Page 145 - Air and gas Drilling Field Guide 3rd Edition

136 CHAPTER 5 Compressors and Nitrogen Generators

produce a peak 270 hp (201 kW) at a speed of 1000 rpm (at API Mechanical Equip-
ment Standards). However, unlike the primary compressor system discussed earlier,
the booster compressor system may be operated at speeds different from the
1000 rpm. The booster prime mover would produce an approximate peak of
230 hp (172 kW) at 900 rpm and a peak of 300 hp (224 kW)at 1100 rpm.
This booster compressor system unit is usually operated in series with the pri-
mary compressor system. When the drilling rig requires compressed air at pres-
2
sures above the 350 psig (241 N/cm gauge) maximum capability of the primary,
the air flow from the primary is conducted to the inlet of the booster. In this series
configuration, the booster is engaged and the volumetric flow rate from the pri-
2
mary is further compressed to pressures above the 350 psig (241 N/cm gauge)
level. However, the booster can also be used to compress pipeline natural gas to
pressures above typical pipeline pressures for use on a drilling rig.

5.7.2 Four-Stage Reciprocating Compressor System
The compressor system unit shown in Figure 5-20 is another unusual design.
This is a semitrailer-mounted unit. The compressor is a large Dresser Clark
CFB-4, four-stage reciprocating piston compressor. The compressor is operated
at a rotating speed of 900 rpm. At this speed the compressor produces a volumet-
ric flow rate of 1200 acfm (566.3 actual liters/sec) and a continuous maximum
2
pressure of 1000 psig (690 N/cm gauge) at API Mechanical Equipment Stan-
dards. The compressor can produce a maximum pressure of 1200 psig (828 N/
2
cm gauge) in intermittent service. Technically, this compressor system is a pri-
mary compressor system unit, but in application the unit performs as a combined
primary booster all-in-one compressor system.

FIGURE 5-20. Semitrailer-mounted, four-stage reciprocating piston compressor system unit
(courtesy of Air Comp Drilling).