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1、I NTER NAT I O NA L STANDARD IS0 1928 Second edition 1995-09-01 Solid mineral fuels - Determination of gross calorific value by the bomb calorimetric method, and calculation of net calorific value Combustibles minraux solides - Dtermination du pouvoir calorifique suprieur selon la mthode la bombe ca
2、lorimtrique, et calcul du pouvoir calorifique infrieur Reference number IS0 1928:1995(E) COPYRIGHT International Organization for Standardization Licensed by Information Handling Services COPYRIGHT International Organization for Standardization Licensed by Information Handling Services 4851703 Ob280
3、32 482 IS0 1928:1995(E) Contents Page 1 Scope 1 2 Normative references . 1 3 Definitions . 2 4 Principle . 2 4.1 Gross calorific value . 2 4.2 Net calorific value . 3 5 Reagents . 3 6 Apparatus 4 7 Preparation of test sample 7 8 Calorimetric procedure 7 8.1 General . 7 8.2 Preparing the bomb for mea
4、surement . 9 8.3 Assembling the calorimeter . 9 8.4 Combustion reaction and temperature measurements . 10 8.5 Analysis of products of combustion . 10 8.6 Corrected temperature rise . 11 8.7 Reference temperature 12 9 Calibration 12 9.1 Principle 12 9.2 Calibrant 13 9.3 Valid working range of the eff
5、ective heat capacity E . 13 9.4 Ancillary contributions 14 9.5 Calibration procedure 14 9.6 Calculation of effective heat capacity for the individual experiment 14 O IS0 1995 All rights reserved . Unless otherwise specified. no part of this publication may be reproduced or utilized in any form or by
6、 any means. electronic or mechanical. including photocopying and microfilm. without permission in writing from the publisher . International Organization for Standardization Case Postale 56 CH-1 21 1 . Genve 20 Switzerland Printed in Switzerland II COPYRIGHT International Organization for Standardiz
7、ation Licensed by Information Handling Services COPYRIGHT International Organization for Standardization Licensed by Information Handling Services m 4851903 Ob28033 319 m 0 IS0 IS0 1928:1995(E) 9.7 Precision of the mean value of the effective heat capacity E 9.8 Redetermination of the effective heat
8、 capacity . 10 Gross calorific value 10.1 General . 10.2 Coal combustions . 10.3 Coke combustions 10.4 Calculation of gross calorific value . 10.5 Expression of results 10.6 Calculation to other bases 11 Precision 11.1 Repeatability limit . 11.2 Reproducibility limit 12 Calculation of net calorific
9、value at constant pressure . 12.1 General . 12.2 Calculations . 13 Test report . Annexes A B C D E F G 16 16 17 17 17 17 17 19 20 20 20 20 20 20 20 21 Adiabatic bomb calorimeters . 22 Isoperibol and static-jacket bomb calorimeters . 25 Automated bomb calorimeters 30 Checklists for the design and pro
10、cedures of combustion experiments . 33 Examples to illustrate some of the calculations used in this International Standard 37 List of symbols used in this International Standard . 41 Key-word index 43 . 111 COPYRIGHT International Organization for Standardization Licensed by Information Handling Ser
11、vices COPYRIGHT International Organization for Standardization Licensed by Information Handling Services IS0 19281995(E) 0 IS0 Foreword IS0 (the International Organization for Standardization) is a worldwide federation of national standards bodies (IS0 member bodies). The work of preparing Internati
12、onal Standards is normally carried out through IS0 technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with IS
13、O, also take part in the work. IS0 collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an Int
14、ernational Standard requires approval by at least 75 YO of the member bodies casting a vote. International Standard IS0 1928 was prepared by Technical Committee ISO/TC 27, Solid mineral fuels, Subcommittee SC 5, Methods of analysis. This second edition cancels and replaces the first edition (IS0 192
15、8:1976), which has been technically revised. Annexes A, B and C form an integral part of this International Standard. Annexes D, E, F and G are for information only. iv COPYRIGHT International Organization for Standardization Licensed by Information Handling Services COPYRIGHT International Organiza
16、tion for Standardization Licensed by Information Handling Services 4851903 Ob28035 191 INTERNATIONAL STANDARD 8 IS0 IS0 1928: 1995( E) Solid mineral fuels - Determination of gross calorific value by the bomb calorimetric method, and calculation of net calorific value WARNING - Strict adherence to al
17、l of the provisions prescribed in this International Standard should ensure against explosive rupture of the bomb, or a blow-out, provided that the bomb is of proper design and construction and in good mechanical condition. 1 Scope This International Standard specifies a method for the determination
