1、Designation: D887 13Standard Practices forSampling Water-Formed Deposits1This standard is issued under the fixed designation D887; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A number in parentheses i
2、ndicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 These practices cover the sampling of water-formeddeposits for chemical, physical, biological, or radiologicalanalysis. The practices cover both field and lab
3、oratory 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 Exchangers8to10Practice BSampling Water-Formed Deposits From SteamTurbines11 to 141.2 The general procedures
4、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 and judgment inapplying these procedures to his specific problem.1.3 The values stated in inch-pound unit
5、s are to be regardedas standard. The values given in parentheses are mathematicalconversions to SI units that are provided for information onlyand are not considered standard.1.4 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibi
6、lity of the user of this standard to establish appro-priate safety and health practices and determine the applica-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 Chlor
7、ide Ion In WaterD934 Practices for Identification of Crystalline Compoundsin Water-Formed Deposits By X-Ray DiffractionD1129 Terminology Relating to WaterD1193 Specification for Reagent WaterD1245 Practice for Examination of Water-Formed Depositsby Chemical MicroscopyD1293 Test Methods for pH of Wat
8、erD2331 Practices for Preparation and Preliminary Testing ofWater-Formed DepositsD2332 Practice for Analysis of Water-Formed Deposits byWavelength-Dispersive X-Ray FluorescenceD3483 Test Methods forAccumulated Deposition in a SteamGenerator TubeD4412 Test Methods for Sulfate-Reducing Bacteria in Wat
9、erand Water-Formed Deposits3. Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 biological deposits, nwater-formed deposits oforganisms or the products of their life processes.3.1.1.1 Discussion- The biological deposits may be com-posed of microscopic organisms, as in slimes, or of
10、 macro-scopic types such as barnacles or mussels. Slimes are usuallycomposed of deposits of a gelatinous or filamentous nature.3.1.2 corrosion products, na result of chemical or electro-chemical reaction between a metal and its environment.3.1.2.1 Discussion- A corrosion deposit resulting from theac
11、tion of water, such as rust, usually consists of insolublematerial deposited on or near the corroded area; corrosionproducts may, however, be deposited a considerable distancefrom the point at which the metal is undergoing attack.3.1.3 scale, na deposit formed from solution directly inplace upon a s
12、urface.3.1.3.1 Discussion- Scale is a deposit that usually will retainits physical shape when mechanical means are used to removeit from the surface on which it is deposited. Scale, which mayor may not adhere to the underlying surface, is usuallycrystalline and dense, frequently laminated, and occas
13、ionallycolumnar in structure.3.1.4 sludge, n a water-formed sedimentary deposit.3.1.4.1 Discussion- The water-formed sedimentary depositsmay include all suspended solids carried by the water and traceelements which were in solution in the water. Sludge usuallydoes not cohere sufficiently to retain i
14、ts physical shape whenmechanical means are used to remove it from the surface onwhich it deposits, but it may be baked in place and be hard andadherent.1These practices are under the jurisdiction of ASTM Committee D19 on Waterand are the direct responsibility of Subcommittee D19.03 on Sampling Water
15、 andWater-Formed Deposits, Analysis of Water for Power Generation and Process Use,On-Line Water Analysis, and Surveillance of Water.Current edition approved Jan. 1, 2013. Published February 2013. Originallyapproved in 1946. Last previous edition approved in 2008 as D887 08. DOI:10.1520/D0887-13.2For
16、 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 ASTM website.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700,
17、 West Conshohocken, PA 19428-2959. United States13.1.5 water-formed deposits, nany 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 Discussion- Deposits formed from or by water in allits phases may be further cla
18、ssified as scale, sludge, corrosionproducts, or biological deposit. The overall composition of adeposit or some part of a deposit may be determined bychemical or spectrographic analysis; the constituents actuallypresent as chemical substances may be identified by micro-scope or x-ray diffraction stu
19、dies. Organisms may be identifiedby microscopic or biological methods.3.2 DefinitionsFor definitions of other terms used in thesepractices, refer to Definitions D1129.4. Summary of Practices4.1 These practices describe the procedures to be used forsampling water-formed deposits in both the field and
20、 labora-tory from boiler tubes and turbine 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
21、 is representative. The most critical factors 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
22、 component corrosion, erosion, the failuremechanism, 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
23、water contaminants, and condenser coolingwater 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 th
24、e American Chemical Society,where such specifications are available.3Other 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 Reference to water that is used forreagent p
