ASTM D6646-03(2008)
(Test Method)Standard Test Method for Determination of the Accelerated Hydrogen Sulfide Breakthrough Capacity of Granular and Pelletized Activated Carbon
Standard Test Method for Determination of the Accelerated Hydrogen Sulfide Breakthrough Capacity of Granular and Pelletized Activated Carbon
SIGNIFICANCE AND USE
This method compares the performance of granular or pelletized activated carbons used in odor control applications, such as sewage treatment plants, pump stations, etc. The method determines the relative breakthrough performance of activated carbon for removing hydrogen sulfide from a humidified gas stream. Other organic contaminants present in field operations may affect the H2S breakthrough capacity of the carbon; these are not addressed by this test. This test does not simulate actual conditions encountered in an odor control application, and is therefore meant only to compare the hydrogen sulfide breakthrough capacities of different carbons under the conditions of the laboratory test.
This test does not duplicate conditions that an adsorber would encounter in practical service. The mass transfer zone in the 23 cm column used in this test is proportionally much larger than that in the typical bed used in industrial applications. This difference favors a carbon that functions more rapidly for removal of H2S over a carbon with slower kinetics. Also, the 1 % H2S challenge gas concentration used here engenders a significant temperature rise in the carbon bed. This effect may also differentiate between carbons in a way that is not reflected in the conditions of practical service.
This standard as written is applicable only to granular and pelletized activated carbons with mean particle diameters less than 2.5 mm. Application of this standard to activated carbons with mean particle diameters (MPD) greater than 2.5 mm will require a larger diameter adsorption column. The ratio of column inside diameter to MPD should be greater than 10 in order to avoid wall effects. In these cases it is suggested that bed superficial velocity and contact time be held invariant at the conditions specified in this standard (4.77 cm/sec and 4.8 sec). Although not covered by this standard, data obtained from these tests may be reported as in paragraph 12 along with additional informatio...
SCOPE
1.1 This test method is intended to evaluate the performance of virgin, newly impregnated or in-service, granular or pelletized activated carbon for the removal of hydrogen sulfide from an air stream, under the laboratory test conditions described herein. A humidified air stream containing 1 % (by volume) hydrogen sulfide is passed through a carbon bed until 50 ppm breakthrough of H2S is observed. The H2S adsorption capacity of the carbon per unit volume at 99.5 % removal efficiency (g H2S/cm3 carbon) is then calculated. This test is not necessarily applicable to non-carbon adsorptive materials.
1.2 This standard as written is applicable only to granular and pelletized activated carbons with mean particle diameters (MPD) less than 2.5 mm. See paragraph 5.3 if activated carbons with larger MPDs are to be tested.
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
General Information
Relations
Buy Standard
Standards Content (Sample)
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation:D6646 −03(Reapproved 2008)
Standard Test Method for
Determination of the Accelerated Hydrogen Sulfide
Breakthrough Capacity of Granular and Pelletized Activated
Carbon
This standard is issued under the fixed designation D6646; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope 4. Summary of Test Method
1.1 Thistestmethodisintendedtoevaluatetheperformance
4.1 Breakthrough capacity is determined by passing a
of virgin, newly impregnated or in-service, granular or pellet- stream of humidified air containing 1 volume% hydrogen
izedactivatedcarbonfortheremovalofhydrogensulfidefrom
sulfide through a sample of granular or pelletized activated
an air stream, under the laboratory test conditions described carbon of known volume under specified conditions until the
herein. A humidified air stream containing 1% (by volume)
concentrationofhydrogensulfideintheeffluentgasreaches50
hydrogen sulfide is passed through a carbon bed until 50 ppm ppmv.
breakthrough of H S is observed.The H S adsorption capacity
2 2
of the carbon per unit volume at 99.5% removal efficiency (g
5. Significance and Use
H S/cm carbon) is then calculated.This test is not necessarily
5.1 This method compares the performance of granular or
applicable to non-carbon adsorptive materials.
pelletized activated carbons used in odor control applications,
1.2 This standard as written is applicable only to granular
such as sewage treatment plants, pump stations, etc. The
and pelletized activated carbons with mean particle diameters
method determines the relative breakthrough performance of
(MPD) less than 2.5 mm. See paragraph 5.3 if activated
activatedcarbonforremovinghydrogensulfidefromahumidi-
carbons with larger MPDs are to be tested.
