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1、IS0 7935 92 4853903 0523765 877 I N T E R NAT I O NA L STANDARD IS0 7935 First edition 1992-1 2-1 5 Stationary source emissions - Determination of the mass concentration of sulfur dioxide - Performance characteristics of automated measuring methods missions de sources fixes - Dtermination de la conc
2、entration en masse de dioxyde de soufre - Caractristiques de performance des mthodes de mesurage automatiques Reference number IS0 7935:1992(E) - _ - IS0 7935 72 4851903 0521966 703 IS0 7935:1992(E) Contents Page Scope 1 Normative references . 2 Definitions . 2 Description of the automated measuring
3、 systems 3 Numerical values of performance characteristics and their applicability 4 Annexes A Determination of main performance characteristics of automated measuring systems 6 B Additional performance characteristics 10 C Bibliography 11 O IS0 1992 All rights reserved. No part of this publication
4、may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without per- mission in writing from the publisher. International Organization for Standardization Case Postale 56 CH-1 21 1 Genve 20 Switzerland Printed in Switzerland COPYRIGH
5、T International Organization for Standardization Licensed by Information Handling Services COPYRIGHT International Organization for Standardization Licensed by Information Handling Services IS0 7935 92 m 4851903 0521967 b4T m IS0 7935:1992(E) Forei rord IS0 (the International Organization for Standa
6、rdization) is a worldwide federation of national standards bodies (IS0 member bodies). The work of preparing International 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 t
7、o be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. IS0 collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. Draft Internation
8、al Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote. International Standard IS0 7935 was prepared by Technical Committee lSO/TC 146, Air qualit
9、y, Sub-Committee SC 1, Stationary source emissions. Annex A forms an integral part of this International Standard. Annexes B and C are for information only. iii COPYRIGHT International Organization for Standardization Licensed by Information Handling Services COPYRIGHT International Organization for
10、 Standardization Licensed by Information Handling Services . - IS0 7735 72 4851703 0521768 586 IS0 7935:1992(E) Introduction Sulfur dioxide can arise in considerable quantities from combustion of fossil fuels used for energy generation, industrial activities processing sulfur or sulfur containing ma
11、terial, and from combustion of sulfur con- taining waste. The waste gas from these processes, containing sulfur di- oxide, is usually discharged into the ambient atmosphere, via a duct or a chimney . For evaluating the mass concentration of sulfur dioxide present in the waste gas of stationary sourc
12、e emissions, a number of highly developed methods of integrated sampling and subsequent determination by chemi- cal analysis and automated measuring systems are available. Considerable experience exists on their application under plant conditions. One of these methods is standardized as IS0 7934. IS
13、0 7934 is used for example in comparative measurements, where the automated measuring methods are involved. The automated technique is capable of continuous measurement of the mass concentration of sulfur dioxide. For methods where performance characteristics are given, the values of performance cha
14、racteristics are used to decide whether a method is suit- able for a given measuring task (see IS0 6879:1983, clause 1). Values of the main performance characteristics of automated measuring systems, capable of determining the mass concentration of sulfur dioxide present in waste gas stationary emis
15、sion sources, are given in clause 5. Additional performance characteristics are given in informative annex B. The procedure for evaluating the values of the performance characteristics listed in clause 5, is described in normative annex A. COPYRIGHT International Organization for Standardization Lic
16、ensed by Information Handling Services COPYRIGHT International Organization for Standardization Licensed by Information Handling Services IS0 7935 92 9 4851903 0523969 432 m Performance characteristics INTERNATIONAL STANDARD IS0 7935:1992(E) Numerical value Stationary source emissions - Determinatio
17、n of the mass concentration of sulfur dioxide - Performance letection limit Effect of interfering substances Response time Integral performance (SA) characteristics of automated 2 % 1) I2%1)2) Q 200 s 3) * 2,5 % 4) 1 Scope This International Standard specifies a complete set of values of performance
18、 characteristics for auto- mated measuring systems for the continuous measurement of the mass concentrations of sulfur dioxide in stationary source emissions. NOTE 1 If the performance characteristics of an auto- mated measuring system are listed according to table 1, this ensures that the automated
