1、Designation: D6624 06 D6624 12Standard Practice forDetermining a Flow-Proportioned Average Property Value(FPAPV) for a Collected Batch of Process Stream MaterialUsing Stream Analyzer Data1This standard is issued under the fixed designation D6624; the number immediately following the designation indi
2、cates the year oforiginal adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.INTRODUCTIONThe determination of an average property v
3、alue that is representative of a batch of petroleumproduct collected and isolated in a tank or vessel has always been a challenge. Historically, theindustry practice has been to follow the appropriate procedures prescribed in Practices D4057, D5842,or D4177 to extract one sample (or a limited few, t
4、aken from top, middle, and bottom) from the tankor vessel after the content is mixed by any of several means to ensure the material is homogeneousprior to sample extraction. The extracted sample is then sent to a laboratory for analysis. Dependingon the property and its criticality, the average prop
5、erty value can also be obtained by independentlyanalyzing each of the top, middle, and bottom samples and the results averaged, or, the three tanksamples 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 19
6、60s, the potential forreal-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 blendor process stream, two approaches have been developed and implemented. One depends on the use o
7、fa composite sampler, a vessel into which a sample of the flowing process or blended product streamis introduced at a flow-rate proportional to the flow-rate of the product stream (Practice D4177). Thissample, collected over the period of time required to generate the batch quantity of product, is t
8、henanalyzed using a primary test method in the laboratory. Multiple laboratory analyses on one or morealiquots of composite sample can be averaged to provide a more precise estimate of the property valuethan a single analysis.A second technique utilizes the results produced by on-line, at-line, or i
9、n-line analyticalmeasurement systems that continually test material from the process or in-line blended stream for thedesired 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 sh
10、ipped) at any time duringthe production process, a unique real time flow-proportioned averaging technique evolved. Byappropriate 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 obtain
11、ed by recursivelycalculating a flow-proportion average using all available property values from the analyticalmeasurement system and the measured incremental quantity of product flow associated with eachcycle. The determination of this flow-proportioned average property value is the subject of thisp
12、ractice.1 This practice is under the jurisdiction of ASTM Committee D02 on Petroleum Products and Lubricants and is the direct responsibility of Subcommittee D02.25 onPerformance Assessment and Validation of Process Stream Analyzer Systems.Current edition approved July 1, 2006June 1, 2012. Published
13、 July 2006October 2012. Originally approved in 2001. Last previous edition approved in 20012006 asD662401.06. DOI: 10.1520/D6624-06.10.1520/D6624-12.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
14、previous version. Becauseit 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 versionof the standard as published by ASTM is to be considered the official document.Copyright AST
15、M International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States11. Scope Scope*1.1 This practice covers a technique for calculating a flow-proportioned average property value (FPAPV) for a batch of in-lineblended product or process stream material that is collect
16、ed over time and isolated in a storage tank or vessel, using a combinationof 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 assessmentof other ap
17、propriate process measurements or values, to calculate a flow-proportioned average property value in accordance withflow 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 propertyvalue and quantit
18、y 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 responsibilityof the user of this standard to establish appropriate safety
19、 and health practices and determine the applicability of regulatorylimitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D3764 Practice for Validation of the Performance of Process Stream Analyzer SystemsD4057 Practice for Manual Sampling of Petroleum and Petroleum ProductsD4177 Practi
20、ce for Automatic Sampling of Petroleum and Petroleum ProductsD5842 Practice for Sampling and Handling of Fuels for Volatility MeasurementD6299 Practice for Applying Statistical Quality Assurance and Control Charting Techniques to Evaluate Analytical Measure-ment System Performance3. Terminology3.1 D
21、efinitions:3.1.1 analysis cycle time, nperiod of time required to properly obtain and analyze a representative sample of the processstream material.3.1.2 flow-proportioned average property value (FPAPV), naverage property value of the collected material in the tank orvessel, calculated by using the
22、flow-proportioned average technique described in the practice of all measurements performed onaliquots of the material while it is flowing into the tank or vessel.3.1.2.1 DiscussionThe term property as used in this practice can be the physical, chemical, or performance property measurements as provi
23、ded byon-line, at-line analyzer systems, or, can be the deviation of such measurements from a desired value.3.1.2.2 DiscussionThe FPAPV can include a value contributed by material (commonly referred to as a tank heel) present in the collection tank orvessel before the start of delivery of the curren
24、t process stream material.3.1.3 fit-for-use, nproduct, system, or service that is suitable for its intended use.3.1.4 linearly mixable, adjproperty is deemed to be linearly mixable in a mass or volume measurement unit if the propertyof the mixed material can be calculated from the quantities and pro
25、perties of the materials used to produce the mixture.3.1.4.1 DiscussionThe general equations describing this linearly mixable attribute are as follows:PMIXED5A1P11A2P21A3P31A4P41.1ANPNA11A21A31A41.1AN(1)AMIXED5A11A21A31A41.1AN (2)2 For referenced ASTM standards, visit the ASTM website, www.astm.org,
26、 or contact ASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.D6624 122where:AN = quantity of material N,PN = property of material N,PMIXED = property of mixed material, andAMIXED = quantity
27、 of mixed material.3.1.4.2 DiscussionThe material being mixed can be from the same process stream over time.3.1.5 total analyzer system response time, ntime interval between when a step change in property characteristic at the sampleloop inlet and when the analyzer output indicates a value c corresp
