ASTM D240-92(1997)e2
(Test Method)Standard Test Method for Heat of Combustion of Liquid Hydrocarbon Fuels by Bomb Calorimeter
Standard Test Method for Heat of Combustion of Liquid Hydrocarbon Fuels by Bomb Calorimeter
SCOPE
1.1 This test method covers the determination of the heat of combustion of liquid hydrocarbon fuels ranging in volatility from that of light distillates to that of residual fuels.
1.2 Under normal conditions, this test method is directly applicable to such fuels as gasolines, kerosines, Nos. 1 and 2 fuel oil, Nos. 1-D and 2-D diesel fuel and Nos. 0-GT, 1-GT, and 2-GT gas turbine fuels.
1.3 This test method is not as repeatable and not as reproducible as Test Method D4809.
1.4 The values stated in SI units are to be regarded as the standard.
1.5 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.For specific hazard statements, see Sections 7 and 9 and A1.10 and Annex A3.
General Information
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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NOTICE: This standard has either been superseded and replaced by a new version or
withdrawn.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.
e2
Designation: D 240 – 92 (Reapproved 1997) An American National Standard
AMERICAN SOCIETY FOR TESTING AND MATERIALS
100 Barr Harbor Dr., West Conshohocken, PA 19428
Reprinted from the Annual Book of ASTM Standards. Copyright ASTM
Standard Test Method for
Heat of Combustion of Liquid Hydrocarbon Fuels by Bomb
Calorimeter
This standard is issued under the fixed designation D 240; 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 (e) indicates an editorial change since the last revision or reapproval.
This test method has been adopted for use by government agencies to replace Method 2502 of Federal Test Method Standard No. 791b.
e NOTE—Editorial correction were made in April 1997.
e NOTE—Paragraph 8.1 was corrected editorially in March 1999.
1. Scope E 1 Specification for ASTM Thermometers
E 200 Practice for Preparation, Standardization, and Stor-
1.1 This test method covers the determination of the heat of
age of Standard Solutions for Chemical Analysis
combustion of liquid hydrocarbon fuels ranging in volatility
from that of light distillates to that of residual fuels.
3. Terminology
1.2 Under normal conditions, this test method is directly
3.1 Definitions:
applicable to such fuels as gasolines, kerosines, Nos. 1 and 2
3.1.1 gross heat of combustion, Qg (MJ/kg)—the quantity of
fuel oil, Nos. 1-D and 2-D diesel fuel and Nos. 0-GT, 1-GT,
energy released when a unit mass of fuel is burned in a constant
and 2-GT gas turbine fuels.
volume enclosure, with the products being gaseous, other than
1.3 This test method is not as repeatable and not as
water that is condensed to the liquid state.
reproducible as Test Method D 4809.
3.1.1.1 Discussion—The fuel can be either liquid or solid,
1.4 The values stated in SI units are to be regarded as the
and contain only the elements carbon, hydrogen, nitrogen, and
standard.
sulfur. The products of combustion, in oxygen, are gaseous
1.5 This standard does not purport to address all of the
carbon dioxide, nitrogen oxides, sulfur dioxide, and liquid
safety concerns, if any, associated with its use. It is the
water. In this procedure, 25°C is the initial temperature of the
responsibility of the user of this standard to establish appro-
fuel and the oxygen, and the final temperature of the products
priate safety and health practices and determine the applica-
of combustion.
bility of regulatory limitations prior to use. For specific hazard
3.1.2 net heat of combustion, Qn (MJ/kg)—the quantity of
statements, see 7.5, 7.7, 7.8 and 9.3.
energy released when a unit mass of fuel is burned at constant
2. Referenced Documents pressure, with all of the products, including water, being
gaseous.
