Turbine Flow Meter Research
Metering Research Facility
AGA Report 7 closed-coupled configuration is being tested on the MRF low-pressure loop (LPL).
Goals and Topics of the Turbine Flow Meter Research Study
Turbine meter research provides information to assist the American Gas Association (AGA) Transmission Measurement Committee (Task Group No. 12) with the revision of the gas turbine meter standard for custody transfer applications (AGA Report No. 7, Measurement of Gas by Turbine Meters). The revised document will be a performance-based standard, which will require the development of a performance verification test protocol and the selection of criteria to evaluate meter performance. Past research at the Metering Research Facility (MRF) determined the extent and magnitude of pressure-related trends in meter calibrations and established the best division between "low" and "high" pressures for measurement uncertainty requirements in the revised standard. The program also tested installation effects and possible bias due to meter bodies being used with different meter cartridges (i.e., cartridge change-out effects.)
In 2001, work began to revise the AGA gas turbine meter standard, Report No. 7, to reflect recent advances in turbine technology and broader use of these meters. Research has been performed at the MRF for the past four years to support this update.
- In 2001, tests were performed to evaluate the operation of standard-capacity and new high-capacity turbine meters in the various installation configurations described in the 1996 version of AGA-7, to determine if changes to the recommended configurations were needed.
- Another research program investigated pressure-related shifts in meter calibration over a range of gas densities ranging from low-pressure air to high-pressure natural gas mixtures. Based on the research findings, the next edition of AGA-7 will recommend that meters be calibrated at flowing conditions similar to the conditions at which they will be used.
- Tests in 2004 evaluated measurement uncertainties due to the installation of a cartridge in a turbine meter body other than the one in which it was originally flow calibrated. This helped to determine potential errors in cartridge change-out practices followed by many meter users.
Benefit of Turbine Flow Meter Research to Industry
Approximately 30% of the meters used in gas pipelines in the United States are conventional turbine meters. In response to the evolution of ultrasonic flow meters for gas measurement applications, the new generation of turbine meters have an extended flow range and more on-board, self-diagnostic capabilities than the conventional designs.
The potential benefits from the recent turbine meter research lie primarily in the areas of improved field measurement accuracy and lower metering costs. If any adverse effects of meter installation and operation can be identified and eliminated, the reduction of measurement bias errors will directly impact revenues received from gas sales and transportation services, presently unrecovered costs for unaccounted-for gas, and costs associated with dispute settlements and adjustments.