1、Designation: D 1072 06Standard Test Method forTotal Sulfur in Fuel Gases by Combustion and BariumChloride Titration1This standard is issued under the fixed designation D 1072; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the yea
2、r of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method is for the determination of total sulfurin combustible fuel gases, when present in sulfur conce
3、ntra-tions between approximately 25 and 700 mg/m3(1 to 30 grainsper 100 cubic feet). It is applicable to natural gases, manufac-tured gases, mixed gases, and other miscellaneous gaseousfuels.1.2 The values stated in inch-pound units are to be regardedas standard.1.3 This standard does not purport to
4、 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:2D 1193 Sp
5、ecification for Reagent Water3. Summary of Test Method3.1 A metered sample of gas is burned in a closed system inan atmosphere of sulfur-free air. The oxides of sulfur producedare absorbed in sodium carbonate solution, where they areoxidized to sulfate. The sulfate in the absorbent solution isdeterm
6、ined by titration with standardized barium chloridesolution, using tetra-hydroxy-quinone (THQ) as an indicator.4. Interferences4.1 There are no known interferences for the determinationof total sulfur in fuel gases when combustion is followed bybarium chloride titration. However, users employing bar
7、iumchloride titration following collection of sulfur dioxide byalternative procedures are cautioned that ammonia, amines,substances producing water soluble cations, and fluorides willinterfere with the titration.5. Apparatus5.1 Burner (Fig. 1), as specified in the Appendix X1.5.2 Chimneys, Absorbers
8、 and Spray Traps,(Fig. 2), asspecified in the Appendix X1.5.3 Flow meterA calibrated capillary flow meter forpredetermining and indicating the rate of flow of gas to theburner. The capillary selected should be of such size that at therequired rate of flow the differential pressure is at least 20 cmo
9、f water. A scale divided into millimeters will then provide areading precision of 6 0.5 %. Other metering devices, includ-ing but not limited to rotameters or dry displacement meters,are suitable provided the reading precision is 6 0.5 % or better.A flow controlling valve is attached to the inlet co
10、nnection ofthe flow meter.5.4 Vacuum SystemA vacuum manifold equipped with avacuum regulating device, valves, and other necessary accou-terments. An example vacuum system capable of performingmultiple test measurements is shown in Fig. 3. Other vacuumsystem configurations can be used to perform this
11、 test method.The vacuum system shall be connected to a vacuum pumpcapable of providing a steady gas flow of 3 L of air per minutethrough each absorber and capable of maintaining a constantmanifold pressure of approximately 40 cm of water belowatmospheric pressure.5.5 Air-Purifying SystemA device sup
12、plying purified airto the burner manifold at a constant pressure of approximately200 mm of water and to the chimney manifold at a pressure of1 to 2 cm of water. An example system configuration formultiple tests is illustrated in Fig. 4; however, other air-purifying system configurations can be used
13、to perform this testmethod. The tubing that connects the chimneys to the manifoldshall be of an internal diameter not smaller than 0.63 cm inorder to prevent unnecessary restriction of airflow.1This test method is under the jurisdiction ofASTM Committee D03 on GaseousFuels and is the direct responsi
14、bility of D03.05 on Determination of SpecialConstituents of Gaseous Fuels.Current edition approved June 1, 2006. Published June 2006. Originallyapproved in 1954. Last previous edition approved in 1999 as D 1072 90 (1999).2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact
15、 ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.5.6 ManometerA water mano
16、meter for indicating the gaspressure at the point of volume measurement. It is connectedbetween the flowmeter and the burner, with one leg open to theatmosphere.6. Reagents and Materials6.1 Reagents Purity Reagent grade chemicals shall beused in all tests. Unless otherwise indicated, it is intended
17、thatall reagents shall conform to the specifications of the Commit-tee on Analytical Reagents of the American Chemical Society,where such specifications are available.3Other grades may beused, provided it is first ascertained that the reagent is ofsufficiently high purity to permit its use without a
18、dverselyimpacting the accuracy of the determination. WarningSodium hydroxide is corrosive and can cause severe damage toeyes and skin. Inhalation will irritate the nose, throat and lungs.It reacts exothermically with water.6.2 Purity of WaterUnless otherwise indicated, referencesto water shall be un
19、derstood to mean reagent water conformingto Specification D 1193.6.3 AlcoholEthyl alcohol, denatured by Formula 30 or3-A, or isopropyl alcohol.6.4 Barium Chloride,(CAS No: 10361-37-2), Standard So-lution (1 mL = 1 mg S)Dissolve 7.634 g of barium chloride(BaCl22H2O) in water and dilute to 1 L. The so
20、lution isstandardized gravimetrically by precipitation as barium sulfateor by titration against sulfuric acid (see 6.12)6.5 Hydrochloric Acid (CAS No 7647-01-0)(2.275-g HCl/L) Titrated against Na2CO3solution (see 6.15), using methylorange indicator. Adjusted such that 1 mL of HCl solution isequivale
21、nt to 1 mL of Na2CO3solution.6.6 Hydrogen Peroxide (30 %)(H2O2;CAS No: 7722-84-1).6.7 iso-Propanol (CAS No. 67630)6.8 Potassium Hydrogen Phthalate (KHP; CAS No 877-24-7) Dry use.6.9 Phenolphthalein (CAS No 77-09-8)6.10 Methyl Orange (CAS No 547-58-0) IndicatorSolutionDissolve 0.1 g of methyl orange
22、in 100 mL of water.6.11 Silver Nitrate (CAS No 7761-88-8)Solution (17-gAgNO3/L)Dissolve 1.7 g of silver nitrate (AgNO3)in100mL of water. Store in a brown bottle.6.12 Sodium Carbonate (CAS No 5968-11-6) Solution(3.306-g Na2CO3/L)Dissolve 3.306 g of sodium carbonate(Na2CO3) in water and dilute to 1 L.