2.1 ASTM Standards:
3.1.2.1 Discussion—The fuel can be either liquid or solid,
D 129 Test Method for Sulfur in Petroleum Products (Gen-
and contain only the elements carbon, hydrogen, oxygen,
eral Bomb Method)
nitrogen, and sulfur. The products of combustion, in oxygen,
D 1018 Test Method for Hydrogen in Petroleum Fractions
are carbon dioxide, nitrogen oxides, sulfur dioxide, and water,
D 3701 Test Method for Hydrogen Content of Aviation
all in the gaseous state. In this procedure, the combustion takes
Turbine Fuels by Low Resolution Nuclear Magnetic Reso-
place at a constant pressure of 0.101 MPa (1 ohm), and 25°C
nance Spectrometry
is the initial temperature of the fuel and the oxygen, and the
D 4809 Test Method for Heat of Combustion of Liquid
final temperature of the products of combustion.
Hydrocarbon Fuels by Bomb Calorimeter (Intermediate
4 3.1.3 The following relationships may be used for convert-
Precision Method)
ing to other units (conversion factor is exact):
1 cal (International Table calorie) 5 4.1868 J
1 Btu (British thermal unit) 5 1055.06 J
1 cal (I.T.)/g 5 0.0041868 MJ/kg
This test method is under the jurisdiction of ASTM Committee D-2 on
1 Btu/lb 5 0.002326 MJ/kg
Petroleum Products and Lubricants and is the direct responsibility of Subcommittee
D02.05 on Properties of Fuels, Petroleum, Coke and Oil Shale.
3.2 Definitions of Terms Specific to This Standard:
Current edition approved Apr. 15, 1992. Published June 1992. Originally
3.2.1 energy equivalent—(effective heat capacity or water
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published as D 240 – 57 T. Last previous edition D 240 – 87 (1991) .
Annual Book of ASTM Standards, Vol 05.01.
Annual Book of ASTM Standards, Vol 05.02.
Annual Book of ASTM Standards, Vol 14.03.
Annual Book of ASTM Standards, Vol 05.03.
Annual Book of ASTM Standards, Vol 15.05.
D 240
equivalent) of the calorimeter is the energy required to raise the vehicles, and hydrofoils. The range of such craft between
temperature 1° expressed as MJ/°C. refueling is a direct function of the heat of combustion and
density of the fuel.
1 MJ/kg 5 1000 J/g (1)
In SI the unit of heat of combustion has the dimension J/kg, 6. Apparatus
but for practical use a multiple is more convenient. The MJ/kg
6.1 Test Room, Bomb, Calorimeter, Jacket, Thermometers,
is customarily used for the representation of heats of combus-
and Accessories, as described in Annex A1.
tion of petroleum fuels.
7. Reagents
NOTE 1—The energy unit of measurement employed in this test method
7.1 Benzoic Acid, Standard —Benzoic acid powder must be
is the joule with the heat of combustion reported in megajoules per
compressed into a tablet or pellet before weighing. Benzoic
kilogram.
acid pellets for which the heat of combustion has been
3.3 Symbols:
determined by comparison with the National Bureau of Stan-
3.3.1 The net heat of combustion is represented by the
dards sample are obtainable commercially for those laborato-
symbol Q and is related to the gross heat of combustion by the
n
ries not equipped to pellet benzoic acid.
following equation:
7.2 Gelatin Capsules.
Q ~net, 25°C!5 Q ~gross, 25°C!2 0.2122 3 H (2)
n g
7.3 Methyl Orange or Methyl Red Indicator.
7.4 Mineral Oil.
where:
7.5 Oxygen—Commerical oxygen produced from liquid air
Q (net, 25°C) 5 net heat of combustion at constant
n
can be used without purification. If purification is necessary see
pressure, MJ/kg
A1.11.
Q (gross, 25°C) 5 gross heat of combustion at constant
g
volume, MJ/kg
NOTE 2—Warning: Oxygen vigorously accelerates combustion. See
H 5 mass % of hydrogen in the sample.
Annex A3.2.
7.6 Pressure-Sensitive Tape—Cellophane tape 38 mm
4. Summary of Test Method
(1 ⁄2in.) wide, free of chlorine and sulfur.
