Page 421 - Reciprocating Compressors Operation Maintenance

4O6 Reciprocating Compressors: Operation and Maintenance

CYLINDER SIZING:

14" cylinder

R.L. = P 2 x A HE - P, x A CE
= (386 x 154) - (150 x 147) = 37,400 Ibs.

9-5T cylinder

R. L. = (1000 x 72.8) - (386 x 65.8) = 47,400 Ibs.

This exceeds the allowable rod load of the two-cylinder machine!
Therefore, the four-cylinder machine must be checked for road load:

3
9- //' cylinder
R.L. = 386 x 74.7 - 150 x 67.6 = 18,700 Ibs.

6-%" cylinder

R.L. = 1000 x 35.8 - 386 x 28.7 = 24,700 Ibs.

This is within the limit of the machine. Therefore, the compressor for
the application will be a 9-% x 9-% x 6-M x 6-% x 14, two-stage with a
1,200 HP, 400 rpm driver. Note that the dew point of the gas should be
checked at interstage condition to make certain that no fraction has gone
into the two-phase region. Interstage pressure must be altered by cylinder
sizing if this occurs.

Existing Machine for a New Service

You have an existing compressor available. It is a 13 x 9-% x 16 com-
pressor with a 1200 HP driver at 300 rpm. What will be the performance
of this machine for the service in the preceding example?