1、Designation: D6646 03 (Reapproved 2014)Standard Test Method forDetermination of the Accelerated Hydrogen SulfideBreakthrough Capacity of Granular and Pelletized ActivatedCarbon1This standard is issued under the fixed designation D6646; the number immediately following the designation indicates the y
2、ear oforiginal adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method is intended to evaluate the performa
3、nceof virgin, newly impregnated or in-service, granular or pellet-ized activated carbon for the removal of hydrogen sulfide froman air stream, under the laboratory test conditions describedherein. A humidified air stream containing 1 % (by volume)hydrogen sulfide is passed through a carbon bed until
4、 50 ppmbreakthrough of H2S is observed. The H2S adsorption capacityof the carbon per unit volume at 99.5 % removal efficiency (gH2S/cm3carbon) is then calculated. This test is not necessarilyapplicable to non-carbon adsorptive materials.1.2 This standard as written is applicable only to granularand
5、pelletized activated carbons with mean particle diameters(MPD) less than 2.5 mm. See paragraph 5.3 if activatedcarbons with larger MPDs are to be tested.1.3 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of th
6、is 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:2D2652 Terminology Relating to Activated CarbonD2854 Test Method for Apparent Density of ActivatedCarbonD2867 Test Metho
7、ds for Moisture in Activated CarbonE300 Practice for Sampling Industrial Chemicals3. Terminology3.1 Terms relating to this standard are defined in D2652.4. Summary of Test Method4.1 Breakthrough capacity is determined by passing astream of humidified air containing 1 volume % hydrogensulfide through
8、 a sample of granular or pelletized activatedcarbon of known volume under specified conditions until theconcentration of hydrogen sulfide in the effluent gas reaches 50ppmv.5. Significance and Use5.1 This method compares the performance of granular orpelletized activated carbons used in odor control
9、 applications,such as sewage treatment plants, pump stations, etc. Themethod determines the relative breakthrough performance ofactivated carbon for removing hydrogen sulfide from a humidi-fied gas stream. Other organic contaminants present in fieldoperations may affect the H2S breakthrough capacity
10、 of thecarbon; these are not addressed by this test. This test does notsimulate actual conditions encountered in an odor controlapplication, and is therefore meant only to compare thehydrogen sulfide breakthrough capacities of different carbonsunder the conditions of the laboratory test.5.2 This tes
11、t does not duplicate conditions that an adsorberwould encounter in practical service. The mass transfer zone inthe 23 cm column used in this test is proportionally muchlarger than that in the typical bed used in industrial applica-tions. This difference favors a carbon that functions morerapidly for
12、 removal of H2S over a carbon with slower kinetics.Also, the 1 % H2S challenge gas concentration used hereengenders a significant temperature rise in the carbon bed. Thiseffect may also differentiate between carbons in a way that isnot reflected in the conditions of practical service.5.3 This standa
13、rd as written is applicable only to granularand pelletized activated carbons with mean particle diametersless than 2.5 mm. Application of this standard to activatedcarbons with mean particle diameters (MPD) greater than 2.5mm will require a larger diameter adsorption column. The ratioof column insid
14、e diameter to MPD should be greater than 10 inorder to avoid wall effects. In these cases it is suggested thatbed superficial velocity and contact time be held invariant atthe conditions specified in this standard (4.77 cm/sec and 4.81This test method is under the jurisdiction of ASTM Committee D28
15、onActivated Carbon and is the direct responsibility of Subcommittee D28.04 on GasPhase Evaluation Tests.Current edition approved Aug. 15, 2014. Published September 2014. Originallyapproved in 2001. Last previous edition approved in 2008 as D6646 03 (2008).DOI: 10.1520/D6646-03R14.2For referenced AST
16、M 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.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohoc
17、ken, PA 19428-2959. United States1sec).Although not covered by this standard, data obtained fromthese tests may be reported as in paragraph 12 along withadditional information about column diameter, volume ofcarbon, and volumetric flow rate used.5.4 For pelletized carbons, it is felt that the equiva
18、lentspherical diameter of the pellet is the most suitable parameterfor determining the appropriate adsorption column insidediameter. The equivalent spherical diameter is calculatedaccording to the following equation.Deqv53 XdXhd12 Xh(1)where:d = the diameter, andh = the length of the pellet in mm.An
19、 average of 50 to 100 measurements is recommended todetermine the average length of a pellet. AnnexA3 is a table toguide the user in selecting bed diameter and flow rates fromtypical equivalent diameters (or MPD) of pelletized carbon.6. Apparatus and Materials6.1 (561) % Hydrogen Sulfide in Nitrogen
20、 Mixture. Theconcentration of hydrogen sulfide in the gas test mixture mustbe known. It is recommended that gas cylinders specificallymanufactured for holding hydrogen sulfide gas be used. Ana-lyzed and certified hydrogen sulfide in nitrogen gas mixturescan be purchased from specialty gas suppliers.
