Field Performance Testing and Test Codes for Gas Compressors

Abstract

Field testing of gas compressor packages requires the accurate determination of efficiency, capacity, head, and power in sometimes less than ideal working environments. The results of field tests have significant implications for the compressor manufacturers and their customers, as economic considerations demand that the performance and efficiency of an installation are verified to assure a project's return on investment. Thus, for the compressor manufacturers, as well as for the end user, an accurate determination of the compressor performance in the field is of vital interest. While field performance tests have to be executed under conditions dictated by the situation at site, factory test codes like ASME PTC10 and International Organization for Standardization (ISO) 5389 provide guidance. The former code was recently revised, so a discussion of this revised code in the context of site performance testing is appropriate. A key change in PTC10 is the method to calculate polytropic work, which affects data reduction. It also affirms a method to calculate error propagation and test uncertainties. The discussion includes the appropriate use of equations of State (EOS) and the definition of steady-state requirements. Different methods to define valid operating conditions for the test based on similarity considerations are compared. However, field tests, unlike factory tests, are ultimately conducted based on the conditions at site that may or may not conform with test codes. Therefore, calculation of test uncertainties and the use of observations not covered by the codes are emphasized. The paper attempts to provide guidance for the conduct of field performance tests.