18、 of the gross calorific value of a solid mineral fuel at constant volume and at the reference temperature 25 “C in a bomb calorimeter calibrated by combustion of certified benzoic acid. The result obtained is the gross calorific value of the analysis sample at constant volume with all the water of t
19、he combustion products as liquid water. In practice, fuel is burned at constant (atmospheric) pressure and the water is not condensed but is removed as vapour with the flue gases. Under these conditions, the operative heat of combustion is the net calorific value of the fuel at constant pressure. Th
20、e net calorific value at constant volume may also be used; formulae are given for calculating both values. General principles and procedures for the calibrations and the fuel experiments are presented in the main text, whereas those pertaining to the use of a particular type of calorimetric instrume
21、nt are described in annexes A to C. Annex D contains checklists for performing calibration and fuel experiments using specified types of calor- imeters. Annex E gives examples to illustrate some of the calculations. 2 Normative references The following standards contain provisions which, through ref
22、erence in this text, constitute provisions of this International Standard. At the time of publication, the editions indicated were valid. All standards are subject to revision, and parties to agreements based on this International Standard are encouraged to investigate the possi- bility of applying
23、the most recent editions of the standards indicated below. Members of IEC and IS0 maintain registers of currently valid International Standards. IS0 331 :I 983, Coal - Determination of moisture in the analysis sample - Direct gravimetric method. IS0 651 :I 975, Solid-stem calorimeter thermometers. I
24、S0 652: 1975, fnclosed-scale calorimeter thermometers. IS0 687: 1974, Coke - Determination of moisture in the analysis sample. IS0 1 170:1977, Coal and coke - Calculation of analyses to different bases. a COPYRIGHT International Organization for Standardization Licensed by Information Handling Servi
25、ces COPYRIGHT International Organization for Standardization Licensed by Information Handling Services 4851703 Ob28036 O28 IS0 1928:1995(E 0 IS0 IS0 1770:1981, Solid-stem general purpose thermometers. IS0 1771 : 1981, Enclosed-scale general purpose thermometers. 3 Definitions For the purposes of thi
26、s International Standard, the following definitions apply. 3.1 gross calorific value at constant volume: The absolute value of the specific energy of combustion, in joules, for unit mass of a solid fuel burned in oxygen in a calorimetric bomb under the conditions specified. The products of combustio
27、n are assumed to consist of gaseous oxygen, nitrogen, carbon dioxide and sulfur dioxide, of liquid water (in equilibrium with its vapour) saturated with carbon dioxide under the conditions of the bomb reaction, and of solid ash, all at the reference temperature. 3.2 net calorific value at constant v
28、olume: The absolute value of the specific energy of combustion, in joules, for unit mass of the fuel burned in oxygen under conditions of constant volume and such that all the water of the reaction products remains as water vapour (in a hypothetical state at 0,l MPa), the other products being as for
29、 the gross calorific value, all at the reference temperature. 3.3 net calorific value at constant pressure: The absolute value of the specific heat (enthalpy) of combustion, in joules, for unit mass of the fuel burned in oxygen at constant pressure under such conditions that all the water of the rea
30、ction products remains as water vapour (at 0.1 MPa), the other products being as for the gross calorific value, all at the reference temperature. 3.4 reference temperature: The international reference temperature for thermochemistry of 25 “C is adopted as the reference temperature for calorific valu
31、es (see 8.7). NOTE 1 The temperature dependence of the calorific value of coal or coke is small about 1 J/(g-K). 3.5 effective heat capacity of the calorimeter: The amount of energy required to cause unit change in tem- perature of the calorimeter. 3.6 corrected temperature rise: The change in calor
32、imeter temperature caused solely by the processes taking place within the combustion bomb. It is the total observed temperature rise corrected for heat exchange, stirring power, etc. (8.6). NOTE 2 The change in temperature may be expressed in terms of other units: resistance of a platinum or thermis
33、tor thermometer, frequency of a quartz crystal resonator, etc., provided that a functional relationship is established between this quantity and a change in temperature. The effective heat capacity of the calorimeter may be expressed in units of energy per such an arbitrary unit. Criteria for the re
34、quired linearity and closeness in conditions between calibrations and fuel experiments are given in 9.3. A list of the symbols used and their definitions is given in annex F. 4 Principle 4.1 Gross calorific value A weighed portion of the analysis sample of the solid fuel is burned in high-pressure o
