1、Designation: D 4179 01 (Reapproved 2006)Standard Test Method forSingle Pellet Crush Strength of Formed Catalyst Shapes1This standard is issued under the fixed designation D 4179; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the
2、year 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 test method covers determining the resistance offormed catalysts to compressive force and is applicable
3、toregular catalyst shapes such as tablets and spheres. Extrudates,granular materials, and other irregular shapes are specificallyexcluded.1.2 This test method determines the average crush strengthin the range from 0 to 50 lbf (0 to 220 N).1.3 The values stated in inch-pound units are to be regardeda
4、s standard. The values given in parentheses are mathematicalconversions to SI units that are provided for information onlyand are not considered standard.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 t
5、his standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2E 177 Practice for Use of the Terms Precision and Bias inASTM Test MethodsE 456 Terminology Relating to Quality and St
6、atisticsE 691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test Method3. Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 pelletsany catalyst shapetablets, spheres, or othersimilar configurationthat is not otherwise excluded from thescope of this
7、 test method.3.1.2 tabletstableted cylindrical catalyst particles, eithersolid or hollow core, with lengths that do not vary from themean by more than 610 %.4. Summary of Test Method4.1 Individual pellets taken from a representative sample areplaced between two flat surfaces, subjected to a compress
8、iveload, and the force required to crush the pellet is measured. Theprocedure is replicated and the average of all measurementstaken is determined.5. Significance and Use5.1 This test method is intended to provide informationconcerning the ability of a catalyst shape to retain physicalintegrity duri
9、ng use.6. Apparatus6.1 A suitable compression testing device is required, con-sisting of the following:6.1.1 Calibrated Gauge, marked for direct reading of theforce in pounds (newtons). Additionally, a suitable system(mechanical, hydraulic, or pneumatic) must be provided so thatthe rate of force app
10、lication is both uniform and controllablewithin specified limits.6.1.2 Tool Steel Anvils, between which the sample will becrushed. The faces of the tool steel anvils shall be smooth andfree from recesses or ridges that would interfere with uniformcontact along the major axis of the pellet. When test
11、ing tabletsor spheres, the anvils may be of any convenient size or shapeas long as their length and width are greater than the corre-sponding dimensions of the tablet or pellet being tested (seeFig. 1).7. Sampling7.1 A test sample of 50 to 200 individual pieces shall beobtained from larger composite
12、s by riffling or splitting inaccordance with STP 447A,3(paragraph 5.12) with the aim ofobtaining a representative sample that represents shape andsize distribution of the larger composite. The size of the sampleshall depend on the precision required and the homogeneity ofthe material being tested.7.
13、2 Heat the test sample(s) at 400 6 15C for not less than3 h. Normally, this treatment can take place in air; however, in1This test method is under the jurisdiction of ASTM Committee D32 onCatalysts and is the direct responsibility of Subcommittee D32.02 on Physical-Mechanical Properties.Current edit
14、ion approved April 1, 2006. Published April 2006. Originallyapproved in 1982. Last previous edition approved in 2001 as D 417901.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume informati
15、on, refer to the standards Document Summary page onthe ASTM website.3STP 447A, Manual on Test Sieving Methods, ASTM International, WestConshohocken, PA 19428.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.the case of materials that
16、might react with air at elevatedtemperatures (such as prereduced catalysts) the heat treatmentshould take place in an inert atmosphere.7.3 After heating, cool the test sample(s) in a desiccator orother suitable container to eliminate the possibility of moistureadsorption prior to testing.NOTE 1Since
17、 many catalyst formulations are strong adsorbents, theuse of 4A indicating (cobalt-treated) molecular sieves as a desiccatingmedium is suggested. Regenerate the desiccant at 220 to 260C, asrequired.8. Calibration and Standardization8.1 Prior to use, set the test apparatus to zero and calibratewith a