21、 Annex A1 andAnnex A2 present methods that may be used to check thehydrogen sulfide concentration of hydrogen sulfide/nitrogengas mixtures. It is recommended that the hydrogen sulfideconcentration be checked if gas cylinders are stored for morethan three months, particularly after being partially de
22、pleted.Other organic contaminants that may be present in the hydro-gen sulfide tank can affect the adsorption capacity of the carbonbeing tested.6.2 Hydrogen Sulfide Detector. The hydrogen sulfide detec-tor used in this test must be demonstrated to reliably detect 50ppm hydrogen sulfide in a humidif
23、ied air stream. In addition tocertain “solid state” detectors, electrochemical type hydrogensulfide sensors, e.g., Ecolyzer Model 6400 or Interscan LD-17,have been evaluated and fit this requirement. Other means ofhydrogen sulfide detection may be selected, as long as they arecarefully calibrated an
24、d evaluated for this application.6.3 Adsorption Tube. The adsorption tube is shown in Fig.1. Adsorption tubes are not commercially available; however,they can be custom fabricated by a scientific glassblower. Theperforated support shown is necessary to support the carbonbed and to enhance diffusion
25、of the gases. (Adjust dimensionsaccordingly from Annex A3, specifically diameter.)6.4 Flowmeter (0-500 mL/min Nitrogen; see Annex A3 forGuide to Higher Flow Range for Particles 2.5 mm MPD).For hydrogen sulfide/N2control, it is recommended that thewettable parts of this flow meter be made of PTFE or
26、othercorrosion resistant material. Rotameter floats should be madefrom non-metallic materials such as glass or sapphire.6.5 Flowmeter (0-2000 mL/min Air; see Annex A3 for Guideto Higher Flow Range for Particles 2.5 mm MPD).NOTE 1Mass flow controllers have been found to be more reliablethan flowmeter
27、s and are highly recommended due to their ability toautomatically maintain precise gas flow rates. Rotameters are satisfactoryfor this method, but may require more frequent attention in maintainingproper test gas flows for the duration of the test.6.6 Two Stage Cylinder Regulator, Suitable for Corro
28、siveGas Service, for Hydrogen Sulfide Gas Cylinder.6.7 Air Line Pressure RegulatorLow Pressure. To main-tain up to 10 psig pressure for up to 2 liters of air/min flow rate(see Annex A3 for guide to airflow for tubes used for particles2.5 mm MPD)6.8 Two Metering Valves. Suitable valves are the Whitey
29、SS-21-RS4 (H2S/N2) and B-21-RS4 (air). Other similar valvesmay be used. If the rotameters in 6.4 and 6.5 are equipped withtheir own high quality metering valves, these valves are notneeded.6.9 Source of Dry, Contaminant-Free Air Capable of Deliv-ering up to 2 liters/min Through the Test System (high
30、er flowfor larger particles, 2.5 mm MPD, see Table A3.2.)FIG. 1 Schematic of Adsorption TubeD6646 03 (2014)26.10 Gas Bubbler. (Ace Glass cat .#5516 gas washing bottleequipped with gas dispersion fritted tube, cat. #7202, porositycode “C,” or equivalent to this.) The glass bubbler should beimmersed i
31、n a constant temperature bath regulated at 25C toensure the generation of a 80 % RH air stream for the final gasmixture (after mixing with dry H2S/N2). The porous bubblershould be immersed under at least 3 inches of water toconsistently saturate the air stream with water during thecourse of the test
32、. (A larger gas washing bottle should be usedif larger particles than 2.5 mm (Equivalent Diameter) and alarger bed are used. Increase size proportionately with airflow).6.11 Hydrogen Sulfide Calibration Gas Mixture, 20 to 50ppmv, in nitrogen, to be used as a span or calibration gas for thehydrogen s
33、ulfide detector. (Available from specialty gas supplycompanies.)6.12 Timer. A count up timer that can be tripped at the 50ppmv set point of the H2S monitor and is capable of retainingthe tripped time.6.13 Vibratory Feeder (see ASTM D2854).6.14 Powder Funnel.6.15 Temperature Controlled Water Bath to
34、maintain thewater bubbler at 25C 6 2C.6.16 Other miscellaneous hardware needed to set up theapparatus in Fig. 2. Polyethylene tubing is suitable for carryingthe H2S/N2flow. Clamped ball and socket joints are convenientfor quick connect and disconnect of the absorption column andcalibration bubbler (
35、see Annex A2) from the system.7. Safety Precautions7.1 Several potential hazards are associated with conductingthis test procedure. It is not the purpose of this standard toaddress all potential health and safety hazards encounteredwith its use. The user is responsible for establishing appropri-ate