28、onding to the 99.5 % of the subsequent change in analyzerresults; the total analyzer system response time is the sum of the sample loop lag time, the same conditioning loop lag time, andthe total analyzer response time. D37644. Significance and Use4.1 Contractual or local regulation, or both, permit
29、ting, the FPAPV calculated according to this practice can be used to representthe 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 collectedmaterial is expected to be more represe
30、ntative and more precise than an estimate based on a small number of analyses on a fewsamples.NOTE 1Theoretically speaking, the true property distribution for an infinite number of batches with essentially identical FPAPVs is expected to beGaussian, centered at the FPAPV value, with a standard devia
31、tion 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 correlationequation, the FPAPV can also be used as a suitable prediction of that propert
32、y.4.4 The most recently updated FPAPV can be used to represent the property of the material currently accumulated in the tankor vessel for process control or material disposition decisions, or both.5. General Requirements5.1 The analytical and flow measurement instrumentation systems shall be instal
33、led in compliance with the principles set forthin API TP-550.35.2 The property being measured shall be linearly mixable within the range of the property measurements used to calculateFPAPV, and with respect to the quantity units (volume or mass).5.3 The integrity of the design, physical components a
34、nd assemblies of both the analytical measurement system (inclusive ofthe sampling subsystem), and the instrumentation for flow quantity measurement shall be determined and documented at the timeof commissioning and at regular intervals thereafter. Factors to be addressed shall include, but not be li
35、mited to, the following:5.3.1 The sampling system design and operation shall ensure a sample representative of the process stream is delivered to theapplicable process stream analyzer.5.3.2 The process stream shall have dynamics such that the there is no substantial change in the property over the t
36、ime periodrequired to produce the analytical measurement system result used for FPAPV calculation at the end of each analysis cycle timeshall be representative of the property of the material produced during that time period.each FPAPV update calculation.5.3.3 Analyzer functions shall be in proper c
37、ondition to produce accurate property measurement results.5.3.4 During the calculation of FPAPV, inferential or other validation strategies shall be in place to ensure the analyticalmeasurement system results are representative of the material in the process stream. The effectiveness of these strate
38、gies shall besupported by data.NOTE 2Examples of these strategies can include, but are not limited to, the following: monitoring of appropriate system parameters to ensure eachsample is representative of the manufacturing process stream being analyzed; continuous comparison of an expected value of t
39、he stream measured versusactual result; monitoring for unusually large or unusually small changes of analytic data; monitoring of key analytical instrumentation parameters.5.3.5 Fit-for-use condition of the flow quantity measurement instrumentation shall be regularly verified using suitableequipment
40、 and apparatus.5.4 The analytical measurement system shall be commissioned, validated, and thereafter regularly monitored using a suitablydesigned internal quality assurance program that meets the appropriate requirements and criteria of Practice D3764 and thetechniques of Practice D6299.3 Part II P
41、rocess Stream Analyzers, Manual on Installation of Refinery Instruments and Control Systems, available from American Petroleum Institute, 1220 L St. NW,Washington, DC 200058197.D6624 123NOTE 3It is recommended that a statistician be consulted to ensure the proper application of Practices D6299 and D
42、3764.5.5 The final FPAPV shall be calculated based on fit-for-use data obtained from at least 90 % of the material collected.5.5.1 For the balance of the volume (up to 10%) that has no fit-for-use analyzer data, for the purpose of calculating FPAPV, anestimate based on knowledge of the manufacturing
43、 process, or another equivalent measurement, or both, shall be used. Themaximum error associated with this estimate that is deemed acceptable by this practice shall be no more than 2.5% of the trueproperty value.5.5.2 For measurement systems that are operated continuously and not started up nor shut
44、 down in batch mode insynchronization with the manufacturing process, the quality of the initial unmeasured volume can be estimated by applying theanalyzer result after waiting the total analyzer system response time (Practice D3764) from the initiation of the manufacturingprocess.5.6 For measuremen
45、t systems that are operated in batch mode in synchronization with the manufacturing process (that is, startedup and shut down with the manufacturing process), the statistical control status of the FPAPV measurement system shall bevalidated in accordance with Practice D6299 (or equivalent) at least o
46、nce for each batch, preferably in the beginning. Thefrequency of in-statistical-control validation when the manufacturing process is active shall commensurate with the establishedstability of the measurement system.5.7 The fit-for-use condition shall be initially validated with at least 15 data poin
47、ts using the approach described in PracticeD6299 for “Measurement System Bias Estimated from Multiple Measurements of a Single Check Standard.” In this case, thedifference between test results from aliquots of material that are obtained and analyzed with the measurement process (test method)that the
48、 FPAPV is intended to represent versus the actual calculated FPAPVs are assessed. This validation shall be subsequentlycarried out as part of a statistical quality assurance program meeting the requirement and guidelines of Practice D6299 for systemstability.NOTE 4It is recommended that a statistici
49、an be consulted to ensure the proper application of Practice D6299.5.8 If the FPAPV is used to predict another property value through the use of a correlation equation, the correlation equationshall be validated in accordance with Practices D3764, D6299, or other appropriate statistically equivalent techniques.6. FPAPV Calculation6.1 Determination of the flow-proportioned average property value is as follows:6.1.1 If the collecting tank or vessel contains a residual quantity of material from a previous batch (tank heel), obtain arepresentative sample of that
