ASTM D6624-14
(Practice)Standard Practice for Determining a Flow-Proportioned Average Property Value (FPAPV) for a Collected Batch of Process Stream Material Using Stream Analyzer Data
Standard Practice for Determining a Flow-Proportioned Average Property Value (FPAPV) for a Collected Batch of Process Stream Material Using Stream Analyzer Data
SIGNIFICANCE AND USE
4.1 Contractual or local regulation, or both, permitting, the FPAPV calculated according to this practice can be used to represent the average property of the quantity of material collected.
4.2 Due to the averaging and appropriate weighting of analysis results, the FPAPV estimate of the property for the collected material is expected to be more representative and more precise than an estimate based on a small number of analyses on a few samples.
Note 1: Theoretically speaking, the true property distribution for an infinite number of batches with essentially identical FPAPV's is expected to be Gaussian, centered at the FPAPV value, with a standard deviation that is no less than the long term site precision standard deviation of the analyzer system.
4.3 If the measured property value can be used to predict another property value through the use of an appropriate correlation equation, the FPAPV can also be used as a suitable prediction of that property.
4.4 The most recently updated FPAPV can be used to represent the property of the material currently accumulated in the tank or vessel for process control or material disposition decisions, or both.
SCOPE
1.1 This practice covers a technique for calculating a flow-proportioned average property value (FPAPV) for a batch of in-line blended product or process stream material that is collected over time and isolated in a storage tank or vessel, using a combination of on-line or at-line measurements taken at regular intervals of the property and flow rates.
1.2 The FPAPV methodology uses regularly collected on- line or at-line process analyzer measurements, flow, and assessment of other appropriate process measurements or values, to calculate a flow-proportioned average property value in accordance with flow quantity units of material produced.
1.3 When the collecting vessel contains a heel (retained material prior to receipt of the production batch), both the property value and quantity of the heel material can be predetermined and factored into the calculation of the FPAPV for the new batch.
1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
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Designation: D6624 − 14
Standard Practice for
Determining a Flow-Proportioned Average Property Value
(FPAPV) for a Collected Batch of Process Stream Material
1
Using Stream Analyzer Data
This standard is issued under the fixed designation D6624; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
INTRODUCTION
The determination of an average property value that is representative of a batch of petroleum
product collected and isolated in a tank or vessel has always been a challenge. Historically, the
industrypracticehasbeentofollowtheappropriateproceduresprescribedinPracticesD4057,D5842,
or D4177 to extract one sample (or a limited few, taken from top, middle, and bottom) from the tank
or vessel after the content is mixed by any of several means to ensure the material is homogeneous
prior to sample extraction. The extracted sample is then sent to a laboratory for analysis. Depending
on the property and its criticality, the average property value can also be obtained by independently
analyzing each of the top, middle, and bottom samples and the results averaged, or, the three tank
samples are mixed and testing for the property is performed on the mixture.
With the introduction of in-line blending and process stream analysis in the 1960s, the potential for
real-time delivery to a pipeline, barge, ship, or tank car compartment was envisioned.
To determine the average property value that is representative of a batch of product from a blend
or process stream, two approaches have been developed and implemented. One depends on the use of
a composite sampler, a vessel into which a sample of the flowing process or blended product stream
is introduced at a flow-rate proportional to the flow-rate of the product stream (Practice D4177 or
D7453). This sample, collected over the period of time required to generate the batch quantity of
product, is then analyzed using a primary test method in the laboratory. Multiple laboratory analyses
on one or more aliquots of composite sample can be averaged to provide a more precise estimate of
the property value than a single analysis.
A second technique utilizes the results produced by on-line, at-line, or in-line analytical
measurement systems that test material from the process or in-line blended stream for the desired
property at regular intervals as it flows to a collection tank, pipeline, or shipping compartment. To
determine the average property value of all the material collected (or shipped) at any time during the
productionprocess,auniquerealtimeflow-proportionedaveragingtechniqueevolved.Byappropriate
selectionofaproductiontimeperiodorcycle,theaveragepropertyvalueforthecollected(orshipped)
material at any time in the production or shipment cycle is obtained by recursively calculating a
flow-proportion average using all available property values from the analytical measurement system
and the measured incremental quantity of product flow associated with each cycle.The determination
of this flow-proportioned average property value is the subject of this practice.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
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D6624 − 14
1. Scope* or vessel, calculated by using the flow-proportioned average
technique described in the practice of all measurements per-
1.1 This practice covers a technique for calculating a
formed on aliquots of the material while it is flowing into the
flow-proportionedaveragepropertyvalue(FPAPV)forabatch
tank or vessel.
