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[farid.k]

Hye team.

 

Again just want to ask again regarding compressor. This is continuity from my previous post regarding compressor but more detail.

 

Kindly refer sketch for detail.

 

My questions are:

 

1.By referring the option 1, what if I remain the existing drier and add one new bigger drier for 1 new compressor? The drier size is slightly bigger than existing. And I will operate 1 x drier existing and 1 x new bigger drier. I afraid that, existing drier has different delta P across drier, say existing drier delta P is 10 kPa and new drier 50 kPa, is there any problem?  I think should be ok since the different is small. And we also can specify to vendor to have allowable pressure drop to make it same as existing.

2.By referring option 1, is it any possibility for the flow unequally distributed and can cause one of the drier will be main and the second drier will become minor and will result poor dew point or poor drier process? Anybody has experience about this?

3.In order to eliminate problem 1 and 2, they proposed to demolish existing drier and just add two new bigger drier (to refer option 2) and operating philosophy would be 1 running 1 standby. However demolishing the existing drier for me is not economical and in term of constructability problem will be a major since need to wait total shutdown.

4.Some proposed to have option 3 (totally separate system and just tie in at main header). Yea it is quite straight forward and constructability is easier, lesser tie in point but for me in term of operation flexibility is lesser compared to option 1. Any comment on this option?

5.Any better idea/advice for additional compressor in parallel service? For info, this is for plant air and instrument air supply and compressor type is centrifugal. I read somewhere that, Centrifugal compressors are not as well suited to parallel operation as axial and all types of positive displacement compressors. This is because of their relatively flat curve shape. The flatter curve makes load sharing difficult. Currently existing compressor has deteriorated problem which the volumetric capacity decreases slowly and quite significant number. After major overhaul, flowrate become normal but just temporarily and again deteriorate slowly. Does it because a poor load sharing controls system arrangement? For me, as long as compressor has same head capacity even different flowrate should be ok. If different head, the compressor with the greater head capability forces the other compressor to operate at a reduced flow. Any has experience same thing and can comment on this? i think this should be due to rapid user flowrate demand change and cause compressor to operate near the surge line.

Attached Files

•  ACTUAL.pdf   24.1KB   12 downloads
•  OPTION 1.pdf   34.01KB   8 downloads
•  OPTION 2.pdf   31.65KB   6 downloads
•  OPTION 3.pdf   35.63KB   5 downloads

Edited by farid.k, 07 April 2015 - 09:14 PM.