EN ISO 16784-2-2008 en Corrosion of metals and alloys - Corrosion and fouling in industrial cooling water systems - Part 2 Evaluation of the performance of cooling water treatment .pdf

1、BRITISH STANDARDBS EN ISO 16784-2:2008Corrosion of metals and alloys Corrosion and fouling in industrial cooling water systems Part 2: Evaluation of the performance of cooling water treatment programmes using a pilot-scale test rigICS 77.060g49g50g3g38g50g51g60g44g49g42g3g58g44g55g43g50g56g55g3g37g5

2、4g44g3g51g40g53g48g44g54g54g44g50g49g3g40g59g38g40g51g55g3g36g54g3g51g40g53g48g44g55g55g40g39g3g37g60g3g38g50g51g60g53g44g42g43g55g3g47g36g58BS EN ISO 16784-2:2008This British Standard was published under the authority of the Standards Policy and Strategy Committee on 9 February 2006 BSI 2008ISBN 97

3、8 0 580 60550 5National forewordThis British Standard is the UK implementation of EN ISO 16784-2:2008. It is identical with ISO 16784-2:2006. It supersedes BS ISO 16784-2:2006 which is withdrawn.The UK participation in its preparation was entrusted to Technical Committee ISE/NFE/8, Corrosion of meta

4、ls and alloys.A list of organizations represented on this committee can be obtained on request to its secretary.This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application. Compliance with a British Standard cannot confer

5、 immunity from legal obligations.Amendments/corrigenda issued since publicationDate Comments29 August 2008 This corrigendum renumbers BS ISO 16784-2:2006 as BS EN ISO 16784-2:2008EUROPEAN STANDARDNORME EUROPENNEEUROPISCHE NORMEN ISO 16784-2April 2008ICS 77.060English VersionCorrosion of metals and a

6、lloys - Corrosion and fouling inindustrial cooling water systems - Part 2: Evaluation of theperformance of cooling water treatment programmes using apilot-scale test rig (ISO 16784-2:2006)Corrosion des mtaux et alliages - Corrosion et entartragedes circuits de refroidissement eau industriels - Parti

7、e 2:valuation des performances des programmes detraitement deau de refroidissement sur banc dessai pilote(ISO 16784-2:2006)Korrosion von Metallen und Legierungen - Korrosion undFouling in industriellen Khlwassersystemen - Teil 2:Bewertung der Leistung von Khlwasser-Behandlungsprogrammen unter Anwend

8、ung eines Modell-Prfstands (ISO 16784-2:2006)This European Standard was approved by CEN on 21 March 2008.CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this EuropeanStandard the status of a national standard without any alteration.

9、 Up-to-date lists and bibliographical references concerning such nationalstandards may be obtained on application to the CEN Management Centre or to any CEN member.This European Standard exists in three official versions (English, French, German). A version in any other language made by translationu

10、nder the responsibility of a CEN member into its own language and notified to the CEN Management Centre has the same status as theofficial versions.CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland,France, Germany, Greece,

11、Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal,Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.EUROPEAN COMMITTEE FOR STANDARDIZATIONCOMIT EUROPEN DE NORMALISATIONEUROPISCHES KOMITEE FR NORMUNGManagement Centre

12、: rue de Stassart, 36 B-1050 Brussels 2008 CEN All rights of exploitation in any form and by any means reservedworldwide for CEN national Members.Ref. No. EN ISO 16784-2:2008: EForeword The text of ISO 16784-2:2006 has been prepared by Technical Committee ISO/TC 156 “Corrosion of metals and alloys”

13、of the International Organization for Standardization (ISO) and has been taken over as EN ISO 16784-2:2008 by Technical Committee CEN/TC 262 “Metallic and other inorganic coatings” the secretariat of which is held by BSI. This European Standard shall be given the status of a national standard, eithe

14、r by publication of an identical text or by endorsement, at the latest by October 2008, and conflicting national standards shall be withdrawn at the latest by October 2008. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. CEN and/o

15、r CENELEC shall not be held responsible for identifying any or all such patent rights. According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Cyprus, Czech Republic,

16、 Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and the United Kingdom. Endorsement notice The text of ISO 16784-2:2006 has been

17、 approved by CEN as a EN ISO 16784-2:2008 without any modification. ii BS EN ISO 16784-2:2008iiiContents Page Introduction v 1 Scope . 1 2 Normative references . 1 3 Terms and definitions. 1 4 Principle. 3 5 Reagents and materials . 3 5.1 Water characteristics 4 5.2 Preparation of synthetic test wat