35、xygen in a bomb calorimeter under specified conditions. The effective heat capacity of the calorimeter is determined in calibration experiments by combustion of certified benzoic acid under similar conditions, accounted for in the certificate. The corrected temperature rise is established from obser
36、vations of temperature before, during and after the combustion reaction takes place. The duration and frequency of the temperature observations depend on the type of calorimeter used. Water is added to the bomb initially to give a saturated vapour phase prior to combustion, thereby allowing all the
37、water formed, from the hydrogen and moisture in the sample, to be regarded as liquid water. The gross calorific value is calculated from the corrected temperature rise and the effective heat capacity of the calorimeter, with allowances made for contributions from ignition energy, combustion of the f
38、use(s) and for ther- 2 COPYRIGHT International Organization for Standardization Licensed by Information Handling Services COPYRIGHT International Organization for Standardization Licensed by Information Handling Services 0 IS0 4853303 0628037 Tb4 = IS0 1928:1995(E) mal effects from side reactions su
39、ch as the formation of nitric acid. Furthermore, a correction is applied to account for the difference in energy between the aqueous sulfuric acid formed in the bomb reaction and gaseous sulfur dioxide, .e. the required reaction product of sulfur in the fuel. 4.2 Net calorific value The net calorifi
40、c value at constant volume and the net calorific value at constant pressure of the fuel are obtained by calculation from the gross calorific value at constant volume determined on the analysis sample. The calculation of the net calorific value at constant volume requires information about the moistu
41、re and hydrogen contents of the analysis sample. In principle, the calculation of the net calorific value at constant pressure also requires information about the oxygen and nitrogen contents of the sample. 5 Reagents 5.1 Oxygen, at a pressure high enough to fill the bomb to 3 MPa, pure with an assa
42、y of at least 99,5 % (V/V), and free from combustible matter. NOTE 3 Oxygen made by the electrolytic process may contain up to 4 % (Vn3 of hydrogen. 5.2 Fuse 5.2.1 Ignition wire, of nickel-chromium 0.16 mm to 0,20 mm in diameter, platinum 0.05 mm to 0,lO mm in di- ameter, or another suitable conduct
43、ing wire with well-characterized thermal behaviour during combustion. 5.2.2 Cotton fuse, of white cellulose cotton, or equivalent, if required (see note 8 to 8.2.1). 5.3 Crucible lining material, for coke only. 5.3.1 Paste, of fused aluminosilicate cement passing a 63 pm test sieve and suitable for
44、use up to a temperature of 1 400 O C , mixed with water. 5.3.2 Aluminium oxide, fused, of analytical reagent quality, passing a 180 pm test sieve and retained on a 106 pm test sieve. 5.4 Standard volumetric solutions and indicators, only for use when analysis of final bomb solutions is re- qui red.
45、5.4.1 Barium hydroxide solution, cBa(OH)J = 0,05 mol/l. 5.4.2 Sodium carbonate solution, c(Na,CO,) = 0,05 mol/l. 5.4.3 Sodium hydroxide solution, c(Na0H) = 0,1 mol/l. 5.4.4 Hydrochloric acid solution, c(HCI) = 0,l mol/l. 5.4.5 Screened methyl orange indicator, 1 g/l solution. Dissolve 0,25 g of meth
46、yl orange and 0,15 g of xylene cyanole FF in 50 mI of 95 % (VA4 ethanol and dilute to 250 ml with water. 5.4.6 Phenolphthalein, I O g/l solution. Dissolve 2,5 g of phenolphthalein in 250 ml of 95 YO (VA4 ethanol. 3 COPYRIGHT International Organization for Standardization Licensed by Information Hand
47、ling Services COPYRIGHT International Organization for Standardization Licensed by Information Handling Services = 4853903 0626038 9TO W IS0 1928:1995(E) 0 IS0 5.5 Benzoic acid, of calorimetric-standard quality, certified by (or with certification unambiguously traceable to) a recognized standardizi
48、ng authority. NOTE 4 Benzoic acid is the sole substance recommended for calibration of an oxygen-bomb calorimeter. For the purpose of checking the overall reliability of the calorimetric measurements, test substances, e.g. ndodecane, are used. Test sub- stances are mainly used to prove that certain
49、characteristics of a sample, e.g. burning rate or chemical composition, do not introduce bias in the results. A test substance shall have a certified purity and a well-established energy of combustion. The benzoic acid is burned in the form of pellets. It is normally used without drying or any treatment other than pelletizing; consult the sample certificate. It does not absorb moisture from the atmosphere at relative humidities below 90 %. The benzoic acid shall be used as close to certification conditions as is feasible; significant departures from these conditions shall