4.1 Heat of combustion is determined in this test method by
7.7 Alkali, Standard Solution:
burning a weighed sample in an oxygen bomb calorimeter
7.7.1 Sodium Hydroxide Solution (0.0866 N)—Dissolve 3.5
under controlled conditions. The heat of combustion is com-
g of sodium hydroxide (NaOH) in water and dilute to 1 L.
puted from temperature observations before, during, and after
Standardize with potassium acid phthalate and adjust to 0.0866
combustion, with proper allowance for thermochemical and
N as described in Method E 200.
heat transfer corrections. Either isothermal or adiabatic calo-
NOTE 3—Warning: Corrosive. Can cause severe burns or blindness.
rimeter jackets can be used.
Evolution of heat produces a violent reaction or eruption upon too rapid
4.1.1 Temperatures can be measured in Celsius degrees.
mixture with water. See Annex A3.1.
4.1.1.1 Temperatures can be recorded in either Fahrenheit
7.7.2 Sodium Carbonate Solution (0.0725 M)—Dissolve
degrees or ohms or other units when using electric thermom-
3.84gofNa CO in water and dilute to 1 L. Standardize with
2 3
eters. Use the same units in all calculations, including stan-
potassium acid phthalate and adjust to 0.0725 M as described
dardization.
in Practice E 200.
4.1.2 Time is expressed in calculations in minutes and
7.8 2,2,4-Trimethylpentane (isooctane), Standard.
decimal fractions thereof. It may be measured in minutes and
seconds.
NOTE 4—Warning: Extremely flammable. Harmful if inhaled. Vapors
4.1.3 Masses are measured in grams and no buoyancy may cause flash fire. See Annex A3.3.
corrections are applied.
8. Standardization
5. Significance and Use
8.1 Determine the Energy Equivalent of the Calorimeter—
Average not less than six tests using standard benzoic acid.
5.1 The heat of combustion is a measure of the energy
These tests should be spaced over a period of not less than
available from a fuel. A knowledge of this value is essential
three days. Use not less than 0.9 g nor more than 1.1 g of
when considering the thermal efficiency of equipment for
standard benzoic acid (C H COOH). Make each determination
producing either power or heat. 6 6
according to the procedure described in Section 9 and compute
5.2 The heat of combustion as determined by this test
the corrected temperature rise, t, as described in 10.1 or 10.2.
method is designated as one of the chemical and physical
Determine the corrections for nitric acid (HNO ) and firing
requirements of both commercial and military turbine fuels and 3
wire as described in 10.3 and substitute in the following
aviation gasolines.
equation:
5.3 The mass heat of combustion, the heat of combustion
per unit mass of fuel, is a critical property of fuels intended for
use in weight-limited craft such as airplanes, surface effect Obtainable from the National Institute of Standards Technology, Gaithersburg,
MD 20899 as standard sample No. 39.
Obtainable from the National Institute of Standards Technology, Gaithersburg,
MD 20899 as standard sample No. 217b.
7 10
Derivation of equations have been filed at ASTM Headquarters. Request RR: See Jessup, R. S., “Precise Measurement of Heat of Combustion with a Bomb
D02-1346. Calorimeter,” NBS Monograph 7, U. S. Government Printing Office.
D 240
W 5 ~Q 3 g 1 e 1 e !/t (3)
1 2 Q 5 MJ/kg.
s
Some fuels contain water and particulate matter (ash) that
where:
will degrade calorimetric values. If the heat of combustion is
W 5 energy equivalent of calorimeter, MJ/°C,
required on a clean fuel, filter the sample to remove free water
Q 5 heat of combustion of standard benzoic acid, MJ/g,
and insoluble ash before testing.
calculated from the certified value,
9.1.1 For highly volatile fluids, reduce loss with use of
g 5 weight of standard benzoic acid sample, g,
tape or gelatin capsule mineral oil.
t 5 corrected temperature rise, as calculated in 10.1 or
9.1.2 Tape—Place a piece of pressure-sensitive tape across
10.2,° C,
e 5 correction for heat of formation of nitric acid, MJ, the top of the cup, trim around the edge with a razor blade, and
seal tightly. Place 3 by 12-mm strip of tape creased in the
and
middle and sealed by one edge in the center of the tape disk to
e 5 correction for heat of combustion of firing wire, MJ.
give a flap arrangement. Weigh the cup and tape. Remove from
the balance with forceps. Fill a hypodermic syringe with the
8.1.1 Repeat the standardization tests after changing any
sample. The volume of sample can be estimated as follows:
part of the calorimeter and occasionally as a check on both
calorimeter and operating technique.