18、ers using mother solutions 4 6 Apparatus 5 6.1 Temperature measurement 5 6.2 Circulation-rate monitor . 5 6.3 Make-up, evaporation and blow-down measurement . 5 6.4 Cooling tower 5 7 Test method. 6 7.1 Procedure 6 7.1.1 Cleaning of the test assembly . 6 7.1.2 Test tube preparation and pre-treatment

19、. 6 7.1.3 System water content. 6 7.1.4 Procedure to fill the cooling water system 6 7.1.5 Heating the test tubes 7 7.1.6 Flow rate 7 7.1.7 Blow-down and half-life 8 7.1.8 Biocide treatment 8 7.1.9 Make-up water for cooling-tower use . 8 7.2 Determination of analytical and control parameters. 8 7.3

20、Test data reporting . 9 7.4 Test termination 9 8 Assessment of results 9 8.1 Recording of cooling water quality. 9 8.2 Treatment of the test tubes 9 8.3 Assessment of results on deposition and fouling 9 8.4 Assessment of results on corrosion 10 9 Test report . 11 Annex A (informative) Test data shee

21、t on the performance of cooling water treatment programmes 12 Annex B (informative) Further information on some methods of measurement and test 15 Bibliography . 19 BS EN ISO 16784-2:2008blankvIntroduction Due to more stringent environmental requirements and escalating costs of water, there is an in

22、dustrial need to improve the safety, reliability and cost-effectiveness of open recirculating cooling water systems. Correspondingly, it is important to establish a standard framework for evaluating the performance of cooling water treatment programmes. The aim is to provide users of cooling systems

23、 and vendors of treatment materials for those systems with a procedure to make consistent evaluations of cooling water treatment programmes on a pilot scale. BS EN ISO 16784-2:2008blank1Corrosion of metals and alloys Corrosion and fouling in industrial cooling water systems Part 2: Evaluation of the

24、 performance of cooling water treatment programmes using a pilot-scale test rig 1 Scope This part of ISO 16784 applies to corrosion and fouling in industrial cooling water systems This part of ISO 16784 describes a method for preliminary evaluation of the performance of treatment programmes for open

25、 recirculating cooling water systems. It is based primarily on laboratory testing but the heat exchanger testing facility can also be used for on-site evaluation. This part of ISO 16784 does not include heat exchangers with cooling water on the shell-side (i.e. external to the tubes). 2 Normative re

26、ferences The following referenced documents 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. ISO 3696:1987, Water for analytical labo

27、ratory use Specification and test methods ISO 8407:1991, Corrosion of metals and alloys Removal of corrosion products from corrosion test specimens ISO 8501-1:1988, Preparation of steel substrates before application of paints and related products Visual assessment of surface cleanliness Part 1: Rust

28、 grades and preparation grades of uncoated steel substrates and of steel substrates after overall removal of previous coatings ISO 11463:1995, Corrosion of metals and alloys Evaluation of pitting corrosion 3 Terms, abbreviations and definitions For the purposes of this document, the following terms,

29、 abbreviations and definitions apply. 3.1 ATP adenosine tri-phosphate, an active chemical present in living bacteria NOTE ATP concentrations can be indirectly measured and are used as an indicator for the presence of biology in cooling water BS EN ISO 16784-2:20082 3.2 blow-down discharge of water f

30、rom the cooling water circuit expressed as a discharge rate 3.3 Cfu colony forming units which are a unit of measure for the amount of bacteria in cooling water 3.4 cooling tower tower used for evaporative cooling of circulating cooling water, normally constructed of wood, plastic, galvanized metal

31、or ceramic materials 3.5 cooling water treatment adjustment of cooling water chemistry by which corrosion and fouling can be controlled 3.6 cycles of concentration ratio of the concentration of specific ions in the circulating cooling water to the concentration of the same ions in the make-up water

32、3.7 heat rejection capacity amount of heat that can be rejected by a cooling-tower system 3.8 half-life time needed to reduce the initial concentration of a non-degradable and/or non-precipitable compound to 50 % of its concentration in the cooling water 3.9 make-up water total water mass per time u

33、nit, which is added to the system to compensate for the loss of water due to evaporation, blow-down, leakage and drift loss 3.10 Reynolds number dimensionless form, LVwhich is proportional to the ratio of inertial force to viscous force in a flow system where: L is the characteristic dimension of th

