API MPMS 6.2:2004 pdf download
API MPMS 6.2:2004 pdf download.Manual of Petroleum Measurement Standards Chapter 6一-Metering Assemblies Section 2- Loading Rack Metering Systems.
The multiple additive injector panel may only support a single meter and will not support tuore than one additive dispensed at a time. The loading rack electronics call be configured to deliver the exact amount of additive betwe a configured volume reaches the preset amount. This volume is normally the volume of liquid required to flush the load arm from the point of additive injection to coupling with the vehicle. Once the additive is dispense. an additive flush l)UnlP can be activated to provide the additional line pressure required to flush main product through the additive panel assembly. For instances where additives may be selected by product recipe, it is advisable to complete the additive injection by a predetermined volume prior to the end of load to allow the dispensed additive to flush into the vehicle and offer clear product for the next batch.
7.5 ADDITIVE ACCOUNTiNG
A printout of total amounts of additives dispensed by individual vehicle compartment should be available from the loading rack accounting system. This data may be included in the communications interface to the terminal automation system for the option of including additive amounts on the bill of lading and for EPA-required inventory reporting purposes. Additive injectors may be equipped with display totalizers to provide manual readouts of additive volumes.
8 Meter Proving
8.1 METHODS
The method used 11w proving loading rack meters (volumetric prover, pipe prover, or master meter) will determine loading rack design requirements. In choosing a proving method factors such as time constraints, truck lane dimensions, number of meters, and asailahility of product return lines should be considered. Meter calibration adjustments should be set via electronic or mechanical calibrators so that the meter totalizer will reflect a meter accuracy that is as close to unity as possible and within the tolerances stated in NIST Handbook 44. by local weights and measures authority, or by internal company requirements. For custody transfer loading rack operations, net meter proving and standard volumes should be utilized when required by Handbook 44, Section N.5. The proving frequency may be ba.sed on throughput volume. time, weights and measures requirements, seasonal temperature changes. historical meter pcrflwrnancc. or a combination ol’ these factors. In addition, meters should be re-proved when subjected to repairs or changes that may affect measurement accuracy. When using electronic presets with multiple flow rate configurations, the establishment of multiple meter factors may be required.
8.1.1 Volumetric Provers (Tanks or Cans)
The volumetric prover method is the most widely accepted method by weights and measures ofiuciak. This method provides a direct volumetric comparison between the test meter and a N 1ST-certified vessel. Care should be taken when selecting a tank prover for rack meter proving. Variables such as size, construction material, and design should be considered. It is recommended that only volumetric provers meeting the design criteria prescribed in NIST Handbook 105-3 and API MPMSCh. 4, Section 4 be utilized. It is also important to ensure that normal operating conditions are reproduced during the proving process. Vapor recovery hoses and grounding equipment should he connected prior to beginning the process and flow rate stability should be achieved.
Loading rack systems typically incorporate low flow startup and shutdown sequences to reduce static electricity (see API RI’ 2003) and system shock. These changes in flow rates can affect meter accuracy and are included in each calibration run. Due to the size difference of the prover and truck cornpartments. the accuracy of the calculated meter factor may be adversely affected for meters with poor linearity. Therefore, prover size, truck compartment size and meter linearity should be considered when utilizing the volumetric prover method. When meter linearity is not suflicient. it is recommended that meter factors be utilized to correct for inaccuracies for each operational flow rate (i.e., low and high flow rates). To help correct for the above inaccuracies the low flow rate factor should be cstablished and applied prior to proving at the high rate.
