Non-Metallic Pressure Safety Valve in HCL Service 1

[Metcorr]

At one of our plants, we have a HCL transmission line of about 2 inches. The line handles HCL at 35% concentrations and at about 50C temperature that can reach in summer season. A PSV was originally installed of Stainless Steel 316 which has history of leakage. While reviewing plant data, we now would like to change the PSV with either Hastelloy 276 C or a plastic (PVC, PDVC or PTFE) coated internals of carbon or stainless steel. Can colleagues guide us if non-metallic coated PSV are commercially available and are usually used in process plants.

Views from colleague will be greatly welcome.

MetCorr

 

[gerhardl]

You forgot to include pressure and capacity to determine size, but anyway: I doubt the answer is yes.

With this stuff inside the pipeline you will want to control the emission, and be sure you have a high quality PSV : answer exotic metal.

Perhaps you could find a cheaper solution (if pressure realations suitable) for your process by using bursting discs with bursting and/or leakage detection.

 

[abcmex]

Austenitic stainless steel (like 316 or 304) do not like Chlorine at all .You can go for an exotic alloy if your operational temperature is too high or if you have a lot of money.

A Plastic valve could help you or a coated valve like

http://www.richter-ct.com/data/download/ekatalog/b/en/KSEA-EN.pdf

if the temperature is adequate

rgs.

 

[Metcorr]

Thanks Abcmex and Gerhard for your comments. We are also looking for Non-metallic PSV which are normaly installed on HCL Rail Cars and approved by appropriate code for rail cars only. But, these PSVs are not approved by API or ASTM. Just wondering if we can use them in process plants on HCL service line.

Metcorr

 

[abcmex]

Metcorr,
I think you should clarify which code covers the application and use an approved valve for the specific code.

rgs.

 

[moltenmetal]

ITT Richter sells a teflon-lined ductile iron PSV, if you want to avoid using solid non-metallic materials due to temperature/pressure.

 

[JimCasey]

I think I would take a look at the Crosby (Tyco) JQ. It has been around for a long time, approved for Chlorine transport on rail cars.

The primary seal is lead, with a breaking pin. Then there is a secondary spring-closed SRV component with Monel wetted parts. So the valve can relieve, then reseal.

I don't condemn or endorse Richter, but I think that I would be nervous with all that TFE stacked up and left with a large spring load on it.