BS 1170-1983 Recommendations for treatment of water for marine boilers《船用锅炉的水处理推荐标准》.pdf

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1、BRITISH STANDARD BS 1170:1983 Incorporating Amendment No. 1 Recommendations for Treatment of water for marine boilers UDC 628.16:621.181:629.12BS1170:1983 This British Standard, having been prepared under the directionof the Environment andPollution Standards Committee, was published underthe author

2、ity of the BoardofBSI and comes into effect on 29 July 1983 BSI 10-1999 First published December 1947 First revision November 1957 Second revision August 1968 Third revision July 1983 The following BSI references relate to the work on this standard: Committee reference EPC/37 Draft for comment 79/50

3、529 DC ISBN 0 580 13238 2 Committees responsible for this British Standard This British Standard was published under the direction of the Environment and Pollution Standards Committee EPC/-. Its representation was entrusted to Technical Committee EPC/37 upon which the following bodies were represent

4、ed: Chemical Industries Association Department of Industry (Laboratory of the Government Chemist) Fabric Care Research Association Health and Safety Executive Institute of Energy Institution of Chemical Engineers Institution of Corrosion Science and Technology Institution of Gas Engineers Ministry o

5、f Defence National Coal Board Royal Society of Chemistry Society of Laundry Engineers and Allied Trades Limited The following bodies were also represented in the drafting of the standard, through subcommittees and panels: Association of Shell Boilermakers British Water and Effluent Treatment Plant A

6、ssociation Department of Industry (National Physical Laboratory) Institute of Marine Engineers Water-tube Boilermakers Association Amendments issued since publication Amd. No. Date of issue Comments 4430 October 1983 Indicated by a sideline in the marginBS1170:1983 BSI 10-1999 i Contents Page Commit

7、tees responsible Inside front cover Foreword iii Section 1. General 1 Scope 1 2 References 1 3 Definitions 1 4 Control of treatment ashore and afloat 1 Section 2. Sources of water and limiting impurities for various groups of boilers 5 Sources of water 2 6 Effect of boiler plant design and operating

8、 conditions on required water quality 3 7 Effect of boiler type on required water quality 5 Section 3. Chemical cleaning 8 General 7 9 Pre-commission cleaning of boilers and feed systems 7 10 Post-commission cleaning of boilers 8 Section 4. Objectives of water treatment 11 General 8 12 Scale formati

9、on 8 13 Hideout 9 14 Corrosion 9 15 Steam purity and feed-line corrosion 10 16 Blowdown 10 Section 5. Treatment of feed water 17 Design considerations 11 18 Factors under the control of the engineer 16 Section 6. Treatment of water in the boiler 19 General 19 20 Chemicals 19 21 Limits of treatment 2

10、1 22 Sampling arrangements and equipment 21 23 Group 1 boilers 22 24 Group 2 boilers 26 25 Group 3 boilers 31 26 Group 4 boilers 33 27 Group 5 boilers 37 28 Group 6 boilers 41 Section 7. Preservation of idle boilers 29 Long term storage 47 30 Short term storage 49 Appendix A Explanation of terms 50

11、Appendix B pH value, acidity and alkalinity 53 Appendix C Chemicals used in marine boiler water treatment 53 Appendix D Methods of test 58 Appendix E Preparation of reagents 79 Appendix F On-line instrumentation and automation 84BS1170:1983 ii BSI 10-1999 Page Figure 1 Sample cooling coil for multip

12、le sampling points 22 Figure 2 Alternative methods of adding chemicals 24 Figure 3 Congruent phosphate/pH control graph 42 Figure 4 Maximum concentration of silica in boiler water 45 Figure 5 Effect of mineral acidity on pH value 54 Figure 6 Modified Nessler cylinder 64 Figure 7 Hydraulic system for

13、 sampling suspended solids 78 Table 1 Boiler water, feed water and condensate characteristics for group 1 boilers (up to 17.5 bar) 27 Table 2 Boiler water, feed water and condensate characteristics for group 2 boilers (17.5 bar to 31 bar) 30 Table 3 Boiler water, feed water and condensate characteri

14、stics for group 3 boilers (31 bar to 42 bar) 34 Table 4 Boiler water, feed water and condensate characteristics for group 4 boilers (42 bar to 60 bar) 36 Table 5 Boiler water, feed water and condensate characteristics for group 5 boilers (60 bar to 80 bar) 39 Table 6 Boiler water characteristics for

