DIN EN ISO 16784-2-2008 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、July 2008DEUTSCHE NORM English price group 13No part of this standard may be reproduced without prior permission ofDIN Deutsches Institut fr Normung e. V., Berlin. Beuth Verlag GmbH, 10772 Berlin, Germany,has the exclusive right of sale for German Standards (DIN-Normen).ICS 77.060!$Pdp“1456577www.di

2、n.deDDIN EN ISO 16784-2Corrosion of metals and alloys Corrosion and fouling in industrial cooling water systems Part 2: Evaluation of the performance of cooling water treatmentprogrammes using a pilot-scale test rig (ISO 16784-2:2006)English version of DIN EN ISO 16784-2:2008-07Korrosion von Metalle

3、n und Legierungen Korrosion und Fouling in industriellen Khlwassersystemen Teil 2: Bewertung der Leistung von Khlwasser-Behandlungsprogrammen unterAnwendung eines Modell-Prfstands (ISO 16784-2:2006)Englische Fassung DIN EN ISO 16784-2:2008-07www.beuth.deDocument comprises 25 pagesDIN EN ISO 16784-2:

4、2008-07 2 National foreword This standard has been prepared by Technical Committee ISO/TC 156 “Corrosion of metals and alloys” (Secretariat: SAC, China). Based on the results of the unique acceptance procedure, ISO 16784-2:2006 has been adopted by Technical Committee CEN/TC 262 “Metallic and other i

5、norganic coatings” (Secretariat: BSI, United Kingdom) as a European Standard. The responsible German body involved in its preparation was the Normenausschuss Materialprfung (Materials Testing Standards Committee), Technical Committee NA 062-01-71 AA Korrosion und Korrosions-schutz. The DIN Standards

6、 corresponding to the International Standards referred to in clause 2 of the EN are as follows: ISO 3696:1987 DIN ISO 3696 ISO 8501-1:1988 DIN EN ISO 8501-1 ISO 11463:1995 DIN EN ISO 11463 National Annex NA (informative) Bibliography DIN ISO 3696, Water for analytical laboratory use Specification an

7、d test methods DIN EN ISO 8501-1, Preparation of steel substrates before application of paints and related products Visual assessment of surface cleanliness Part 1: Rust grades and preparation grades of uncoated steel substrates and of steel substrates after overall removal of previous coatings DIN

8、EN ISO 11463, Corrosion of metals and alloys Evaluation of pitting corrosion EUROPEAN STANDARDNORME EUROPENNEEUROPISCHE NORMEN ISO 16784-2April 2008ICS 77.060English VersionCorrosion of metals and alloys - Corrosion and fouling inindustrial cooling water systems - Part 2: Evaluation of theperformanc

9、e 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 - Partie 2:valuation des performances des programmes detraitement deau de refroidissement sur banc dessai pil

10、ote(ISO 16784-2:2006)Korrosion von Metallen und Legierungen - Korrosion undFouling in industriellen Khlwassersystemen - Teil 2:Bewertung der Leistung von Khlwasser-Behandlungsprogrammen unter Anwendung eines Modell-Prfstands (ISO 16784-2:2006)This European Standard was approved by CEN on 21 March 20

11、08.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. Up-to-date lists and bibliographical references concerning such nationalstandards may be obtained on

12、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 translationunder the responsibility of a CEN member into its own language and notified to the CEN Management Centr

13、e 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, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, P

14、ortugal,Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.EUROPEAN COMMITTEE FOR STANDARDIZATIONCOMIT EUROPEN DE NORMALISATIONEUROPISCHES KOMITEE FR NORMUNGManagement Centre: rue de Stassart, 36 B-1050 Brussels 2008 CEN All rights of exploitation in any form and by any means

15、 reservedworldwide for CEN national Members.Ref. No. EN ISO 16784-2:2008: E2 EN ISO 16784-2:2008 (E) DIN EN ISO 16784-2:2008-07 Contents Page Foreword3 Introduction.4 1 Scope 5 2 Normative references 5 3 Terms and definitions .5 4 Principle7 5 Reagents and materials 7 5.1 Water characteristics 8 5.2

16、 Preparation of synthetic test waters using mother solutions 8 6 Apparatus .9 6.1 Temperature measurement.9 6.2 Circulation-rate monitor9 6.3 Make-up, evaporation and blow-down measurement9 6.4 Cooling tower.9 7 Test method. 10 7.1 Procedure 10 7.1.1 Cleaning of the test assembly. 10 7.1.2 Test tube

17、 preparation and pre-treatment .10 7.1.3 System water content. 10 7.1.4 Procedure to fill the cooling water system 10 7.1.5 Heating the test tubes 11 7.1.6 Flow rate 11 7.1.7 Blow-down and half-life . 12 7.1.8 Biocide treatment . 12 7.1.9 Make-up water for cooling-tower use. 12 7.2 Determination of

