ASTM D1072-06(2012)
(Test Method)Standard Test Method for Total Sulfur in Fuel Gases by Combustion and Barium Chloride Titration
Standard Test Method for Total Sulfur in Fuel Gases by Combustion and Barium Chloride Titration
ABSTRACT
This test method is for the determination of total sulfur in combustible fuel gases and is applicable to natural gases, manufactured gases, mixed gases, and other miscellaneous gaseous fuels. For the use of barium chloride titration following collection of sulfur dioxide by alternative procedures, ammonia, amines, substances producing water soluble cations, and fluorides will interfere with the titration. The apparatus includes the following: (1) burner, (2) chimneys, absorbers, and spray traps, (3) flow meter, (4) vacuum system, (5) air-purifying system, and (6) monometer. The schematic diagrams of the gas burner, combustion and absorption apparatus, suction system, and purified air system are provided. Reagent grade chemicals shall be used in all tests and include: (1) water, (2) denatured ethyl or isopropyl alcohol, (3) barium chloride, standard solution, (4) hydrochloric acid, (5) hydrogen peroxide, (6) iso-propanol, (7) potassium hydrogen phthalate, (8) phenolphthalein, (9) methyl orange indicator solution, (10) silver nitrate solution, (11) sodium carbonate solution, (12) sodium hydroxide solution, (13) sulfuric acid, (14) tetrahydroxyquinone indicator, and (15) thorin indicator. The procedure for the following are detailed: (1) calibration and standardization of sodium hydroxide, sulfuric acid, and barium chloride solutions, (2) preparation of apparatus, (3) sulfur determination, (4) analysis of absorbent, and (5) quality assurance. The formula of calculating the volume of gas in standard cubic feet burned during the determination and the concentration of sulfur from the results of titration are given.
SCOPE
1.1 This test method is for the determination of total sulfur in combustible fuel gases, when present in sulfur concentrations between approximately 25 and 700 mg/m3 (1 to 30 grains per 100 cubic feet). It is applicable to natural gases, manufactured gases, mixed gases, and other miscellaneous gaseous fuels.
1.2 The values stated in inch-pound units are to be regarded as standard.
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.
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Standards Content (Sample)
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Designation: D1072 − 06 (Reapproved 2012)
Standard Test Method for
Total Sulfur in Fuel Gases by Combustion and Barium
Chloride Titration
This standard is issued under the fixed designation D1072; 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 alternative procedures are cautioned that ammonia, amines,
substances producing water soluble cations, and fluorides will
1.1 This test method is for the determination of total sulfur
interfere with the titration.
in combustible fuel gases, when present in sulfur concentra-
tions between approximately 25 and 700 mg/m (1 to 30 grains
5. Apparatus
per 100 cubic feet). It is applicable to natural gases, manufac-
5.1 Burner (Fig. 1), as specified in the Appendix X1.
tured gases, mixed gases, and other miscellaneous gaseous
fuels.
5.2 Chimneys, Absorbers and Spray Traps, (Fig. 2), as
specified in the Appendix X1.
1.2 The values stated in inch-pound units are to be regarded
as standard.
5.3 Flow meter—A calibrated capillary flow meter for
predetermining and indicating the rate of flow of gas to the
1.3 This standard does not purport to address all of the
burner. The capillary selected should be of such size that at the
safety concerns, if any, associated with its use. It is the
required rate of flow the differential pressure is at least 20 cm
responsibility of the user of this standard to establish appro-
of water. A scale divided into millimeters will then provide a
priate safety and health practices and determine the applica-
reading precision of 6 0.5 %. Other metering devices, includ-
bility of regulatory limitations prior to use.
ing but not limited to rotameters or dry displacement meters,
2. Referenced Documents
aresuitableprovidedthereadingprecisionis 60.5%orbetter.
A flow controlling valve is attached to the inlet connection of
2.1 ASTM Standards:
the flow meter.
