[Gasification] Gas-o-Fire , adjustable burner

[drew]

Daniel Chisholm wrote:
> On Wed, 2007-17-01 at 11:16 -0800, drew wrote:
>   
> I thought that your primary air adjustment was a pretty slick idea.
>   
To be fair it wasn't my idea, I don't know where I picked it up but I 
saw it somewhere, some of the furnaces and forges I have seen or 
consulted on are designed to warm up on propane, then switch to oil 
(often waste oil) so the burners have to be more adjustable.   
> Is there a reason you chose to point the flare downwards, rather than
> upwards?
>   
The whole arrangement can be spun around the pipe, only the set screws 
hold it on.   In my early runs I ran too high an SV and didn't have any 
thing ontop of the char bed to hold it down, and so had a tar-ifier and 
it would spit big droplets of tar right through the whole thing, having 
it pointed down seemed to make sense.   In the end I was able to make it 
run relatively tar free, by using ceramic balls on top and keeping the 
SV low.    The big problem with this unit was that it was short, only 
24" tall, so at an air injection rate of 2 psi I could only get 10 
minutes out of it.    I did make a longer one 48" but realized that 
using this batch system at 10 minutes per 24" if I wanted to do 1 hours 
work between changes I would need to go to a 12 foot tall unit.    This 
wasn't practical for me so I figured out another approach but haven't 
had time to build it.
> I see some set screws on your outlet just prior to the flare, is there
> anything inside the 1.5" pipe other than the sheet metal flameholder
> ring you mentioned (e.g. throats, mixers etc), or is what we see on the
> outside pretty much it?  Any interior area restriction near the gas/air
> mixing point?
>   
The set screws hold my flame keeper, which in this case is a piece of 
3/4 thin wall ss pipe about 1 1/2 long with the outer end flared (not 
quite as much as on the burner)
>> Using the push compressed air system worked very well for me, and 
>>     
>
>   
I sent quite a few details previously,  including a fancy drawing (I 
liked it anyway).  
http://www.repp.org/discussiongroups/resources/stoves/RT/DTLUD.html 
<http://www.repp.org/discussiongroups/resources/stoves/RT/DTLUD.html>
I see that it's in the stove section, so I will see about migrating a 
copy into the gasification list.
> Any photos or details on your gasifier?  Is it a positive pressure
> setup, or is it actually pressurized (i.e. several or more psi)?  What
> do you use for pressurizing/blowing it?
>   
It is positive pressure, and you can see in the one photo it is running 
at about 2-3 psi, with the air then flowing through a 2 foot tube about 
1/4 id so not much primary air I think because the system is quite heat 
efficent (well insulated hopper, plus ceramic ball "blanket").
> You use your gasifier for forging, right?  How does its performance
> compare using propane, and coal?  What do you use for fuel (and what is
> its m.c.)?
>   
I had hoped to use it for forging, but decided to get out of forging for 
now.  It's burn time wasn't long enough for practical use for forging, 
might have been a great foundry unit though.   I have chopped up the 
tall model (it was unsafe) but still have the smaller model (it's not as 
safe as I would like, but still worth keeping).    I tried quite a few 
fuels,  I sucessfuly flared every thing from forest floor sweepings (inc 
quite a bit of dirt), very old semi composted wood chips, and fairly 
fresh, but dry (to the touch) wood chips.    The worst fuel I tried to 
burn was wood pellets.    As the hopper heated, they would heat, and a 
lot of water vapor would be released, the pellets would then expand like 
popcorn blocking airflow.   

All the Best
Drew
>   

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