23、6.13 Sodium Hydroxide Solution (CAS No 1310-73-2)(100-g NaOH/L)Dissolve 100 g of technical grade sodiumhydroxide (NaOH) pellets in water and dilute to 1 L. Standard-ize against potassium hydrogen phthalate (See 6.1)6.14 Sulfuric Acid(CAS No 7664-93-9) (1+16)Mix 60mL of concentrated sulfuric acid (H2
24、SO4, sp gr 1.84) with 960mL of water.6.15 Tetrahydroxyquinone Indicator (THQ CAS No. 5676-48-2), in powdered form.6.16 Thorin indicator (CAS No. 132-33-2)7. Calibration and Standardization7.1 Sodium Hydroxide Solution Standardization The fol-lowing provides an example procedure for standardization;o
25、ther quantities of reagents, as convenient, can be used. Dryand crushed potassium hydrogen phthalate (KHP) is heated inan oven at 105 C for 2 hours and allowed to cool to roomtemperature in a desiccator. KHP (950 6 50 mg weighed to thenearest 0.1 mg) is placed in an Erlenmeyer flask. Water (70mL) an
26、d 2-4 drops of phenolphthalein are added. Titrate theKHP solution with the sodium hydroxide solution preparedunder 6.13 to a faint pink color. Repeat the titration using asecond portion of KHP. Titrate a 70 mL water blank containing1-4 drops of phenolphthalein to a faint pink color using thesodium h
27、ydroxide solution prepared under 6.13. Repeat thisprocedure and average the results. For both the water blank andthe KHPtitration replicates should agree to 0.05 mLtitrant. Foreach KHP trial, independently calculate the normality for thesodium hydroxide solution according to the following equa-tion:
28、Normality of NaOH 5mg KHP/204.23 mL NaOH 2 avg. mL blank!(1)Values for the two KHP trials should agree within 6 0.5percent. If they do not, repeat the titrations or identify the causefor the excessive discrepancy, or both.7.2 Sulfuric Acid Standardization The following providesan example procedure f
29、or standardization; other quantities ofreagents, as convenient, can be used. Titrate the sulfuric acidsolution prepared under 6.14 against the sodium hydroxidestandardized in 7.1 using 2-4 drops of phenolphthalein as theindicator. Repeat and average the result for the normality of thesulfuric acid.
30、Values for the two trials should agree within 60.5 percent. If they do not, repeat the titrations or identify thecause for the excessive discrepancy, or both.7.3 Barium Chloride Solution Standardization Titratethe barium chloride solution against the previously standard-ized sulfuric acid solution (
31、see 7.2). This can be conveniently3Reagent Chemicals, American Chemical Society Specifications, AmericanChemical Society, Washington, DC. For suggestions on the testing of reagents notlisted by the American Chemical Society, see Analar Standards for LaboratoryChemicals, BDH Ltd., Poole, Dorset, U.K.
