ASTM D887-1982(2003)e1 Standard Practices for Sampling Water-Formed Deposits《水沉积物抽样的标准操作规程》.pdf

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1、Designation: D 887 82 (Reapproved 2003)e1Standard Practices forSampling Water-Formed Deposits1This standard is issued under the fixed designation D 887; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A n

2、umber in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.e1NOTEWarning notes were editorially moved into the standard text in January 2004.1. Scope1.1 These practices cover the sampling of water-formeddep

3、osits for chemical, physical, biological, or radiologicalanalysis. The practices cover both field and laboratory sam-pling. It also defines the various types of deposits. Thefollowing practices are included:SectionsPractice ASampling Water-Formed Deposits From Tubingof Steam Generators and Heat Exch

4、angers8to10Practice BSampling Water-Formed Deposits From SteamTurbines11 to 141.2 The general procedures of selection and removal ofdeposits given here can be applied to a variety of surfaces thatare subject to water-formed deposits. However, the investigatormust resort to his individual experience

5、and judgment inapplying these procedures to his specific problem.1.3 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the appl

6、ica-bility of regulatory limitations prior to use. See Section 7, 9.8,9.8.4.6, and 9.14 for specific hazards statements.2. Referenced Documents2.1 ASTM Standards:2D512 Test Methods for Chloride Ion in WaterD934 Practices for Identification of Crystalline Compoundsin Water-Formed Deposits by X-Ray Di

7、ffractionD993 Test Methods for Sulfate-Reducing Bacteria in Waterand Water-Formed Deposits3D1129 Terminology Relating to WaterD1193 Specification for Reagent WaterD1245 Practice for Examination of Water-Formed Depositsby Chemical MicroscopyD1293 Test Methods for pH of WaterD1428 Test Methods for Sod

8、ium and Potassium in Waterand Water-Formed Deposits by Flame Photometry3D2331 Practices for Preparation and Preliminary Testing ofWater-Formed DepositsD2332 Practice for Analysis of Water-Formed Deposits byWavelength-Dispersive X-Ray FluorescenceD2579 Test Methods for Total Organic Carbon in Water3D

9、3483 Test Methods for Accumulated Deposition in aSteam Generator Tube3. Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 biological depositswater-formed deposits of organ-isms or the products of their life processes.3.1.1.1 The biological deposits may be composed of micro-scopic o

10、rganisms, as in slimes, or of macroscopic types such asbarnacles or mussels. Slimes are usually composed of depositsof a gelatinous or filamentous nature.3.1.2 corrosion productsa result of chemical or electro-chemical reaction between a metal and its environment.3.1.2.1 A corrosion deposit resultin

11、g from the action ofwater, such as rust, usually consists of insoluble materialdeposited on or near the corroded area; corrosion productsmay, however, be deposited a considerable distance from thepoint at which the metal is undergoing attack.3.1.3 scalea deposit formed from solution directly inplace

12、 upon a surface.3.1.3.1 Scale is a deposit that usually will retain its physicalshape when mechanical means are used to remove it from thesurface on which it is deposited. Scale, which may or may notadhere to the underlying surface, is usually crystalline anddense, frequently laminated, and occasion

13、ally columnar instructure.3.1.4 sludgea water-formed sedimentary deposit.3.1.4.1 The water-formed sedimentary deposits may includeall suspended solids carried by the water and trace elementswhich were in solution in the water. Sludge usually does not1These practices are under the jurisdiction of AST

14、M Committee D19 on Water,and is the direct responsibility of Subcommittee D19.03 on Sampling of Water andWater-Formed Deposits, Analysis of Water for Power Generation and Process Use,On-Line Water Analysis, and Surveillance of Water.Current edition approved Oct. 29, 1982. Published March 1983. Origi

15、nallyapproved in 1946. Last previous edition approved in 1982 as D 887 82.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe

16、ASTM website.3Withdrawn.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.cohere sufficiently to retain its physical shape when mechanicalmeans are used to remove it from the surface on which itdeposits, but it may be baked in place an

17、d be hard andadherent.3.1.5 water-formed depositsany accumulation of in-soluble material derived from water or formed by the reactionof water upon surfaces in contact with the water.3.1.5.1 Deposits formed from or by water in all its phasesmay be further classified as scale, sludge, corrosion produc

