1、 TECHNICAL REPORT ANSI/ISATR92.06.032008 (R2013) A Technical Report prepared by ISA and registered with ANSI Feasibility of Chlorine Detection Instrument Testing Reaffirmed 10 March 2013 Copyright 2013 by ISA. All rights reserved. Printed in the United States of America.No part of this publication m
2、ay be reproduced, stored in a retrieval system, or transmitted,in any form or by any means (electronic, mechanical, photocopying, recording, or otherwise), without the prior written permission of the Publisher.ISA67 Alexander DriveP.O. Box 12277Research Triangle Park, North Carolina 27709ANSI/ISATR9
3、2.06.032008 (R2013)Feasibility of Chlorine Detection Instrument TestingISBN: 978-1-937560-96-6 ANSI/ISA-TR92.06.02-2008 (R2013) PREFACE This preface, all footnotes, and annexes are included for informational purposes and are not a part of ISA-TR92.06.02-2008 (R2013). This recommended practice has be
4、en prepared as a part of the service of ISA toward a goal of uniformity in the field of instrumentation. To be of real value, this document should not be static but should be subject to periodic review. Toward this end, the Society welcomes all comments and criticisms and asks that they be addressed
5、 to the Standards and Practices Board Secretary; ISA; 67 Alexander Drive; P. O. Box 12277; Research Triangle Park, NC 27709; Telephone (919) 549-8411; Fax (919) 549-8288; Internet: standardsisa.org. The ISA Standards and Practices Department is aware of the growing need for attention to the metric s
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15、.02-2008 (R2013) 4 ADDITIONALLY, THE USE OF THIS DOCUMENT MAY INVOLVE HAZARDOUS MATERIALS, OPERATIONS OR EQUIPMENT. THE DOCUMENT CANNOT ANTICIPATE ALL POSSIBLE APPLICATIONS OR ADDRESS ALL POSSIBLE SAFETY ISSUES ASSOCIATED WITH USE IN HAZARDOUS CONDITIONS. THE USER OF THIS DOCUMENT MUST EXERCISE SOUN
16、D PROFESSIONAL JUDGMENT CONCERNING ITS USE AND APPLICABILITY UNDER THE USERS PARTICULAR CIRCUMSTANCES. THE USER MUST ALSO CONSIDER THE APPLICABILITY OF ANY GOVERNMENTAL REGULATORY LIMITATIONS AND ESTABLISHED SAFETY AND HEALTH PRACTICES BEFORE IMPLEMENTING THIS DOCUMENT. THE USER OF THIS DOCUMENT SHO
17、ULD BE AWARE THAT THIS DOCUMENT MAY BE IMPACTED BY ELECTRONIC SECURITY ISSUES. THE COMMITTEE HAS NOT YET ADDRESSED THE POTENTIAL ISSUES IN THIS VERSION. The following members of ISA Committee ISA92 approved ANSI/ISA-TR92.06.03-2008: NAME COMPANY Jon Miller, Chair Detector Electronics Corporation Rob
18、ert Seitz, Vice Chair Artech Engineering Mark Coppler, Managing Director Ametek Inc. Chris Brown Enmet Corporation Patrick Byrne FM Approvals Robert Masi Detcon Inc. David Mills Underwriters Laboratories Inc. Alex Spataru The Adept Group Inc. Jerry Thomason Omni Industrial Systems Inc. ANSI/ISA-TR.0
19、6.03-2008 was approved for publication by the ISA Standards and Practices Board on 15 November 2007. NAME COMPANY T. McAvinew, Vice President Jacobs Engineering Group M. Coppler Ametek Inc. E. Cosman The Dow Chemical Company B. Dumortier Schneider Electric D. Dunn Aramco Services Company J. Gilsinn
20、NIST/MEL E. Icayan ACES Inc. J. Jamison Husky Energy Inc. K. Lindner Endress + Hauser Process Solutions AG V. Maggioli Feltronics Corporation A. McCauley Chagrin Valley Controls Inc. G. McFarland Emerson Process Mgmt. Pwr and there are many companies that manufacture instruments for chlorine gas det
21、ection in the workplace. In order to promote a safe work environment, the ISA92 Committee is developing performance standards for gas detection instruments for workplace safety. One of the subcommittees, ISA92.06, has the responsibility of developing a standard for chlorine gas detection. Chlorine d
22、etection instrument performance testsSeveral questions have been posed by the Committee about testing chlorine gas detection instruments. Since the TWA-TLV is low (0.5ppm), it is desirable for the tests to be performed near this chlorine concentration level. For the test to be valid, the concentrati
