Page 475 - Compression Machinery for Oil and Gas

Compressor Testing Chapter 12 455

TABLE 12.1 In-Practice Achievable Uncertainty for Measured Performance
Test Parameters
Recommended
Measurement Uncertainty
Pressure 0.3%–1.0% full
scale
Temperature 0.5–7.0°F
Flow 0.5%–2.0% of value
Gas composition (density, compressibility, gas constant, 0.2%–3.0% of value
specific heat, energy content)
Piston position (encoder) 0.1%–0.3% of 360
degree

Axial and Centrifugal Compressors
For axial and centrifugal compressors, two types of factory tests can be con-
ducted before delivering the compressor to customers: a mechanical run test
and a performance test. Other types of tests can be agreed upon, but are not cov-
ered in this chapter (hydrostatic and gas leakage, overspeed, sound level, etc.).
Fig. 12.2 provides a picture of an OEM test stand for centrifugal compressor
performance testing.
A mechanical run test is conducted to check the compressor mechanical
integrity. Typically, mechanical run test also includes a compressor static leak
test. The objective of the static leak test is to verify all seals functioning up to
specific pressure, including shaft seals and seals on the compressor case. The
compressor is pressurized with suction and discharge ports sealed off with

FIG. 12.2 Centrifugal compressor test stand. (Courtesy of Solar Turbines Incorporated.)