ASTM D6543-2000(2006) Standard Guide to the Evaluation of Measurements Made by On-Line Coal Analyzers《用流线煤分析仪进行的测量评价的标准指南》.pdf

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1、Designation: D 6543 00 (Reapproved 2006)Standard Guide tothe Evaluation of Measurements Made by On-Line CoalAnalyzers1This standard is issued under the fixed designation D 6543; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the y

2、ear of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This guide provides techniques to be used for theevaluation of the measurement performance of on-line coalanal

3、yzers.1.2 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 and health practices and determine the applica-bility of regulatory limitations prior to use.2. Refere

4、nced Documents2.1 ASTM Standards:2D 121 Terminology of Coal and CokeD 2013 Practice for Preparing Coal Samples for AnalysisD 2234/D 2234M Practice for Collection of a Gross Sampleof CoalD 4702 Guide for Quality Management of Mechanical CoalSampling SystemsD 6518 Practice for Bias Testing a Mechanica

5、l Coal Sam-pling SystemE 177 Practice for Use of the Terms Precision and Bias inASTM Test MethodsE 178 Practice for Dealing With Outlying ObservationsE 456 Terminology Relating to Quality and Statistics3. Terminology3.1 Definitions:3.1.1 analyzer system, na coal quality measurement sys-tem which inc

6、ludes an on-line coal analyzer and which mayinclude one or more stages of a coal-sampling system.3.1.2 calibration, nmathematical modeling of analyzerand comparative coal sampling and analysis data. Factors fromthe model are used in the on-line analyzer control software.3.1.3 Grubbs estimator, nan e

7、stimate of the measurementprecision of an on-line analyzer (1-3).33.1.4 on-line analyzer, nan analytical tool consisting ofan instrument and systems, which together provide measure-ments, or estimates, or both, of coal quality parameters.3.1.5 outlier, nan extreme value that statistical testsindicat

8、e to be far enough from other results in a populationunder consideration to cause suspicion that the value is not amember of the population.3.1.6 reference material, nmaterial of stable compositionthat may be used to generate static analyzer measurements.3.1.7 reference system, na measurement system

9、 used tomeasure the characteristics of a lot of coal that are alsomeasured by an on-line-analyzer, and against which the on-lineanalyzer measurements are compared.3.1.8 standardization, ncalibration of an instrument to areference material using static stability measurements.3.1.9 static stability, n

10、an estimate of the measurementprecision of an instrument obtained on material that is notmoving. The estimate normally is expressed as the standarddeviation and average of the measurements for a given periodof time.3.1.10 synchronization error, nan error that occurs fromcomparing measurements made b

11、y an on-line analyzer and areference system that are not measuring exactly the same lotbecause of temporal and/or spatial offsets.4. Summary of Guide4.1 This guide outlines the evaluation of the measurementperformance of an on-line analyzer using comparative mea-surements. The comparative test uses

12、a paired comparison ofanalysis from a reference method using ASTM sampling,sample preparation, and analysis methods for a lot of coal withthe analysis from the on-line analyzer for the same lot of coal.The data resulting from the comparative test may be evaluatedusing graphical and statistical techn

13、iques outlined below.4.2 Various techniques are recommended by on-line ana-lyzer manufacturers for standardization or static testing. These1This guide is under the jurisdiction of ASTM Committee D05 on Coal andCoke and is the direct responsibility of Subcommittee D05.23 on Sampling.Current edition a

14、pproved April 1, 2006. Published April 2006. Originallyapproved in 2000. Last previous edition approved in 2000 as D654300e12For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, r

15、efer to the standards Document Summary page onthe ASTM website.3The boldface numbers in parentheses refer to the list of references at the end ofthis standard.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.techniques are useful for

16、establishing a benchmark beforeconducting a comparative test. These techniques also may beused as diagnostic tests in accordance with methods recom-mended by on-line analyzer manufacturers and graphical andstatistical techniques included in this guide.5. Significance and Use5.1 On-line analyzers are

17、 used to provide quality data onlots of coal. The resulting quality data are used as a productiontool or for some contractual application. This guide providesmeans of evaluating the system and data produced.5.2 The user should become familiar with the documentsterminology and layout. The section on