25、reparation, rinsing or dilution shall be understood tomean water that conforms to the quantitative specifications ofType III reagent water of SpecificationD1193.6.2 Materials:6.2.1 The highest purity material available should be usedfor removing the deposit samples.6.2.2 Filter Paper may contain wat
26、er leachable contami-nants (chloride, fluoride, and sulfur) which can be removed bypretreatment prior to sampling.6.2.3 Polyester 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 using
27、acetone on a wipe material for removing water-formed deposits(see 9.8.4.6).7.1.2 Special handling precautions may be required 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 removin
28、g water-formed depositsamples from equipment in the field (see 9.8).7.2.2 The selection of samples necessarily depends on theexperience 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
29、 of the samplesand the sampling method.7.2.3 The most desirable amount of deposit to be submittedas a sample is not specific. 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
30、a manner that safeguardsagainst change in the particular constituents or properties to beexamined.7.2.5 The selection of sampling 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 analytic
31、al data than would beobtained from one composite sample representing the entiremass of deposit. A typical example is the sampling 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
32、sampled at least twice before beingsubmitted to chemical or physical tests. The gross sample isfirst collected from its point 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
33、 of deposit that can be removed is oftenlimited. In such cases, it is better to submit a single mixedsample (composite) and to describe how the sample wasobtained. For radiological analysis all samples should bechecked for activity levels before preparing a composite sincewide variations in radioact
34、ive content may occur in samples ofsimilar appearance and chemical composition.7.2.8 It is good practice for deposits to be 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
35、and withoutcorrosion and other problems can be compared. Enough3Reagent Chemicals, American Chemical Society Specifications, AmericanChemical Society, Washington, DC. For suggestions on the testing of reagents notlisted by the American Chemical Society, see Analar Standards for LaboratoryChemicals,
36、BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeiaand National Formulary, U.S. Pharmaceutical Convention, Inc. (USPC), Rockville,MD.D887 132information on deposits has been published (1,2)4that acomparison between different types of boilers and differentwater treatments, as well as an
37、 assessment of depositcorrosiveness, are possible. It has been a general experiencethat about 0.2 % of a corrosive 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 compositi
38、on of deposits in an operatingturbine. Chemical thermodynamic data on steam additives andimpurities, such as vapor 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 issh
39、ut down and air is admitted are: (1) reactions with oxygenand carbon dioxide, (2) drying of some deposits and waterabsorption by others, (3) leaching and recrystallization wheremoisture is allowed to condense, and ( 4) formation of ironhydroxide and hematite.PRACTICE ASAMPLING WATER-FORMEDDEPOSITS F
40、ROM TUBING OF STEAMGENERATORS AND HEAT EXCHANGERS8. Scope8.1 This practice covers the sampling of water-formeddeposits 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 an
41、d specifies the procedure for removing tube samplesfrom the unit.9. Field Sampling9.1 Selection of Tube SamplesWhenever 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 gu
42、ideline, 3 ft (0.9m) of tubing is suggested. Table 1 contains a summary of thevarious procedures for selection of samples in the order ofpreference.9.1.1 Preferred Selection Procedure Select one or moreseparate tube samples containing the area of failure, heaviestdeposition, or principle concern (pr
43、imary area) and include anyadjacent or closely related areas of these tube samples thatmight contain deposits significantly 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 th
44、e primary area.9.1.2 Alternative Selection Procedure 1Select 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 significantly differ
45、ent from the primaryarea. Use this procedure when it is impractical to remove thesamples from adjacent rows or other related areas or when it isimprobable that the information gained by such sampling willjustify the additional work involved.9.1.3 Alternative Selection Procedure 2Select one or morese
46、parate tube samples containing the area of failure, heaviestdeposition, or principle concern (primary area). Use thisprocedure when only the tube section containing the primaryarea can be removed or when it is impractical to removeadjacent or closely related areas, or tube samples from adjacentrows
47、or other related areas, or when it is improbable that theinformation gained by such sampling will justify the additionalwork involved.9.1.4 Alternative Selection Procedure 3Select one or moretube samples containing an area adjacent or closely related tothe primary area. Use this procedure only when
48、it is notpossible to obtain a tube section containing the primary area.9.1.5 Alternative Selection Procedure 4Select one or moreseparate 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 t
49、heprimary area, or closely related to the primary area.9.2 Taking the Tube SampleMark the tube that is to beremoved (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 c
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