API MPMS 23.2 2020 pdf free download

API MPMS 23.2 2020 pdf free download.Manual of Petroleum Measurement Standards Chapter 23.2 Reconciliation of Liquid Tank Car(s) Quantities .
1.2 Field of Application The primary application of this publication is in custody transfer measurement systems in which there is provision for measuring all liquids that enter the system and exit the system, as well as liquid inventory within the system. 2 Normative References The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. API Manual of Petroleum Measurement Standards (MPMS) Chapter 2, Tank Calibration (all relevant chapters) API Manual of Petroleum Measurement Standards (MPMS) Chapter 3.1A, Standard Practice for the Manual Gauging of Petroleum and Petroleum Products API Manual of Petroleum Measurement Standards (MPMS) Chapter 3.1B, Standard Practice for Level Measurement of Liquid Hydrocarbons in Stationary Tanks by Automatic Tank Gauging API Manual of Petroleum Measurement Standards (MPMS) Chapter 3.2, Standard Practice for Gauging Petroleum and Petroleum Products in Tank Cars API Manual of Petroleum Measurement Standards (MPMS) Chapter 4.5, Master Meter Provers API Manual of Petroleum Measurement Standards (MPMS) Chapter 4.8, Operation of Proving Systems API Manual of Petroleum Measurement Standards (MPMS) Chapter 4.9.2, Methods of Calibration for Displacement and Volumetric Tank Provers—Part 2—Determination of the Volume of Displacement and Tank Provers by the Waterdraw Method of Calibration API Manual of Petroleum Measurement Standards (MPMS) Chapter 5, Metering (all relevant chapters)
3.9 statistical control The data on a control chart are in a state of statistical control if the data hover in a random fashion around a central mean value, and at least 99 % of the data are within the three standard deviation control limits, and the data do not exhibit any trends with time. 3.10 systems tolerance limits Control limits that define the extremes or conformance boundaries for variations to indicate when an audit or technical review of the facility design, operating variables, and/or computations may need to be conducted to determine sources of errors and changes that may be required to reduce variations. Tolerance limits are normally based on 99 % or greater confidence levels and are used interchangeably with upper and lower control limits (UCLs and LCLs, respectively). 3.11 three standard deviation limit A control limit equal to three standard deviations from the arithmetic mean of the set. 3.12 transloading The transfer of a liquid hydrocarbon commodity from one bulk carrier to another bulk carrier where the quantity and quality transferred is measured via a measurement system. 3.13 warning limits Lines on a control chart that represent a boundary between a predictable and unpredictable process. 4 Measurement Data Analysis 4.1 General Data may be presented in the form of control charts, trending charts, or cumulative charts. Guidelines on such charts may include control limits and trending lines. Charts used for monitoring measurement systems should be living documents and should be updated whenever new data are available. Accumulating data for some period of time and periodically updating charts (e.g. semiannually) serves no useful purpose. Charts and monitoring procedures can be effective only if charts are current and used as constructive tools.
4.2 Loss/Gain (L/G) Analysis L/G is the difference between deliveries and receipts, adjusted for changes in inventory, experienced by a system over a given time period (e.g. day, week, month) or over a single (or multiple) product movements. Losses may be physical (e.g. leaks, evaporation, theft, etc.) or apparent (e.g. errors in measurement, tickets, procedures, etc.). Gains may occur if unmeasured liquid is added to the system—higher than actual receipts. More often, there is no actual physical loss or gain, just simply small measurement inaccuracies or accounting discrepancies. The combination of these small measurement inaccuracies may result in a system being outside of normal or acceptable limits. L/G analysis typically involves collecting data, calculating L/G, and plotting L/G on any of several different types of charts. These charts may include control limits or other analytical guides that are derived from some simple statistical tools. The tools described in this document may be used by anyone and do not require an understanding of statistics. The terms “over/short” and “imbalance” are sometimes used interchangeably with “loss/gain.” The two basic L/G equations (not all inclusive) are shown below. One expresses a loss as a negative value and the other expresses the loss as a positive value.