18、test design and datacollection will provide the means by which all the analysis datawill be gathered. The test design should be carefully consid-ered so as to assure meeting the users requirements.5.3 The procedures defined in this guide can be used to testthe accuracy and precision of an on-line an

19、alyzer, for accep-tance after its installation, to check precision and accuracyduring routine use (quality control), when changes are made tothe system, when the nature of the coal being tested changes,and to determine mathematical factors to be used for calibra-tion of the on-line analyzer.6. Selec

20、tion and Conduct of Performance Evaluations6.1 Introduction:6.1.1 Several techniques can be used to evaluate the perfor-mance of an on-line analyzer. These techniques provide datathat can be evaluated by using the graphical and statisticalmethods described in Section 7 of this guide.6.1.2 At time of

21、 installation, all of the graphical andnumerical methods outlined in this may prove useful. On aroutine basis, conducting any of the instrument stability checksand comparative evaluations that do not disrupt normal opera-tions may prove useful. Control charts may be applied to all theperformance mea

22、sures that are gathered on a routine basis, forexample, mean analysis value of reference material, RMSD,and so forth.6.1.3 In the event that there is a change to the operationalparameters or the equipment associated with the analyzer or thereference system, comparative checks should be performed. In

23、addition to comparative checks, standardization or staticchecks, or both, as recommended by the on-line analyzermanufacturer may be helpful.6.1.4 Changes in the following may impact performanceevaluations. Coal characteristics, such as particle size, sourceof coal, mining techniques, degree of prepa

24、ration, and so forth,which if changed from previous test periods and are not in theanalyzer calibration database, may affect analyzer precisionand accuracy:6.1.4.1 Analyzer components;6.1.4.2 Coal-handling system;6.1.4.3 Laboratory services;6.1.4.4 Sampling technique;6.1.4.5 Coal flow rates; and6.1.

25、4.6 Power disturbances.6.2 Static Stability Measurements for BaselineAssessmentA reference material may be used to provide abaseline assessment of static measurement precision. Thereference material may be used to compare current mean andstandard deviation values with previous mean and standarddevia

26、tion values, previously collected in the same manner. Theresulting comparative data may be used to assess whether anychange in the mean or standard deviation of the static mea-surements may be attributed to a change in the operatingcharacteristics of the analyzer, in the absence of the influenceof s

27、ampling and analysis.6.2.1 Reference materials may include actual coal in asealed container, cast high-carbon solids, or other materialswhich may be provided by the analyzer manufacturer. Theprimary characteristic of these materials is that they not besubject to changes in composition.6.2.2 The resu

28、lts of this evaluation can indicate whetheranalyzer performance has significantly degraded or whether ashift may have occurred. If so, it may be possible to adjust theanalyzer to restore initial performance. If the user wishes onlyto measure current static repeatability, any available coal maybe use

29、d in the analysis zone of the analyzer. Note, however,that the actual standard deviation in static repeatability testsmight be influenced by the composition of the coal beingexamined or analyzer factors, such as the strength of theradioactive sources used by the analyzer or condition ofanalyzer elec

30、tronic components.6.2.3 It is essential that the length of the analysis period bedefined, for example, 1, 2, or 5 min, and be constant in thestatic stability test. The static standard deviation resulting fromthe static stability test decreases as the length of the analysisperiod increases. Static st

31、ability testing may be conducted onthe same day(s) as comparative tests. One type of static testinvolves a comparison of the analyzer to static coal over manyhours.6.3 Comparison of Analyzer System to Reference SystemMeasurements:6.3.1 Once an analyzer installation has been completed andcalibration

32、adjustments have been made, the analyzer ownermay require acceptance testing. Also, the analyzer owner maydecide to relocate the analyzer. In these cases, comparisontests, that is, to compare the analyzer system results toconventional sampling and analysis techniques, will providethe user calibratio

33、n verification data and/or data that could beused for recalibration of the analyzer.6.3.2 Depending upon the comparative technique chosen,there may be need for more than one comparison. Thesecomparisons may be conducted in a batch over several hours ordays or continuously throughout the operational

34、life of theanalyzer system.6.3.3 If two independent conventional coal-sampling andlaboratory analysis measurements can be made from each of aseries of batches of coal interrogated by the analyzer, methodsdeveloped by Grubbs (1-3) can be used to provide unbiasedestimates of the measurement precision

