1、Designation: D7621 12IP 570Standard Test Method forDetermination of Hydrogen Sulfide in Fuel Oils by RapidLiquid Phase Extraction1, 2This standard is issued under the fixed designation D7621; the number immediately following the designation indicates the year oforiginal adoption or, in the case of r
2、evision, 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. Scope*1.1 This test method covers a procedure for the determina-tion of the hydrogen sulfide (H2S) content
3、 of fuel oils such asmarine residual fuels and blend stocks, in the range 0.40 to15.0 mg/kg as measured in the liquid phase.1.2 This test method is applicable for materials with aviscosity up to 3000 mm2s-1at 50C.NOTE 1ASTM specification fuels falling within the scope of this testmethod are: Specifi
4、cation D396 Grade Nos 5 (light), 5 (heavy) and 6.1.3 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.4 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibili
5、ty 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:3D396 Specification for Fuel OilsD4057 Practice for Manual Sampling of Petroleum andPetroleum Produc
6、tsD5705 Test Method for Measurement of Hydrogen Sulfidein the Vapor Phase Above Residual Fuel OilsD6021 Test Method for Measurement of Total HydrogenSulfide in Residual Fuels by Multiple Headspace Extrac-tion and Sulfur Specific DetectionD6300 Practice for Determination of Precision and BiasData for
7、 Use in Test Methods for Petroleum Products andLubricants2.2 ASTM Adjuncts:4ADJ6300 D2PP Determination of Precision and Bias datafor Use in Test Methods for Petroleum Products2.3 ISO Standards:5ISO TR 13739 Petroleum ProductsProcedures for theTransfer of Bunker Fuel(s) to ShipsISO 4259 Petroleum Pro
8、ductsDetermination and Applica-tion of Precision Data in Relation to Methods of Test2.4 Energy Institute Standards:6IP 399 Test Method for Determination of Hydrogen Sulfidein Fuel OilsIP 570 Test Method for Determination of Hydrogen Sulfidein Fuel OilsRapid Liquid Phase Extraction Method3. Terminolo
9、gy3.1 Definitions:3.1.1 residual fuel oil, nfuel oil comprising a blend ofviscous long, short or cracked residue from a petroleumrefining process and lighter distillates (blend stocks) blended toa fuel oil viscosity specification, burned for the generation ofheat in a furnace or firebox or for the g
10、eneration of power in anengine.3.2 Definitions of Terms Specific to This Standard:3.2.1 liquid phase extraction, ntechnique to determine theconcentration of H2S gas trapped in a liquid by continuousanalysis of gases extracted by bubbling air through the testspecimen.4. Summary of Test Method4.1 A we
11、ighed test specimen is introduced into a heated testvessel containing a diluent base oil. Air is bubbled through the1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products and Lubricants and is the direct responsibility of SubcommitteeD02.E0 on Burner, Diesel, Non-Avia
12、tion Gas Turbine, and Marine Fuels.Current edition approved April 15, 2012. Published October 2012. Originallyapproved in 2010. Last previous edition approved in 2010 as D7621-10.DOI:10.1520/D762112.2This test method has been developed through the cooperative effort betweenASTM and the Energy Instit
13、ute, London. The IP and ASTM logos imply that theASTM and IP standards are technically equivalent, but their use does not imply thatboth standards are editorially identical.3For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For A
14、nnual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.4For referenced ASTM adjuncts contact ASTM Customer Service atserviceastm.org.5Available from American National Standards Institute (ANSI), 25 W. 43rd St.,4th Floor, New York, NY 10036, ht
15、tp:/www.ansi.org.6Available from Energy Institute, 61 New Cavendish St., London, WIG 7AR,U.K., http:/www.energyinst.org.uk.1*A Summary of Changes section appears at the end of this standard.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United Sta
16、tes.oil to extract the H2S gas. The H2S is passed, with the air, overan H2S specific electro-chemical detector to enable the H2Scontent of the air to be measured and the amount in the liquidphase to be calculated in mg/kg.5. Significance and Use5.1 Residual fuel oils can contain H2S in the liquid ph
17、aseand this can result in hazardous vapor phase levels of H2Sinstorage tank headspaces. The vapor phase levels can varysignificantly according to the headspace volume, fuel tempera-ture and agitation. Measurement of H2S levels in the liquidphase provides a useful indication of the residual fuel oils
18、propensity to form high vapor phase levels, and lower levels inthe residual fuel oil will directly reduce risk of H2S exposure.It is critical however that anyone involved in handling fuel oil,such as vessel owners and operators, continue to maintainappropriate safety practices designed to protect th
