Overview

Project Phase: P&ID and Design Specification Review Machine Category: Centrifugal Compressors

1. Is there an adequate liquid removal system for compressor suction to each stage?

   _________
   (Yes or No)

   The suction drums must be sized to prevent liquid carry-over that could damage the machine. Worst case operating conditions should be considered. For example: highest suction pressure, highest flow, or two machines operating in parallel using the same suction drum should be considered in drum sizing. Use of crinkled wire mesh in drum outlet (appropriately designed, of course) and tangentially entering inlet nozzle to drum should be considered to provide the most effective liquid separation. A tangentially entering inlet nozzle will effectively increase drum flow capacity at identical inlet conditions by about 40%. This may provide a simple upgrade to increase capacity of existing drums equipped with an inlet nozzle that is perpendicular to drum walls.

   Review suction piping layout to be certain that no liquid traps exist between suction drum and compressor. Suction lines must be sloped to drain either to compressor or to suction drum and not be flat. Liquid slugging and compressor damage can occur as a result of liquid trapped in these low points.

2. Is there a gauge glass, LHA alarm, and LHA trip on this drum?

   _________
   (Yes or No)

   This instrumentation is extremely critical; catastrophic compressor failure and possible personnel injury can occur if the machine ingests significant amounts of liquid. Failure typically initiates in a thrust bearing and...