V 5 ~W 3 0.00032!/~Q 3 D! (6)
8.2 Checking the Calorimeter for Use with Volatile Fuels—
where:
Use 2,2,4-trimethylpentane to determine whether the results
V 5 volume of sample to be used, mL,
obtained agree with the certified value (47.788 MJ/kg, weight
W 5 energy equivalent of calorimeter, J/°C,
in air) within the repeatability of the test method. If results do
Q 5 approximate heat of combustion of the sample, MJ/kg,
not come within this range, the technique of handling the
and
sample may have to be changed (Annex A1.8). If this is not
D 5 density, kg/m , of the sample.
possible or does not correct the error, run a series of tests using
9.1.2.1 Add the sample to the cup by inserting the tip of the
2,2,4-trimethylpentane to establish the energy equivalent for
needle through the tape disk at a point so that the flap of tape
use with volatile fuels.
will cover the puncture upon removal of the needle. Seal down
8.3 Heat of Combustion of Pressure-Sensitive Tape or
the flap by pressing lightly with a metal spatula. Reweigh the
Gelatin/Mineral Oil—Determine the heat of combustion of
cup with the tape and sample. Take care throughout the
either the pressure-sensitive tape or 0.5 g gelatin capsule/
weighing and filling operation to avoid contacting the tape or
mineral oil in accordance with Section 9 using about 1.2 g of
cup with bare fingers. Place the cup in the curved electrode and
tape or 0.5 g gelatin capsule/mineral oil and omitting the
arrange the fuse wire so that the central portion of the loop
sample. Make at least three determinations and calculate the
presses down on the center of the tape disk.
heat of combustion as follows:
9.1.3 Gelatin/Mineral Oil—Weigh the cup and gelatin cap-
Q 5 ~Dt 3 W 2 e !/1000 a (4)
pst 1
sule. The capsule should only be handled with forceps. Add the
sample to the capsule. Reweigh the cup with capsule and
where:
sample. If poor combustion is expected with the capsule, add
Q 5 heat of combustion of the pressure-sensitive tape or
pst
several drops of mineral oil on the capsule and reweigh the cup
mineral oil, MJ/kg,
and contents. Place the cup in the curved electrode and arrange
Dt 5 corrected temperature rise, as calculated in accor-
the fuse wire so that the central portion of the loop contacts the
dance with 10.1 or 10.2,° C,
capsule and oil.
W 5 energy equivalent of the calorimeter, MJ/°C,
9.2 Water in Bomb—Add 1.0 mL of water to the bomb from
e 5 correction for the heat of formation of HNO , MJ,
1 3
a pipet.
and
a 5 mass of the pressure-sensitive tape or gelatin 9.3 Oxygen—With the test sample and fuse in place, slowly
charge the bomb with oxygen to 3.0-MPa (30-atm) gage
capsule/mineral oil, g.
pressure at room temperature (9.3.1). Do not purge the bomb to
Average the determinations, and redetermine the heat of
remove entrapped air.
combustion of the tape or gelatin capsule/mineral oil whenever
a new roll or batch is started.
NOTE 6—Warning: Be careful not to overcharge the bomb. If, by
accident, the oxygen introduced into the bomb should exceed 4.0 MPa, do
9. Procedure
not proceed with the combustion. An explosion might occur with possible
violent rupture of the bomb. Detach the filling connection and exhaust the
9.1 Weight of Sample—Control the weight of sample (in-
bomb in the usual manner. Discard the sample, unless it has lost no
cluding any auxiliary fuel) so that the temperature rise pro-
weight, as shown by reweighing.
duced by its combustion will be equal to that of 0.9 to 1.1 g of
9.3.1 Lower or higher initial oxygen pressures can be used
benzoic acid (Note 5). Weigh the sample to the
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