1、Designation: D 5256 05An American National StandardStandard Test Method forRelative Efficacy of Dynamic Solvent Systems forDissolving Water-Formed Deposits1This standard is issued under the fixed designation D 5256; the number immediately following the designation indicates the year oforiginal adopt
2、ion or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers the determination of the relativeefficacy of dyn
3、amic solvent systems for dissolving water-formed deposits that have been removed from the underlyingmaterial or deposits attached to the underlying material.1.2 The nature of this test method is such that statements ofprecision and bias as determined by round robin tests couldmislead users of this t
4、est method (see Sections 11 and 12).Therefore, no precision and bias statements are made.1.3 The values stated in SI units are to be regarded as thestandard.1.4 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user o
5、f this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D 887 Practice for Sampling Water-Formed DepositsD 1129 Terminology Relating to WaterD 1193 Specification for Reage
6、nt WaterD 2331 Practices for Preparation and Preliminary Testing ofWater-Formed DepositsD 2777 Practice for Determination of Precision and Bias ofApplicable Methods of Committee D19 on WaterD 3263 Test Methods for Corrosivity of Solvent Systemsfor Removing Water-Formed DepositsD 3483 Test Methods fo
7、r Accumulated Deposition in aSteam Generator Tube3. Terminology3.1 Definitions:3.1.1 water-formed depositsany accumulation of in-soluble material derived from water or formed by the reactionof water upon the surface in contact with the water. See 3.1.1.1.3.1.1.1 DiscussionDeposits formed from or by
8、water inall its phases may be further classified as scale, sludge,corrosion products, or biological deposits. The overall compo-sition of a deposit or some part of a deposit may be determinedby chemical or spectrographic analysis; the constituents actu-ally present as chemical substances may be iden
9、tified bymicroscope or x-ray diffraction studies. Organisms may beidentified by microscopical or biological methods.3.1.2 For definitions of other terms used in this test method,refer to Terminology D 1129.3.2 Definitions of Terms Specific to This Standard:3.2.1 dynamic solvent systemany closed loop
10、 system inwhich the solvent is in motion across the deposit surface.3.2.2 single and multiple solvent systemsa single solventsystem is a one-solution treatment.Amultiple solvent system isa treatment using two or more solutions in sequence.3.2.3 solvent systemspecified chemicals or combinationof chem
11、icals, that may include corrosion inhibitors, formulatedto react with and remove deposits.4. Summary of Test Method4.1 This test method consists of determining the ability of adynamic solvent system to dissolve deposits.4.2 For the unattached deposits, this test method consists ofexposing weighed am
12、ounts of deposit to the dynamic solventsystems and determining the weight loss of the exposeddeposit, thereby determining the efficacy of the solvent system.4.3 For the attached deposits, the amount and time requiredto yield a constant amount of certain loss of interest and theamount of deposit not
13、removed determines the relative efficacyof the dynamic solvent system.5. Significance and Use5.1 This test method is useful because the choice of asolvent system for removing water-formed deposits dependsupon the ability of the dynamic solvent system to dissolve bothunattached and attached deposits.
14、6. Apparatus6.1 Common Equipment:1This test method is under the jurisdiction of ASTM Committee D19 on Waterand is the direct responsibility of Subcommittee D19.03 on Sampling Water andWater-Formed Deposits, Analysis of Water for Power Generation and Process Use,On-Line Water Analysis, and Surveillan
15、ce of Water.Current edition approved June 1, 2005. Published June 2005. Originallyapproved 1992. Last previous edition approved in 2000 as D 5256 00.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStanda
16、rds volume information, refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.NOTE 1The equipment listed in this section is basic and serves thefunction of this test method. T
17、his basic test procedure could be modifiedto meet the specific needs of a particular investigation. The test apparatus,however, must be identified and reported with the results. For comparativetype tests, as described in the procedure, it is important that all tests be runin an identical manner.6.2
18、Unattached Deposit Removal (See Fig. 1 and Fig. 2):6.2.1 Balance, capable of weighing to the nearest 0.1 mg.6.2.2 Heating Bath, thermostatically controlled to 61C.6.2.3 Stirrer, controlled agitation.6.2.4 Temperature Indicator.6.2.5 Reaction Flask, stirred tests are best accomplished inround bottom
