NACE RP0300 ISO 16784-1-2006 Corrosion of metals and alloys Corrosion and fouling in industrial cooling water systems Part 1 Guidelines for conducting pilot-scale evaluation of cor re.pdf

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1、INTERNATIONAL STANDARD NACE RP0300/ IS0 16784-1 First edition 2006-03-01 Corrosion of metals and alloys - Corrosion and fouling in industrial cooling water systems - Part 1: G u i de I i nes for con d u ct i n g pi I ot-sca le evaluation of corrosion and fouling control additives for open recirculat

2、ing cooling water systems Corrosion des mtaux et alliages - Corrosion et entartrage des circuits de refroidissement eau industriels - Partie 1: Lignes directrices pour lvaluation pilote des additifs anticorrosion et antitartre pour circuits de refroidissement eau recirculation ouverts Reference numb

3、er NACE RP0300ASO 16784-1 :2006(E) - :Es ONACE/ANSI/ISO 2006 - NACE RP0300/ISO 16784-1 :2006(E) O NACE/ANSI/ISO 2006 These materials are subject to copyright claims of ISO, ANSI, and NACE. No part of this publication may be reproduced in any form, including an electronic retrieval system, without th

4、e prior written permission of NACE. All requests pertaining to the NACE RP0300/ISO 16784-1 standard should be submitted to NACE. All rights reserved. NACE International 1440 South Creek Dr. Houston, Texas 77084-4906 Phone: 281 -228-6200 Fax: 281 -228-6300 E-mail firstserviceOnace.org Web www.nace.or

5、g Published in U.S.A ii O NACE/ANSI/ISO 2006-All rights reserved NACE RP0300ASO 16784-1 :2006(E) Co nt en ts Page Foreword iv Introduction v 1 2 3 4 4.1 4.2 4.3 5 5.1 5.2 6 6.1 6.2 6.3 6.4 7 7.1 7.2 7.3 7.4 7.5 7.6 8 8.1 8.2 8.3 8.4 9 9.1 9.2 9.3 9.4 10 10.1 10.2 10.3 11 11.1 11.2 11.3 Scope 1 Norma

6、tive references . 1 Terms, definitions, symbols and abbreviated terms . 2 Types of testing . 2 Laboratory and off-site testing 2 On-site testing . 2 On-line testing . 2 Test unit design parameters 3 General . 3 Construction materials . 3 Operating parameters . 5 General . 5 Surface temperature . 5 W

7、ater velocity 5 Residence time 5 Water quality 5 General . 5 Natural versus synthetic water supplies 5 Fresh water 6 Seawater and brackish water . 6 RecycleIreuse water 6 Dual and combined make-up systems 6 Contamination . 6 General . 6 Process leaks 7 Biological matter . 7 Airborne solids and gases

8、 . 7 Parameters to be evaluated in pilot test units . 7 Corrosion . 7 Fouling . 8 Practical problems in operating systems - Multiple combinations of problems . 10 Water treatment additives 10 Design of pilot-scale performance testing facilities 10 Objectives 10 The importance of simulating specific

9、application environments . 11 Compromises in pilot-scale performance testing . 11 Pilot-scale facility operations 12 Documentation of design . 12 Record-keeping and reports 13 Repeatability of results and comparison with field performance 13 Bibliography . 14 O NACE/ANSI/ISO 2006-All rights reserved

10、 iii NACE RP0300/ISO 16784-1 :2006(E) Foreword IS0 (the International Organization for Standardization) 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

11、 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 ISO, also take part in the work. IS0 collaborates closely with the International Electrotec

12、hnical Commission (IEC) on all matters of electrotechnical standardization. International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2. The main task of technical committees is to prepare International Standards. Draft International Standards adopted by

13、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. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent righ

14、ts. IS0 shall not be held responsible for identifying any or all such patent rights. IS0 16784-1 was prepared by Technical Committee ISO/TC 156, Corrosion of metals and alloys. IS0 16784 consists of the following parts, under the general title Corrosion of metals and alloys - Corrosion and fouling i

15、n industrial cooling water systems: - Pari 1: Guidelines for conducting pilot-scale evaluation of corrosion and fouling control additives for open recirculating cooling water systems - Pari 2: Evaluation of the performance of cooling water treatment programmes using a pilot-scale test rig iv O NACE/