fied gas stream. Other organic contaminants present in field
operations may affect the H S breakthrough capacity of the
1.3 This standard does not purport to address all of the 2
carbon; these are not addressed by this test. This test does not
safety concerns, if any, associated with its use. It is the
simulate actual conditions encountered in an odor control
responsibility of the user of this standard to establish appro-
application, and is therefore meant only to compare the
priate safety and health practices and determine the applica-
hydrogen sulfide breakthrough capacities of different carbons
bility of regulatory limitations prior to use.
under the conditions of the laboratory test.
2. Referenced Documents
5.2 This test does not duplicate conditions that an adsorber
2.1 ASTM Standards:
wouldencounterinpracticalservice.Themasstransferzonein
D2652Terminology Relating to Activated Carbon
the 23 cm column used in this test is proportionally much
D2854Test Method for Apparent Density of Activated
larger than that in the typical bed used in industrial applica-
Carbon
tions. This difference favors a carbon that functions more
D2867Test Methods for Moisture in Activated Carbon
rapidly for removal of H S over a carbon with slower kinetics.
E300Practice for Sampling Industrial Chemicals
Also, the 1% H S challenge gas concentration used here
engendersasignificanttemperatureriseinthecarbonbed.This
3. Terminology
effect may also differentiate between carbons in a way that is
3.1 Terms relating to this standard are defined in D2652.
not reflected in the conditions of practical service.
5.3 This standard as written is applicable only to granular
This test method is under the jurisdiction of ASTM Committee D28 on
and pelletized activated carbons with mean particle diameters
Activated Carbon and is the direct responsibility of Subcommittee D28.04 on Gas
less than 2.5 mm. Application of this standard to activated
Phase Evaluation Tests.
carbons with mean particle diameters (MPD) greater than 2.5
Current edition approved Aug. 1, 2008. Published September 2008. Originally
mmwillrequirealargerdiameteradsorptioncolumn.Theratio
approved in 2001. Last previous edition approved in 2003 as D6646–03. DOI:
10.1520/D6646-03R08.
ofcolumninsidediametertoMPDshouldbegreaterthan10in
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
order to avoid wall effects. In these cases it is suggested that
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
bed superficial velocity and contact time be held invariant at
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. the conditions specified in this standard (4.77 cm/sec and 4.8
Copyright ©ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA19428-2959. United States
D6646−03 (2008)
sec).Althoughnotcoveredbythisstandard,dataobtainedfrom
these tests may be reported as in paragraph 12 along with
additional information about column diameter, volume of
carbon, and volumetric flow rate used.
5.4 For pelletized carbons, it is felt that the equivalent
spherical diameter of the pellet is the most suitable parameter
for determining the appropriate adsorption column inside
diameter. The equivalent spherical diameter is calculated
according to the following equation.
3XdXh
D 5 (1)
eqv
d12Xh
where:
d = the diameter, and
h = the length of the pellet in mm.
An average of 50 to 100 measurements is recommended to
determinetheaveragelengthofapellet.AnnexA3isatableto
guide the user in selecting bed diameter and flow rates from
typical equivalent diameters (or MPD) of pelletized carbon.
6. Apparatus and Materials
6.1 (561) % Hydrogen Sulfide in Nitrogen Mixture. The
concentration of hydrogen sulfide in the gas test mixture must
be known. It is recommended that gas cylinders specifically
manufactured for holding hydrogen sulfide gas be used. Ana-
lyzed and certified hydrogen sulfide in nitrogen gas mixtures
can be purchased from specialty gas suppliers. Annex A1 and
Annex A2 present methods that may be used to check the
hydrogen sulfide concentration of hydrogen sulfide/nitrogen
gas mixtures. It is recommended that the hydrogen sulfide
concentration be checked if gas cylinders are stored for more
than three months, particularly after being partially depleted.
Other organic contaminants that may be present in the hydro-
gensulfidetankcanaffecttheadsorptioncapacityofthecarbon
FIG. 1Schematic of Adsorption Tube
being tested.
