Valve materials for Benfield solution

[DesertEagle01]

Hi,

we are currently facing problems with valves in a Benfield solution line. We are using ball valves (Class 900, 6"). The ball valves are made of stainless steel (316L) with the ball and the seat being hardened with Chromium Carbide. It seems like the Chroumium Carbide hardfacing is chemically not resistant to the Benfield solution since one valve got stuck and we can see chemical attack on the ball and the seat (both surfaces).

Can someone recommend resistant material combinations for this type of media. Is someone using gate valves instead of ball valves for this application?

 

[gerhardl]

The reason you have not yet got an answer is probably that this is not easy answers and experienced operators readily available.

I have no experience, but ckecking I find that the proces involves removal of CO2 and H2S with liquid Potassium Carbonate. This will be a highly corrosive environment, probably with particles and perhaps temperatures well above room temperatures.

For recommended valve inner materials you will find listed higher qualities of non-corrosive steels and exotic materials. The only indication you will find about chrome is that chrome is not mentioned, indicating that you should avoid chrome.

As chrome hardening indicates that a hardened surface is sought, perhaps because of possible abrasion. If abrasion is a problem a high-quality ceramic type could be considered, only economic if standing time is double or more than for high quality steel or exotic materials.