15、 group 6 boilers (80 bar to 130 bar) 48 Table 7 Feed water and condensate characteristics for group 6 boilers (80 bar to 130 bar) 48 Table 8 Dilutions for phosphate determination 74 Publications referred to Inside back coverBS1170:1983 BSI 10-1999 iii Foreword This British Standard, having been prep

16、ared under the direction of the Environment and Pollution Standards Committee, supersedes BS1170:1968 which is withdrawn. The first British Standard intended as an introduction to water treatment for marine boilers was published in December 1947. Since that time marine engineers have come to realize

17、 that the water in ships, boilers has to conform to recognized standards if efficiency is to be maintained. Since the publication of BS1170:1968, boiler pressures and steam temperatures have again been increased in the never-ending search for more economic working. These increases in pressure and te

18、mperature have demanded a purer supply of water and more sophisticated treatment. This revised edition caters for boilers operating at pressures up to130 bar 1)by adding a sixth range of pressure to the five previously dealt with. For boilers operating above130bar, the control of treatment and the r

19、equirements for the limits of impurities in the feed water would be even more stringent. Other changes made for this edition include considerable expansion of the glossary of terms (Appendix A), explanation of the concepts of pH value, acidity and alkalinity (Appendix B), inclusion of a section on s

20、afe handling of chemicals (Appendix C), new ship-board methods for determination of copper, iron, silica and suspended solids (Appendix D), 16 additions to the list of reagents (Appendix E), and the inclusion of a brief outline on on-line instrumentation and automation (Appendix F). Each of the cont

21、rol tests in Appendix D is preceded by a short introduction to the principles underlying the chemical reactions. No method of test for nitrate is available that can readily be carried out on board ship; to obtain an estimate of this contaminant, a sample is taken and sent ashore for analysis. The st

22、andard should enable an engineer to control boiler water and feed water treatment under all normal working conditions. Detailed instructions for use when conditions are abnormal are beyond the scope of this standard and expert advice should be obtained from qualified advisers. Basic methods of chemi

23、cal treatment are described from which it should be possible to select a suitable treatment for most ships, bearing in mind the quality of make-up feed water, the boiler pressure and whether a deaerator is fitted or not. In all cases alkaline treatment chemicals are used, often with various oxygen s

24、cavengers. The use of neutralizing and filming amines for protection against corrosion of the steam and condensate systems, hydrazine for oxygen removal and anti-foams for preventing carry-over are included. A British Standard does not purport to include all the necessary provisions of a contract. U

25、sers of British Standards are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pages i to iv, pages1to86, an inside back cover and a

26、back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover. 1) 1 bar = 10 5N/m 2= 100 kPa = approximately 14 lbf/in 2 .iv blankBS1170:1983 BSI 10-1999 1 Section 1. General 1 Scope T

27、his British Standard gives recommendations on the treatment of water for marine boilers with working pressures up to130bar. It applies to six groups of boilers, classified according to their operating pressures as follows (seealso17.1). Group 1. Boilers up to17.5bar Group 2. Boilers from17.5bar to31

28、bar Group 3. Boilers from31bar to42bar Group 4. Boilers from42bar to60bar Group 5. Boilers from60bar to80bar Group 6. Boilers from80bar to130bar Section 6 of the standard gives detailed information on each of these groups. This section gives recommendations for feed water and condensate as well as f

29、or the water in the boilers. This standard is concerned with water conditions for boilers and associated plant, but is not intended to cover all details of the maintenance of equipment. 2 References The titles of the publications referred to are listed on the inside back cover. 3 Definitions For the

30、 purposes of this British Standard, the following definitions apply. (See alsoAppendix A.) 3.1 feed water water fed by the feed pumps to the boiler 3.2 boiler water water circulating within the boiler containing dissolved solids from the feed water and also conditioning chemicals 3.3 make-up water w

31、ater added to replace system water losses, e.g.from blowdown NOTE 1This is sometimes known as extra feed or make-up feed. NOTE 2Suitable water quality is normally produced by evaporation, though base exchange softening or evaporation followed by demineralization may be used. 3.4 condensate water for

32、med by condensation of steam from the boiler 4 Control of treatment ashore and afloat In order to secure uniformity and continuity of water treatment throughout a fleet of vessels, it is important to organize a system of supervision and control on lines similar to those suggested in this standard. I

