Charcoal Gasifier for Generator

Small Engines Charcoal Gasification
#161

Post Mortem

This morning, before work, we decided to open up the gasifier to look for clues.

The first thing we found was that the filter media was causing an obstruction.

filter clog.jpg1600×900 456 KB

The fiberglass insulation was pressed up tight against the gas inlet. So, all of the dust and moisture just collected in one spot. Fortunately, it wasn’t sticky like tar. Just water and dust, apparently.

Then we took off the lid to the gasifier. I don’t know if you can see it in this picture, but there was a lot of condensation on the lid. I was really amazed that there was that much water coming from the charcoal. The charcoal itself felt bone dry.

lid mosture.jpg1600×1383 635 KB

The big surprise came when we dumped out the charcoal. Surprisingly, it had consumed less than a gallon in the 20 minutes of starting and running.

But in that short amount of time, we had completely melted our nozzle.

I knew that “nozzle erosion” was a concern with these systems, but I never dreamed that we could turn steel into slag that quickly. Here is what the nozzle looked like.

nozzle melted.jpg1600×738 312 KB

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#162

Thanks Kyle
I haven’t got to this point yet but your struggles teach me

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#163

A few fixes

Based on these findings, we made a few fixes.

We made some screens to hold the insulation off the inlet and outlet of the filter.

I was amazed at what a difference this made to the amount of air blowing through the system.

Previously, I had just assumed that the blower was weak when working through all the charcoal, the filter, etc.

Now that the system was blowing with some force, we leak checked it again. This turned up several air leaks that had not shown up with the weaker air pressure previously. We got those all squared away.

We replaced the nozzle. But just with another black pipe nipple since we didn’t have access to any stainless steel.

Also, we took Dave’s excellent suggestion and took the starter rope off the generator.

We tried cranking it with a drill on gasoline. It was really hard starting this time (not because of the drill - just ornery). But the drill worked fine. We would have been blue in the face if we had hand-cranked it this time.

Now that we had tightened up the ship, and had a new way of starting, we were ready for another test.

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#164

The 3rd Run

This evening, we tried a third run.

The increased airflow made a big difference when we flared the unit. Previously, the flame from the flare stayed in the flare can. Now, it leaped out of the can 3 feet in the air.

Big Flare.jpg1600×2844 1.03 MB

We decided to “go for the gusto” and try starting entirely on charcoal gas (no gasoline).

We had already run the generator dry of gasoline about 30 minutes before in a run-down test.

We cranked on it with the drill, and fiddled with the gas mixture. It took a while to start, but I can’t say that it was any worse than starting on gasoline had been about 30 minutes before. The sweet spot for the mixture was right around half-open (this contrasts with our experience the night before, when the air needed to be almost completely shut off, probably because of air leaks in the system).

As you can see, the fire heated up to a blinding glow very quickly.

nozzle glow.jpg1600×1221 487 KB

With the melted nozzle on our mind, we didn’t waste any time throwing the exhaust gas to it this time. That moderated things to a more mellow glow.

We didn’t have to mess with much of anything, or shake the barrel or anything else. The thing just sat there and ran like a top. After things were all warmed up, the sweet spot seemed to be having the exhaust return valve about 3/4 open, and having the air intake between 1/2 and 3/4 open.

Even with things moderated this way, I began to be concerned that we may be melting the nozzle again. As an experiment, I decided to open the exhaust return valve fully.

This cooled things off enough that we lost power, and the generator died. But it had been running perfectly for about 14 minutes. Much better all the way around than the previous night. And we were super-excited to have started up completely on charcoal gas without any petrol or ether helping us along.

We were very happy with these results.

PS: During the run, we found a new leak. The bilge blower has an exit for the wires. Charcoal gas was blowing out of this small opening. It needs to be plugged with RTV.

Anyway, I am anxious to share some video of the gasifier in action. I will try to figure out how to upload some videos.

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#165

Don:

The generator seems to have an automatic throttle associated with the governor. I don’t know if I can throttle it manually without giving it a fit?

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#166

David - You nailed it. Melted nozzle.

#167

Dave - My big screen is 1/2 inch by 1 inch.

Now that I see that all of this stuff is going to work, I am going to go ahead and invest in some properly sized screen materials ordered from the internet.

And you nailed it too. Melted nozzle and air leaks.

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#168

Thought you would like this… we all have one…

IMG_20130218_203526.jpg2592×1944 1.17 MB

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#169

Nozzle Question

I have seen talk on some other threads about the various experiments some of you have tried with different nozzles.

Have any of you found a solution that you consider entirely satisfactory?

What kind of life are you getting out of your nozzles?

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#170

Ha, that’s the luck.

I was trying to test uploading a video to youtube and linking to it from here.