18、ts,or biological deposit. The overall composition of a deposit orsome part of a deposit may be determined by chemical orspectrographic analysis; the constituents actually present aschemical substances may be identified by microscope or x-raydiffraction studies. Organisms may be identified by micro-s

19、copic or biological methods.3.2 DefinitionsFor definitions of other terms used in thesepractices, refer to Definitions D 1129.4. Summary of Practices4.1 These practices describe the procedures to be used forsampling water-formed deposits in both the field and labora-tory from boiler tubes and turbin

20、e components. They giveguidelines on selecting tube and deposit samples for removaland specify the procedures for removing, handling, and ship-ping of samples.5. Significance and Use5.1 The goal of sampling is to obtain for analysis a portionof the whole that is representative. The most critical fac

21、tors arethe selection of sampling areas and number of samples, themethod used for sampling, and the maintenance of the integrityof the sample prior to analysis. Analysis of water-formeddeposits should give valuable information concerning cyclesystem chemistry, component corrosion, erosion, the failu

22、remechanism, the need for chemical cleaning, the method ofchemical cleaning, localized cycle corrosion, boiler carryover,flow patterns in a turbine, and the rate of radiation build-up.Some sources of water-formed deposits are cycle corrosionproducts, make-up water contaminants, and condenser cooling

23、water contaminants.6. Reagents and Materials6.1 Purity of ReagentsReagent grade chemicals shall beused in all cases. Unless otherwise indicated, it is intended thatall reagents shall conform to the specifications of the Commit-tee on Analytical Reagents of the American Chemical Society,where such sp

24、ecifications are available.4Other grades may beused, provided it is first ascertained that the reagent is ofsufficiently high purity to permit its use without lessening theaccuracy of analysis.6.1.1 Purity of Water Unless otherwise indicated, refer-ences to water should be understood to mean Type II

25、I reagentwater, Specification D 1193.6.2 Materials:6.2.1 The highest purity material available should be usedfor removing the deposit samples.6.2.2 Filter Paper may contain water leachable contami-nants (chloride, fluoride, and sulfur) which can be removed bypretreatment prior to sampling.6.2.3 Poly

26、ester Tape may contain impurities of antimonyand cadmium which must be considered during analysis.7. Hazards7.1 Warnings:7.1.1 Special safety precautions are necessary in usingacetone on a wipe material for removing water-formed deposits(see 9.8.4.6).7.1.2 Special handling precautions may be require

27、d forworking with water-formed deposits containing radioactivenuclides (see 9.14).7.2 Cautions:7.2.1 Extreme care must be taken not to damage theunderlying surface when removing water-formed depositsamples from equipment in the field (see 9.8).7.2.2 The selection of samples necessarily depends on th

28、eexperience and judgment of the investigator. The intended useof the sample, the accessibility and type of the deposit, and theproblem to be solved will influence the selection of the samplesand the sampling method.7.2.3 The most desirable amount of deposit to be submittedas a sample is not specific

29、. The amount of deposit should beconsistent with the type of analysis to be performed.7.2.4 The samples must be collected, packed, shipped, andmanipulated prior to analysis in a manner that safeguardsagainst change in the particular constituents or properties to beexamined.7.2.5 The selection of sam

30、pling areas and number ofsamples is best guided by a thorough investigation of theproblem. Very often the removal of a number of samples willresult in more informative analytical data than would beobtained from one composite sample representing the entiremass of deposit. A typical example is the sam

31、pling of depositsfrom a steam turbine. Conversely, in the case of a tube failurein a steam generator, a single sample from the affected areamay suffice.7.2.6 Most deposits are sampled at least twice before beingsubmitted to chemical or physical tests. The gross sample isfirst collected from its poin

32、t of formation in the field and thenthis sample is prepared for final examination in the laboratory.7.2.7 A representative sample is not an absolute prerequi-site. The quantity of deposit that can be removed is oftenlimited. In such cases, it is better to submit a single mixedsample (composite) and

33、to describe how the sample wasobtained. For radiological analysis all samples should bechecked for activity levels before preparing a composite sincewide variations in radioactive content may occur in samples ofsimilar appearance and chemical composition.7.2.8 It is good practice for deposits to be

34、taken andanalyzed every time a turbine is opened for repairs or inspec-tion. Deposit history can then supplement chemical records ofa unit, and deposit chemistry of units with and withoutcorrosion and other problems can be compared. Enough4Reagent Chemicals, American Chemical Society Specifications,