6.2 Hydrogen Sulfide Detector . The hydrogen sulfide de- 6.5 Flowmeter (0-2000 mL/minAir; see AnnexA3 for Guide
to Higher Flow Range for Particles > 2.5 mm MPD).
tector used in this test must be demonstrated to reliably detect
50ppmhydrogensulfideinahumidifiedairstream.Inaddition
NOTE 1—Mass flow controllers have been found to be more reliable
to certain “solid state” detectors, electrochemical type hydro-
than flowmeters and are highly recommended due to their ability to
gen sulfide sensors, e.g., Ecolyzer Model 6400 or Interscan
automatically maintain precise gas flow rates. Rotameters are satisfactory
for this method, but may require more frequent attention in maintaining
LD-17, have been evaluated and fit this requirement. Other
proper test gas flows for the duration of the test.
means of hydrogen sulfide detection may be selected, as long
6.6 Two Stage Cylinder Regulator, Suitable for Corrosive
as they are carefully calibrated and evaluated for this applica-
tion. Gas Service, for Hydrogen Sulfide Gas Cylinder.
6.7 Air Line Pressure Regulator—Low Pressure. To main-
6.3 Adsorption Tube. The adsorption tube is shown in Fig.
tainupto10psigpressureforupto2litersofair/minflowrate
1. Adsorption tubes are not commercially available; however,
(see AnnexA3 for guide to airflow for tubes used for particles
they can be custom fabricated by a scientific glassblower. The
>2.5 mm MPD)
perforated support shown is necessary to support the carbon
bed and to enhance diffusion of the gases. (Adjust dimensions
6.8 Two Metering Valves. Suitable valves are the Whitey
accordingly from Annex A3, specifically diameter.)
SS-21-RS4 (H S/N ) and B-21-RS4 (air). Other similar valves
2 2
maybeused.Iftherotametersin6.4and6.5areequippedwith
6.4 Flowmeter (0-500 mL/min Nitrogen; see Annex A3 for
their own high quality metering valves, these valves are not
Guide to Higher Flow Range for Particles > 2.5 mm MPD).
needed.
For hydrogen sulfide/N control, it is recommended that the
wettable parts of this flow meter be made of PTFE or other 6.9 Source of Dry, Contaminant-Free Air Capable of Deliv-
corrosion resistant material. Rotameter floats should be made ering up to 2 liters/min Through the Test System (higher flow
from non-metallic materials such as glass or sapphire. for larger particles, >2.5 mm MPD, see Table A3.2.)
D6646−03 (2008)
6.10 Gas Bubbler.(AceGlasscat.#5516gaswashingbottle forquickconnectanddisconnectoftheabsorptioncolumnand
equipped with gas dispersion fritted tube, cat. #7202, porosity calibration bubbler (see Annex A2) from the system.
code “C”, or equivalent to this.) The glass bubbler should be
immersed in a constant temperature bath regulated at 25°C to 7. Safety Precautions
ensure the generation of a 80% RH air stream for the final gas
7.1 Severalpotentialhazardsareassociatedwithconducting
mixture (after mixing with dry H S/N ). The porous bubbler
2 2
this test procedure. It is not the purpose of this standard to
should be immersed under at least 3 inches of water to
address all potential health and safety hazards encountered
consistently saturate the air stream with water during the
with its use. The user is responsible for establishing appropri-
course of the test. (Alarger gas washing bottle should be used
atehealthandsafetypracticesbeforeuseofthistestprocedure.
if larger particles than 2.5 mm (Equivalent Diameter) and a
Determine the applicability of Federal and State regulations
larger bed are used. Increase size proportionately with air
before attempting to use this standard test method.
flow).
7.2 Personnel conducting the hydrogen sulfide adsorption
6.11 Hydrogen Sulfide Calibration Gas Mixture, 20 to 50
capacity procedure should be aware of potential safety and
ppmv,innitrogen,tobeusedasaspanorcalibrationgasforthe
health hazards associated with the chemicals used in this
hydrogensulfidedetector.(Availablefromspecialtygassupply
procedure.The “Material Safety Data Sheet” (MSDS) for each
companies.)
reagent listed in Section 6 should be read and understood.
6.12 Timer. A count up timer that can be tripped at the 50 Special precautions to be taken during use of each reagent are
ppmv set point of the H S monitor and is capable of retaining
included on the MSDS. First aid procedures for contact with a
the tripped time. chemical are also listed on its MSDS. The MSDS for each
reagent may be obtained from the manufacturer.
