Quote Originally Posted by SURESH YADAV
...can you tell me wt are recommended velocity in suction line and wet return line...
For an ammonia system, particularly suction lines you determine the velocity after you size the pipe for the allowable pressure loss.

In halocarbon (and other) people typically size pipes by velocity, which you have to do to for oil return to the compressor. At whatever velocity they use, the pressure loss will be equal to some value. Then you have to allow for the pressure loss to ensure the compressor capacity is not affected.

The higher the velocity, the greater the pressure loss will be. This contributes to excessive capacity loss for the compressor, an increase in power use, and can allow water hammer to occur in gas lines where liquid may be present.