I learned that just when you think you have this woodgas thing figured out try something new and you will learn some more.
When I was doing my first simple fire demo we decided to try some slipped charcoal right out of Carl's truck. I did not size and grade the charcoal, I just cleaned out my charcoal and dumped his in.. Well, off I went with the demo. After trying and trying to get the weak gas to run the generator, I must have pulled the starting rope 30 times, I noticed that the paint was rapidly burning off the front of the 5 gallon can used as the gasifier. I checked it with my laser thermometer and found we were up over 500 F on the surface right above the intake tube. I shut it down immediately - an apparently none too soon.
After letting it cool for a while we opened the lid and dumped out the charcoal into another metal bucket and found about one inch of the stainless steel "sacrificial" nozzle melted into a puddle. Hooboy... The crowd's eyes were big and there was no usual applause. I got thinking about it and came up with the idea that the charcoal bits were just too large for this application. It seems logical that the large particles allowed more air (too loose of a car-bed) to circulate between the bits and surely made the unit into a rapid-deploy smelting furnace (heater-mode) instead of pulling the charcoal gas out of the reactor to use elsewhere in the generator. It took only a few minutes from light-up to meltdown. It was surprising...
We dumped some remaining unused random sized truck manure over a 1/2" hardware cloth mesh I brought and resized the charcoal down to a smaller more evenly sized feedstock. Then we ran it over a 1/8" screen to let the fines fall through. (garden feedstock) Gary's grandson Colton really enjoyed screening the charcoal. I mixed the resized charcoal with the charcoal I brought made from wood pellets. I also noticed that the corner of the plastic air breather on the generator was broken off and was apparently letting in more air into the mix than usual. Gary got some electrical tape and we fixed it up right quick. After a few more pulls to get a new air/gas mixture setting the thing fired up perfectly.
We ran the generator for almost two hours non-stop. Cool runnings, man! I fired it up a couple more times during the day in my usual way with the now properly sized fuel. It was all good, a couple of one-pull starts. Finally... All said and done I burned about an inch an hour of charcoal from the 5 gallon setup at little to no load on the generator. We did charge Bill's battery and ran a light bulb, but that is a very small load. It would be nice to try it again and increase the load and find out just how much power we can generate and how much fuel would be used.
The variables are many. And we all learned a good lesson on feedstock sizing. The experiments could be endless with this setup. But the point of this unit - the way I intended and built it - was for experimental demonstration purposes only. I wanted a unit that was bare bones, cheap and easy to understand. It is designed as a teaching unit (first me - then others). It looks as close to a living diagram drawing as possible. I would not use this setup for extended use. It is amazing how many times I have demonstrated it in the past month and it is still A-ok. (I will need to make a new sacrificial ss nozzle though)
I had a great time... I rarely have anybody to talk to here on the homestead so I got my fix for a while. Thank you all who came and shared their joy of woodgas.
I guess I'm gonna have to figure out the video thing at some point soon...
I bought the remaining steel tube for the other half of my rails for BioWoody yesterday and hope to have that part done soon. A special thanks to Gary for sharing a water tank with me for my truck gasifier housing. (I'll get even some day) My truck is turning into a group project now. I have used saw blades from Carl & Doug, a burn tube from Greg, and now a housing from Gary. I hope I can get mine running half as good as ya'lls. What a great group. I am blessed to call you friends.
And thanks Miss Beth for taking all the photos.