RE: Flowmeter for hot Fluosilicic Acid

From: <Al>
Date: Mon Apr 26 2004 - 03:53:00 EDT

geez thats a really tough one steve.

I'd be looking for an IRON CHROMIUM NICKEL alloy with >50% nickel content.

nothings gonna be cheap and I cant give you a good and quick answer.

My guess is the mechanisms gonna be SCC and the problems and answers are going be similar to the solutions for polythionic acid materials selection. Do you have some time to do some coupon tests? what about electromagnetic flowmeter.. wont be in the nasties.

<a href="/group/PipingDesign/post?postID=l4rcTj7VuZqVgFli5npnlc39Z94uRsld5f4YjD5zjnjnHrHOoH2YVovflb8NXGg2nG-KEvJd-TE">Altecheng@shaw.ca</a>

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-----Original Message-----
From: Steve McKenzie [mailto:mechproj@xtra.co.nz] Sent: Sunday, April 25, 2004 11:45 PM
To: <a href="/group/PipingDesign/post?postID=VS7kHtPsV9B9cthFFEnly-udwfjajyXzdbNUsmcFQfGYUwbDEnvXbNgixH3KYGM7CnoaGIncaAvDib_KMbBl4H2X">PipingDesign@yahoogroups.com</a> Subject: [PipingDesign] Flowmeter for hot Fluosilicic Acid

Hi there

I am having trouble finding a reliable flowmeter for HFA pH about 1, around 90 deg C, lots of solids. Its a killer brew - seems to attack anything hard and migrate through anything soft except vinyl ester and virgin teflon. Installation is at a Superphosphate manufacture plant.

Magflows have the Hastelloy C electrodes eaten away. Am dubious about ultrasonic - suspect inevitable solids deposits on the pipe wall will cause problems. Same for calometric. Mass flowmeters are a bit dear and the guts would rot out.

System is under pressure so I cant use a weir and level transmitter.

Was wondering about a bend meter with flushed DP tappings.

Any bright ideas out there?

Also pumps for same. Have tried Durco Hastelloy C (corrosion/erosion failure, Ash elastomer lined (migration of fluoride to shell). currently using Coro FRP - chemically OK but it will abrade/fatigue away

Cheers

Steve

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