1、Designation: D 4781 03 (Reapproved 2008)Standard Test Method forMechanically Tapped Packing Density of Fine CatalystParticles and Catalyst Carrier Particles1This standard is issued under the fixed designation D 4781; the number immediately following the designation indicates the year oforiginal adop
2、tion or, in the case of revision, the 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 the determination of the me-chanically tapped p
3、acking density of fine catalyst and catalystcarrier particles smaller than 0.8 mm in diameter.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 prac
4、tices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D 3766 Terminology Relating to Catalysts and CatalysisE 177 Practice for Use of the Terms Precision and Bias inASTM Test MethodsE 456 Terminology Relating to Quality and Statistic
5、sE 691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test Method3. Terminology3.1 DefinitionsSee Terminology D 3766.4. Summary of Test Method4.1 A preconditioned sample of dried fine catalyst or cata-lyst carrier particles is tapped in a graduated cylinder. Themecha
6、nically tapped packing density is determined from theknown mass and tapped volume.5. Significance and Use5.1 This test method is for measuring the mechanicallytapped packing density of powders that are smaller than 0.8mm in diameter, such as Fluidized Catalytic Cracking Catalysts(FCC).6. Apparatus6.
7、1 Graduated Cylinder, capacity 100 mL.6.2 HolderA cylinder holder weighing 454 g (1 lb).6.3 Tapping Device, consisting of a baseplate with wormdrive, with specifications of 250 r/min camshaft speed, tappingstroke travel of 3.2 mm (18 in.).6.4 CounterA four-digit adjustable counter, which can beprese
8、t to deliver number of taps between 1 and 9999.6.5 Desiccator, with a desiccant grade molecular sieve suchas 4A.6.6 Balance having a sensitivity of 0.1 g.6.7 Drying Oven.7. Procedure7.1 Heat an adequate sample at 400 6 15C for not less than3 h. Normally, this treatment can take place in air. However
9、, inthe case of materials that might react with air at elevatedtemperature (such as prereduced catalysts) the heat treatmentshould take place in an inert atmosphere. After heating, coolthe test sample in a desiccator or other suitable container toeliminate the possibility of moisture adsorption prio
10、r to testing.NOTE 1These conditions may not be appropriate for all materials.NOTE 2Since many catalyst formulations are strong adsorbents, theuse of 4A indicating (cobalt-treated) molecular sieves as a desiccatingmedium is recommended. The desiccant should be regenerated at 220 to260C, as required.N
11、OTE 3Multiple samples can be pretreated but must be desiccatedprior to analysis.7.2 Carefully pour between 90 and 100 mL of the testspecimen into the tared-graduated cylinder using a funnel. Toensure proper level, rotate the funnel while pouring the testspecimen. Weigh immediately to the nearest ten
12、th of a gram.The entire transfer time should be between 35 and 50 s.7.3 Preset the counter to 1000 taps.7.4 Start the tapping device.7.5 When tapping is completed, read the tapped volume, V,to the nearest 1 mL by estimating the average level of thecatalyst surface in the cylinder.1This test method i
13、s under the jurisdiction of ASTM Committee D32 onCatalysts and is the direct responsibility of Subcommittee D32.02 on Physical-Mechanical Properties.Current edition approved April 1, 2008. Published May 2008. Originallyapproved in 1988. Last previous edition approved in 2003 as D 478103.2For referen
14、ced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West C
15、onshohocken, PA 19428-2959, United States.8. Calculation8.1 Calculate the mechanically tapped packing density asfollows:MTD 5 W/V (1)where:MTD = mechanically tapped packing density, g/mL,W = mass of catalyst particles, g, andV = volume occupied by particles in measuring cylin-der, mL.9. Precision an
16、d Bias39.1 Test ProgramAn interlaboratory study was conductedin which the named property was measured in two separate testmaterials in four separate laboratories. Practice E 691, modi-fied for non-uniform data sets, was followed for the datareduction. Analysis details are in the research report.9.2
17、PrecisionPairs of test results obtained by a proceduresimilar to that described in the study are expected to differ inabsolute value by less than 2.772 S, where 2.772 S is the 95 %probability interval limit on the difference between two testresults, and S is the appropriate estimate of standard devi
18、ation.Definitions and usage are given in Terminology E 456 andPractice E 177, respectively.Test Result(ConsensusMean), g/mL95 % Repeatability Interval(Within Laboratory) g/mL(mean %)95 % Reproducibility Interval(Between Laboratories) g/mL(mean %)0.61950.93550.005 g/mL (0.87)0.010 g/mL (1.07)0.060 (9
19、.74)0.041 (4.41)9.3 BiasThe procedure in this test method has no biasbecause the value of packing density can be defined only interms of the test method.10. Keywords10.1 catalyst; catalyst carrier; packing densityASTM International takes no position respecting the validity of any patent rights asser
20、ted 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 own responsibility.This standard is subject to revision at any time by
21、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 addressed to ASTM International Headquarters. Your comments will receiv
22、e 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, at the address shown below.This standard is copyrighted by ASTM Intern
23、ational, 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).3Supporting data have been filed at ASTM International Headquarters and maybe obtained by requesting Research Report RR: D32-1026.D 4781 03 (2008)2