D1193 Specification for Reagent Water
5.4 Vacuum System—A vacuum manifold equipped with a
3. Summary of Test Method
vacuum regulating device, valves, and other necessary accou-
3.1 Ametered sample of gas is burned in a closed system in
terments. An example vacuum system capable of performing
an atmosphere of sulfur-free air. The oxides of sulfur produced multiple test measurements is shown in Fig. 3. Other vacuum
are absorbed in sodium carbonate solution, where they are
system configurations can be used to perform this test method.
oxidized to sulfate. The sulfate in the absorbent solution is
The vacuum system shall be connected to a vacuum pump
determined by titration with standardized barium chloride
capable of providing a steady gas flow of 3 Lof air per minute
solution, using tetra-hydroxy-quinone (THQ) as an indicator.
through each absorber and capable of maintaining a constant
manifold pressure of approximately 40 cm of water below
4. Interferences
atmospheric pressure.
4.1 There are no known interferences for the determination
5.5 Air-Purifying System—A device supplying purified air
of total sulfur in fuel gases when combustion is followed by
to the burner manifold at a constant pressure of approximately
barium chloride titration. However, users employing barium
200 mm of water and to the chimney manifold at a pressure of
chloride titration following collection of sulfur dioxide by
1 to 2 cm of water. An example system configuration for
multiple tests is illustrated in Fig. 4; however, other air-
purifyingsystemconfigurationscanbeusedtoperformthistest
ThistestmethodisunderthejurisdictionofASTMCommitteeD03onGaseous
method.The tubing that connects the chimneys to the manifold
Fuels and is the direct responsibility of D03.05 on Determination of Special
Constituents of Gaseous Fuels.
shall be of an internal diameter not smaller than 0.63 cm in
Current edition approved Nov. 1, 2012. Published December 2012. Originally
order to prevent unnecessary restriction of airflow.
approved in 1954. Last previous edition approved in 2006 as D1072 – 06. DOI:
10.1520/D1072-06R12.
5.6 Manometer—A water manometer for indicating the gas
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
pressure at the point of volume measurement. It is connected
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
between the flowmeter and the burner, with one leg open to the
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. atmosphere.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D1072 − 06 (2012)
6.10 Methyl Orange (CAS No 547-58-0) Indicator
Solution—Dissolve 0.1 g of methyl orange in 100 mLof water.
6.11 Silver Nitrate (CAS No 7761-88-8)Solution (17-g
AgNO /L)—Dissolve 1.7 g of silver nitrate (AgNO)in100
3 3
mL of water. Store in a brown bottle.
6.12 Sodium Carbonate (CAS No 5968-11-6) Solution
(3.306-g Na CO /L)—Dissolve 3.306 g of sodium carbonate
2 3
(Na CO ) in water and dilute to 1 L.
2 3
6.13 Sodium Hydroxide Solution (CAS No 1310-73-2)
(100-g NaOH/L)—Dissolve 100 g of technical grade sodium
hydroxide (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 60
NOTE 1—All dimensions in millimetres.
mL of concentrated sulfuric acid (H SO , sp gr 1.84) with 960
2 4
FIG. 1 Gas Burner for Sulfur Determination
mL of water.
6.15 Tetrahydroxyquinone Indicator (THQ CAS No. 5676-
48-2), in powdered form.
6. Reagents and Materials
6.16 Thorin indicator— (CAS No. 132-33-2)
6.1 Reagents Purity—Reagent grade chemicals shall be
used in all tests. Unless otherwise indicated, it is intended that
7. Calibration and Standardization
all reagents shall conform to the specifications of the Commit-
7.1 Sodium Hydroxide Solution Standardization— The fol-
tee onAnalytical Reagents of theAmerican Chemical Society,
lowing provides an example procedure for standardization;
where such specifications are available. Other grades may be
other quantities of reagents, as convenient, can be used. Dry
used, provided it is first ascertained that the reagent is of
and crushed potassium hydrogen phthalate (KHP) is heated in
sufficiently high purity to permit its use without adversely
an oven at 105 °C for 2 hours and allowed to cool to room
impacting the accuracy of the determination. Warning—
temperature in a desiccator. KHP(950 6 50 mg weighed to the
Sodiumhydroxideiscorrosiveandcancauseseveredamageto
nearest 0.1 mg) is placed in an Erlenmeyer flask. Water (70
eyesandskin.Inhalationwillirritatethenose,throatandlungs.
mL) and 2-4 drops of phenolphthalein are added. Titrate the
It reacts exothermically with water.