35、of the analyzer and ofthe conventional sampling and analysis methods.6.3.4 Any two series of measurements are independent iftheir measurement errors are uncorrelated. Correlation ofmeasurement errors can be avoided and independence assuredby use of a true random selection of physical increments orD

36、6543 00 (2006)2samples of material or by using different schemes and equip-ment for collection, preparation, and laboratory analysis of thesamples, or both. A complete treatment of the subject ofindependence of measurements and the various means ofassuring independence is beyond the scope of this gu

37、ide.6.4 Sampling Considerations:6.4.1 Selection of Appropriate Sampling and Sample Prepa-ration MethodsThe following increment collection methods(see Test Methods D 2234) are listed in general order ofpreference; this preference is not rigid. Often, practical con-siderations may supercede increment

38、selection decisions. Themethod to be used for sample preparation should be determinedbefore the beginning of increment collection. Sample prepara-tion techniques should remain consistent (see Method D 2013).Before installation of the analyzer, consideration should begiven to the ability to obtain re

39、presentative samples forcomparison to analyzer measurements and the regimen forsample handling and analysis. For the use of mechanicalsampling systems, inspection (see Guide D 4702) and biastesting (see Practice D 6518) are good methods for evaluationof the systems suitability for the test.6.4.1.1 F

40、ull Stream CutsWhenever possible, the fullstream cut method of increment collection should be used inthe evaluation of an on-line analyzer. This is imperative fordrawing inference using statistical techniques.6.4.1.2 Stopped Belt CutAlthough using “stopped belt”increments allows drawing statistical

41、inferences from the data,the stopped belt increment has limited applicability in theevaluation of on-line analyzers. This especially is true incollection of a sample from the lot interrogated by an analyzeroperating in conjunction with a mechanical sampling system.The stopped belt increment may have

42、 applicability in instancesin which the analyzer is used in conjunction with mechanicalsampling, and the discharge of the analyzer may be meteredonto a belt that is subject to stopping without interference withthe analyzers operation. The stopped belt increment may beuseful in evaluating analyzers t

43、hat are not associated withmechanical sampling and that are being evaluated for veryshort-term performance, that is, less than 1-min results. In suchinstances, each stop of the belt is used to collect a sample froma relatively long portion of the belt. As an example, theanalyzer might collect data f

44、or 30 s and the belt stopped in sucha manner as to allow access to the entire segment of materialinterrogated by the analyzer (typically, 300 ft for a belt running600 ft/min for 30 s). A sample may now be collected byremoving increments from the stopped belt throughout theentire stopped portion. Thi

45、s method reduces the number of beltstops required to assemble a database but is limited inapplicability by the short analysis time and physical require-ments of the facility wherein the equipment is installed.Nevertheless, this technique may be considered when noreliable mechanical technique is avai

46、lable and the alternative isa manual part stream cut.6.4.1.3 Part Stream IncrementsThis mode of sample col-lection may be required in the evaluation of analyzers notassociated with mechanical sampling or in some tests in whichmore than one comparison will be made. Since this type ofsample does not a

47、llow statistical inferences to be drawn in arigorous manner, its use is discouraged. Indeed, the only use ofthis type of comparison might be for control charting purposesrelative to an historical reference.6.4.2 Selection of Reference Sample Point(s):6.4.2.1 Comparative tests can be used to evaluate

48、 theperformance of either the analyzer itself or the “analyzersystem” (consisting of the analyzer and the sampling systemthat feeds it). The comparative evaluations of the analyzersystem can be used to determine the ability of the analyzersystem to measure the characteristics of the main coal stream

49、.The selection of the reference system sample point(s) deter-mines whether the comparative tests will assess the analyzer orthe analyzer system.6.4.2.2 The most direct and practical two-instrument test,when the analyzer is fed the secondary reject of a mechanicalsampling system, uses the final save to compare directly to theanalyzer. A manual or mechanical sample collected from theanalyzer discharge may provide an independent sample, whichmay be used to assess the performance of the analyzer (seeFigs. 1-3).6.4.2.3 There are instances when there is no save sample(see