Re: GAS-L: Re: GASIFIER CAST ENTIRELY FROM HIGH TEMP RESISTANT CLAY

[Arnt Karlsen <arnt@c2i.net>]

On Sun, 2 Sep 2001 07:09:48 +0200, 
"shuster" <shuster@zol.co.zw> wrote
in <002c01c1336e$2447f800$0cf6fcd8@Default>:

> THANKS FOR THE COMMENT.
> MAYBE YOU COULD FIND OUT IF SOMEONE IN S.A.(EG CLAY PIPE
> MANUFACTURERS) COULD CAST MY GASIFIER IN HIGH TEMP RESISTANT CLAY
> WITH SAY 50MM WALL THICKNESS.

..eerie.  A sneeze could blow it up.  I'd use 50 mm steel 
piping, and cover the inside with ash and clay.  I'd leave 
the outside wall bare and use a cover drum to catch radiant 
heat and use that heat to preheat gasifier air supply.

..the gasifier shell must be strong enough to contain sneezes, 
shockwaves etc., _long_enough_ to allow these to escape thru 
the safety valve system.  Most steels come down to below 2-5%
of the published tensile strenght at around 1000 centigrades,
and shells, piping etc, and must be sized accordingly.

> ANYONE CARE TO COMMENT
> BEST REGARDS,
> ASHLEY

..fwiw, I initially tried knocking out the bottoms of 
flower pots and turned them upside down to form a V-hearth.

..typical life was 3 firings, looks like they took the heat 
fine, but cracked on the too rapid light-up, we went from 
20 to about 1200 centigrades in about a minute.  

..the fired red clay loses its red colored oxides, and greys.  
We never tried firing V-hearth pots insitu, has anyone else 
tried this?  

..how about covering a steel cone with clay?

..we went for steel pipe reducer cones supporting an ash 
cone.  Use a "mild" high temp steel, not any of the 
stainless steels.  These alloys are essentially made 
"corrosion resistant" by "moving" the "corrosion resistance 
area" _away_ from where we need it in our gasifiers;  
Stainless steels do fine in the combustion zone, but will 
corrode in the reduction zone, and in the gas piping, due 
to lost surface oxides.  Ditto for titanium.  
High temp "mild steels" are far more resistant and cost 
effective here, as they don't rely on surface oxides.

-- 
..med vennlig hilsen = with Kind Regards from Arnt... ;-)

  Scenarios always come in sets of three: 
  best case, worst case, and just in case.


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