KHP solution with the sodium hydroxide solution prepared
6.2 Purity of Water—Unless otherwise indicated, references
under 6.13 to a faint pink color. Repeat the titration using a
towatershallbeunderstoodtomeanreagentwaterconforming
second portion of KHP.Titrate a 70 mLwater blank containing
to Specification D1193.
1-4 drops of phenolphthalein to a faint pink color using the
6.3 Alcohol—Ethyl alcohol, denatured by Formula 30 or
sodium hydroxide solution prepared under 6.13. Repeat this
3-A, or isopropyl alcohol.
procedureandaveragetheresults.Forboththewaterblankand
theKHPtitrationreplicatesshouldagreeto0.05mLtitrant.For
6.4 Barium Chloride,(CAS No: 10361-37-2), Standard So-
each KHP trial, independently calculate the normality for the
lution (1 mL = 1 mg S)—Dissolve 7.634 g of barium chloride
sodium hydroxide solution according to the following equa-
(BaCl ·2H O) in water and dilute to 1 L. The solution is
2 2
tion:
standardized gravimetrically by precipitation as barium sulfate
or by titration against sulfuric acid (see 6.12)
mg KHP/204.23
Normality of NaOH 5 (1)
mL NaOH 2 avg. mL blank
~ !
6.5 Hydrochloric Acid (CAS No 7647-01-0) (2.275-g HCl/
Values for the two KHP trials should agree within 6 0.5
L)—Titrated against Na CO solution (see 6.15), using methyl
2 3
percent. If they do not, repeat the titrations or identify the
orange indicator. Adjusted such that 1 mL of HCl solution is
cause for the excessive discrepancy, or both.
equivalent to 1 mL of Na CO solution.
2 3
7.2 Sulfuric Acid Standardization— The following provides
6.6 Hydrogen Peroxide (30 %)(H O ;CAS No: 7722-84-1).
2 2
an example procedure for standardization; other quantities of
6.7 iso-Propanol (CAS No. 67630) reagents, as convenient, can be used. Titrate the sulfuric acid
solution prepared under 6.14 against the sodium hydroxide
6.8 Potassium Hydrogen Phthalate (KHP; CAS No 877-
standardized in 7.1 using 2-4 drops of phenolphthalein as the
24-7) —Dry use.
indicator.Repeatandaveragetheresultforthenormalityofthe
6.9 Phenolphthalein (CAS No 77-09-8)
sulfuric acid. Values for the two trials should agree within 6
0.5 percent. If they do not, repeat the titrations or identify the
cause for the excessive discrepancy, or both.
Reagent Chemicals, American Chemical Society Specifications, American
Chemical Society, Washington, DC. For suggestions on the testing of reagents not
7.3 Barium Chloride Solution Standardization— – Titrate
listed by the American Chemical Society, see Analar Standards for Laboratory
the barium chloride solution against the previously standard-
Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia
ized sulfuric acid solution (see 7.2). This can be conveniently
and National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,
MD. accomplished by transferring 10.0 mL sulfuric acid to a flask
D1072 − 06 (2012)
NOTE 1—In the case of those dimensions for which no specific tolerances are designated above, the permissible variation is 610 % to the nearest 1
mm, provided, however, that in no case shall the deviation be greater than 5 mm.
FIG. 2 Detailed Drawing of Combustion and Absorption Apparatus for Sulfur Determination
added. This is titrated to a pink end point using the barium
chloride solution. Repeat the titration and average the results.