36、health and safety practices before use of this test procedure.Determine the applicability of Federal and State regulationsbefore attempting to use this standard test method.7.2 Personnel conducting the hydrogen sulfide adsorptioncapacity procedure should be aware of potential safety andhealth hazard
37、s associated with the chemicals used in thisprocedure. The “Material Safety Data Sheet” (MSDS) for eachreagent listed in Section 6 should be read and understood.Special precautions to be taken during use of each reagent areincluded on the MSDS. First aid procedures for contact with achemical are als
38、o listed on its MSDS. The MSDS for eachreagent may be obtained from the manufacturer.7.3 Safety and health hazard information on reagents usedin this procedure may also be obtained from:7.3.1 Saxs Dangerous Properties of Industrial Materials /Richard J. Lewis, Sr., New York : J. Wiley, 2000.7.3.2 NI
39、OSH/OSHA Pocket Guide to Chemical Hazards,1997, U.S. Department of Labor, Occupational Safety andHealth Administration, Washington, D.C. Available from U.S.FIG. 2 Schematic of Apparatus for Determination of H2S Breakthrough CapacityD6646 03 (2014)3Government Printing Office, Washington, D.C. or at h
40、ttp:/www.cdc.gov/niosh/npg/npg.html.8. Sampling8.1 Guidance in sampling granular activated carbon is givenin recommended Practice E300.9. Calibration9.1 Calibration of flowmeters, mass flow controllers, andhydrogen sulfide detectors shall be performed by standardlaboratory methods.NOTE 2The test app
41、aratus (Fig. 1) has metering valves at therotameter outlets. This is done to minimize changes in gas flow ratescaused by small backpressure changes during this long duration test.However, placement of metering valves in this position invalidates theatmospheric pressure calibration usually supplied b
42、y the rotameter manu-facturer. The apparatus in A2.4.2 may be used to calibrate the rotameters.During this calibration, the gas delivery pressure must be the same as thatused during the actual test.9.2 Determine the percent H2S in the H2S/nitrogen tankusing the methods outlined in Annex A1 or Annex
43、A2 if theH2S/nitrogen tank was not certified by the manufacturer.10. Procedure10.1 Assemble the test apparatus as shown in the schematicdiagram of Fig. 2.10.2 Adjust the H2S/N2and air flow rates to generate a1.0 % H2S stream at a total flow rate of 1450 cm3/min at theone-inch diameter adsorption tub
44、e (see Annex A3 for higherflowrates with larger than 2.5 mm (Equivalent Diameter)particles). This adjustment will depend on the concentration ofH2S in the H2S/N2gas mixture.10.3 Determine the H2S concentration of the actual mixedtest gas using method(s) as outlined in AnnexA1 or AnnexA2of this proce
45、dure. This test should be repeated if any adjust-ment is made on the flow meter(s).10.4 Obtain a representative sample of the as-receivedgranular or pelletized activated carbon to be tested. A300 cm3sample is sufficient for apparent density, moisture and replicateperformance testing. (A larger amoun
46、t should be used if theparticles larger than 2.5 mm (Equivalent Diameter) and a largerdiameter bed are used).10.5 Reduce the sample size to an aliquot for testing usingthe riffling procedure described in E300.10.6 Determine the apparent density of the sample byASTM D2854.10.7 Use an adsorption tube
47、whose volume has been cali-brated to contain 116 mL (see Annex A3 for larger volumes)when filled from the top of the carbon support to a bed depthof approximately 22.9. (The calibrated volume for an adsorp-tion tube can be determined by using a graduated buret todetermine the volume of water require
48、d to fill the adsorptiontube from the top of the carbon support to approximately the22.9 cm mark.)10.8 Tare a clean, dry adsorption tube to the nearest 0.1 g.Note and record.10.9 Fill the adsorption tube with 116 mL of carbon beddepth of approximately 22.9 cm using a vibratory feeder. (Theapparatus
49、described in ASTM D2854, “Standard Test Methodfor Apparent Density of Activated Carbon,” or equivalent issuitable for filling the adsorption tube.) The vibratory feeder isto be adjusted so the adsorption tube is filled at a rate not lessthan 0.75 or exceeding 1.0 mL/sec. (See AnnexA3 for guide tolarger volume if larger than 2.5 mm (Equivalent Diameter)particles are tested.)10.10 Weigh the filled adsorption tube to the nearest 0.1 gm.Note and record.10.11 Carefully transfer the filled adsorption tube to the testsystem and connect it to the test apparatus.NOTE 3If a sample
