Best Practices for Proving Coriolis Meters with Small Volume Provers |
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| M. Buttler |
- Abstract:
- Coriolis meters have many advantages for mass flow and volumetric measurement in a wide variety of applications. Inherent reliability, linearity, and stable meter factor (MF) on a wide variety of products make them an ideal choice for pipeline transfer. With the recent introduction of high flow rate meters, Coriolis technology can now be used in line sizes up to 16”. Custody transfer of products is very common in these large pipelines; in many applications contractual requirements dictate that meters be proved in situ periodically to ensure accurate measurement over time and/or product changes.
Traditionally, large pipe provers have been employed at metering stations. The overall size of a pipe prover and the maintenance costs of the complex four-way valve integral to a bi-directional pipe prover can be a concern. Small volume “piston-type” provers are becoming more common because they have a much smaller foot-print and reduced maintenance costs. Even the largest small volume provers are small (as much as 10 times smaller) compared to pipe provers of similar flow capacity. Small volume provers tend to perturb the flow rate when the piston launches. Because the measuring volume of a small volume prover is so much smaller, this rate change caused by the operation of the prover becomes an integral part of the proving cycle that is measured by the metering device.
Proper sizing of a small volume prover to pair with a Coriolis meter(s) can result in greater proving efficiency, optimum prover size, and reduced maintenance on the prover. This selection and pairing process is especially important when using small volume provers to prove high-precision, high-flowrate Coriolis meters. Data collected to validate Coriolis meter performance with small volume provers in lab testing and field proving has been analyzed to determine which procedural and design factors yield the best results. This analysis has resulted in the development of the concept called “Total Prove Time” (TPT).
In addition, proving methods that apply incremental uncertainty analysis to determine when proving is completed will afford operators the opportunity to attain even greater efficiency. This method of proving involves continuing to collect runs until the repeatability that is equivalent to a meter factor random uncertainty of better than ±0.027% has been reached. This method is outlined in the American Petroleum Industry (API) Manual of Petroleum Measurement Standards (MPMS) Chapter 4.8, Second Edition, Operation of Proving Systems, Annex A, Evaluating Meter Proving Data.
The TPT concept is simple to apply and useful for selecting a small volume prover and Coriolis meter to achieve maximum freedom of choice between prover size selection and operational trade-offs including wear and tear. Diagnostic tools for enhancing overall measurement systems design, troubleshooting, and assessing future pipeline capacity expansions are another benefit that have resulted from this research. - Download:
- IMEKO-TC9-2019-042.pdf
- DOI:
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- Event details
- IMEKO TC:
- TC9
- Event name:
- FLOMEKO 2019
- Title:
18th International Flow Measurement Conference 2019
- Place:
- Lisbon, PORTUGAL
- Time:
- 26 June 2019 - 28 June 2019