19、 measuring system is reliable and gives satisfactory continuous results. The set of data listed in table 1 refers to the perform- ance characteristics of measurement methods, in- cluding all steps from sampling to recording and, if necessary, storage of data. This International Standard is applicabl
20、e to extractive and non-extractive automated sulfur dioxide measur- ing methods. For both methods it implies the appli- cability of zero and calibration gas and the availability of comparable samples. The automated measuring system can be calibrated with calibration gases, by applying the manual met
21、hod described in IS0 7934, or by applying an automated measuring system pre- viously verified according to this International Stan- dard using a different principle of detection. The value of the integral performance (3.7) is determined by using IS0 7934 or an automated measuring system verified acc
22、ording to this International Standard with a different principle of detection. At present, the range over which this specificatiog applies is between O g/m3 to Oll g/m3 and O g/m to 8 g/m3 (see table2 for details). measuring methods NOTE 2 Although it is impossible to give precise testing details, t
23、he requirements and testing principles are also a p plicable to non-extractive systems. Table 1 - Main Performance characteristics I Test methods (see annex Al A.4.2.1 .I A.4.2.1.2 A.4.2.1.3 A.4.2.2 1) Related to the upper limit of measurement. 2) The main interfering substances in the flue gas from
24、 combustion plants are CO2, CO, NO, H20 and, in smaller concentrations, NO2 and NH3. If the water va- pour is not removed from the flue gas of coal and waste fired incinerators, HCI and HN may also interfere. In special cases there may be other interfering substances (e.g. cyanide). 3) Assuming an i
25、ntegration time of 30 min. 4) See 3.7. The facilities at which the values of the performance characteristics given in table 1 have been verified ac- cording to this International Standard in the appropri- ate ranges are listed in table2. 1 COPYRIGHT International Organization for Standardization Lic
26、ensed by Information Handling Services COPYRIGHT International Organization for Standardization Licensed by Information Handling Services IS0 7935 92 = 4851903 0521970 134 IS0 7935:1992(E) Table 2 - Facilities and measuring ranges I Facility Measuring range g/m3 of so2 1) Furnaces for hard coal 0 -
27、1 too-8 o to 0,l O - 0,l to O - 3,O O - 0,l to O - 5,O O - 0,4 to O - 1,0 Furnaces for hard coal with stack gas desulfuration plant Furnaces for brown coal Furnaces for heavy fuel oil Refuse incinerator Coke oven Calcar with heavy fuel oil Sulfuric acid recovery plant o to 1 o to 5 o to 1 1) Related
28、 to 1 01,3 kPa, 273 K and dry gas. 2 Normative references The following standards contain provisions which, through reference in this text, constitute provisions of this International Standard. At the time of publi- cation, the editions indicated were valid. All standards are subject to revision, an
29、d parties to agreements based on this International Standard are encouraged to investigate the possibility of applying the most re- cent editions of the standards indicated below. Members of IEC and IS0 maintain registers of cur- rently valid International Standards. IS0 6879:1983, Air quality - Per
30、formance character- istics and related concepts for air quality measuring methods. IS0 7934:1989, Stationary source emissions - De- termination of the mass concentration of sulfur diox- ide - Hydrogen peroxide/barium perchlorateflhorin method. 3 Definitions For the purposes of this International Sta
31、ndard, the following definitions apply. 3.1 automated measuring system (AMs): A com- plete system -that may be attached to a chimney to continuously measure and record the mass concen- tration of sulfur dioxide passing through the chimney. 3.2 analyser: Analytical part in an extractive AMs. 3.3 veri
32、fied AMs: AMS previously verified in IS0 7935. 3.4 calibration gas: A gas of known and reliable composition that may be used to check the response of an AMs. 3.5 comparative measurements: Measurements that are performed in the same chimney in the same sampling plane for the same period of time. 3.6
33、manual method: The test method defined in IS0 7934 for the manual sampling and analysis of stationary source emissions containing sulfur dioxide. 3.7 integral performance, sA: The integral perform- ance is a measure of the working accuracy of the AMs. It is calculated according to the formula for st
34、andard deviations. The integral performance is derived from the differ- ence in the pairs of measured values of sulfur dioxide by the AMS under investigation, and by an IS0 man- ual method or a verified AMS of different measuring principle on the basis of a sufficient number of com- parative measure
