ASTM D6624-01

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
An American National Standard
Designation:D6624–01
Standard Practice for
Determining a Flow-Proportioned Average Property Value
(FPAPV) for a Collected Batch of Process Stream Material
Using Stream Analyzer Data
This standard is issued under the fixed designation D 6624; 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 (e) 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 D 4057,
D 5842, or D 4177 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
homogeneouspriortosampleextraction.Theextractedsampleisthensenttoalaboratoryforanalysis.
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 D 4177). 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 continually test material from the process or in-line blended stream for the
desired property 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-
proportionaverageusingallavailablepropertyvaluesfromtheanalyticalmeasurementsystemandthe
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. Scope of in-line blended product or process stream material that is
collected over time and isolated in a storage tank or vessel,
1.1 This practice covers a technique for calculating a
using a combination of on-line or at-line measurements of the
flow-proportioned average property value (FPAPV) for a batch
property and flow rates.
1.2 The FPAPV methodology uses regularly collected on-
This practice is under the jurisdiction of ASTM Committee D02 on Petroleum
line or at-line process analyzer measurements, flow, and
Products and Lubricantsand is the direct responsibility of Subcommittee D02.25on
assessment of other appropriate process measurements or
Performance Assessment and Validation of Process Stream Analyzer Systems for
values, to calculate a flow-proportioned average property value
Petroleum and Petroleum Products.
in accordance with flow quantity units of material produced.
Current edition approved Jan. 10, 2001. Published March 2001.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D6624–01
A · P 1 A · P 1 A · P 1 A · P 1. 1 A · P
1.3 When the collecting vessel contains a heel (retained
1 1 2 2 3 3 4 4 N N
P 5
MIXED
A 1 A 1 A 1 A 1. 1 A
material prior to receipt of the production batch), both the 1 2 3 4 N
(1)
property value and quantity of the heel material can be
A 5 A 1 A 1 A 1 A 1. 1 A (2)
pre-determined and factored into the calculation of the FPAPV
MIXED 1 2 3 4 N
for the new batch.
where:
1.4 This standard does not purport to address all of the
A = quantity of material N,
N
safety concerns, if any, associated with its use. It is the
P = property of material N,
N
responsibility of the user of this standard to establish appro-
P = property of mixed material, and
MIXED
priate safety and health practices and determine the applica-
A = quantity of mixed material.
MIXED
bility of regulatory limitations prior to use.
3.1.4.2 Discussion—The material being mixed can be from
the same process stream over time.
2. Referenced Documents
4. Significance and Use
2.1 ASTM Standards:
D 3764 Practice for Validation of Process StreamAnalyzers
4.1 Contractual or local regulation, or both, permitting, the
FPAPV calculated according to this practice can be used to
D 4057 Practice for Manual Sampling of Petroleum and
represent the average property of the quantity of material
Petroleum Products
collected.
D 4177 Practice for Automatic Sampling of Petroleum and
4.2 Due to the averaging and appropriate weighting of
Petroleum Products
analysis results, the FPAPV estimate of the property for the
D 5842 Practice for Sampling and Handling of Fuels for
collected material is expected to be more representative and
Volatility Measurement
more precise than an estimate based on a small number of
D 6299 Practice for Applying Statistical Quality Assurance
analyses on a few samples.
Techniques to Evaluate Analytical Measurement System
4.3 If the measured property value can be used to predict
Performance
another property value through the use of an appropriate
correlation equation, the FPAPV can also be used as a suitable
3. Terminology
prediction of that property.
4.4 The most recently updated FPAPV can be used to
3.1 Definitions:
represent the property of the material currently accumulated in
3.1.1 analysis cycle time, n—the period of time required to
the tank or vessel for process control or material, or both,
properly obtain and analyze a representative sample of the
disposition decisions.
process stream material.
3.1.2 flow-proportioned average property value (FPAPV),
5. General Requirements
n—the average property value of the collected material in the
5.1 The analytical and flow measurement instrumentation
tank or vessel, calculated by using the flow-proportioned
systems shall be installed in compliance with the principles set
average technique described in the practice of all measure-
forth in API TP-550.
ments performed on aliquots of the material while it is flowing
5.2 The property being measured shall be linearly mixable
into the tank or vessel.
within the range of the property measurements used to calcu-
3.1.2.1 Discussion—The term property as used in this
late FPAPV, and with respect to the quantity units (volume or
practicecanbethephysical,chemical,orperformanceproperty
mass).
measurements as provided by on-line, at-line analyzer systems,
5.3 The integrity of the design, physical components and
or, can be the deviation of such measurements from a desired
assemblies of both the analytical measurement system (inclu-
value.
sive of the sampling subsystem), and the instrumentation for
3.1.2.2 Discussion—The FPAPV can include a value con-
flow quantity measurement shall be determined and docu-
tributed by material (commonly referred to as a tank heel)
mented at the
...