6.13 Vibratory Feeder (see ASTM D2854).
7.3 Safety and health hazard information on reagents used
6.14 Powder Funnel.
in this procedure may also be obtained from:
6.15 Temperature Controlled Water Bath to maintain the
7.3.1 Sax’s Dangerous Properties of Industrial Materials /
water bubbler at 25°C 6 2°C.
Richard J. Lewis, Sr., New York : J. Wiley, 2000.
6.16 Other miscellaneous hardware needed to set up the 7.3.2 NIOSH/OSHA Pocket Guide to Chemical Hazards,
apparatusinFig.2.Polyethylenetubingissuitableforcarrying 1997, U.S. Department of Labor, Occupational Safety and
theH S/N flow.Clampedballandsocketjointsareconvenient Health Administration, Washington, D.C. Available from U.S.
2 2
FIG. 2Schematic of Apparatus for Determination of H S Breakthrough Capacity
D6646−03 (2008)
Government Printing Office, Washington, D.C. or at http:// 10.9 Fill the adsorption tube with 116 mL of carbon [bed
www.cdc.gov/niosh/npg/npg.html. depthofapproximately22.9cm]usingavibratoryfeeder.(The
apparatus described in ASTM D2854, “Standard Test Method
8. Sampling
for Apparent Density of Activated Carbon”, or equivalent is
suitable for filling the adsorption tube.)The vibratory feeder is
8.1 Guidanceinsamplinggranularactivatedcarbonisgiven
to be adjusted so the adsorption tube is filled at a rate not less
in recommended Practice E300.
than0.75orexceeding1.0mL/sec.(SeeAnnexA3forguideto
larger volume if larger than 2.5 mm (Equivalent Diameter)
9. Calibration
particles are tested.)
9.1 Calibration of flowmeters, mass flow controllers, and
10.10 Weighthefilledadsorptiontubetothenearest0.1gm.
hydrogen sulfide detectors shall be performed by standard
Note and record.
laboratory methods.
10.11 Carefully transfer the filled adsorption tube to the test
NOTE 2—The test apparatus (Fig. 1) has metering valves at the
rotameter outlets. This is done to minimize changes in gas flow rates system and connect it to the test apparatus.
caused by small backpressure changes during this long duration test.
NOTE 3—If a sample of non-impregnated, low moisture, virgin carbon
However, placement of metering valves in this position invalidates the
is being evaluated for adsorption capacity, it is advised that it be
atmospheric pressure calibration usually supplied by the rotameter manu-
conditioned for several hours with only humidified air passing through it
facturer.The apparatus in A2.4.2 may be used to calibrate the rotameters.
to equilibrate the moisture content of the carbon with the moisture in the
During this calibration, the gas delivery pressure must be the same as that
airstream.Themoisturecontentofthecarbonwillaffectthebreakthrough
used during the actual test.
capacity
9.2 Determine the percent H S in the H S/nitrogen tank
2 2
Start the H S/air flow and simultaneously start the timer.
using the methods outlined in Annex A1 or Annex A2 if the
H S/nitrogen tank was not certified by the manufacturer.
2 10.12 Continue the H S/air flow until a breakthrough of 50
ppmv is indicated. Record the time elapsed from the start of
10. Procedure
H S/air flow to 50 ppm breakthrough.
10.1 Assemble the test apparatus as shown in the schematic
10.13 Repeat 10.2-10.12 on replicate portions of the carbon
diagram of Fig. 2.
sample. A minimum of one replicate analyses must be per-
10.2 Adjust the H S/N and air flow rates to generate a formed.
2 2
1.0% H S stream at a total flow rate of 1450 cm /min at the
one-inch diameter adsorption tube (see Annex A3 for higher
11. Calculation
flowrates with larger than 2.5 mm (Equivalent Diameter)
11.1 Calculate the hydrogen sulfide breakthrough capacity
particles).This adjustment will depend on the concentration of
of the test sample using the following equation:
H S in the H S/N gas mixture.
2 2 2
gH S
10.3 Determine the H S concentration of the actual mixed
...
