Quick action blind

[Danlap]

Dear All,

Would really appreciate some feedback from users with experiences using quick action blind.
My team is in the process of replacing 42" flare line - 250 degC spectacle blind + Triple offset butterfly valve configuration with quick action blind + triple offset bv.

My biggest concern is even though the sales catalog says it could sustain up to 400 deg C, but isn't below configuration especially the sliding O-Ring and PTFE part (no. 22 and or 23) which act as primary and secondary barrier is prone for medium and high temperature.
We have use below design for Nitrogen, smaller size and ambient temperature. But never for critical flare application and size this big

I can easily ask the manufacturer, but I have concern over another sales pitch answer without proven reference.
Thank you in advance for the support and information.


Regards,
MR

https://nosuchvalve.com

All valves will last for years, except the ones that were poorly manufactured; are still wrongly operated and or were wrongly selected

http://www.eng-tips.com/faqs.cfm?&rat1=2&fid=376

 

[gerhardl]

Hello Danlap!

This is obviously a rather high-cost component, designed to solve a more demanding process situation. In my opinion it will not solve the general-purpose dependability and quality check just answering yes or no to your question. (I would, by the way, say no).

By asking this question I suspect 'something' is new, or either not sufficient in the old solution or not complete equal to the old solution, and as such not easy to comment by a short answer. Is this blind a new addition, not previously integrated in the total system?

Closing situation, closing time, time/temperature curve, firesafe (to what degree)? Alternative solutions? (Knife-gate valve in SS?)

For your problem I would not recommend a supplier not highly qualified and with references to earlier supply of similar solutions that have proved to perform over time

Best luck!

 

[Danlap]

Hi gerhardl,

Thank you for the comments. I am also a bit reluctant for this path.
A brief background:
My plant is consists dozens of Production unit that shares a kind of Ring loop flare system. Not really toxic, however it's not convenient to work on the other side shall the block valve is not tight enough, and or residences around the area complaining about the smell.
And the classic driver are Process, money (shall blinding the line take takes to long), safety (shall the block valve cannot tight shut off the line), small percentage of triple offset BV problem perceived as all Butterfly-valve will have the same risk, also same paradigm for Gate valve for fouling service, last but not least spatial constraint to install different type of face to face other than current Butterfly valve

Install of quick actions blinds, this reduces the time that the flare system is open during the turning of a pair of glasses from 20 min to 5 min - as a result, the flare line remains at pressure.

Red dot is currently normal blind, and 24 is triple offset butterfly valve which is not fully shut due to fouling built up. 23 and 25 is Production unit representation. 24 is 42" and part of similar other 8 configuration creating a loop kind of system.

And refer to my early attachment, the vendor said that it will be replaced with expansion joint

And the O-ring sealing can be replaced with SWG

Reference for similar size and higher temperature claimed have been supplied to some Korean and China Coal Plant

Having said that, does the expansion joint / bellows only barrier subject for PED? even though we only operate the flare around 3-5 bar maximum

Excuse me for the basic question. This is the time when people questions over "why not?" just overwhelming me on top of my daily function.

Thanks again,
kind regards,
MR

https://nosuchvalve.com

All valves will last for years, except the ones that were poorly manufactured; are still wrongly operated and or were wrongly selected

http://www.eng-tips.com/faqs.cfm?&rat1=2&fid=376

 

[mk3223]

It's always a good thing to improve the system for safety and reliability, as well as the environmental impact to the surrounding community.
For better understanding the device, ask vendor to provide service applications in details in the similar process plants like yours.
Regarding the expansion joint, is it an issue of corrosion because it's to be the low pocket along the flare line?