18、analytical and control parameters 12 7.3 Test data reporting . 13 7.4 Test termination 13 8 Assessment of results . 13 8.1 Recording of cooling water quality. 13 8.2 Treatment of the test tubes . 13 8.3 Assessment of results on deposition and fouling 13 8.4 Assessment of results on corrosion 14 9 Te

19、st report . 15 Annex A (informative) Test data sheet on the performance of cooling water treatment programmes 16 Annex B (informative) Further information on some methods of measurement and test 19 Bibliography. 23 Foreword 3 The text of ISO 16784-2:2006 has been prepared by Technical Committee ISO/

20、TC 156 “Corrosion of metals and alloys” 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

21、the status of a national standard, either 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

22、 the subject of patent rights. CEN and/or 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, Be

23、lgium, Bulgaria, Cyprus, Czech Republic, 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 noti

24、ce The text of ISO 16784-2:2006 has been approved by CEN as a EN ISO 16784-2:2008 without any modification. EN ISO 16784-2:2008 (E) DIN EN ISO 16784-2:2008-07 Introduction Due to more stringent environmental requirements and escalating costs of water, there is an industrial need to improve the safet

25、y, 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 and vendors of treatment material

26、s for those systems with a procedure to make consistent evaluations of cooling water treatment programmes on a pilot scale. 4 EN ISO 16784-2:2008 (E) DIN EN ISO 16784-2:2008-07 1 Scope This part of ISO 16784 applies to corrosion and fouling in industrial cooling water systems This part of ISO 16784

27、describes a method for preliminary evaluation of the performance of treatment programmes for open 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

28、heat exchangers with cooling water on the shell-side (i.e. external to the tubes). 2 Normative references 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

29、 referenced document (including any amendments) applies. ISO 3696:1987, Water for analytical laboratory 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

30、 application of paints and related products Visual assessment of surface cleanliness Part 1: Rust 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 corrosi

31、on 3 Terms, abbreviations and definitions For the purposes of this document, the following terms, 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 th

32、e presence of biology in cooling water 5 EN ISO 16784-2:2008 (E) DIN EN ISO 16784-2:2008-07 3.2 blow-down discharge of water from 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 t

33、ower tower used for evaporative cooling of circulating cooling water, normally constructed of wood, plastic, galvanized metal 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 t

34、he concentration of specific ions in the circulating cooling water to the concentration of the same ions in the make-up water 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 an

35、d/or non-precipitable compound to 50 % of its concentration in the cooling water 3.9 make-up water total water mass per time unit, 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 i

36、s proportional to the ratio of inertial force to viscous force in a flow system where: L is the characteristic dimension of the 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

37、the fluid viscosity, expressed in kilograms per metre per second (kg/m/s) 3.11 surface temperature temperature of the interface 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 6 EN IS

38、O 16784-2:2008 (E) DIN EN ISO 16784-2:2008-07 3.13 tower fill portion of a cooling tower, which constitutes its primary heat-transfer surface, over which water 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

39、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-transfer tube wall, preferably as close to the tube wall as possible 4 Principle A test assembly of metallic test tubes is submitted under heat-transfe

40、r 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 representative of service conditions. For laboratory testing, the cooling water composition is designed to reflect the chemistry for the service applicat

41、ion but modified with the appropriate treatment programme under investigation. The adoption of synthetic chemistry in laboratory tests can be effective for comparative purposes, e.g. screening, but will not be representative of service conditions. The effect of the cooling water circulation and the

42、treatment programme on the corrosion and fouling of the test tubes is assessed using a number of measurement parameters. 5 Reagents and materials The cooling water composition of the test should reflect the likely service application. For laboratory testing using synthetic water, only reagents of re

43、cognized analytical grade and only water complying with the minimum requirements of grade 3 of ISO 3696 shall be used. There are two main operating environments, 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

44、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 conditions, compositions of make-up and recirculating water, and test results. The second approach involves using a synthetic water simulating the o

45、n-site circulating water for the required number of cycles. The use of synthetic circulating water obviates the need to concentrate the synthetic water to obtain the desired cycles of concentration. This approach simplifies the test by avoiding the use of the pilot cooling tower. Synthetic circulati

46、ng water will usually contain a higher level of dissolved ionic solids than corresponding natural water, thus making the synthetic water more corrosive. 7 EN ISO 16784-2:2008 (E) DIN EN ISO 16784-2:2008-07 5.1 Water characteristics The natural or synthetic water(s) used should be characterized as sp

47、ecified 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 measured for on-site waters. Table 1 Composition of make-up and circulating cooling water No. Component Value Units

48、 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-mg/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

49、 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 Synthetic 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 calculated so that, when the solutions are mixed in the prop