[Gasification] wood gasifiers

[Greg and April]

Interesting, I picked up several 100lb propane tanks ( from different 
companies ) and they are all 14 in. ( give or take .5 due to dents and 
such ).    I wonder if this uniformity is due to the industrial nature of 
100lb tanks - since they need equipment to be moved around.

I have 3 100lb tanks left over from other projects, and was trying to figure 
out how to use them to make char. ( at this point I would use the gas to 
fuel the process ).    A couple of the tanks still have valves I have not 
removed, and I wonder if I can incorporate them since couplings are easy to 
obtain.

Greg H.


----- Original Message ----- 
From: "jim mason" <jimmason at whatiamupto.com>
To: "Discussion of biomass pyrolysis and gasification" 
<gasification at listserv.repp.org>
Sent: Sunday, April 06, 2008 18:37
Subject: Re: [Gasification] wood gasifiers


SNIP

>
> yes, the one in the picture is made from propane tanks and other
> common obtainium tanks.  the unit is now made with purpose rolled
> tubes, given the hassle i've encountered trying to make this work at
> scale with only scrap tanks.
>
> while scrap tanks are easy to find, the difficulty in recovering and
> altering them is often more than expected.  purging, greasy surfaces,
> variations in dimension, rust, sourcing, hauling etc often become
> rather significant.  while i am a big fan of obtainium, i also note
> its challenged application in situations where you are trying for
> reproducable and standardized dimensions.  interchangable parts
> require this standardization.  even providing a purpose cut round
> plate or ring to weld to a cylinder assumes the cylinder is of
> standard dimension.
>
> nonetheless, the GEK unit is designed around common 10", 12" and
> 14.xx" OD tanks.    these are cut to make the tubes for the vessels.
> 10" is commonly used for small air tanks and some odd propane tanks.
> 12" is the standard for 5, 10 and 15gal propane.  14.xxx is common for
> 25 gal.  these actually vary between 14.5 and 15.1" in OD.  i was
> surprised how much even contemporary ones vary.  there is no ISO
> standard.  or at least one that is adhered too.
>
> thus the problems with reproducability, or just easy assembly, when
> you are trying to weld premade rings around and to the bottom of found
> tanks.  an 1/8" off becomes significant.
>
> therefore i decided that purpose made tubes and plates are likely
> desired for most.  with such we can guarantee accuracy of parts and
> easy assembly with minimum tools and fabricating expertise.  the
> problem was finding an inexpensive way to make the tubes.  buying them
> as large premade pipe is difficult, as large tube is rare and
> expensive.  stainless chimney inserts are actually on the inch
> dimensions, with kaowool between the tubes.  you can buy a 12" OD, 10"
> ID ss chimney insert in 12", 18" and 24" lengths.  these are great,
> but expensive.  and the point here is to be able to modify easily,
> thus ss is a bit overkill for a non heat intensive surface.  so we
> just decided to roll the tubes ourselves.   with the round plates, you
> have a "jig" to fit and hold the rolled sheet while you weld it
> perfectly into shape.  no free air assembly.
>
> so yes, i started at the junkyard, but ended up affirming the value
> added of purpose manufacturing, if such can be done cheaply.  and
> making that purpose manufacturing mirror common obtainium shapes and
> sizes gives flexibility so that an individual can go either way, as
> their circumstances suggest.
>
> this might be an interesting strategy for a variety of diy and dev
> world building concerns.  in such realms we often follow one or the
> other path.   i don't think i've seen a situation which attempts to
> combine both in a motivated way.  i just stumbled upon this strategy
> and have come to like it very much.  so i'm going to test it out and
> see if it proves useful (or not).
>
>
> j
>
>
>