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More efficient wood gas generator  RSS feed

 
Henri Lentonen
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Hi,

I have some ideas for wood gas.

First, peltiers could be used to generate electricity which could be used to produce hydrogen and oxygen from water. For those unfamiliar with peltiers, they generate electricity as the other side is cold and other side is hot.

I havent try this, but I assume it would give better burning of the wood gas.

Some gasoline cars have been modified so that with gasoline, hydrogen and oxygen are injected to the engine. The problem is that you need special equipment to adjust the ignition of the car engine, since hydrogen will burn much more quickly than gasoline, so the engine might even break down: so the spark will have to come later.

Also, you need energy for electrolysis to break down the water into gases. But if we do this with electricity from peltiers, it would save energy as heat from car is energy gone to waste.

But, this thread isnt about cars: but I am planning woodgas to power up my home.

I just copy here message I posted to other peltier subject:

Using peltiers is very good option as part in off-grid system if designed properly.

Since they last long (life age) and are easy to operate without difficult electric devices between and circuits.

Also they are cheap - 60W peltier is about 2 euros from ebay. Note that it is its maximum power consumption and you will not ever get 60 watts out of one peltier.

As told also here, the main problem isnt to heat them up but to cool down the other side.

Also, you should notice that too much temperature will kill the peltiers or at least, shorten their life age and efficiency greatly.

As they are semiconductors just like LEDs, I would not try to use them at maximum power: just like LEDs, it is best to use them with little power and have more LEDs to produce the same light, or in this case: have more peltiers to produce the same electricity.

There is special peltiers designed for high temperatures up to 200 celsius (392 F).

Normally you shouldnt use them above 80 celsius (176 F) - just like LEDs. That causes them to break down faster and they will produce less and less electricity over time - just as LEDs break down like this, that they dim down.

Also the max temperature difference in the cold side and hot side is about 70 celsius (158 F).

It means basically, that we cannot cool down the other side too much.

So these are the basic limits of the peltiers: we cannot heat them up too much, or even cool them down too much.

So instead we think how to make the hot side very hot and cold side very cold, we should think how we can make them work without that they break down eventually and "dim down" like LEDs - producing less and less electricity.

So like solar panels, we need a big panel of peltiers so it will work properly.

Best way might be, that water would be used to reserve the heat and the container would be coated with peltiers, which produce electricity even after the fire goes out. This will also prevent the peltiers to heat up too much, or that the maximum temperature difference wont be gone over.

So if the water would be 80 degrees celsius, then the cold side can be only 10 celsius, and not anymore below 10 celsius.

I am thinking, that instead of fan (which consumes energy) you would use the energy from the convection from the hot air of burning wood, to move also cold air into other place where it cools down the peltiers.

One option I think, would be install the peltiers inside ground so that the earth would cool down them.

Basic info about peltiers as generators:

https://en.wikipedia.org/wiki/Thermoelectric_generator

The video in the first post does not work anymore, here is another one:



---

I made this topic, not just couse of peltiers: but to also share some other ideas of maximizing the efficiency from woodgas.

I am not expert on the subject, so I will have to ask some questions also.

When the woodgas is formed with pyrolysis, how much pressure is formed?

Can we use this pressure also, for example: for turning a motor like in wind energy, and that motor would produce electricity also?

Or as I am planning a prototype, it would simply act as the aeration motor which provides spirulina the aeration.

Or is the pressure enough from the exhaust to act as aeration to spirulina alone? It needs energy, to pump air underwater.

So spirulina is a part of this, since when you burn things you end up with CO2, which is then: a food to spirulina.

As you feed the CO2 to spirulina, it will take the C and release the O2.

Of course, when you burn the woodgas: the exhaust emissions are too hot, so we just simply have peltiers now which will take away the heat and make electricity, and then the exhaust gas is aerated to spirulina.

The problem is, that too much CO2 will also kill the spirulina. So we would have to adjust the volume of the gas or have massive ponds of spirulina.

So is anyone with wood gas equipment willing to test what will happen when you put oxygen and hydrogen from electrolysis to the burning chamber? I mean just a stove or something, dont try this with car engines or similar, couse of the adjustement of the ignition!

Also would be cool to see someone to produce also energy with peltiers from woodgas.

I had something else in my mind... but I often forgot things. Maybe I remember it later or then it wasnt anything important!
 
Roberto pokachinni
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I don't have tons of thoughts about your ideas, except what immediately comes to mind when working with hydrogen.  It needs to be compressed in order to be useful, and a compressed cylinder of hydrogen is pretty much a bomb.  People do this, and they pay the ultimate price if they don't do it exactly right.  While it is a very effective potential fuel, there are reasons that it is not wide spread in use.
 
Henri Lentonen
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Thank you for reply Roberto!

But is there a reason why we just cannot make hydrogen at the same rate, we use it?

So then you dont need to compress it and no bombs.

Some videos of people burning hydrogen without pressure, why we could not use this also by adding the gases oxygen and hydrogen from electrolysis: directly to the air, that goes to the stove and burns the gas?








 
Henri Lentonen
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Here is more advanced equipment, but there also isnt any pressurize chamber?

 
Fred King
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Before thinking about designing a prototype you should learn more about woodgas. Adding hydrogen to it would not be a problem infact woodgas contains up to 20% hydrogen and it helps balance the other slower burning gases. A great place to learn about woodgas from people who are using it every day and have for years is Drive On Wood. Com fourm.  The people there combined have driven hundreds of thousands of miles and powered tractors and generators for years.  They're very helpful to someone starting out and the library section of the home page has enough information so you can ask the right questions.  Have fun. Fred
 
Henri Lentonen
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Yes I have read that much, that it contains hydrogen.

So adding more hydrogen and also: oxygen, would be good, yes?

And when we get those gases: from heat, with peltiers and water electrolysis, it makes the wood gas burning more efficient.

I have so much already to read, from everything else: but thanks for the advice for the library!

For now, I just leave this idea for those, who already are professionals in this area, so maybe someone will try how it works.
 
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