This document is not anASTM standard and is intended only to provide the user of anASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation:D6646–01 Designation: D 6646 – 03 (Reapproved 2008)
Standard Test Method for
Determination of the Accelerated Hydrogen Sulfide
Breakthrough Capacity of Granular and Pelletized Activated
Carbon
This standard is issued under the fixed designation D 6646; 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 (´) indicates an editorial change since the last revision or reapproval.
1. Scope
1.1 This test method is intended to evaluate the performance of virgin, newly impregnated or in-service, granular or pelletized
activated carbon for the removal of hydrogen sulfide from an air stream, under the laboratory test conditions described herein. A
humidified air stream containing 1 % (by volume) hydrogen sulfide is passed through a carbon bed until 50 ppm breakthrough of
H S is observed. The H S adsorption capacity of the carbon per unit volume at 99.5 % removal efficiency (g H S/cm carbon) is
2 2 2
then calculated. This test is not necessarily applicable to non-carbon adsorptive materials.
1.2 This standard as written is applicable only to granular and pelletized activated carbons with mean particle diameters (MPD)
less than 2.5 mm. See paragraph 5.3 if activated carbons with larger MPDs are to be tested.
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility
of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory
limitations prior to use.
2. Referenced Documents
2.1 ASTM Standards:
D 2652Definition of Terms Relating to Activated Carbon Terminology Relating to Activated Carbon
D 2854Determination of Apparent Density of Activated Carbon Test Method for Apparent Density of Activated Carbon
D 2867 Test For Methods for Moisture in Activated Carbon
E 300 Practice for Sampling Industrial Chemicals
3. Terminology
3.1 Terms relating to this standard are defined in D 2652.
4. Summary of Test Method
4.1 Breakthroughcapacityisdeterminedbypassingastreamofhumidifiedaircontaining1volume %hydrogensulfidethrough
asampleofgranularorpelletizedactivatedcarbonofknownvolumeunderspecifiedconditionsuntiltheconcentrationofhydrogen
sulfide in the effluent gas reaches 50 ppmv.
5. Significance and Use
5.1 This method was developed to compare compares the performance of granular or pelletized activated carbons used in odor
control applications, such as sewage treatment plants, pump stations, etc. The method is a means of determiningdetermines the
relative breakthrough performance of activated carbon for removing hydrogen sulfide from a humidified gas stream. Other organic
contaminants present in field operations may affect the H S breakthrough capacity of the carbon; these are not addressed by this
test. It is unlikely that this test will exactly simulate actual conditions encountered in an odor control application, and it is therefore
meant only as a relative comparison method. S breakthrough capacity of the carbon; these are not addressed by this test. This test
does not simulate actual conditions encountered in an odor control application, and is therefore meant only to compare the
hydrogen sulfide breakthrough capacities of different carbons under the conditions of the laboratory test.
5.2 This test does not duplicate conditions that an adsorber would encounter in practical service. The mass transfer zone in the
This test method is under the jurisdiction of ASTM Committee D28 on Activated Carbon and is the direct responsibility of Subcommittee D28.04 on Gas Phase
Evaluation Tests.
Current edition approved April 10, 2001. Published July 2001.
Current edition approved Aug. 1, 2008. Published September 2008. Originally approved in 2001. Last previous edition approved in 2003 as D 6646–03.
For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
, Vol 15.01.volume information, refer to the standard’s Document Summary page on the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D 6646 – 03 (2008)
23 cm column used in this test is proportionally much larger than that in the typical bed used in industrial applications. This
difference favors a carbon that functions more rapidly for removal of H S over a carbon with slower kinetics. Also, the 1 % H S
2 2
challenge gas concentration used here engenders a significant temperature rise in the carbon bed. This effect may also differentiate
between carbons in a way that is not reflected in the conditions of practical service.
5.3 This standard as written is applicable only to granular and pelletized activated carbons with mean particle diameters less
than 2.5 mm. Application of this standard to activated carbons with mean particle diameters (MPD) greater than 2.5 mm will
require a larger diameter adsorption column. The ratio of column inside diameter to MPD should be greater than 10 in order to
avoid wall effects. In these cases it is suggested that bed superficial velocity and contact time be held invariant at the conditions
specified in this standard (4.77 cm/sec and 4.8 sec).Although not covered by this standard, data obtained from these tests may be
reported as in paragraph 12 along with additional information about column diameter, volume of carbon, and volumetric flow rate
used.
