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Page history last edited by jim mason 12 years, 2 months ago

First-Run Start-Up Instructuions for GEK v3.0



return to How to Build and Run the GEK Gasifier 


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.  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 don’t 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. 


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.





Start up Instructions

(Can someone please add pictures to this?)


These instructions assume you have completed the fabrication instructions here (if you welded your own) as well as the assembly instructions here (if you bought the kit complete).   Before your first firing, make sure you have your nozzles set to the correct height.


With the preliminaries done, now come the fun part.  Here's what you need to do to start making gas.



1. Insulation Fill

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.  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. Charcoal Prefill

You have to prefill the hearth of a gasifier with charcoal.  Once running, it will generate its own.  But for the first start, you have to provide it.  Do NOT ignore this step and just fill the whole reactor with biomass.  You will get a huge tarry mess!


The goal is to 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.


USE REAL WOOD CHARCOAL!  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 quickly.  You will see this as white smoke at the beginning of the start.




3. Ignition:

a) 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. 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.

b) If you have an ignition port, make sure that the charcoal is filled an inch above the ignition nozzle, and afix the reactor lid, and open the five air inlets. Introduce propane about an inch from the inlet so as to provide oxygen for the propane torch. Be sure to close the cap on the ignition port when reactor is lit.


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.  HIGH IS TOO MUCH FLOW for the default GEK configuration.  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.





Comments (9)

Ken Boak said

at 3:40 pm on Jan 20, 2009

Jim, List,

Tonight we fired up the GEK for the first time - 100% successful.

Filled cone with broken up lumpwood charcoal. Lit that with air blower on slow speed. Waited 5 minutes for things to heat up and added my trashy wood chip fuel, slowly.

Turned blower to full, and battonned down the lid. Slowly added more fuel. Had flarable gas after about 5 minutes.

Filled up the integral fuel space and had consistent good flare for 1 hour 5 minutes. Flare colour was orange/mauve.

1/2" of condensate in the cyclone jar - and about half pint of condensate in the plastic gas hose - outside temperature was 6C

Best gas produced when nozzle ring was about 850C. Had it rise to 1050C which meant that the fuel had bridged and requires some stirring and poking.

This low grade fuel needs constant poking - so a mechanical stirrer will be essential.

Not many tar stains - so looks like we have a winner.

Hope to post some pictures later.


Szabolcs Tarjanyi said

at 5:26 am on Feb 23, 2009


When someone want to the start up first, how can control( or set up) the air quantity? Isn't better solution only one valve for air not five?


(account deleted) said

at 2:58 pm on Mar 1, 2009

I supplied the materials to get Marcus Bryners GEK Version 1.0 pre-charged and first fired. We used wood ash as the reactor vessel jacket insulate material.
It took 12 Liters of wood ash to fill the inner and outer reactor jacket space, and fill the area at the base of the nozzle uprights aruond the cast reduction cone to a level 1" (13MM) below the top edge of the reduction cone, and then about 1/2 a liter of ash was worked through the grate to normalize and insulate the very bottom of the outer gas cowling.
It took 3 Liters of wood charcoal ( OAK and FIR) to fill the reduction cone with shaking down spreading onto the grate and then filling around the air nozzles across the hearth area to a level 1" above the nozzles. Combustion was started with a cup (240ml) of kerosene poured directly onto the center of the charcoal.

Jay Martin said

at 8:25 am on Mar 14, 2009

Hello all,

I have welded and assembled my GEL v2.3 and not quite sure how to wire the blower motor. I thought I understood
the wiring connection, but when I bring the different wires (red, yellow, and orange) into the circuit the motor speed doesn't appear to change, just the amperage draw tends to increase for the "higher" speeds. From what I understand, the black AND brown are both connected to the ground and the green AND one of the other colored wires (depending on the desired speed) are connected to the "hot" wire? Please correct me or clarify the required connections.

Jay M

bk said

at 8:35 am on Mar 14, 2009

Hi Jay,

I don't have one in front of me, but IIRC:
Black/Brown connected to each other (capped).
Green -> Ground
Yellow, Red, Orange -> Positive

We should have clearer instructions up on this. See if the above works, and I'll migrate it into this page.


Jay Martin said

at 9:29 am on Mar 14, 2009

B K,

Thanks for clearing up my confusion. You memory is correct. The max amp draw is still less than 10 amps for the high speed setting. This is better than the 40 I was seeing when wired incorrectly. It was always running at high speed.

Thanks again, maybe I will get it fired up yet today. I still need to wire in the 3-speed switch I found.

Jay M

jim mason said

at 10:29 am on Mar 14, 2009

jay, remember that the top speed on the fan is too much pull for the default 3" gek configuration with most fuels. this higher capacity setting is there to support expansion you might want to do later.

you should use the middle speed for your first run. you may want to use high to get the char going in the beginning and early in the run to get the temps up, then once things are going, go back to the mid speed. if you leave t on high you will likely overpull the bell. remember that you can see this by inserting the thermocouple probe through the bung in the gas cowling at grate level, and pushing it in over the top of the ss tubes, so it is right at the bell exit. your temp here should hover around 625-650C . this is the temp as which the reduction reactions end. if the temp goes much above this, you are not finishing reduction in the bell, and pulling it down onto the grate.

do post some pictures of your progress when you can. i put a page up for you here:

and remember to prefill with good char before lighting. not doing this is the most common mistake on first go.


john kinstler said

at 10:06 am on Mar 28, 2009


Trying to put finishing touches on gek. I'm trying to find switch that will work for the motor. Do you have a source that I might look into, or a specification that I can ask for? Not having much luck on that part. Also, after much hunting around, I finally found something at Home Depot for this "clay sealant" you recommend. It's called Duct Seal and is made by Gardner Bender. The it was in the electrical dept. The guy said electricians use it for fireproofing electrical ductwork seals. Is this something like what you are recommending? Because nobody at least three Home Depots in Chicago ever heard of clay sealant like what I thought you were describing.

But, other than, I'm getting close to finishing it up. Hopefully soon, we can starting running some tests on my junkmail fuel briquette system.


Jay Martin said

at 12:01 pm on Mar 28, 2009


I got my switch from a hardware store. It is similar to what you would find in a typical 3-speed floor fan. They had it in one of those sets that have lots fo switches and knobs in it. Mine was for 110v AC, but it works great for this 12v application. I did have to ask for some help to find it. It wasn't in the electrical department.


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