of in-line blended product or process stream material that is
3.1.2.1 Discussion—The term property as used in this prac-
collected over time and isolated in a storage tank or vessel,
tice can be the physical, chemical, or performance property
using a combination of on-line or at-line measurements taken
measurementsasprovidedbyon-line,at-lineanalyzersystems,
at regular intervals of the property and flow rates.
or, can be the deviation of such measurements from a desired
1.2 The FPAPV methodology uses regularly collected on-
value.
line or at-line process analyzer measurements, flow, and
3.1.2.2 Discussion—The FPAPV can include a value con-
assessment of other appropriate process measurements or
tributed by material (commonly referred to as a tank heel)
values,tocalculateaflow-proportionedaveragepropertyvalue
present in the collection tank or vessel before the start of
in accordance with flow quantity units of material produced.
delivery of the current process stream material.
1.3 When the collecting vessel contains a heel (retained
3.1
...
This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: D6624 − 12 D6624 − 14
Standard Practice for
Determining a Flow-Proportioned Average Property Value
(FPAPV) for a Collected Batch of Process Stream Material
1
Using Stream Analyzer Data
This standard is issued under the fixed designation D6624; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
INTRODUCTION
The determination of an average property value that is representative of a batch of petroleum
product collected and isolated in a tank or vessel has always been a challenge. Historically, the
industry practice has been to follow the appropriate procedures prescribed in Practices D4057, D5842,
or D4177 to extract one sample (or a limited few, taken from top, middle, and bottom) from the tank
or vessel after the content is mixed by any of several means to ensure the material is homogeneous
prior to sample extraction. The extracted sample is then sent to a laboratory for analysis. Depending
on the property and its criticality, the average property value can also be obtained by independently
analyzing each of the top, middle, and bottom samples and the results averaged, or, the three tank
samples are mixed and testing for the property is performed on the mixture.
With the introduction of in-line blending and process stream analysis in the 1960s, the potential for
real-time delivery to a pipeline, barge, ship, or tank car compartment was envisioned.
To determine the average property value that is representative of a batch of product from a blend
or process stream, two approaches have been developed and implemented. One depends on the use of
a composite sampler, a vessel into which a sample of the flowing process or blended product stream
is introduced at a flow-rate proportional to the flow-rate of the product stream (Practice D4177 or
D7453). This sample, collected over the period of time required to generate the batch quantity of
product, is then analyzed using a primary test method in the laboratory. Multiple laboratory analyses
on one or more aliquots of composite sample can be averaged to provide a more precise estimate of
the property value than a single analysis.
A second technique utilizes the results produced by on-line, at-line, or in-line analytical
measurement systems that test material from the process or in-line blended stream for the desired
property at regular intervals as it flows to a collection tank, pipeline, or shipping compartment. To
determine the average property value of all the material collected (or shipped) at any time during the
production process, a unique real time flow-proportioned averaging technique evolved. By appropriate
selection of a production time period or cycle, the average property value for the collected (or shipped)
material at any time in the production or shipment cycle is obtained by recursively calculating a
flow-proportion average using all available property values from the analytical measurement system
and the measured incremental quantity of product flow associated with each cycle. The determination
of this flow-proportioned average property value is the subject of this practice.
1
This practice is under the jurisdiction of ASTM Committee D02 on Petroleum Products Products, Liquid Fuels, and Lubricants and is the direct responsibility of
Subcommittee D02.25 on Performance Assessment and Validation of Process Stream Analyzer Systems.
Current edition approved June 1, 2012Oct. 1, 2014. Published October 2012October 2014. Originally approved in 2001. Last previous edition approved in 20062012 as
D6624D6624 – 12.–06. DOI: 10.1520/D6624-12.10.1520/D6624-14.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
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D6624 − 14
1. Scope*
1.1 This practice covers a technique for calculating a flow-proportioned average property value (FPAPV) for a batch of in-line
blended product or process stream material that is collected over time and isolated in a storage tank or vessel, using a combination
of on-line or at-line measurements taken at regular intervals of the property and flow rates.
1.2 The FPAPV methodology uses regularly collected on- line or at-line process analyzer measurements, flow, and assessment
of other appropriate process measurements or values, to calculate
...
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