19、e crew, tankfarm operators and others who can be exposed to H2S.5.1.1 The measurement of H2S in the liquid phase isappropriate for product quality control, whilst the measurementof H2S in the vapor phase is appropriate for health and safetypurposes.5.2 This test method was developed so refiners, fue
20、l termi-nal operators and independent testing laboratory personnel canrapidly and precisely measure the amount of H2S in the liquidphase of residual fuel oils.NOTE 2Test Method D7621 is one of three test methods for quanti-tatively measuring H2S in residual fuels. Test Method D5705 is a simplefield
21、test method for determining H2S levels in the vapor phase. TestMethod D6021 is an analytical test method to determine H2S levels in theliquid phase.5.3 H2S concentrations in the liquid and vapor phase at-tempt to reach equilibrium in a static system. However thisequilibrium and the related liquid an
22、d vapor concentrations canvary greatly depending on temperature and the chemicalcomposition of the liquid phase. A concentration of 1 mg/kg(g/g) (ppmw) of H2S in the liquid phase of a residual fuelcan typically generate an actual gas concentration of 50 to100 L/L (ppmv) of H2S in the vapor phase but
23、 the equilibriumof the vapor phase is disrupted the moment a vent or accesspoint is opened to collect a sample.NOTE 3Because of the reactivity, absorptivity and volatility of H2S,any measurement method only provides an H2S concentration at a givenmoment in time.6. Apparatus6.1 GeneralThe apparatus,
24、as detailed in Annex A1,comprises an air pump, test vessel, heating jacket, filters, H2Sspecific detector, integral computer, automatic solenoid valves,gas flow detectors, a disposable syringe, anda1mLpositivedisplacement pipette.6.2 Analytical Balance, single pan or double pan balancecapable of wei
25、ghing to the nearest 0.001 g.6.3 Syringe, 20 mL polypropylene disposable type, forintroduction of the diluent oil (see 7.1), accuracy 61%.6.4 Refrigerator (optional), for storing the test sample (see8.5). The refrigerator shall be of a type suitable for storingflammable, volatile materials.6.5 Oven/
26、Water Bath (optional), for warming the sample to40C with an accuracy of 62C (see 9.4.2.1). The oven shallbe of a type suitable for use with volatile materials.7. Reagents and Materials7.1 Diluent Oil,7proprietary water white API Group 2 baseoil with a typical viscosity of 100 mm2s-1at 40 C.7.2 Refer
27、ence Material,7pressurized nitrogen, of at least99.999 % (v/v) purity, containing a certified level of H2S(nominally 25 mg/kg).7.3 Cleaning Materials, technical grade.7.3.1 Toluene.7.3.2 Petroleum Ether (60/80).7.3.3 Acetone.8. Sampling8.1 Unless otherwise agreed, samples shall be taken inaccordance
28、 with Practice D4057 or ISO TR 13739.8.2 During sampling operations, care shall be taken toensure that the integrity of the material is maintained and thepossible loss of H2S is kept to a minimum. The precision of thismethod is critically dependent on the sampling, thermal his-tory, and handling of
29、the test sample.8.3 Draw the sample directly into a suitable clean H2S inertcontainer, of a minimum volume of 500 mL, with an impervi-ous gas-tight closure. Suitable containers include amber glassbottles and epoxy lined containers. The closure aperture shallallow the drawing of a test specimen with
30、the syringe or pipette(see A1.1.13 and A1.1.12).8.3.1 Epoxy lined containers shall be visually inspected toensure that the lining has not been damaged and that thecontainers are not dented.8.3.2 To ensure sample integrity fill the sample container toapproximately 95 % full and cap immediately.NOTE 4
31、Lower volume containers may be used, however the precisioncould be affected.8.4 If a dedicated H2S sample cannot be taken, then the H2Smeasurement shall be the first test carried out on the sample asany additional handling can lead to loss of H2S and low results.8.5 Take the samples to the laborator
32、y as soon as ispracticable after sampling. Test immediately if possible. Ifsamples are not tested immediately, store in a cool place suchas a refrigerator (6.4), and analyze within 3 days aftersampling.9. Preparation of Apparatus9.1 GeneralFollow the manufacturers instructions forthe correct set up,
33、 verification, calibration and operation of theapparatus.9.2 Location of ApparatusUse the apparatus under asuitable fume hood or equivalent well-ventilated work space,and vent the gas exit tube to a suitable extractor as the test will7The following reagents and materials were used to develop the pre
34、cisionstatements: Seta Diluent SA4000-004 and Seta Verification Gas SA4001-001.Stanhope-Seta, Chertsey, Surrey, KT16 8AP, UK. This is not an endorsement orcertification by ASTM International.D7621 122release small amounts of H2S gas during test specimenintroduction and during the measurement.9.3 Fil
