ASTM_D_6624_-_20.pdf

Designation:D662420Standard 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 indicates 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 value 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,taken 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 property 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 1960s,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 ofa 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 orD7453).This sample,collected over the period of time required to generate the batch quantity ofproduct,is then analyzed using a primary test method in the laboratory.Multiple laboratory analyseson one or more aliquots of composite sample can be averaged to provide a more precise estimate ofthe property value than a single analysis.A second technique utilizes the results produced by on-line,at-line,or in-line analyticalmeasurement systems that test material from the process or in-line blended stream for the desiredproperty at regular intervals as it flows to a collection tank,pipeline,or shipping compartment.Todetermine the average property value of all the material collected(or shipped)at any time during theproduction process,a unique real time flow-proportioned averaging technique evolved.By appropriateselection 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 aflow-proportion average using all available property values from the analytical measurement systemand the measured incremental quantity of product flow associated with each cycle.The determinationof 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 StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade(TBT)Committee.1.Scope*1.1 This practice covers a technique for calculating aflow-proportioned average property value(FPAPV)for a batchof in-line blended product or process stream material that iscollected over time and isolated in a storage tank or vessel,using a combination of on-line or at-line measurements takenat 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,andassessment of other appropriate process measurements orvalues,to calculate a flow-proportioned average property valuein accordance with flow quantity units of material produced.1.3 When the collecting vessel contains a heel(retainedmaterial prior to receipt of the production batch),both theproperty value and quantity of the heel material can bepredetermined and factored into the calculation of the FPAPVfor the new batch.1.4 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is theresponsibility of the user of this standard to establish appro-priate safety,health,and environmental practices and deter-mine the applicability of regulatory limitations prior to use.1.5 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decis