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API MPMS 8.2 2020 pdf free download

API MPMS 8.2 2020 pdf free download.Manual of Petroleum Measurement Standards Chapter 8.2 Standard Practice for Automatic Sampling of Petroleum and Petroleum Products. Discussion—The system consists ofa sample extrac- tor with an associated controller and flow-measuring or timing device, collectively referred to as an automatic sampler or auto-sampler. In addition, the system may include a flow conditioner, slipstream, sample probe, and sample condition- ing. Discussion—Systems may deliver the sample di- rectly to an analytical device or may accumulate a composite sample for offline analysis, in which case, the system includes sample mixing and handling and a primary sample container. Discussion—Automatic sampling systems may be used for liquids. 3.1.2 batch, n—discrete shipment of commodity defined by a specified quantity, a time interval, or quality. 3.1.3 component testing, n—process of individually testing the components of a system. 3.1.4 dead volume, n—in sampling, the volume trapped between the extraction point and the primary sample container. Discussion—This represents potential for contami- nation between batches. 3.1.5 droplet dispersion, adj—degree to which a fluid in an immiscible fluid mixture is composed of small droplets distrib- uted evenly throughout the volume of the pipe. 3.1.6 flow-proportional sample, n—sample taken from a pipe such that the rate of sampling is proportional throughout the sampling period to the flow rate of the fluid in the pipe. 3.1.7 free water, n—water that exists as a separate phase. 3.1.8 grab, n—volume of sample extracted from a flowing stream by a single actuation of the sample extractor. 3.1.9 homogeneous, adj—quality of being uniform with respect to composition, a specified property or a constituent throughout a defined area or space. 3.1.10 linefill, n—volume of fluid contained between two specified points in piping or tubing. 3.1.11 sample controller, n—device used in automatic sam- pling that governs the operation of a sample extractor.
3.2.3 portable sample container, n—vessel that can be manually transported. 3.2.4 primary sample container, n—container in which a sample is initially collected, such as a glass or plastic bottle, a can, a core-type thief, a high-pressure cylinder, a floating piston cylinder, or a sample container in an automatic sampling system. 3.2.5 profile average, n—in sampling, the average of all point averages. 3.2.6 profile testing, n—procedure for simultaneously sam- pling at several points across the diameter of a pipe to identify the extent of cross-sectional stratification. 3.2.7 representative sample, n—portion extracted from a total volume that contains the constituents in the same propor- tions that are present in that total volume. 3.2.8 sample, n—portion extracted from a total volume that may or may not contain the constituents in the same propor- tions as are present in that total volume. 3.2.9 sample probe, n—device extending through the meter tube or piping into the stream to be sampled. 3.2.10 sampling, n—all the steps required to obtain a sample that is representative of the contents of any pipe, tank, or other vessel, based on established error and to place that sample into a container from which a representative test specimen can be taken for analysis. 3.2.11 sampling system, n—system capable of extracting a representative sample from the fluid flowing in a pipe. Discussion—system capable of extracting a repre- sentative sample from the fluid flowing in a pipe. (ISO 1998-6) 3.2.12 sampling system verification test, n—procedure to establish that a sampling system is acceptable for custody transfer. 3.2.13 secondary sample container, n—vessel that receives an aliquot of the primary sample container for the purpose of analysis, transport, or retention. 3.2.14 stationary sample container, n—vessel that is physi- cally fixed in place.
6. Design Criteria 6.1 The following items shall be addressed when designing a sampling system: 6.1.1 Volume of sample required for analysis and retention; 6.1.2 Conditions (temperature, pressure, viscosity, density, minimum and maximum flow rates, sediment, water, and contaminants); 6.1.3 Type of fluid (crude oil, gasoline, diesel, kerosine, or aviation fuel); 6.1.4 Grabs per Batch—Ensure the sample extractor(s) samples at a high enough frequency to obtain the required number of grabs without exceeding the limits of the equipment or other sampling system constraints. Increasing the number of grabs taken per batch reduces sampling uncertainty as de- scribed in Annex A1. For large custody transfer batch quantities, to ensure representativeness of the total volume of extracted sample in the sample container, some operators have set an expectation that is equivalent to a margin oferror of0.01 with 95% confidence. Eq A1.6 calculates this to be 9604 grabs per batch. In practice, a rounded up recommended value of 10 000 grabs per batch is often used in industry. Small batch sizes, small capacity of the primary sample container and other sampling system constraints may result in designs with a different design criterion than 9604 grabs per batch. For additional information on refined product sampling, refer to Section 19.

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