1、 IT IS THE USERS RESPONSIBILITY TO ESTABLISH APPROPRIATE PRECAUTIONARY PRACTICES AND TO DETERMINE THE APPLICABILITY OF REGULATORY LIMITATIONS PRIOR TO USE. EFFECTIVE HEALTH AND SAFETY PRACTICES ARE TO BE FOLLOWED WHEN UTILIZING THIS PROCEDURE. FAILURE TO UTILIZE THIS PROCEDURE IN THE MANNER PRESCRIB
2、ED HEREIN CAN BE HAZARDOUS. SAFETY DATA SHEETS (SDS) OR EXPERIMENTAL SAFETY DATA SHEETS (ESDS) FOR ALL OF THE MATERIALS USED IN THIS PROCEDURE SHOULD BE REVIEWED FOR SELECTION OF THE APPROPRIATE PERSONAL PROTECTION EQUIPMENT (PPE). COPYRIGHT 1982, 1985, 1990, 2014 UOP LLC. All rights reserved. Nonco
3、nfidential UOP Methods are available from ASTM International, 100 Barr Harbor Drive, P.O. Box C700, West Conshohocken, PA 19428-2959, USA. The UOP Methods may be obtained through the ASTM website, www.astm.org, or by contacting Customer Service at serviceastm.org, 610.832.9555 FAX, or 610.832.9585 P
4、HONE. Packed Apparent Bulk Density of Molecular Sieves UOP Method 563-14 Scope This method is for determining the packed apparent bulk density (ABD) of molecular sieves on an as-received basis. Apparent bulk density is an empirical value defined as mass per unit volume, which includes the void space
5、s between the particles, and is reported as grams per milliliter (g/mL). Reference UOP Method 999, “Precision Statements in UOP Methods,” www.astm.org Outline of Method A 100-mL graduated cylinder is slowly filled with a representative sample in a dry nitrogen atmosphere. While it is being filled, t
6、he cylinder is agitated with a mechanical vibrator. After additional vibration time, the sample mass and volume are recorded. The mass per unit volume of the sample is calculated. Apparatus References to catalog numbers and suppliers are included as a convenience to the method user. Other suppliers
7、may be used. Balance, readable to 0.01 g Cylinder, graduated, borosilicate glass, 100-mL capacity, $T 24/40 joint, one-milliliter subdivisions, calibrated “to contain,” with TFE stopper, Fisher Scientific, Cat. Nos. 08-567-1B and 14-642-17C, respectively Flow meter, 0-1200 mL/min (0-2.5 SCFH), Omega
8、 Engineering, Cat. No. FL-3402C Funnel, powder, glass, 65-mm ID, 15-mm stem OD, Fisher Scientific, Cat. No. 10-346A Rag, shop wiping, local supply Regulator, nitrogen, two-stage, 0-345 kPa (0-50 psi), Matheson, Model No. 81-580 Timer, 60-minute, Fisher Scientific, Cat. No. 06-656-1E Transformer, var
9、iable, 120 V, 10 A, VWR Scientific, Cat. No. 62546-251 2 of 4 563-14 Tubing, Tygon, approximately one-meter long, 4.8-mm ID, by 7.9-mm OD, Fisher Scientific, Cat. No. 14-169-3B Vibrating table, Syntron Model J-1, FMC Technologies Reagents and Materials References to catalog numbers and suppliers are
10、 included as a convenience to the method user. Other suppliers may be used. Nitrogen, extra dry, 99.9% minimum purity Procedure The analyst is expected to be familiar with general laboratory practices and the equipment being used. Dispose of used supplies and samples in an environmentally safe manne
11、r according to applicable regulations. Apparatus Set Up 1. Plug the timer into a 120 V outlet. 2. Set the timer outlet switch to off and plug the transformer into the timer outlet. 3. Plug the vibrator into the transformer. This configuration automatically starts the vibrator when the timer is turne
12、d on and shuts it off when the timer reaches zero. 4. Place a shop wiping rag or similar cloth across the top of the vibrator. The cloth, which reduces the noise, can be held in place with rubber bands. 5. Attach the nitrogen regulator to the nitrogen source. 6. Connect the inlet side of the flow me
13、ter to the low pressure side of the regulator and attach approximately one meter of Tygon tubing to the discharge side of the flow meter. Analysis Molecular sieves absorb moisture from the air very quickly. The measured ABD varies according to the moisture content of the sieve and, therefore, exposu