23、on of the gas applied to the instrument under test has to be known to a significantly higher precision and accuracy3than the allowed tolerance of the instrument response. As currently written, many of the instrument performance tests require the instrument to give a reading or activate an alarm base
24、d on a difference in gas concentration of 0.1ppm.4Effect of humidity5The standard for chlorine gas detection instruments (ISA-92.06.01-1998) includes a performance requirement that the instrument detect a chlorine gas test mixture of known concentration within set tolerances over a non-condensing hu
25、midity range between around 15 and 90+ percent. There has been a lot of debate within the Committee about whether this test is valid. There are two principal arguments in this discussion. The first argument is that humidity is a very important parameter that should be tested since many of the locati
26、ons where chlorine detection instruments are used are very humid. Many paper mills, for example, operate with the atmosphere almost constantly saturated with water vapor. Therefore, a performance standard for chlorine detection instruments should include a test of the effects of humidity on the chlo
27、rine sensor response._ 1Cl2(g) + 2e 2Cl; E= 1.358V vs. SHE; CRC Handbook of Chemistry the humidity test may not be a valid performance criterion since the true chlorine (Cl2) concentration would not be known at high humidities if these vapor-phase reactions occurred to a significant extent. The Comm
28、ittee agreed to try to find out as much as possible about the reactions of chlorine with water vapor and combine these with experimental results to produce recommendations for ISA-92.06.01-1998. This report is a summary of the results of this investigation. Publication of this Technical Report that
29、has been registered with ANSI has been approved by ISA, 67 Alexander Drive, Research Triangle Park, NC 27709. This document is registered as a Technical Report according to the Procedures for the Registration of Technical Reports with ANSI. This document is not an American National Standard and the
30、material contained herein is not normative in nature. Comments on the content of this document should be sent to ISA, 67 Alexander Drive, Research Triangle Park, NC 27709, E-mail: standardsisa.org. Abstract This report has been written to answer questions about the feasibility of performing the test
31、s described in the ISA standard for chlorine gas detection instruments (ISA-92.06.01-1998). The report discusses two questions; the first is the availability of a chlorine gas supply of sufficient accuracy and precision for performing the tests, and the second is the viability of testing a gas detec
32、tion instrument with chlorine under a variety of humidity conditions. The report surveys the available chemical literature, presents experimental and calculated results of humidity testing, and summarizes information on test gas generation and analysis. Key Words Accuracy, Chlorine, Cl2, Gas, HCl, H
33、OCl, Hypochlorous acid, Humidity, Hydrochloric acid, Instrument, Precision, Sensor, Standard 9 ANSI/ISATR92.06.032008 (R2013)CONTENTS1 Introduction.112 Review of chlorine chemistry .112.1 Chlorine.112.2 Chlorine oxides.122.3 Oxy acids and anions132.4 Water solubility132.5 Vapor phase reactions133 Se
34、nsor manufacturers specifications.143.1 Draeger .143.2 City Technology 143.3 Transient humidity effects.144 Experimental results.144.1 Overall approach.144.2 Chlorine instrument tests: Bacharach .154.3 Chlorine instrument tests: Mine Safety Appliances.154.4 Chlorine instrument tests: NCASI .174.5 Ch
35、lorine instrument tests: National Draeger .184.6 Equilibrium calculations .194.7 Titration of humidified chlorine 215 Discussion of results.225.1 Summary results from instrument/sensor tests.235.2 Specification in Standard ISA-92.06.01-1998, Section 7.14.1 246 Sources of chlorine test gas.246.1 Gas
36、tanks246.2 Electrochemical generators.256.3 Permeation Tubes257 Analysis of chlorine gas concentration.257.1 Literature methods for chlorine test gas analysis258 Recommendations for testing with chlorine258.1 Experimental considerations.258.2 Correction for water vapor.269 Other gas performance stan