5.4 For pelletized carbons, it is felt that the equivalent spherical diameter of the pellet is the most suitable parameter for
determining the appropriate adsorption column inside diameter. The equivalent spherical diameter is calculated according to the
following equation.
3XdXh
D 5 (1)
eqv
d 1 2Xh
where:
d = the diameter, and
h = the length of the pellet in mm.
An average of 50 to 100 measurements is recommended to determine the average length of a pellet.AnnexA3 is a table to guide
the user in selecting bed diameter and flow rates from typical equivalent diameters (or MPD) of pelletized carbon.
6. Apparatus and Materials
6.1 (561) % Hydrogen Sulfide in Nitrogen Mixture. The concentration of hydrogen sulfide in the gas test mixture must be
known. It is recommended that gas cylinders specifically manufactured for holding hydrogen sulfide gas be used. Analyzed and
certified hydrogen sulfide in nitrogen gas mixtures can be purchased from specialty gas suppliers.AnnexA1 andAnnexA2 present
methods that may be used to check the hydrogen sulfide concentration of hydrogen sulfide/nitrogen gas mixtures. It is
recommended that the hydrogen sulfide concentration be checked if gas cylinders are stored for more than three months,
particularly after being partially depleted. Other organic contaminants that may be present in the hydrogen sulfide tank can affect
the adsorption capacity of the carbon being tested.
6.2 Hydrogen Sulfide Detector . The hydrogen sulfide detector used in this test must be demonstrated to reliably detect 50 ppm
hydrogen sulfide in a humidified air stream. In addition to certain “solid state” detectors, electrochemical type hydrogen sulfide
sensors, e.g., Ecolyzer Model 6400 or Interscan LD-17, have been evaluated and fit this requirement. Other means of hydrogen
sulfide detection may be selected, as long as they are carefully calibrated and 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. The perforated support shown is necessary to support the carbon bed and to
enhance diffusion of the gases. (Adjust dimensions accordingly from Annex A3, specifically diameter.)
6.4 Flowmeter (0-500 mL/min Nitrogen; see Annex A3 for Guide to Higher Flow Range for Particles > 2.5 mm MPD). For
hydrogen sulfide/N control, it is recommended that the wettable parts of this flow meter be made of PTFE or other corrosion
resistant material. Rotameter floats should be made from non-metallic materials such as glass or sapphire.
6.5 Flowmeter (0-2000 mL/min Air; see Annex A3 for Guide to Higher Flow Range for Particles > 2.5 mm MPD).
NOTE 1—Mass flow controllers have been found to be more reliable than flowmeters and are highly recommended due to their ability to automatically
maintain precise gas flow rates. Rotameters are satisfactory for this method, but may require more frequent attention in maintaining proper test gas flows
for the duration of the test.
6.6 Two Stage Cylinder Regulator, Suitable for Corrosive Gas Service, for Hydrogen Sulfide Gas Cylinder.
6.7 Air Line Pressure Regulator—Low Pressure. To maintain 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 particles >2.5 mm MPD)
6.8 Two Metering Valves. Suitable valves are the Whitey SS-21-RS4 (H S/N ) and B-21-RS4 (air). Other similar valves may
2 2
be used. If the rotameters in 6.4 and 6.5 are equipped with their own high quality metering valves, these valves are not needed.
6.9 Source of Dry, Contaminant-Free Air Capable of Delivering up to 2 liters/min Through the Test System (higher flow for
larger particles, >2.5 mm MPD, see Table A3.2.)
6.10 Gas Bubbler.(AceGlasscat.#5516gaswashingbottleequippedwithgasdispersionfrittedtube,cat.#7202,porositycode
“C”, or equivalent to this.) The glass bubbler should be immersed in a constant temperature bath regulated at 25°C to ensure the
generation of a 80 % RH air stream for the final gas mixture (after mixing with dry H S/N ). The porous bubbler should be
2 2
immersed under at least 3 inches of water to consistently saturate the air stream with water during the course of the test. (Alarger
gas washing bottle should be used if larger particles than 2.5 mm (Equivalent Diameter) and a larger bed are used. Increase size
proportionately with air flow).