18、ny commercially available force gauge with markedgraduations of no more than12 lbf (2 N) and having accuracytraceable to the National Institute of Standards andTechnology,or other similar authority.9. Procedure9.1 Remove from the desiccator only that number of pelletsthat can be tested within a 10-m
19、in period. (WarningEnsurethat moisture pick-up in the 10-min period will not signifi-cantly affect the pellet crush strength.)9.2 Place a single catalyst pellet between the anvils of thecompression testing device. Orient each pellet in the samedirection before crushing. For those pellets capable of
20、beingtested in different orientations, report the one used. Fig. 1shows pellets in radial and axial orientations. Use tweezers,forceps, or other suitable device or procedure to prevent thetransfer of moisture from the operators hands to the piecebeing tested.9.3 Apply increasing force at a uniform r
21、ate in the range of1 to 10 lbf/s (4.4 to 44 N/s) until the pellet crushes or collapses.Compression of surface irregularities or limited fracturing of apellet followed by continued resistance to increasing load arenot to be used as criteria for determining the end-point of thistest.9.4 Read and recor
22、d, to the nearest one-half graduation, theforce indicated on the calibrated dial of the apparatus at theinstant of collapse.9.5 Separate the anvils and remove all residue with a softcloth or brush. Ensure that the faces of the anvils are free fromadhering particles.9.6 Repeat steps 9.2 through 9.5 u
23、ntil all pellets in thesample have been crushed. Record the crush strength for eachpellet tested.10. Calculation10.1 Calculate the average crush strength ( X), retaining onemore decimal place than the recorded values, as follows:Xlbf N! 5 (X!/n! (1)where:(X = the sum of all observed crush strengths
24、andn = the number of pellets crushed.10.2 Calculate the standard deviation of the n readings tothree significant digits as follows:S 5( X 2 X!2n 2 1lbf N! (2)where:S = standard deviation of the individual strengthvalues and(X X)2= sum of the squares of the deviations of eachrecorded reading from the
25、 average strength.NOTE 2Many calculators are programmed to perform these opera-tions and to report average and standard deviation directly. It is importantto verify that the program chosen uses the n 1 denominator rather thann in calculating standard deviation.11. Report11.1 Report the average crush
26、 strength to one more decimalplace than the recorded data on the individual strengths. Forpellets capable of being tested in different orientations, the oneused should be reported.11.2 Report the 80 % spread (that is, the range within which80 % of the individual pellet strengths are expected to fall
27、,assuming that individual pellets form a normal distribution).Calculate as follows:80 % spread 5 X6 1.28S (3)11.3 Report the 95 % reliability of the average reported in11.1. This is the uncertainty inherent in the reported average,expressed as the range within which 95 % of the averages of aninfinit
28、e number of test samples of n pellets would be expectedto fall were they to be similarly drawn from the same lot andtested. Calculate as follows:95 % reliability 5 X6 1.96 S/=n (4)11.4 Report the applied rate of force increase, if available.12. Precision and Bias412.1 Test ProgramAn interlaboratory
29、study was con-ducted in which the named property was measured in two4Supporting data have been filed at ASTM International Headquarters and maybe obtained by requesting Research Report RR:D321004 and RR:D321024.FIG. 1 Radial and Axial CrushD 4179 01 (2006)2separate test materials in six separate lab
30、oratories. PracticeE 691, modified for nonuniform data sets, was followed for thedata reduction. Analysis details are in the research report.12.2 PrecisionPairs of test results obtained by a proce-dure similar to that described in the study are expected to differin absolute value by less than 2.772
31、S, where 2.772 S is the95 % probability interval limit on the difference between twotest results, and S is the appropriate estimate of standarddeviation. Definitions and usage are given in TerminologyE 456 and Practice E 177, respectively.Test Result (ConsensusMean) lbf95 % Repeatability Inter-val (
32、Within Laboratory)lbf (% of mean)95 % Reproducibility Inter-val (Between Laborato-ries) lbf (% of mean)20.19 (Spheres) 1.22 (6.03) 1.76 (8.74)16.50 (Tablets) 1.00 (6.03) 2.77 (16.8)12.3 BiasThis test method is without known bias.13. Keywords13.1 catalyst; crush strength; single pelletASTM Internatio
33、nal takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their
34、 own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be
35、 addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards
36、, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).D 4179 01 (2006)3
