PR-015-15601-R01 Pulsation Effects on Ultrasonic Meters Phase II

Transmission and storage operations frequently move natural gas using reciprocating compressors that may generate flow pulsations. Most measurement systems cannot accurately measure the flow rate of a pulsating gas stream, and the resulting errors can cause inaccurate gas volumes and accounting imbalances. A previous PRCI research project tested whether recent advances in ultrasonic meters may allow them to function without measurement error in pulsating flows. This project expanded on the previous work and tested similar ultrasonic meters to look for relationships between ultrasonic meter transducer sampling rates, the frequency and amplitudes of pulsations from reciprocating compressors, and meter accuracy. Diagnostics and flow data were collected from the meters and analyzed, and a useful relationship was found between the pulsation conditions and the meter measurement error. The findings were used to recommend a basis for installing ultrasonic meters in gas pipelines with varying pulsations. Additional testing evaluated a fast-response differential pressure transducer connected across a plate flow conditioner as a potential pulsation diagnostic tool.