ASTM D4781-99

NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
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Designation: D 4781 – 99
Standard Test Method for
Mechanically Tapped Packing Density of Fine Catalyst
Particles and Catalyst Carrier Particles
This standard is issued under the fixed designation D 4781; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope 5.4 Counter—A four-digit adjustable counter, which can be
preset to deliver number of taps between 1 and 9999.
1.1 This test method covers the determination of the me-
5.5 Desiccator, with a desiccant grade molecular sieve such
chanically tapped packing density of fine catalyst and catalyst
as 4A.
carrier particles smaller than 0.8 mm in diameter.
5.6 Balance having a sensitivity of 0.1 g.
1.2 This standard does not purport to address all of the
5.7 Drying Oven.
safety concerns, if any associated with its use. It is the
responsibility of the user of this standard to establish appro-
6. Procedure
priate safety and health practices and determine the applica-
6.1 Heat an adequate sample at 673 K (400°C ) 6 15 K for
bility of regulatory limitations prior to use.
not less than 3 h. Normally, this treatment can take place in air.
2. Referenced Documents However, in the case of materials that might react with air at
elevated temperature (such as prereduced catalysts) the heat
2.1 ASTM Standards:
treatment should take place in an inert atmosphere. After
E 177 Practice for Use of the Terms Precision and Bias in
heating, cool the test sample in a desiccator or other suitable
ASTM Test Methods
2 container to eliminate the possibility of moisture adsorption
E 456 Terminology Relating to Quality and Statistics
prior to testing.
E 691 Practice for Conducting an Interlaboratory Study to
Determine the Precision of a Test Method
NOTE 1—These conditions may not be appropriate for all materials.
NOTE 2—Since many catalyst formulations are strong adsorbents, the
3. Summary of Test Method
use of 4A indicating (cobalt-treated) molecular sieves as a desiccating
medium is recommended. The desiccant should be regenerated at 493 K
3.1 A preconditioned sample of dried fine catalyst or cata-
(220°C) to 533 K (260°C), as required.
lyst carrier particles is tapped in a graduated cylinder. The
NOTE 3—Multiple samples can be pretreated but must be desiccated
mechanically tapped packing density is determined from the
prior to analysis.
known weight and tapped volume.
6.2 Carefully pour between 90 and 100 mL of the test
4. Significance and Use
specimen into the tared-graduated cylinder using a funnel. To
ensure proper level, rotate the funnel while pouring the test
4.1 This test method is for measuring the mechanically
specimen. Weigh immediately to the nearest tenth of a gram.
tapped packing density of powders that are smaller than 0.8
The entire transfer time should be between 35 and 50 s.
mm in diameter, such as Fluidized Catalytic Cracking Catalysts
6.3 Preset the counter to 1000 taps.
(FCC).
6.4 Start the tapping device.
5. Apparatus
6.5 When tapping is completed, read the tapped volume, V,
to the nearest 1 mL by estimating the average level of the
5.1 Graduated Cylinder, capacity 100 mL.
catalyst surface in the cylinder.
5.2 Holder—A cylinder holder weighing 454 g (1 lb).
5.3 Tapping Device, consisting of a baseplate with worm
...