34、e flow system, expressed in metres (m) V is the linear velocity, expressed in metres per second (m/s) is the fluid density, expressed in kilograms per cubic metre (kg/m3) is the fluid viscosity, expressed in kilograms per metre per second (kg/m/s) 3.11 surface temperature temperature of the interfac

35、e between the cooling water film and the heat-transfer surface, whether the surface be the tube wall or the outside of a fouling deposit 3.12 TOC total organic carbon BS EN ISO 16784-2:200833.13 tower fill portion of a cooling tower, which constitutes its primary heat-transfer surface, over which wa

36、ter flows as evaporation occurs 3.14 wall shear stress shear stress of the fluid film immediately adjacent to the tube wall NOTE The wall shear stress is expressed in N/m2. 3.15 wall temperature temperature sensed by a thermocouple placed between the heater element and the inside of the heat-transfe

37、r tube wall, preferably as close to the tube wall as possible 4 Principle A test assembly of metallic test tubes is submitted under heat-transfer conditions to the circulation of cooling water for a specified period. This may be connected directly to the cooling water system on-site, to be represent

38、ative of service conditions. For laboratory testing, the cooling water composition is designed to reflect the chemistry for the service application but modified with the appropriate treatment programme under investigation. The adoption of synthetic chemistry in laboratory tests can be effective for

39、comparative purposes, e.g. screening, but will not be representative of service conditions. The effect of the cooling water circulation and the treatment programme on the corrosion and fouling of the test tubes is assessed using a number of measurement parameters. 5 Reagents and materials The coolin

40、g water composition of the test should reflect the likely service application. For laboratory testing using synthetic water, only reagents of recognized analytical grade and only water complying with the minimum requirements of grade 3 of ISO 3696 shall be used. There are two main operating environm

41、ents, which may be adopted. The first is to use the make-up water as used in the specific cooling system on-site (a variation on this is to use synthetic make-up water), and concentrate it to the required number of cycles in the test system. Annex A includes forms recommended for recording test cond

42、itions, compositions of make-up and recirculating water, and test results. The second approach involves using a synthetic water simulating the on-site circulating water for the required number of cycles. The use of synthetic circulating water obviates the need to concentrate the synthetic water to o

43、btain the desired cycles of concentration. This approach simplifies the test by avoiding the use of the pilot cooling tower. Synthetic circulating water will usually contain a higher level of dissolved ionic solids than corresponding natural water, thus making the synthetic water more corrosive. BS

44、EN ISO 16784-2:20084 5.1 Water characteristics The natural or synthetic water(s) used should be characterized as specified in Table 1.This Table should be used to record compositions of both the circulating water and the make-up water, if used. Turbidity, total silica, bacteria and ATP need only be

45、measured for on-site waters. Table 1 Composition of make-up and circulating cooling water No. Component Value Units 1 pH pH units2 Conductivity S/cm 3 Total hardness a 4 Alkalinity p a 5 Alkalinity m a 6 Ca2+mg/l 7 Mg2+mg/l 8 Na+mg/l 9 K+mg/l 10 NH4+mg/l 11 Fe2+mg/l 12 Cu2+mg/l 13 Al3+mg/l 14 CO32-m

46、g/l 15 HCO3-mg/l 16 Cl-mg/l 17 SO42-mg/l 18 NO3-mg/l 19 PO43-mg/l 20 SiO2mg/l 21 Cl2mg/l 22 Turbidity FTU or NTU 23 Suspended solids mg/l 24 Bacteria UFC/ml or UFC/l 25 ATP RLU aThe unit of measurement will depend on the test method. 5.2 Preparation of synthetic test waters using mother solutions Sy

47、nthetic test waters are normally prepared in the laboratory at the time of use by mixing mother or stock solutions. One mother solution contains the alkalinity. The other mother solution contains the hardness and other salts required in the test water The composition of these two solutions is calcul

48、ated so that, when the solutions are mixed in the proper proportion, they prepare either the circulating test water or an appropriate make-up water. Typical mother solutions are shown in B.1. Alternatively, mother solutions may be prepared as concentrates and subsequently diluted with demineralised

49、water. BS EN ISO 16784-2:200856 Apparatus The core of the test assembly is the heat exchanger section - described further in 6.1 to 6.4. The test assembly comprises two or more metal heat-transfer tubes, made of the relevant alloy used in the on-site heat exchanger, mounted in series (Figure B.1) or in parallel (Annex B.3, Figure B.2). Conduction and convection of electrically generated heat occurs through the heat-transfer tube wall into the circulating cooling water. The materials-of-construction of the test assembly shall be chosen so as n