Carl’s questions pre-building a Charcoal gasifier for a 5-7hp engine

Small Engines Charcoal Gasification
#41

Thanks everyone, lots of helpful info.

I did think of this, and might just put a momentary switch on the wire that grounds the plug. Wouldnt hurt to have a way to shut the thing off…

We may both be confused, what configuration do you use on your air and gas valves, Koen? Are they plumbed the way I have it set up above, or do you put your “throttle” valve below the T and have woodgas coming unrestricted into the T opposite the air intake?

Do you have a picture of this setup? I am not sure I am following you entirely, but it sounds like you are changing the timing of the engine by using an independent power supply to fire the plug? I am not an expert on small engines, so I dont quite understand how the change in timing will change how the engine behaves. Now I am curious, though.

This may well be the case, I am more of a DC guy, so alternators are a little bit confusing to me. I suppose It would have a system to prevent the engine from overcharging the start batteries that it is designed to charge.

As for the diversion loads being a waste of precious woodgas, I disagree. My primary diversion is a 20 gallon hot water heater that preheats water for my propane on-demand heater, and once the thermostat kicks that off, I start space-heating my shed where my shower is. I am not sure if it is really very efficient, but If i can burn less propane I consider it a win.

This seems like a very good point, which I had not considered. I might actually think about mounting the intake manifold directly to the frame I am going to build, and then use a section of flexible hose to make the final connection to the engine. What do you think of that idea? That might make it easier to swap out valves and reconfigure everything anyway.

I went with the brass ball valve because it seemed the least prone to having parts that would melt. I know that in theory the charcoal gas should not be hot, but I wasnt sure if it would be better to err on the side of caution. At some point the engine is going to start running poorly if the gas is too hot, right? Has anyone tried to measure the upper limit for gas temp before an engine either stops running or gets damaged?

Haha, I was looking at a 24" model, but now that you mention it… I DO want to be able to roll 36" material! :grinning:

#42

Hey OrCarl, nice rainy day,eh.
It is well proven that an actual 5 horsepower engine will only be able to belt drive generator make at most 1000-1200 watts.
Now factor your 5 horsepower back for charcoal gas fueling a low compression; flat head flows restrictive; somewhat worn-out engine and you will do well to make 800 watts charging. Hope for at least 500 watts.

No problem on the pre-ordered 24VDC “one-wire”. When/if you wish I can step you trough too making it fully externally controllable.
In my best Tom Cruise, Days of Thunder: “There is nothing I can’t do, and haven’t done on auto alternators”.
SI brushless. Dual 12/24 volt. Dual 24/32 volt. NOT SI - - - diode-less charging. 12,000 hour service life conversions upgrades. Totally, and semi-sealed explosion proof units. (marine and mining) Roundy, rounder car low drag 10 amp units. Bloodmoble refrigerator charging units. GeoMetro electric oven pizza delivery cars. Boys Scouts Christmas lights boats. Crane swing generators(alternator-chargers).
For 16 years it was how I earned my salts. Doing nothing else. After 16 years, I got bored. The newer factory units designs actually got better and better, more and more capable. But less and less repairable.
I moved on to other DYI power-making pursuet’s.

Use this first system as your trainer. Improve from then known experiences.
Very, very few only ever make just one system!
Regards
tree-farmer Steve unruh

5 Likes
#43

Hi Carl, I’ll concur with Koen that the throttle control should be between the engine and the “T”. Where you currently have it will probably work, but for some reason I do feel it is optimal. Do not worry about too much chargas heat at this location. The chargas heat remains fairly constant until the charcoal bed gets depleted to a certain point. At that point, the temperature starts to rapidly rise. This is also the time when the CO can escape from the charcoal reducing zone and enter your engine as CO2. In other words, when the temp gets up to 150 or so, shut it down. Therefore all of your fittings on the engine can be made of plastic. I use plastic because I keep the carburater in place and since it is made from pot metal, is inherently weak. Since your arrangement is directly screwed into the engine block, the weight is really not an issue.
Go ahead and buy a slip roll, but a 5 gallon sheet metal pail with a lid will get you going and will be a lot cheaper. For now, I’d recommend a bottom nozzle made from a 1" pipe flange. Don’t worry about nozzles for now, just get the engine running on chargas. I’d even tell you to forget about the filter for now. Use a 10 foot legnth of sump pump hose to connnect the gasifier to the engine. A lot of the dust will settle out in the pipe.
So,oooo with a five gallon steel pail with a gasket lid, two pipe flanges, a short 1"pipe nipple, eight #10 screws, a little RTV gasket material, 10 feet of sump pump hose and your present engine set up, you are ready to run. Whooops, you also need the charcoal graded to 1/8" to 3/4", and then you are ready to run. With all that material at hand, you should be able to get this engine running in three hours.
Ready?
Gary in PA and also a Tree Farmer (love those trees)

7 Likes
#44

This is excellent advice, and I will try and provide some meaningful measurements and results for anyone else who decides to go where i am headed. I think I may have hit a bit of a bump in that the alternator that I received is marked as as 12volt model. I am hoping they will get it straightened out and send me a replacement. This is the one drawback to ordering things online.

1200 watts is the max rating of my alternator, so shooting for 500-600 watts seems like a good place to start. I found a 6" pulley that should let me get ~2.4x gearing once I get my engine actually turning and that might add a little more mass to the shaft.

I will make a point of sorting out some charcoal maybe sometime this week, and then i can start doing some testing on actually producing gas.

3 Likes
#45

You can buy all kinds of regulator if that is a GM alternator and easy and cheap to replace.

#46

Just heard back from the customer service department, and it sounds like the regulator on my alternator was switched out - but the sticker on the side still says 12 volts because that is the base model that they use. They say it should start charging at 800 RPM, so my 1:1 gearing might actually work. If not I can try the larger pulley.

2 Likes
#47

As a side note; the faster an alternator is turned the more efficient it is, to a point. I think the reason is that less current needs to be pumped in to the rotor. But that is a minor point right now. Keep going !

1 Like
#48

My goal is to build gasifier that runs on charcoal I want use gas with a tankless water heater in my house, considering all its advantages,if we believe this review . What advice do you have for my question?

#49

Doable, but using carbon monoxide indoors is no joke. High quality CO detectors required. I recommend an antique copper coil water heater. These were widely used along side tall copper tanks before WWII. I picked up a couple of these 30 years ago. They look cool and come with a gas burner that works great with charcoal gas.

1 Like
#50

I love my tankless water heater. What I would never do, is allow wood or charcoal gas in my house.

2 Likes
#51

Put the water heater out side and insulate it well. Get a large ag bag and. Convert it into a gas bag. Make a skeleton silo to put the bag in. Once a day or so fill the bag up with gas. The water heater can draw from the bag as needed.

             ☺
2 Likes
#52

I have always had gas instant water heaters in the houses i had in the UK they were dual units that also ran the central heating as well as well as hot tap water and the units were normally fitted in the kitchens or pantry out of the way , now living in Australia and was surprised to see that here they are nearly always fitted on a outside wall and running away in all kinds of weather conditions with no problems at all and no insulation , it would be a fairly easy job to re jet our unit for wood gas i would imagine ,
we also have outside ducted gas house heating and that unit sits outside next to the water heater , if only the wife would allow me to wood gas them both :joy:
The white unit is the water heater and brown unit is ducted heater .

20171127_115157
20171127_1151572655×1493 1.82 MB

5 Likes