what is difference between working point elevation and centerline elevation?

1, The center line is what it is and cannot be changed. A "Working Point is what ever you want it to be for your project. It could be the bottom of the pipe. It could be the invert (inside bottom) of the pipe. It could be the top of the pipe. It can be any thing you want or fits the situation as long as you define what you want it to be.

2, A "PSV" releases pressure. A "PRV" releases pressure. A "TSV" releases pressure. The only difference is in what it is called.

Based on the technical level of your questions, I hope you are not specifying components for this LNG project.

Are you a student?

no i am not student , i am a piping engineer

on LNG carraing pipe these two PSV and TSV are there.

outlet of Both valves are Natural gas.

A PSV relieves the pressure due to an upset in operation to protect people and equipment.

A TSV protects a blocked-in equipment,generaly a pipe, which is left standing full of product, that can expand under rising thermal conditions as outside temp, heat tracing failure etc.

calculations for either of them are very different.

In general a PSV is much bigger in size than a TSV

Hope this gives a general idea.

All above mentioned calculations are to be certified

God help us all.

Travis