Parallel ESD valve and temporary strainer with PDT related to comp

[saiedmehdipour]

Dear All,

would you please do me a favor and tell me the scientific reason of merked item on attached file:

1-why usually used 2 ESD on/off valve in parallel mode and furnished them by PDT (also the reason of PDT and typical allowable DP in both side of ESD valves, according which standard.)in inlet of seperator suction drum.
2-beside why usually used temporary strainer at the nearest place inlet of compressor and furnished it with PDT and ESD signal(what is the typical allowable range of PDT for shutdown,according which standard).
Notes on attached file refer to:

Note2 : "not fully open" status of XV-019 to trip compressor.
Note4 : temporary strainer at minimum distance from compressor inlet.
Note27: open of the main shutdown valve (XV-019) is not allwed when there is a large differantial pressure.

By Best Wishes,

 

[MikeClay]

1. One of the valves is a smaller pressuring valve. It limits the rate of compressor pressurization and equalilzes the pressure around the larger main inlet SDV. It is common to have a small equaliztion valve to reduce the opening force of a large valve it also limits wear and tear on the main valve. The PDT is probably a permissive to open the main valve once the differential pressure is below an allowable value.

2

 

[MikeClay]

Lets try this again

1. One of the valves is a smaller pressuring valve. It limits the rate of compressor pressurization and equalilzes the pressure around the larger main inlet SDV. It is common to have a small equaliztion valve to reduce the opening force of a large valve it also limits wear and tear on the main valve. The PDT is probably a permissive to open the main valve once the differential pressure is below an allowable value.

2. The temporary strainer is to catch any start up trash. You want it close to maximize the chance of catching the trash. The PDT is nice to have for plugging indication; however, I don't necessarily see that there is a connection between the PDT and the compressor controls. It looks to me that only the TT is connected to the controls.

--Mike--

 

[MortenA]

A not asked for comment:

I would recommend an additional isolation valve upstream the small ESDV. This will allow you to inspect the small ESDV without having to stop the production.

Best regards

Morten