The replicate titrations should agree within 0.5 percent. If they
do not, repeat the titrations or identify the cause for the
excessive discrepancy, or both. Using this same procedure,
perform duplicate blank titrations using water in place of
sulfuric acid solution. The replicate titrations should agree
within 0.5 percent. Calculate the normality of the barium
chloride solution according to the following equation:
FIG. 3 Suction System for Sulfur Determination
10.0 mL x N Sulfuric Acid
Normality of Barium Chloride 5 (2)
~avg. mL 2 avg. blank!
where 40 mL iso-propanol and 2-4 drops thorin indicator are
D1072 − 06 (2012)
to liberate approximately 250 to 500 Btu/h (Note 2). This rate
should be indicated by two index marks on the columns of the
flowmeter U-tube or timing a rate-index device. Make the
primary air connection from the purified air line to the upper
side arm of the burner by means of rubber or plastic tubing.
NOTE 2—Using this gas rate, the chimney and absorber should not
become overheated during a test. The appropriate volumetric rate of gas
flow will therefore depend on the heating value of the gas being tested.
8.5 Wash the spray trap, absorber, and chimney well with
water before each test. Charge the larger bulb of the absorber
with 10 mL of Na CO solution (Note 3) and 20 mL of water.
2 3
Attach the spray trap and chimney, and connect them,
respectively, to the vacuum line and to the purified air line
using rubber or plastic tubing. Close the chimney opening
using a cork or other suitable plug.
NOTE 3—This quantity of Na CO solution is adequate to absorb the
2 3
SO from the combustion products of 1 ft of gas containing 15 grains of
3 3 3
sulfur per 100 ft (0.03 m of gas containing 350 mg/m of sulfur.) For
FIG. 4 Purified Air System for Sulfur Determination
higher concentrations of sulfur in the gas, the volume of Na CO solution
2 3
should be proportionately increased, but the total initial liquid volume in
the absorber should not exceed 30 mL.
7.4 An auto titration can be used to determine the concen-
tration of both sodium hydroxide and sulfuric acid.
9. Procedure
9.1 Prior to each test, purge the flowmeter, burner, and
8. Preparation of Apparatus
connection with the gas sample, and light the flame on the
8.1 Place 300 to 400 mL of NaOH solution in the first
burner. Adjust the gas-flow rate by its valve to conform with
scrubber(Fig.4)andthesameamountofH O -H SO solution
2 2 2 4
the requirements prescribed in 8.4.Adjust the primary air flow
(300mLofwater,30mLofH SO ,and30mLofH O (30 %
2 4 2 2
so that a soft blue flame is obtained, with no yellow tip.
w/w)) in the second scrubber. Replace these solutions when-
ever the volume becomes less than two thirds of the original.
9.2 To start a determination, insert the burner into the
chimney, fastening it in place with rubber bands or springs.
8.2 When the apparatus is first assembled, adjust the valve
Check, and readjust if necessary, gas flows to obtain a stable
between the vacuum manifold and the spray trap so that
flame. Note the time at which the burner was inserted, or note
approximately 3 L of air per minute will be drawn through the
the meter reading if an integrating meter is used.
absorber when the chimney outlet is open to the atmosphere,
3 3
the absorber is charged with 30 6 2 mL of water, and the
9.3 Continue the test until approximately 0.03 m (1 ft )of
pressure in the vacuum manifold is maintained at approxi-
gas is burned. Maintain the flowmeter differential at a constant
mately 40 cm of water below atmospheric. When all adjust-
value during this period. Note the time, or the meter reading
ments have been made, remove the water from the absorbers.
when using an integrating meter, and remove the burner from
the chimney, replacing it with the cork or other suitable plug,
8.3 With the burner control valve closed, the valve to the
vacuum regulator fully open, and the pressure in the vacuum and continuing the suction on the absorber until the latter
manifold adjusted to approximately 40 cm of water below attains room temperature. Extinguish the flame.
atmospheric, turn on the purified air. Adjust the chimney
9.4 Unless an integrating-type meter is used for gas
manifold control valve so that, at the required flow through the
measurements, disconnect the burner from the flowmeter.
absorber, only a small stream of air escapes at the pressure-
Replace it with a connection to a calibrated wet-test meter that
relief valve, a
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