ASTM_D_6646_-_03_2014.pdf

Designation:D664603(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 year 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 performanceof 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 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 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 this 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 Methods 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 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 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 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 test 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 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 standard 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 inside 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 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 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.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 sec).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