33、t is advisable to secure the cooperation of water treatment consultants for this purpose. It cannot be too strongly emphasized that control, including regular testing, is the keystone upon which success of treatment depends, and if a companys own chemical staff is not available, a member of the engi

34、neer superintendents staff should be trained in water treatment.BS1170:1983 2 BSI 10-1999 The application and control of any chemical treatment should be in the hands of the engineer in charge of the boilers and the success of the treatment can be assured only by close cooperation between the engine

35、ers and those responsible for specifying the treatment. It is recommended that this cooperation should include the shore staff, i.e. superintendents and those responsible for maintaining the supply of materials. There is, therefore, an administrative as well as a technical effort required, the forme

36、r requiring first attention. The development of a particular case may be visualized in stages somewhat as follows. a) Contact between consultants and the engineer superintendent. Collection of information on boiler problems, e.g. on feed water, failures and matters of general interest. General discu

37、ssion of methods of treatment and control. b) Inspection of the boilers. Discussion with ships chief engineers. c) Formulation of chemical treatment and methods of application and control. d) Presentation and explanation to the engineer superintendent and discussion of arrangements to put the chosen

38、 chemical treatment into effect. e) Training of ships staff in control tests and routine application of chemicals, and similar training of any members of shore staff who will be responsible for supervision of water treatment and maintenance of chemical supplies throughout the fleet. f) Arrangements

39、for regular inspection of boilers and test records by trained members of staff. g) Regular discussion of difficulties and improvements with specialists. These items give some idea of the steps required to institute properly controlled water treatment. Section 2. Sources of water and limiting impurit

40、ies for various groups of boilers 5 Sources of water 5.1 General. There are three main types of water used to prepare make-up feed for marine boilers: evaporated waters, fresh or shore waters, and sea and tidal waters. River waters are used to a lesser extent. 5.2 Evaporated waters. These waters are

41、 obtained by distilling either fresh water or sea water. With sea water for boilers of groups4,5and6, it is better to double-evaporate or, alternatively, after a single evaporation, to pass the water through a mixed-bed demineralizing plant. Evaporated water should not contain more than4mg/L of diss

42、olved solids and usually as little as1mg/L. Within certain limits contamination at this level should not affect the type of treatment. The dissolved oxygen content may be as high as3mg/L to4.5mg/L but this depends on how long ago the water was evaporated and whether a large surface area has been in

43、contact with the air. 5.3 Fresh or shore waters. Immediately it forms, rain water is probably one of the purest waters in nature, but it subsequently dissolves various gases of which oxygen, carbon dioxide and sulphur dioxide are usually the most important as far as boiler plants are concerned. The

44、carbon dioxide and sulphur dioxide combine with the water to form carbonic and sulphurous acids. These subsequently dissolve limestone and other minerals when the water passes through and over the earths crust. Other substances, e.g. common salt (sodium chloride), Epsom salts (magnesium sulphate) an

45、d decaying vegetable matter, also dissolve in the water which then becomes a complex solution, depending on the composition of the ground through and over which it has passed. The dissolved oxygen content is usually of the order of9mg/L to10.5mg/L. No two waters are exactly alike and a full analysis

46、 of shore water is usually obtainable from the water authority of the port in question. Some waters may be very soft but acid in nature, e.g. moorland or peaty waters; others may be very hard and alkaline. In addition all waters contain small amounts of silica in solution and may have varying quanti

47、ties of solid matter in suspension. The dissolved salts may be divided into two classes; salts of calcium and magnesium (commonly referred to as hardness salts) and other salts. The commonest of the former are the bicarbonates, chlorides, sulphates and sometimes nitrates; these are potential scale-f

48、orming compounds. The other salts consist principally of sodium bicarbonate, sodium chloride, sodium sulphate and sodium nitrate; these do not produce scale. Whenever possible, waters containing the lowest quantity of calcium and magnesium salts and/or corrosive compounds (e.g. chlorides) should be

49、used in preference to others.BS1170:1983 BSI 10-1999 3 All fresh water is liable to contamination by sea water once on board. The composition may also be changed as a result of attempts to prevent corrosion of storage tanks, either by adding lime to the water or by the action of the water on cement or other alkaline materials that may be used to cover the walls. 5.4 Sea and tidal waters. The sea receives an enormous contribution of water from rivers and at the same time loses a large volume of water by evaporation. River waters provide a contin