19、flasks.6.2.6 Condenser.6.2.7 Glass Filter Crucibles, Gooch 30-mL low form coursefritted disc crucibles.6.2.8 Vacuum Oven, for drying residual deposits.6.2.9 Desiccator.6.3 Attached Deposit Removal (See Fig. 3):6.3.1 Solvent Heater/Solvent Reservoir.6.3.2 Sample Holder.6.3.3 Flow Controller.6.3.4 Sam
20、ple System (usually with cooler).6.3.5 Pressure Relief.6.3.6 Pump.6.3.7 Flow Meter.6.3.8 Temperature Controller.7. Reagents7.1 Purity of ReagentsAll solvent materials such as acids,inhibitors, and other additives shall be of the grade normallyemployed in chemical cleaning practices for the removal o
21、fwater-formed deposits. Unless otherwise indicated, it is in-tended that all chemicals shall conform to the specifications ofthe Committee onAnalytical Reagents of theAmerican Chemi-cal Society,3where such specifications are available.7.2 Purity of WaterUnless otherwise indicated referencesto water
22、shall be understood to mean reagent water conformingto Type IV of Specification D 1193.3Reagent Chemicals, American Chemical Society Specifications, AmericanChemical Society, Washington, DC. For Suggestions on the testing of reagents notlisted by the American Chemical Society, see Annual Standards f
23、or LaboratoryChemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeiaand National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,MD.A: Condenser, B: Temperature Measurement, C: Stirrer, D: Heated ReactionFlaskFIG. 1 Low Temperature Test EquipmentA: Stirrer, B: P
24、ressure Control (Gauge, Vent and Relief), C: Temperature Mea-surement, D: Temperature Control, E: Heated AutoclaveFIG. 2 High Temperature Test EquipmentA: High Point Pressure Relief, B: Pressure Gauge, C: Vent, D: Solvent AdditionValve, E: Temperature Measurement, F: Flow Measurement, G: Tube Sample
25、Holder, H: Variable Speed Pump, I: Sample Valve With Integral Cooler, J: Regu-lated Heat SourceFIG. 3 Dynamic Test EquipmentD52560528. Sampling8.1 Collect and preserve the sample in accordance withPractices D 887 (see Note 2).NOTE 2If Method A of Test Methods D 3483 is being used, thedeposit removed
26、 in that test can be used in this test method.8.2 Collect and preserve the sample(s) obtained during thecleaning of attached deposit sample.9. Procedure9.1 Prepare a water solution of the solvent systems to betested using a weight percentage basis for the acid or otheractive material including any a
27、dditives. Add only inhibitorssupplied in liquid form on a volume basis as prescribed by themanufacturer.9.2 Unattached Deposits:9.2.1 Preparation of Sample:9.2.1.1 Preliminary ExaminationExamine the sample ascollected, using a microscope if available, for structure, color,odor, oil matter, appearanc
28、e of mother liquor if any, and othercharacteristics of note (for example, attraction to magnet).Record the results for future reference. Further informationabout examination and documentation of the nature of depositscan be found in Practices D 2331.(1) Filtration and other steps in the preparation
29、of thesample may frequently be bypassed; for example, a moistsample that contains no separated water or an apparent drysample shall be started in accordance with 9.2.1.3(1), and a drysample shall be started in accordance with 9.2.1.4.9.2.1.2 Filtration of SampleIf the sample includes anappreciable q
30、uantity of separated water, remove the solidmaterial by filtration. Save the filtrate, undiluted, pendingdecision as to whether or not its chemical examination isrequired. Transfer all of the solid sample to the filter, using thefiltrate to rinse the sample container if necessary. Air-drying orparti
31、al air-drying of the filter is frequently helpful towardeffecting a clean separation of the deposit.9.2.1.3 Sample DryingRemove the drained solid samplefrom the filter, being careful to avoid gross contamination withfilter paper. Spread the entire quantity of sample in a thin layeron a nonreactive,
32、impervious surface.(1) Oven DryingDry the sample using a vacuum oven ata temperature that will not degrade the deposit. A commonchoice is 52C (125F) and 34 kPa (absolute) (20 in. ofmercury). Place the sample in a desiccator and allow it to coolto room temperature. Weigh the sample to the nearest 0.0
33、1 g.Repeat until constant weight is obtained.Arecord of the weightloss during drying is often used.(2) Air DryingAir dry the entire quantity of solid, spreadit in a thin layer on a nonreactive impervious surface. A recordof the loss of weight during air drying is often used.9.2.1.4 Choose a represen
34、tative portion of the dried samplefor testing.9.2.2 Pour a measured volume of the test solvent (see 9.1)into the chosen test apparatus (see Section 6).9.2.2.1 The weighed deposit can be added to the solventprior to heating the solvent; however, a controlled and reportedtemperature must be maintained