14、re of the sample to air must be minimized. 1. Weigh the dry, empty, 100-mL graduated cylinder with stopper to the nearest 0.01 g. 2. Set the nitrogen regulator to 140-280 kPa (20-40 psi) and adjust the flow meter to approximately 900 mL/min (2 SCFH). 3. Insert the free end of the Tygon tubing all th
15、e way down to the bottom of the graduated cylinder and purge for at least one minute. 4. Adjust the transformer to a setting of approximately 65% so that approximately 75 volts are supplied to the vibrator. 5. Set the timer to five minutes. Place the cylinder containing the purge tubing on the vibra
16、tor and insert the funnel into the top of the cylinder. 6. Pull the purge tube up until it is just below the bottom of the funnel. This position maintains a nitrogen blanket during the test. 3 of 4 563-14 7. Turn on the timer, which activates the vibrator, and begin pouring the sample into the funne
17、l using a slow circular motion so that 95-100 mL of the sample are added uniformly over a one-minute period. 8. Remove the nitrogen purge and funnel, stopper the cylinder and quickly adjust the transformer so that the sieves at the surface are moving in a rapid manner but not jumping wildly. This us
18、ually is a small 3% adjustment. 9. Continue to vibrate the sample until the timer shuts off the vibrator. The total vibration time must be 5 0.1 minutes. 10. Remove the cylinder from the vibrator, record the volume of sample to the nearest 0.5 mL and obtain the mass of the stoppered cylinder contain
19、ing the sample to the nearest 0.01 g. Calculations Calculate the packed ABD, as received, to three decimal places using the following formula: ABD, as received, g/mL = V TW where: T = mass of empty graduated cylinder, g V = volume of sample in the cylinder after vibration, mL W = mass of sample and
20、cylinder, g Precision Precision statements were determined using UOP Method 999, “Precision Statements in UOP Methods.” Repeatability, Site Precision, and Reproducibility A nested design was carried out for determining ABD in three laboratories, by two analysts in each laboratory, with each analyst
21、performing analyses on two separate days, performing two analyses each day for a total of 24 analyses. Using a stepwise analysis of variance procedure, the within-day, within-lab, and between-lab estimated standard deviations (esd) were calculated at the concentration means listed in the Table. Two
22、tests performed in one laboratory by the same analyst on the same day should not differ by more than the repeatability allowable differences shown in the Table with 95% confidence. Two tests performed in one laboratory by different analysts on different days should not differ by more than the site p
23、recision allowable differences shown in the Table at the concentrations listed (95% probability). Two tests performed in different laboratories by different analysts, on different days should not differ by more than the reproducibility allowable differences shown in the Table at the concentrations l
24、isted (95% probability). Table Repeatability, Site Precision, and Reproducibility, mass-% Repeatability Site Precision Reproducibility Mean Within- Day esd Allowable Difference Within- Lab esd Allowable Difference Between- Lab esd Allowable Difference 0.784 0.0047 0.014 0.0072 0.025 0.0126 0.044 The
25、 data in the Table represent short-term estimates of the repeatability of the method. When the test is run routinely, the use of a control standard and a control chart is recommended to generate an estimate of long-term repeatability. 4 of 4 563-14 Time For Analysis The elapsed time and labor requir
26、ement are identical, 0.6 hour. Suggested Suppliers Fisher Scientific, 300 Industry Dr., Pittsburgh, PA 15275, USA, 1-412-490-8300, FMC Technologies, Inc., 57 Cooper Ave., Homer City, PA 15748, USA, 1-724-479-4500, Matheson Tri-Gas, 166 Keystone Dr., Montgomeryville, PA 18936, USA, 1-215-641-2700, Omega Engineering, Inc., One Omega Dr., P.O. Box 4047, Stamford, CT 06907, USA, 1-203-359-1660, VWR International, 1310 Goshen Parkway, West Chester, PA 19380, USA, 1-610-431-1700,