16、ANSI/ISO 2006-All rights reserved NACE RP0300ASO 16784-1 :2006(E) Introduction Environmental requirements, water shortages, and business pressures have forced industrial plants and power stations to operate with longer production runs, reduced maintenance outages, fewer operating personnel, and incr

17、eased stress on cooling water systems. Similarly, commercial refrigeration (heating, ventilating, and air conditioning HVAC) systems have experienced increased heat loads and requirements for a long-term, continuous, cooling water supply to computer facilities, large retail establishments, campuses,

18、 and office complexes. Under these increasingly severe conditions, cooling water chemical treatment programmes are expected to maintain optimum operating efficiency and, at the same time, protect the economic life of the equipment by inhibiting corrosion, mineral scaling, microbiological fouling, an

19、d miscellaneous deposition on heat-transfer surfaces. Cooling system design and operating characteristics vary widely, within individual plants, from site to site, and worldwide. Thus, selection and optimization of water treatment programmes must be a site-specific process. In most systems, optimize

20、d cooling water chemical treatment is the key to successful long-term operations. The subject of this part of IS0 16784 is, therefore, the establishment of criteria for the pilot-scale evaluation of the performance of cooling water additives under field-specific operating conditions. This part of IS

21、0 16784 is intended for use by cooling system owners/operators, water treatment companies and others who must evaluate the performance of cooling water additives under field-specific operating conditions. This part of IS0 16784 was developed on the basis of NACE RP0300 141. O NACE/ANSI/ISO 2006-All

22、rights reserved V INTERNATIONAL STAN DARD NACE RP0300ASO 16784-1 :2006(E) Corrosion of metals and alloys - Corrosion and fouling in industrial cooling water systems - Part 1: Guidelines for conducting pilot-scale evaluation of corrosion and fouling control additives for open recirculating cooling wa

23、ter systems 1 Scope This part of IS0 16784 applies to corrosion and fouling in industrial cooling water systems. This part of IS0 16784 covers the criteria that must be defined and implemented in a pilot-scale testing programme to select water treatment programmes for use in specific recirculating c

24、ooling water systems. This part of IS0 16784 covers only open recirculating cooling water systems. Closed cooling systems and once-through cooling water systems are specifically excluded. This part of IS0 16784 applies only to systems incorporating shell-and-tube heat exchangers with standard uncoat

25、ed smooth tubes and cooling water on the tube side. Heat exchangers with shell-side water, plate and frame and/or spiral heat exchangers, and other heat exchange devices are specifically excluded. However, when the test conditions are properly set up to model the surface temperature and shear stress

26、 in more complex heat-transfer devices, the test results may predict what may occur in an operating heat exchanger of that design. The test criteria established in this part of IS0 16784 are not intended to govern the type of bench and pilot-scale testing normally carried out by water treatment comp

27、anies as part of their proprietary product-development programmes. However, water treatment companies may choose to use the criteria in this part of IS0 16784 as guidelines in the development of their own product-development test procedures. 2 Normative references The following referenced documents

28、are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. IS0 8044:1999, Corrosion of metals and alloys - Basic terms and definitions IS0 1678

29、4-2, Corrosion of metals and alloys - Corrosion and fouling in industrial cooling water systems - Pari 2: Evaluation of the performance of cooling water treatment programmes using a pilot-scale test rig O NACE/ANSI/ISO 2006-All rights reserved 1 NACE RP0300/ISO 16784-1 :2006(E) 3 Terms, definitions,

30、 symbols and abbreviated terms For the purposes of this document, the terms and definitions given in IS0 8044:1999 and the following abbreviations and symbols apply. ASTM: ASTM International BOD: Biological oxygen demand COD: Chemical oxygen demand HVAC: Heating, ventilating, and air conditioning LP

31、R: Linear polarization resistance MIC: Microbiologically influenced corrosion NACE: NACE International PVC: Polyvinyl chloride s/V ratio: Surface-to-volume ratio UNS: Unified Numbering System 4 Types of testing 4.1 Laboratory and off-site testing 4.1.1 Laboratory testing, or testing at alternative o

32、ff-site locations, may in some cases be necessary for selecting cooling water chemical treatment programmes. This type of testing could be used for new construction start-up programmes, when operating systems are not available, or for evaluating alternative treatment programmes. In such cases, the e

33、valuation should include site-specific design criteria and environmental regulations that affect the cooling water system. Site-specific water supplies should be used whenever possible. All criteria in this part of IS0 16784 relating to water compositions, test unit configuration, heat exchanger des