I wasn’t sure which video I uploaded (it took forever).

As luck would have it, it was the one video that I really didn’t plan to share.

This is the chaotic one from last night when we were having all the trouble keeping the gasifier running, shaking it, spraying ether, etc.

Anyway, enjoy the comedy…

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#171

Hi Kyle , good to hear your sorting out problems so quickly .
On the nozzle front , don’t even worry about stainless steel pipe , black iron pipe or galvanised pipe nipples will work just as well as a nozzle holder , I am not sure what diameter pipe you are using for your nozzle , but if its 1 inch then I use these http://www.ebay.com.au/itm/WP17-18-26-sery-tig-welding-Short-Alumina-Large-Gas-Lens-Nozzle-53N89-5PCS-/310387546430?hash=item48448a193e:g:40IAAOSwbqpTrhYW

All you need to do is fix one onto the end of your pipe nipple and these will last many many hours of run time on full belt ! ( mine have lasted over 100 hours a lot of the time )
I encase my nozzle in refractory cement so that the pipe just rests on the top of the alumina tig nozzle , that allows just enough heat to transfer along the pipe to aid turning the water drip into steam , just remember that these nozzles will break from thermal shock if you put stone cold water spray onto them while running , another reason I encased then rather than thread them onto the pipe is expansion rates of 2 materials or different .
I will also say that I find a water drip better than exhaust return for engines needing that extra power boost , it just seems to work better for me , although stick with what you have till you feel a need to try something else .
Dave

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#172

Here’s the video

I meant to post. This is my very first run of the generator after getting the gasifier finished. As you can see, it ran more smoothly the first time than it did the second time.

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#173

Great job Kyle. There’s no better feeling than to have an engine run on wood/charcoal the you processed in a bunch of cans and tubes you fabricated.
From my understanding, the sizing of your fuel is a big deal. I witnessed it first hand in Arkansas with @AlDenninger. He had melted a stainless steel nozzle due to slightly larger fuel size. When I get my charcoal gasifier built, I want to separate 2-3 different sized charcoal, if that’s possible. But just to see the difference. My guess is ¼-½" is going to be optimal. He also had a piece of stainless that he rolled to wrap around his nozzle in hopes to slide a different one on as needed.
Another power boost I have noticed has been a waste oil drip at the inlet of the gasifier.
Thanks for sharing your experiences

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#174

Dave - I am having a little trouble visualizing your nozzle setup. Could you post a picture or elaborate?

#175

Hi Kyle

The filter media in the 5 gallons gamma is the mineral wool?

No fabric to contain it?

Thank you for the many explanations that you are giving your experiences .This helps me a lot

Thierry

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#176

Looked in the gasifier to see what last night’s run did.

Sure enough, the nozzle was melted again, and we were trying to be careful that time.

Also, the little screen at the top of the gasifier was pretty stopped up. Surprising, since it didn’t do that on the first run. I am assuming that it happened because the gasifier is breathing better now after fixing the filter restriction.

Anyway, looks like my top priority at this point is solving the nozzle problem.

The most convenient solution would simply be a screw in pipe nipple made out of high temp. material.

I am having a couple of nipples quoted.

A tungsten nipple (custom fab) with a melting point over 6000 F.

A titanium nipple (off the shelf) with a melting point of around 3000 F.

I figure the tungsten will definitely be too expensive.

Will have to see on the titanium.

My fall back plan is to take some of that soft refractory fire brick, drill a hole through it, and slip it over the nipple.

I might also try Dave’s TIG tips once I understand better how he is doing that.

#177

Yes Trigaux. Just fiberglass batting at this point, like you would put in the wall of a house.

Might add some wool fabric on either end later.

Have wire mesh holding it away from the intake and exit port.

#178

Ouch!

Just got the quote on the tungsten pipe nipple.

“approx $682 per pc without the threading.”

#179

Kyle I have had pretty good success so far with this nozzle

a-nozzle mount.jpg1200×675 265 KB

I turned down a nipple so the ceramic TIG cup just screws on. Cross slits in the nipple hopefully helps for expansion.
A stainless sleeve protects it. I have about 20 hours on it now - so far -so good.
b-assembled nozzle.jpg1200×675 216 KB

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#180

I’m enjoying your thread Kyle. When looking at more rugged gasifier nozzles, I came across titanium bicycle parts.
Here’s a used pipe 27mm dia. that is reasonable. Might be worth a try. Good luck on your build.

http://www.ebay.com/itm/KORE-LITE-2-SEATPOST-27-2-MM-BLACK-AND-SELLE-ITALIA-FLIGHT-TITANIUM-SEAT-COMBO-/111964388797?hash=item1a1198fdbd:g:Gw8AAOSwGYVXCbzt

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