Properties of a good wood gasifier

Moisture and heat economy. Sounds familiar :smile:

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Shaking mechanism, …

https://youtu.be/dL9c6fuL13o

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That looks super slick!

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That is slick. What is the shaker motor from?

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Hi Tom, I used a magnetic switch from the starter, I’ll see how it works during operation. As you can easily see, another 12V relay is connected, which disconnects the magnet in the upper position, and the spring pushes the core down, …

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Silencer and air heater for additional drying of wood chips, …

I also tried to operate the asynchronous generator independently by connecting capacitors, the thing works, but a controller will be needed to control the voltage

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Today was a beautiful day in our places, but I took a short break from green energy production, I burned charcoal and filled it with wood chips from spruce branches, the generator was just bouncing off the power, …
https://youtu.be/LhS3X7DeoO4

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Fully functional!

Any idea about diesel/ wood ratio?

Condens from exhaust gas? Cool!:smiley::smiley::smiley:
Do expect problems with heat exc caused by condensing?

Did you fix the problem to shut the generator off when there is no power generated?

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Hi Joep, today the system operated for 4 hours and consumed 1.5 liters of oil and 15 kg of wood, constantly producing around 4 kW of power. The magnetic on / off switch works and turns off when the current drops below 1A, namely I added capacitors to compensate the reactive current (3 x 30 mF connected in a triangle directly to the motor), the current in the conductors decreased by 5A. My son Domen is trying to program a controller that would control the system, namely the mixing ratio based on the lambda probe, interval shaking, disconnection from the mains under conditions of low power, high temperature, maybe even a lambda signal. I do not understand what you mean, problems with exc heat?

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Supersystem. I love your aproach. Impressive!

You let the exhaustgases go through a heat exchanger to dry the wood? Does there condensate the exhaust gases? The 6 mm airline that is dripping?

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Yes, the exhaust gases cool down and the steam condenses and drains down the pipe, … the last waste energy for drying.

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Keep us posted Tone, running everyday? How are the controls doing? Fuelpump is set to max 10% or can it jump to 100% if there is no woodgas?

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Joep, I don’t start the generator every day, I’m a little afraid of the night cold, because I have water in the system, I have to make an isolated space in this place … I open the diesel pump only at startup, then limit the fuel gasifies in the nozzle itself and an air bubble forms in the system, then the engine loses power because there is no good ignition. The diesel limit must not be less than approx. 10%. As I already wrote, the asynchronous electric motor works well with the mains, and with added capacitors (3x30 yF) we compensate for reactive current and can also operate independently, only that the capacitance needs to be adjusted to consumption, which I have not done yet.

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Let me bother you a little more with my view on the shortcomings of the gasifier, namely the increase in resistance in the reduction zone and the problems at low load. In petrol carburettors this is solved with twin nozzles , the first small ones are for idle and the second large one is for full load , but I wonder why not use this in a gasifier ? I think that would solve a lot of problems, you may remember that I have already posted this sketch, but twice is better than never.

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Must ask, to come in from below with the air, do not you cool down the reduction then?

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Jan, if I analyze a little, the air coming from below is already quite preheated on the branched grille and at the same time the exhaust gas cools down, I will probably make an even larger grille for the next construction, so the grille is also an exchanger. The central nozzle will be made of a hollow drill for drilling stones, the inner hole is 7 mm, otherwise high-alloy steel is temperature resistant. Given the preheating of the air in the area under reduction, I do not count on a drop in temperature in the hot zone.

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I think it is a great idea, Tone. This design of yours might be more sensitive to an optimum size of wood chunk to prevent “constipation”. :sunglasses:

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Thank you Tone. Looking at your drawing I see what Mike is seeing. To little of a restriction opening for Charcoal and fines to flow through.
Let’s talk about the restriction opening, and what is happening here in milliseconds at this opening. This is a very vital point in gasification. It is a high frequency point, vacuum point, heat transfer point, and magnetic point for the gases and their structures to go through. Now we know some gases are bonded to together stronger then others. We will just talk about two gases right now that we are changing. H2O and CO2 in to H2 and CO. I am sure you and everyone knows that the Oxygen is removed from each. The important thing is the flow of Charcoal and fines ash needs to be a continuous movement through the restriction opening with out stopping. To put a picture in your mind. Think how lava flows. I am sure you have seen this on videos. That is what’s happening inside the gasifier. The Air/gas velocity is changing higher and lower all the time.
So looking at the drawing and you will see what Mike and I both see. A spot where all the things above can stop and plugged up. It needs to be larger at the restriction opening.
The drill nozzles is not helping with the restriction opening going up through it.
How about moving the restriction opening up to where the drill nozzle ends and make the pipe and opening larger and changeable for sizes.
Bob
Edit: also I don’t think the center nozzle will hold up to the heat that it will be subjected to. It will probably melt down. The Charcoal is white hot in this area. 2000 to 3000 degrees f.
Bob

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I think someone forgot about such a state of matter as plasma! :joy:
In factory gasifiers for trucks at 100m³ / h, produced in the USSR, there was a limit of only 82 mm and no one complained about constipation and insufficient power (compared to a limit of 150 mm).

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My idea of what happens in the hot zone is that pyrolysis takes place above the glowing embers and pyrolysis gases are produced which rise up the middle below the top and return to the glowing ember zone along the wall , in effect this is how the wood is cooked into charcoal which slides down , these pieces of charcoal gradually get smaller on their way down , as carbon is consumed in the reduction. The smaller and smaller pieces of charcoal mixed with ash will slide towards the restriction orifice where the gas velocity is highest, so this should allow the condensed fragments to move through the restriction orifice as well, but only if the charcoal is still glowing, if it stops glowing higher up in the fire tube, the condensation of the charcoal and ash under the flow of pyrolysis gases will cause a blockage occurring high up in the fire tube.

That’s why it would be good to have the air inlet close to the restrictor and also close to the centre , so the charcoal would always glow in that area and even if too much air came in it would be used up down on the grate to outgas the charcoal dust , a similar effect is used by a Swede in a separate room on the grid , Jan has attached a photo of this somewhere.

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