35、 AmericanChemical Society, Washington, DC. For suggestions on the testing of reagents notlisted by the American Chemical Society, see Analar Standards for LaboratoryChemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeiaand National Formulary, U.S. Pharmaceutical Convention, Inc

36、. (USPC), Rockville,MD.D 887 82 (2003)e12information on deposits has been published (1, 2)5that acomparison between different types of boilers and differentwater treatments, as well as an assessment of deposit corro-siveness, are possible. It has been a general experience thatabout 0.2 % of a corros

37、ive impurity, such as chloride, in adeposit, is a division between corrosive and noncorrosivedeposits.7.2.9 Deposits taken after a turbine is open do not exactlyrepresent chemical composition of deposits in an operatingturbine. Chemical thermodynamic data on steam additives andimpurities, such as va

38、por pressures of solutions, ionization, andvolatility data are needed to reconstruct chemistry of environ-ment during operation.7.2.10 Typical changes which occur after the hot turbine isshut down and air is admitted are: (1) reactions with oxygenand carbon dioxide, (2) drying of some deposits and w

39、aterabsorption by others, (3) leaching and recrystallization wheremoisture is allowed to condense, and ( 4) formation of ironhydroxide and hematite.PRACTICE ASAMPLING WATER-FORMEDDEPOSITS FROM TUBING OF STEAMGENERATORS AND HEAT EXCHANGERS8. Scope8.1 This practice covers the sampling of water-formedd

40、eposits from tubing of steam generators and heat exchangers.It covers both field and laboratory sampling of water-formeddeposits. It gives guidelines on selecting tube samples forremoval and specifies the procedure for removing tube samplesfrom the unit.9. Field Sampling9.1 Selection of Tube Samples

41、Whenever feasible, removethe tube containing the water-formed deposit. The length oftubing removed depends on the amount of deposits present andthe type of analyses to be performed. As a guideline, 3 ft (0.9m) of tubing is suggested. Table 1 contains a summary of thevarious procedures for selection

42、of samples in the order ofpreference.9.1.1 Preferred Selection ProcedureSelect one or moreseparate tube samples containing the area of failure, heaviestdeposition, or principle concern (primary area) and include anyadjacent or closely related areas of these tube samples thatmight contain deposits si

43、gnificantly different from the primaryarea. Also, one or more tube samples is selected from adjacentrows or other related areas that might contain deposits signifi-cantly different from the primary area.9.1.2 Alternative Selection Procedure 1Select one ormore separate tube samples containing the are

44、a of failure,heaviest deposition, or principle concern (primary area) andinclude any adjacent or closely related areas of these tubesamples that might contain deposits significantly different fromthe primary area. Use this procedure when it is impractical toremove the samples from adjacent rows or o

45、ther related areasor when it is improbable that the information gained by suchsampling will justify the additional work involved.9.1.3 Alternative Selection Procedure 2Select one ormore separate tube samples containing the area of failure,heaviest deposition, or principle concern (primary area). Use

46、this procedure when only the tube section containing theprimary area can be removed or when it is impractical toremove adjacent or closely related areas, or tube samples fromadjacent rows or other related areas, or when it is improbablethat the information gained by such sampling will justify theadd

47、itional work involved.9.1.4 Alternative Selection Procedure 3Select one ormore tube samples containing an area adjacent or closelyrelated to the primary area. Use this procedure only when it isnot possible to obtain a tube section containing the primaryarea.9.1.5 Alternative Selection Procedure 4Sel

48、ect one ormore separate tube samples from adjacent rows or other relatedareas. Use this procedure only when it is not possible toremove a tube section from the primary area, adjacent to theprimary area, or closely related to the primary area.9.2 Taking the Tube SampleMark the tube that is to beremov

49、ed (sampled) with a crayon. A long arrow can be used toshow: (1) the ligament that is facing into the furnace, and (2)which end of the tube is up. Mark the tube before it is removed.The marking should not involve the use of a hammer and dieor paint.9.2.1 Whenever possible, remove the tube samples bysawing. The tube should be dry-cut (no oil). Grinding wheelsand cutting torches can be used to obtain tube samples whichcannot be sawed. Grinding wheels and cutting torches canproduce sufficient heat to alter the composition of the depositnear the cutting point. If a gri