In the continuing saga off no-smoke charcoal making, I’ve added air injection to the system.
In recent runs, I could tell the fire wasn’t getting enough oxygen. There were a couple reasons I knew this.
- when running just the stove, I got a red jet flame out of the top. A picture from a previous post:
If everything were running optimially, there’d be enough oxygen inside the stove that all combustion can happen inside the stove. Said another way, volitile gases waited til being exposed to outside air before doing their thing.
another reason; pretty much the same as #1, when making charcoal, I got a red flame around the paint can. I want it to be a nice bright flame under the can.
So I’ve added a supercharger.It’s kinda hard to see in the thumbnail, I drilled four small holes in the length of pipe between the cap and the coupling (actually, it’s called a nipple… heh heh, he said nipple ;-)). The other end of the pipe, but the valve is a connector that allows me to hook it to my air compressor.
Air flows from the compressor through the valve (the throttle), through the pipe that runs …
actually this is take four.
exit hole on top. Mistake. lots of uncombusted smoke
exit hole on bottom. Better, but still lots of smoke
pipe extention to inject smoke into the heart of fire. That worked, but the ducting I was using still leaked smoke.
Somehow, the thought of using an old paint can came to mind. I looked at my collection of paint and I found two that were bad. I took the old primer can with thick yogurt consistency. Plus there was only 1.5″ left.
I cleaned it out and drilled a 1/2″ hole in the bottom for the pipe. Notice the elbow to reduce the chance of stuff getting in there. Also the small hardware cloth cage to ensure a clear path to the pipe. The outside of the can is a 3/4″ wash with threads cut into it using the pipe thread cutter I got from Harbor Freight.
Here, you can kinda see the pipe extending down into the fire.
The first batch had some smoke, but I suspected that’s the coating on the can burning off.
The results are pretty good, though not very much of it. Need to find a larger paint …
When wood burns, what’s really going on?
As I understand it, it’s a 2.5 step process.
1) Heating the wood causes it to vaporize into its component molecules.
1.5) depending on the temperature, the longer, more complex molecules decompose into simpler molecules. Larger molecules don’t burn as well. Axle grease doesn’t really burn. Gasoline does. If you heat up axle grease enough, it will break down to something that will burn.
2) The simpler molecules burn and the larger ones got up in smoke.
The point of my rocket stove is that the fire happens in a hot space and I get more complete combustion due to that concentration. That’s been working pretty well.
Over the last year or two, I’ve read a couple times about Terra Preta and how it can be used to help revitalize farming soil and also serve as carbon sequestration. After I hear about it again on Science Friday. In the story, the guest described the charcoal making process as simply heating wood to about 400 or 450 degress F in an oxygen poor environment. This was also something that I’d read and thought about before due to this site
So I figured, why …