32、, and the United States Pharmacopeiaand National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,MD.NOTE 1All dimensions in millimetres.FIG. 1 Gas Burner for Sulfur DeterminationD1072062accomplished by transferring 10.0 mL sulfuric acid to a flaskwhere 40 mL iso-propanol and 2-4 dro
33、ps thorin indicator areadded. This is titrated to a pink end point using the bariumchloride solution. Repeat the titration and average the results.The replicate titrations should agree within 0.5 percent. If theydo not, repeat the titrations or identify the cause for theexcessive discrepancy, or bot
34、h. Using this same procedure,perform duplicate blank titrations using water in place ofsulfuric acid solution. The replicate titrations should agreewithin 0.5 percent. Calculate the normality of the bariumchloride solution according to the following equation:Normality of Barium Chloride 510.0 mL x N
35、 Sulfuric Acidavg. mL2avg. blank!(2)NOTE 1In the case of those dimensions for which no specific tolerances are designated above, the permissible variation is 610 % to the nearest 1mm, provided, however, that in no case shall the deviation be greater than 5 mm.FIG. 2 Detailed Drawing of Combustion an
36、d Absorption Apparatus for Sulfur DeterminationFIG. 3 Suction System for Sulfur DeterminationD10720637.4 An auto titration can be used to determine the concen-tration of both sodium hydroxide and sulfuric acid.8. Preparation of Apparatus8.1 Place 300 to 400 mL of NaOH solution in the firstscrubber (
37、Fig. 4) and the same amount of H2O2-H2SO4solution(300 mL of water, 30 mL of H2SO4, and 30 mL of H2O2(30 %w/w) in the second scrubber. Replace these solutions when-ever the volume becomes less than two thirds of the original.8.2 When the apparatus is first assembled, adjust the valvebetween the vacuu
38、m manifold and the spray trap so thatapproximately 3 L of air per minute will be drawn through theabsorber when the chimney outlet is open to the atmosphere,the absorber is charged with 30 6 2 mL of water, and thepressure in the vacuum manifold is maintained at approxi-mately 40 cm of water below at
39、mospheric. When all adjust-ments have been made, remove the water from the absorbers.8.3 With the burner control valve closed, the valve to thevacuum regulator fully open, and the pressure in the vacuummanifold adjusted to approximately 40 cm of water belowatmospheric, turn on the purified air. Adju
40、st the chimneymanifold control valve so that, at the required flow through theabsorber, only a small stream of air escapes at the pressure-relief valve, a small stream of air enters at the vacuumregulator, and the pressure in the chimney manifold is 1 to 2 cmof water. Minor adjustment of the vacuum
41、regulator andvacuum control valve may be necessary to achieve thiscondition.NOTE 1It is convenient to balance the air-flow system by regulatingthe pressure in the vacuum manifold. This is done by raising or loweringthe air-inlet tube in the vacuum regulator by sliding it in a rubber sleeve.8.4 When
42、first assembling the apparatus, connect the gassample line using glass or aluminum tubing to the inlet of theflowmeter. Connect the outlet of the flowmeter in a similar wayto the lower side arm of the burner. Adjust the valve forcontrolling the rate of flow of gas so that gas is burned at a rateto l
43、iberate approximately 250 to 500 Btu/h (Note 2). This rateshould be indicated by two index marks on the columns of theflowmeter U-tube or timing a rate-index device. Make theprimary air connection from the purified air line to the upperside arm of the burner by means of rubber or plastic tubing.NOTE
44、 2Using this gas rate, the chimney and absorber should notbecome overheated during a test. The appropriate volumetric rate of gasflow will therefore depend on the heating value of the gas being tested.8.5 Wash the spray trap, absorber, and chimney well withwater before each test. Charge the larger b
45、ulb of the absorberwith 10 mL of Na2CO3solution (Note 3) and 20 mL of water.Attach the spray trap and chimney, and connect them, respec-tively, to the vacuum line and to the purified air line usingrubber or plastic tubing. Close the chimney opening using acork or other suitable plug.NOTE 3This quant
46、ity of Na2CO3solution is adequate to absorb theSO2from the combustion products of 1 ft3of gas containing 15 grains ofsulfur per 100 ft3(0.03 m3of gas containing 350 mg/m3of sulfur.) Forhigher concentrations of sulfur in the gas, the volume of Na2CO3solutionshould be proportionately increased, but th
47、e total initial liquid volume inthe absorber should not exceed 30 mL.9. Procedure9.1 Prior to each test, purge the flowmeter, burner, andconnection with the gas sample, and light the flame on theburner. Adjust the gas-flow rate by its valve to conform withthe requirements prescribed in 8.4. Adjust t
48、he primary air flowso that a soft blue flame is obtained, with no yellow tip.9.2 To start a determination, insert the burner into thechimney, fastening it in place with rubber bands or springs.Check, and readjust if necessary, gas flows to obtain a stableflame. Note the time at which the burner was
49、inserted, or notethe meter reading if an integrating meter is used.9.3 Continue the test until approximately 0.03 m3(1 ft3)ofgas is burned. Maintain the flowmeter differential at a constantvalue during this period. Note the time, or the meter readingwhen using an integrating meter, and remove the burner fromthe chimney, replacing it with the cork or other suitable plug,and continuing the suction on the absorber until the latterattains room temperature. Extinguish the flame.9.4 Unless an integrating-type meter is used for gas mea-surements, disconnect
