Dear Steve,
I learn from the company site that Gylon is modified PTFE.
Spiral wound gaskets would be definitely more reliable with variations in pressures and the temperatures which maybe there.
Gylon, the manufacturer claims has all the properties required,but I could not get details.
History could be the only support for not changing.Difficult decision. I would vote for Spiral wound.
Regards
C. Ponnu
Steve McKenzie <mechproj@xtra.co.nz> wrote: Gents+1
an autoclave that I have "inherited" has oxygen injection lines which
oxidise sulphide ore slurry; releasing heat and forming acid. The
object is to shatter quartz encapsulation of gold particles in the
slurry by thermal shock and chemical attack thereby improving
downstream cyanide leach recovery ($$$). It works. Temperatures are
around 250C and pressures around 31 bar.
I think the internal (hot)oxy injection lines are Ferallium (havent
had time to find out) and (cold) external lines are stainless;
probably 316.But much of the wet area pipework is titanium, for
corrosion resistance. Titanium + oxygen is normally a no-no as Ti can
burn in oxygen. Ferallium doesnt burn but is becoming difficult to
source.
Flanges on the autoclave are Ti spiral wound. This is OK because the
oxy concentrations are fairly low and can be adjusted by partial
pressure regulation.
The external 36 bar(cold)oxy lines are flanged (typically 50NB) with
fawn (I think) Gylon gaskets which appear to have held up well (4
years).
However it has been suggested replacing with spiral wound gaskets and
I cant see the point. Presumably the flange faces would need to be
ground, and I expect a spiral wound gasket would not be as forgiving
as Gylon when it comes to alignment and torquing.
The question is: what advantage would there be in changing from Gylon to spiral wound, given successful operating experience with the former?
Personally I can only see disadvantages, but feel I may be missing something.
Your conjecture/experience would be appreciated.
Cheers
Steve
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[Non-text portions of this message have been removed] Received on Wed Sep 15 04:16:00 2004
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