6.11 Hydrogen Sulfide Calibration Gas Mixture, 20 to 50 ppmv, in nitrogen, to be used as a span or calibration gas for the
D 6646 – 03 (2008)
FIG. 1 Schematic of Adsorption Tube
hydrogen sulfide detector. (Available from specialty gas supply companies.)
6.12 Timer. A count up timer that can be tripped at the 50 ppmv set point of the H S monitor and is capable of retaining the
tripped time.
6.13 Vibratory Feeder (see ASTM D 2854).
6.14 Powder Funnel.
6.15 Temperature Controlled Water Bath to maintain the water bubbler at 25°C 6 2°C.
6.16 Other miscellaneous hardware needed to set up the apparatus in Fig. 2. Polyethylene tubing is suitable for carrying the
H S/N flow. Clamped ball and socket joints are convenient for quick connect and disconnect of the absorption column and
2 2
calibration bubbler (see Annex A2) from the system.
7. Safety Precautions
7.1 Several potential hazards are associated with conducting this test procedure. It is not the purpose of this standard to address
all potential health and safety hazards encountered with its use. The user is responsible for establishing appropriate health and
safety practices before use of this test procedure. Determine the applicability of Federal and State regulations before attempting
to use this standard test method.
7.2 Personnel conducting the hydrogen sulfide adsorption capacity procedure should be aware of potential safety and health
hazards associated with the chemicals used in this procedure. The “Material Safety Data Sheet” (MSDS) for each reagent listed
in Section 6 should be read and understood. Special precautions to be taken during use of each reagent are included on the MSDS.
First aid procedures for contact with a chemical are also listed on its MSDS. The MSDS for each reagent may be obtained from
the manufacturer.
7.3 Safety and health hazard information on reagents used in this procedure may also be obtained from:
7.3.1 Sax’s Dangerous Properties of Industrial Materials / Richard J. Lewis, Sr., New York : J. Wiley, 2000.
D 6646 – 03 (2008)
FIG. 2 Schematic of Apparatus for Determination of H S Breakthrough Capacity
7.3.2 NIOSH/OSHA Pocket Guide to Chemical Hazards, 1997, U.S. Department of Labor, Occupational Safety and Health
Administration, Washington, D.C. Available from U.S. Government Printing Office, Washington, D.C. or at http://www.cdc.gov/
niosh/npg/npg.html.
8. Sampling
8.1 Guidance in sampling granular activated carbon is given in recommended Practice E 300.
9. Calibration
9.1 Calibration of flowmeters, mass flow controllers, and hydrogen sulfide detectors shall be performed by standard laboratory
methods.
NOTE 2—The test apparatus (Fig. 1) has metering valves at the rotameter outlets. This is done to minimize changes in gas flow rates caused by small
backpressure changes during this long duration test. However, placement of metering valves in this position invalidates the atmospheric pressure
calibration usually supplied by the rotameter manufacturer. The apparatus inA2.4.2 may be used to calibrate the rotameters. During this calibration, the
gas delivery pressure must be the same as that used during the actual test.
9.2 Determine the percent H S in the H S/nitrogen tank using the methods outlined in Annex A1 or Annex A2 if the
2 2
H S/nitrogen tank was not certified by the manufacturer.
10. Procedure
10.1 Assemble the test apparatus as shown in the schematic diagram of Fig. 2.
10.2 Adjust the H S/N and air flow rates to generate a 1.0 % H S stream at a total flow rate of 1450 cm /min at the one-inch
2 2 2
diameter adsorption tube (see Annex A3 for higher flowrates with larger than 2.5 mm (Equivalent Diameter) particles). This
adjustment will depend on the concentration of H S in the H S/N gas mixture.
2 2 2
10.3 Determine the H S concentration of the actual mixed test gas using method(s) as outlined in Annex A1 or Annex A2 of
this procedure. This test should be repeated if any adjustment is made on the flow meter(s).
10.4 Obtain a representative sample of the as-received granular or pelletized activated carbon to be tested. A 300 cm sample
is sufficient for apparent density, moisture and replicate performance testing. (Alarger amount should be used if the particles larger
than 2.5 mm (Equivalent Diameter) and a larger diameter bed are used).
10.5 Reduce the sample size to an aliquot for testing using the riffling pro
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.