35、ters:9.3.1 The inlet air filter shall be replaced every 3 months, orearlier if any discoloration is visible.9.3.2 Follow the manufacturers instructions regarding thereplacement intervals of the air pump and moisture filters.9.3.3 Replace the moisture filter if any discoloration isvisible.9.4 Sample
36、Preparation:9.4.1 To minimize the loss of H2S gas, do not homogenizeor transfer the sample to another container, and avoid shakingthe sample before taking a test specimen.9.4.2 The sample needs to be flowing freely enough to allowthe test specimen to be drawn into the syringe or pipette (seeA1.1.13
37、and A1.1.12).9.4.2.1 A sample that is not free flowing at ambient tem-perature shall be gently warmed in a water bath or oven (see6.5) set at a temperature not exceeding 40C.9.4.2.2 Samples with viscosities greater than 3000 mm2s-1at 50C may be tested, but the precision could be affected.9.4.3 By us
38、ing a smaller volume of sample it is possible toextend the range of the instrument to over 200 mg/kg but theprecision could be affected.NOTE 5It has been found that samples with a viscosity over500 mm2s-1, at 50C, usually require warming.9.5 Test VesselClean the test vessel and screw cap beforeeach
39、test. Fit the screw cap tightly.9.6 Liquid TrapEmpty and clean the liquid trap if anyliquid or discoloration is visible.9.7 H2S DetectorFollow the manufacturers instructionsfor installing a new calibrated detector and verify the perfor-mance immediately afterwards as described in 10.2.3.NOTE 6Toluen
40、e, followed by petroleum ether (60/80), and acetone,are effective in cleaning the test vessel, cap, and liquid trap (see 7.3).10. Calibration and Standardization10.1 Ensure that all of the manufacturers instructions forverification and calibration of the mechanical and electronicsystems, and operati
41、on of the apparatus are followed. Calibra-tion functions are separated from the usual operator controlsand are all implemented electronically using the integraldisplay and keyboard.10.2 Verification:10.2.1 Air Flow RateVerify that the air flow rate is 375 655 mL/min, at least once a year using a sui
42、table flow meterconnected to the air output connection. If the flow rate isincorrect, recalibrate the flow (see 10.3.1).10.2.2 Test Vessel Heater JacketVerify that the tempera-ture of the heater jacket is 60.0 6 1.0 C, at least every sixmonths, by inserting a calibrated temperature sensor into thehe
43、ater jacket. If the temperature is incorrect, recalibrate (see10.3.2).10.2.3 H2S DetectorVerify the performance of the detec-tor at least every month, or when a new detector is fitted, atzero using air, and at a nominal 25 mg/kg vapor concentrationlevel using pressurized nitrogen (see 7.2) containin
44、g a certifiedlevel of H2S.10.3 Calibration:10.3.1 Air Flow RateThe air flow adjustment is imple-mented electronically.10.3.2 Test Vessel Heater JacketThe temperature adjust-ment is implemented electronically.10.3.3 H2S DetectorThe detector is factory calibratedusing the reference material (see 7.2)
45、(static calibration) andusing factory calibration liquids with known mg/kg liquidconcentrations of H2S (dynamic calibration). This calibrationinformation is held digitally on the detector assembly and isread directly by the computer in the apparatus. The calibrationenables results in mg/kg to be cal
46、culated from the test results.The dynamic calibration is a function of the detector andapparatus, and has a fixed value.10.3.3.1 The static calibration is implemented electronicallyfollowing a verification (see 10.2.3).11. Procedure11.1 At switch on, the H2S apparatus shall control the testvessel he
47、ater jacket to 60.0 6 1.0 C, and purge by pumping airdirectly to the detector.11.2 Remove the screw cap from the cleaned test vessel (see9.5) and introduce 20.0 6 0.5 mL of diluent oil (see 7.1) usingthe syringe (see 6.3) and then replace the screw cap. Place thetest vessel in the temperature contro
48、lled heating jacket and fitthe input/output tubing.11.3 Air is pumped through the diluent in the test vessel andto the detector for 5 min. This allows the diluent oil to warmup, and the system to be purged.11.4 Air is then pumped directly to the detector, bypassingthe test vessel, to allow the test
49、specimen to be introducedwithout purge air affecting the concentration of the H2S.Ensure that the instrument is operating in bypass mode beforeintroducing the test specimen. Introducing the test specimenbefore this condition is met will likely result in premature lossof H2S and an erroneously low result. If this is suspected or theinstrument indicates that an incorrect procedure has beenfollowed, abandon the test and repeat using a fresh testspecimen.11.5 Depending on the expected H2S concentration, drawthe appropriate volume of the sample fr
