sequence open/close valve question
sequence open/close valve question
(OP)
Dear all Professional engineer
I have a simple question about the on-off valve open sequence question. (drawing is attached)
There are four valves(Tag no is XV-A,B,C,D)located on the inlet pipe of the reactor.
The supply pressure is 12 barg, and the reactor operation pressure is 7 barg.
The operation tech told me that open the valve D first then , B,C, A in order to avoid the water hammer.
Could you please explain to me
how we can tell the kind of the process valve open/close sequence step when we encounter simlar problem?
I wlll really appreciate that any other paper or website you can suggest to me
Thank you very much
I have a simple question about the on-off valve open sequence question. (drawing is attached)
There are four valves(Tag no is XV-A,B,C,D)located on the inlet pipe of the reactor.
The supply pressure is 12 barg, and the reactor operation pressure is 7 barg.
The operation tech told me that open the valve D first then , B,C, A in order to avoid the water hammer.
Could you please explain to me
how we can tell the kind of the process valve open/close sequence step when we encounter simlar problem?
I wlll really appreciate that any other paper or website you can suggest to me
Thank you very much





RE: sequence open/close valve question
Best regards
Morten
RE: sequence open/close valve question
RE: sequence open/close valve question
The process fluid is EO(ethylene oxide), and its boiling point is 11 C @ 1 atm. The process condtion is op=12 barg, and oT=-25 C. and the pipe layout before entering the reactor should not have U shape type to avoid vapor accumulation. The PSV outlet pipe will be put in the pipe line between the EO supply and reactor to avoid EO vapor accumulation.
I am not sure my poit is right or not. Please make a comment if I am wrong.
Thank you very much.
RE: sequence open/close valve question
But, I'm also going to suggest that, because the fluid is EO, you must have a triconics interlock system with at least 2 - double block and bleed valves to assure isolation of the EO. If you don't use double block and bleeds, you'll need 4 valves. Do you monitor the pressures between the valves to assure there is no leaking?
RE: sequence open/close valve question
Francis
www.controldraw.co.uk
www.s88control.blogspot.com