the dust. You can not filter tar it is impossible as it is suspended in the gas. If I do run media i use very little just enough to get the ash out. But you should follow Bens advice on that, for me saving these small engines is not priority they are really expendable for $200 bucks. If I get a year out of one I got my moneys worth and Ill just get a new one.
I had assumed that it would be possible to scale down Ben’s gasifier by making all the openings smaller, fewer jets, smaller filter etc. Sounded logical, but maybe not possible in the real world. Ben says nothing smaller than 500cc in the book. But he did suggest I try charcoal with the smaller engine. I will try a few more times before buying a bigger generator.
Hi Greg, were you trying to start the genset with a load on it. If so just try it with no Eletrical load on the genset.
Also have you tried just using a blower on it on the suction side and try flaring it, now you have the leaks fixed.
The chopped hay could be to dense. Some open foam in the filter would be fine, you are just dealing with fine char dust when using charcoal in your gasifier unit.
And what Matt said, it wanted to run, make very small adjustments on the air mixing valve.
How long did you flare it or run the gasifier with the blower before trying to start it with the genset? On my charcoal gasifier I make sure it will flare easily.
Bob
Hi Bob, Yes, There was a lamp plugged in. I’ll try next time without anything.
I ran it about 20-30 minutes before the flare was strong. It’s hard to say an exact time because it flares easier from a wider diameter opening, I guess because the gas is moving slower. Also, it flares easier if I turn the blower speed down just before flaring. So, you are suggesting flaring from a one inch pipe, at maximum blower speed, and only then try starting the engine, correct?
I flare my gasifier to get it warmed up.
Then I shut down my blower and close the flare valve and open my gas valve to my genset and try starting it by adjusting the air. when it starts I make small adjustments to the air valve.
My charcoal gasifier is big enough to run a small vechile or a small genset.
Bob
If you can flare it at lower blower speed. Then that should be good to run your genset, it should be able to draw off the gasifier.
One other trick is to run the genset first and warm it up on it’s normal fuel. Then try starting it up on chargas.
Bob
For my filtering I use a series bank cyclonic final stage filter system. This has been very effective, as by the time the gas has reached this point, it is very wet / sticky. So when any left over debris hits these filters it like a fly landing on fly tape. They self wash, are non restrictive and are virtually zero maintenance.
On the Flex Power System there is an option for a marble bed filter with fluid wash system. It is very effective in cooling the gas and giving the moisture in suspension something to collect on to. Then after this the cyclone final filters aid in removing any left over moisture from this process.
When using just charcoal in your Gasifier you do not need to make real small like most charcoal gasifiers, because the wood size that the Ben Peterson gasifier uses normally cooks the wood into larger chunks of charcoal and then break down into smaller pieces as it moves down to the grate. If you put all grate size pieces in and above the nozzles it might consepate the fire tube and cause it to draw a higher vaccum to run. This happens on down draft gasifiers. I still think the filter media might be be the problem though, just to much restriction for the suction vaccum on the the genset to pull gas efficiently.
Bob
