Introduction: How to Light Up a GEK Biomass Gasifier
You've now completed fabrication, assembled all the pieces together, so now comes the fire. Here's what you need to do to start making gas.
Before you start, and whenever you run a gasifier, please remember the following . . .
Warning: A gasifier is a dangerous thermo-chemical device. Like most useful tools, it will do damage if used incorrectly. A gasifier purposely generates carbon monoxide and other dangerous volatile organic gases as an interim step before complete combustion of the gas in a flare or engine. Acute exposure to carbon monoxide can be harmful or fatal. Engines like carbon monoxide. Humans do not. Carbon monoxide is colorless, odorless, and will quickly colonize your hemoglobin, leaving no sites left for oxygen to land. Exposure to other VOCs is similarly problematic. (In short, it is somewhat like smoking cigarettes, just exponentially worse.)
So dont be an idiot. Always use a gasifier outdoors, and with extensive ventilation. Always stay out of the smoke and/or produced gas before it is combusted. Know that this is NOT typical campfire smoke. Do NOT treat it as if it were. The carbon monoxide concentrations in gasifier gas are higher than in other "smokes". You can get in trouble quickly, usually before you realize it. SO STAY OUT OF GASIFIER GAS AT ALL TIMES.
Always have a fast reacting carbon monoxide meter in the area where you are working. Ideally, hang one on a tether around your neck. Carbon monoxide meters are available at more hardware stores in the smoke detector section.
Step 1: What You Need
Here are the things you will need to start the GEK
1. Charcoal. Real charcoal, like mesquite BBQ charcoal. Or left over charcoal from your fireplace. Not pressed charcoal briquettes.
2. Propane Torch: One is minimum. Two is better.
3. Insulation material: a bag of perlite, ash or charcoal fines to fill insulating annular ring in reactor.
Step 2: Making Fire
With the preliminaries done, now come the fun part. Here's what you need to do to start making gas.
1. Fill the annular ring in the downdraft reactor with insulating material. This can be charcoal dust, ash, perlite, pumice or kaowool.
(Optional: You can also fill the inert area down in the bottom around the outside of the reduction bell if you like. The material in this area does not move, and is only there to increase the insulation around the reduction bell. Thus you can use ash, perlite or pumice in here also, but likely not kaowool. Just stop about an inch below the reduction bell lip. You do not want the insulation material getting into the reduction bell. Upwards from here should here should only be charcoal.)
2. Fill the bottom of the reactor, as well as the reduction bell with charcoal. Use chunks of about .5" - 1" cross section. No dust, as that will foul the reduction on start. Fill all the way up to about 1" above the nozzles. Make sure the charcoal fully filling all the lower spaces and nooks and crannies. Turn the ash grate vigorously to settle things. Shake the GEK a bit. Be rough.
(It is important that you start with real wood charcoal, not Kingsford or the like, which is mostly pressed coal dust. Get some charcoal from your fireplace or firepit, or mesquite BBQ charcoal. Make sure the charcoal is fully pyrolysed. To the degree that you use imcompletely pyrolysed charcoal, you will get tar on start up. To the degree you use wet charcoal, you will have steam on start up. Charcoal is very hydroscopic so it is likely your charcoal will be wetter than you imagine. Such is OK as it will vaporize off. You will see this as white smoke at the beginning of the start.)
3. You will be starting the reactor with the lid off. This makes it easier to use a lighting fluid, which makes all things easier. I suggest diesel. But just a little. Like one or two cups. Try not to use gasoline, as it is lights with quite a "whoosh" Of course be careful. And do NOT have the top lid on when you light it, or you will get a boom inside and a biomass cannon out any open holes.
4. Close off the regular air inlets on the top of the reactor with 1/2" caps. We want the air to pull down through the open top, not through the air inlets, to get the charcoal going at first.
5. Recheck that all caps and plugs are in place. There should be no place for air to leak into the gasifier. Is your ash grate crank in place? The ash port lid tight? The lighting hole plug tight? All the instrumentation ports capped or with instruments?
6. Manual pilot light and safety flare. To help burn off the tar and steam smoke on start up, it is good to lay a regular hand propane torch in the bottom inlet of the swirl burner. This will keep a good large pilot flame at where the syngas enters the swirl burner, and keep things clean until the syngas flame will sustain itself. The extra flare will cover lots of mistake as well as prevent unburned gas from floating around your work area. Get a hand propane torch so you can do this.
7. Turn the fan on the middle setting. Look at the sticker on the motor to understand the wiring. Also, make sure you have a 12vdc power supply that can supply at least 10 amps for the fan motor.
8. Light the charcoal on fire with a torch or small rag dropped into the reactor. Keep your face clear, in case there is a "whoosh". Soon you should see a growing red region in the center of the bed, right above the reduction bed. Allow this to grow until it is reasonably established, and you have the urge to add more fuel on top. This usually takes about 2 minutes.
9. Take the air inlet caps off. The fire is now established and we want to move it to in front of the nozzles.
10. Now you need your raw biomass. Not more charcoal. You need biomass to have pyrolysis so that there is tar to burn in the combustion zone. Fill the biomass to the top of the reactor.
(As for fuel, wood pellets are easy for the first run. You are assured new ones are dry and properly sized. But they will likely fall apart if you let them sit in the reactor after the run. The steam breaks down their binding. You can also used small and squarish wood chips for fuel. Or nut shells. Or cut off 2x4s into 1x1 cubes.)
11. Check to make sure your lid seal is in order, and put on the lid. Tighten nuts until you are sure there are no leaks.
12. Turn the ash grate and shake the unit to make sure all the fuel is settled in. Be vigorous. You can't hurt it.
13. You can now turn off your propane pilot light torch. But keep it handy in case the syngas flare goes out and you need to relight it quickly. Remember do not breathe the gas when it is unburned. After it is burned it is very clean.
14. Check the fuel level every few minutes through the fill port until you get a feel for how quickly it lowers. Do not let it go more than halfway to the nozzles before you refill.
15. Try and break it. Figure out how and why it works. Change the fuels. Change all the internals around. Ponder the mysteries. Make it better. Tell others what you did.