35、 so that the results betweentests can be readily compared.9.2.3 Heat the solvent to the test temperature while stirringat the specified RPM (see Note 3).NOTE 3A stir rate of 60 to 90 RPM is commonly used.9.2.4 Take a portion of the deposit (see 9.2.1), weigh to thenearest 0.01 g and record an origin
36、al deposit weight. Thedeposit weight should meet a solvent volume/deposit weightratio for this specified application (see Note 4).NOTE 4A solvent volume/deposit weight ratio of 100 mL solvent/1 gdeposit is commonly used.9.2.5 After the solvent has stabilized at the test temperature,draw a sample for
37、 analysis, then add the deposit to the solvent.This is considered as “time zero.”9.2.6 If required, samples can be drawn at periodic timeintervals. Maintain strict control of all sample weights (tonearest 0.01 g).9.2.7 At the termination of the test, cool and filter thesolvent.9.2.7.1 Weigh a clean,
38、 dry filter crucible to the nearest0.01 g. Record the weight as original crucible weight.9.2.7.2 Filter the solvent-deposit mixture through theweighed filter crucible. Vacuum filtration increases the filtra-tion rate.9.2.7.3 Rinse the filter crucible and residual deposit withwater.9.2.7.4 Dry the cr
39、ucible and residual deposit in the vacuumoven. Choose a temperature and vacuum that will not degradethe residual deposit. A common choice is 52C (125F) and 34kPa (absolute) (20 in. of mercury).9.2.7.5 Place the dried crucible and residue in the desiccatorand allow them to cool to room temperature.9.
40、2.7.6 Weigh the crucible plus residue to the nearest 0.01 g.9.2.7.7 Repeat 9.2.7.4 to 9.2.7.6 until a constant weight isobtained. Record this weight as the final crucible weight.9.3 Attached Deposit (Comparative Tests):9.3.1 Establish accumulated deposition in accordance withTest Methods D 3483 on a
41、 portion of the sample adjacent toand representative of the section to be tested below. Furtherinformation about examination and documentation of thenature of deposits can be found in Practices D 2331.9.3.2 The ratio of the weight of attached deposit on the testspecimen to test apparatus volume must
42、 be recorded andshould be appropriate for the application (see Note 5).NOTE 5Due to the constraints imposed by the solvent circulationsystem, the solvent volume/deposit weight ratio on attached deposits isoften larger than desired. This excess capacity can be partially compen-sated by reducing the c
43、oncentration of the active components of thesolvent. However, in all cases the actual cleaning operation should bedesigned and controlled according to the accepted practice for theparticular solvent system being applied and not according to the valuesgenerated by this test method.9.3.3 Use a measure
44、d volume of test solvent to fill the testapparatus.9.3.4 Establish solvent flow in the test apparatus. Thesolvent flow should bypass the test specimen until the properflow rate, system pressure, and solvent temperature is reached.9.3.4.1 Establish and record the solvent flow rate based onthe cross s
45、ection area of the test specimen.D52560539.3.5 Heat the solvent to the appropriate test temperature.After the solvent temperature and flow rate have stabilized,draw a sample for analysis.9.3.6 Establish flow through the test specimen. This isconsidered as “time zero.”9.3.7 Monitor and record flow ra
46、te, pressure and tempera-ture during the test interval.9.3.8 Draw samples at periodic time intervals and analyzefor ions of choices.9.3.9 If necessary, use intermediate visual examinations todetermine cleaning efficacy.9.3.10 At the completion of the test period, determined by9.3.8 and 9.3.9, determ
47、ine the remaining deposit accumulationaccording to Test Methods D 3483 (see Note 6). This value aswell as the time required to achieve the level of cleanliness isused as the relative measure of cleaning efficacy for attacheddeposit.NOTE 6Since the remaining deposit may be acid insoluble, thepreferre
48、d method is Method A of Test Methods D 3483.10. Calculation10.1 Unattached Deposits:10.1.1 Determine the amount of deposit that was dissolvedby subtracting the amount not dissolved (see 9.2.7) from theoriginal deposit weight (see 9.2.4).10.1.2 Express the efficacy of the solvent system as thepercent
49、 deposit dissolved, by dividing the amount dissolved(see 10.1.1) by the original amount (see 9.2.4) and convertingthe resultant decimal to a percentage.10.1.3 Use the following formula to calculate solvent effi-cacy:SE 5OS 2 FS!OS3 100 (1)where:SE = solvent efficacy,OS = original deposit weight, g, andFS = final deposit residue weight, g.10.2 For Attached Deposits:10.2.1 Determine the amount of deposit that was removedby subtracting the final deposit accumulation (see 9.3.10) fromthe original deposit accumulation (see 9.3.1).10.2.2 Express the efficacy of the
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