34、ign, and operating conditions should be followed insofar as possible. 4.1.2 No laboratory or off-site testing programme can completely duplicate plant conditions. Site-specific factors, such as process leaks, microbiological growth, corrosion products, airborne contamination, etc., may affect the op

35、eration of cooling water systems and the performance of chemical treatment programmes in ways that override the results of laboratory or off-site testing programmes. 4.2 On-site testing 4.2.1 Whenever possible, water treatment programmes should be evaluated on site, using plant water supplies and ac

36、tual design and operating conditions, particularly those that cannot be duplicated in the laboratory. Criteria for these effects are discussed in 9.1.2. 4.2.2 Specific attention shall be given to site-specific rules and environmental regulations that may affect the types of chemical products that ca

37、n be used, the allowable amount and composition of blowdown water, and air quality regulations affecting cooling tower discharge. 4.3 On-line testing Whenever possible, all off-site, laboratory, and on-site pilot-scale testing should be validated by monitoring actual performance results on-line. Pil

38、ot units can be adapted for on-line work by using a sidestream from the plant circulating cooling water as feedwater, bypassing the pilot unit cooling tower. Such on-line testing serves to validate the off-IineAaboratory tests. Cooling systems may be evaluated on-line; however, the data collected wi

39、ll be the result of the combination of any existing treatment and all additional chemicals that were added for the evaluation period. On-line testing in this way can be useful for optimizing the treatment programme to meet specific plant requirements. For example, small quantities of a treatment che

40、mical may be added just 2 O NACE/ANSI/ISO 2006-All rights reserved NACE RP0300ASO 16784-1 :2006(E) ahead of the test heat exchanger to measure the effects of increasing additive dosage, or the possible synergistic effects of a new chemical added to the existing treatment programme. 5 Test unit desig

41、n parameters 5.1 General Careful evaluation of the mechanical design and operation of each cooling water system is a necessary prerequisite for designing a pilot-scale water treatment product-evaluation programme. It may not be practical to simulate a specific critical plant heat load or water flow

42、pattern exactly. Contamination in a pilot cooling tower may not develop in the same way as in the plant systems; compromises may therefore be necessary. In all such cases, plant design and operations must be followed as closely as possible, and deviations must be noted in the test reports. 5.2 Const

43、ruction materials 5.2.1 Cooling towers 5.2.1.1 Small cooling tower basins may be made of uncoated, plastic-coated, galvanized low-carbon steel, or stainless steel. Large tower basins are usually concrete. Splash fill may be wood, ceramic, or plastic. It is not important that the pilot cooling tower

44、duplicates the design of the plant towers. However, if the plant system contains galvanized steel, galvanized steel should be included as a non-heat-transfer test material in the pilot system. 5.2.2 Special requirements for film fill 5.2.2.1 If the plant cooling towers contain film fill, a section o

45、f this fill (if available) should be used in the pilot tower. Film fill consists of closely packed layers of lightweight plastic material, normally PVC, arranged in a honeycomb-like structure. This maximizes the surface area over which water must flow, and thereby improves evaporation efficiency. Ho

46、wever, the increased surface area also encourages deposit formation in the fill. 5.2.2.2 Deposits may consist of mineral scales formed by evaporation of water, corrosion products and silt carried into the tower, and microbiological deposits. Biofilms tend to act as a “glue” that encourages other dep

47、osits to adhere to the fill. Because the space between adjacent layers of fill is often quite small, deposited material may “bridge” the fill and block water flow. This is a serious problem, because film fill cannot be cleaned chemically unless water can flow through all parts of the fill. 5.2.2.3 M

48、echanical cleaning, including water lancing, often damages the lightweight fill material. In addition, the weight of a significant deposit in the film fill can mechanically damage it. Hence, one performance requirement of any cooling water chemical treatment programme intended for use in a film-fill

49、 cooling tower shall be to prevent bridging of the fill. 5.2.2.4 The condition of film fill in an operating cooling tower can be monitored by using a “fill test box.” This is simply a section of fill, roughly a 0.6 m (2 ft) cube, enclosed in a supporting box open at the top and bottom. The box is exposed to the “rain” falling below the fill in the cooling tower, in an accessible location. A slippery feeling on the fill surfaces, or appearance of a visible deposit layer, indicates fouling conditions in the fill. 5.2.2.5 A fill test box is a very useful qualitative monitoring tool