35、ments spread over the period of un- attended operation (see annex A). NOTES 3 It is not possible to determine the standard deviation of an AMS under repeatable working conditions because - commercially available calibration gas mixtures contain- ing sulfur dioxide do not have all the properties of a
36、ctual waste gas and do not cover all possible influences; - the mass concentration of sulfur dioxide in waste gas usually varies with time; - it is not possible to maintain the properties of a waste gas present in the waste gas flue when it is transferred into a vessel. 4 The reason that the integra
37、l performance is defined as a measure of the working accuracy, is that it contains, in addition to random errors, all the effects of interfering sub- stances, changes in temperature and power line as well as zero drifts and span drifts. It also includes the standard de- viation of the IS0 manual met
38、hod or the verified AMS using a different principle of detection, which can be determined separately and eliminated if necessary. Furthermore, it in- cludes the effects, for the different methods, of a different response time to variations in the composition of the waste gas. The integral performanc
39、e defined in this subclause is an upper limiting value for the AMs. Relevant systematic errors of the measured values of the IS0 manual method, or the verified AMS using a different principle of detection, have to be known and taken into account. 3.8 chimney: Stack or final exit duct on a stationary
40、 process used for the dispersion of residual process gases. 3.9 mass concentration: The concentration of a substance in an emission, expressed in milligrams per cubic metre or grams per cubic metre. 2 COPYRIGHT International Organization for Standardization Licensed by Information Handling Services
41、COPYRIGHT International Organization for Standardization Licensed by Information Handling Services IS0 7935 92 4851903 0521971 070 3.10 stationary source emissions: Those waste gases that have been emitted from a stationary plant or process and are exhausted to a chimney for dis- persion into the at
42、mosphere. 4 Description o f the automated measuring systems 4.1 Introduction There are two types of automated measuring sys- tems: - extractive methods; - non-extractive methods, known as in-situ or Examples of the components of these systems are given in figures 1 and 2. Using the extractive method
43、, the representative gas sample is taken from the stack with a sampling probe and conveyed to the analyser through the sample line and sample gas conditioning system. The values de- termined are often recorded or stored by means of electronic data processing. The non-extractive method does not requi
44、re any sample processing. In addition, it takes into consider- ation a larger part of the waste gas. Most of the methods described in 4.2 and 4.3 are able to deter- mine sulfur dioxide specifically. Methods which rely on conductometty determine total sulfur oxides. cross-duct measuring methods. 4.2
45、Extractive methods The extractive methods enable separation of the sampling and analysis parts, thereby facilitating main- tenance operations. The main parts are - a sample probe; - a sample line; - a gas conditioning system; IS0 7935:1992(E) - an analytical part. Certain extractive methods also inc
46、lude sample di- lution. The sample probe is placed inside the duct containing gaseous effluents. The choice of locations may sometimes be difficult, since the measurement to be made needs to be representative and calibration should be possible. The design of the sample probe and the gas con- ditioni
47、ng system essentially depends on physico- chemical characteristics (composition of the gaseous phase, particle concentration, temperature, water dew point, etc.) of the effluents to be analysed and the principle of the analyser used. Since particulate matter and humidity may influence the measuremen
48、t, the line contains a particulate filter and a humidity elimination device. In order to limit sulfur dioxide losses and inconsistent readings, the line is frequently heated. The analytical detection methods most commonly used are absorption, using infrared or ultraviolet radi- ation, fluorescence,
49、using ultraviolet radiation, interferometry and conductometty. 4.3 Non-extractive methods For in-situ or cross-duct methods, an optical device is used which is positioned directly in the duct of gaseous effluents. It consists of two modules, one being a radiation emittor, the other a receptor of the radiation which has passed through the gases con- taining sulfur dioxide. Installation of these two modules, in relation to the duct, depends on the apparatus used. The signals from the receptor are subsequently pro- cessed, in order to convert the data into concen- tration, expressed