What is unique about the Master Meter Method of Prover Calibration for Alyeska Pipeline is all calibrations were performed with the same master prover by employees with extensive experience in operating that prover. It is reasonable to assume that, regardless of the method of prover calibration, using different contractors with different equipment and people certainly would increase the spread in data. Since the Master Meter Method of Calibration is a 2nd tier transfer of the master prover waterdraw volume, it is even more crucial to calibrate the master prover with the same equipment and operators each time. To achieve the highest accuracy it is best to perform the waterdraw calibration of the master prover in a controlled environment to eliminate externally induced errors. Although the Master Meter Method is not intended to replace the Waterdraw Method of Calibration, there are several advantages of using this method. The Master Meter Method eliminates the need to clean the prover which requires an extensive amount of labor hours and results in thousands of gallons of hydrocarbon-contaminated water that must be properly disposed of. The high cost of cleaning the prover may be small when compared to the cost of the measurement error that could be introduced because of cleaning. After cleaning the prover, there is no way to determine the actual volume of the prover prior to calibration or if the volume changes with time after the process liquid is reintroduced. Calibrating provers using the Master Meter Method requires a minor modification to the piping if the connection points are not already installed. The cost of this modification is minor when analyzing the potential cost savings of changing calibration methods. For some provers the cost of processing the hazardous waste can be greater than the total of all other costs of the calibration. Because the prover does not need to be removed from service for cleaning, the time required to perform a Master Meter Method calibration is also reduced. As standard practice for TAPS, detector switches are removed for inspection, rebuilding or replacement prior to each prover calibration. It should be noted that the results from the Master Meter Method of Prover Calibration suggest that removing detector switches has no significant affect on bidirectional prover volumes. It should not be assumed nor is it implied that this applies to other types of provers. Because of the importance of determining a prover volume it warrants mentioning again in closing that regardless of the calibration method used, the proper experience, knowledge and equipment is required to determine accurate displacement prover volumes necessary to meet API standards.


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    Titel :

    Master meter prover certifications per API MPMS 4.9.3


    Beteiligte:


    Erscheinungsdatum :

    2012


    Format / Umfang :

    10 Seiten, 8 Bilder, 2 Quellen



    Medientyp :

    Aufsatz (Konferenz)


    Format :

    Print


    Sprache :

    Englisch