37、dards2710 Acknowledgments27This page intentionally left blank. 11 ANSI/ISATR92.06.032008 (R2013)1 IntroductionThis report has been written to provide support to the work of the ISA92.06 Subcommittee responsible for drafting a performance standard for chlorine detection instruments. The scope of the
38、standard is limited to those instruments intended for the determination of chlorine gas in air to enhance workplace safety. In Committee discussions two technical questions were raised; the first was the feasibility of generating chlorine gas concentrations with sufficient accuracy and precision nec
39、essary for the performance tests. The second question was whether there was a significant reaction between chlorine and water in the vapor phase since the extent of this reaction would impact the validity of the proposed humidity performance test.The first part of the report discusses issues related
40、 to the question of the possible interaction of chlorine with water vapor in the gas phase. The latter part of the report discusses the generation of chlorine gas.This report is divided into several sections. The first section provides a brief overview of the chemistry of chlorine and related compou
41、nds. This section is intended to provide an outline of the chemical basis for later discussions and to summarize the results obtained from literature searches. Since a standard is by necessity based on the current technology, the available information from sensor manufacturers is summarized so that
42、a comparison between the proposed specifications and manufacturers specifications can be made. Several instrument tests have been performed by both the NCASI and several manufacturers using both Draeger and City Technology chlorine sensors. These tests were aimed at finding the effect that humidity
43、has on the response of the instrument to a nominal chlorine concentration. Lastly, a theoretical approach using free energy calculations was used to estimate the thermodynamic feasibility of the proposed vapor-phase reactions between chlorine and water. The second part of the report addresses source
44、s of chlorine test gas and the feasibility of generating chlorine test gas mixtures with sufficient accuracy and precision necessary to do the performance testing called for by the standard (ISA-92.06.01-1998). This section also provides information about the analysis of chlorine test gas mixtures a
45、nd a short section with some practical experimental recommendations for working with chlorine.2 Review of chlorine chemistry 6,7,8,9The chemistry of chlorine is briefly reviewed as relevant to this report. Particular emphasis is placed on the reactions of chlorine with water and the products and equ
46、ilibrium formed. Further information may be found in the references cited.2.1 ChlorineElemental chlorine is a greenish yellow diatomic gas, Cl2, with a molecular weight of 70.9 g/mol; atomic number 17; mp -101.0C, bp -34.05C; and its density is approximately two and a half times that of air. Chlorin
47、e occurs most commonly in nature as the chloride ion in sea water and in salt deposits. It was first isolated in 1774 by Karl Scheele, who did not recognize it as an element; the elemental nature of chlorine_ 6Merck Index, 11thEdition, Publ. Merck and for the world, the amount of chlorine produced i
48、s estimated at 47.3 million tons (1994). Chlorine and chlorine derivatives are used in a huge array of products ranging from polymers, elastomers, solvents, lubricating oils, pharmaceuticals, paper chemicals, and so forth. Further details may be found in a recent review of the chlorine industry and
49、its environmental impact.122.2 Chlorine oxidesChlorine forms a number of oxides. The oxides tend to be strong oxidizing agents and are very reactive. They are briefly included in the report since they are related to the oxo anions discussed below.Dichlorine monoxide (Cl2O)13 is a well characterized yellow-red gas, boiling point 2C that forms a yellow solution in water, containing hypochlorous acid (HOCl) of which dichlorine monoxide is formally the anhydride. The major use of Cl2O is as a bleaching agent for wood pulp.
