ASTM D4778-2015 Standard Test Method for Determination of Corrosion and Fouling Tendency of Cooling Water Under Heat Transfer Conditions《测定传热条件下冷却水腐蚀和结垢性的标准试验方法》.pdf
《ASTM D4778-2015 Standard Test Method for Determination of Corrosion and Fouling Tendency of Cooling Water Under Heat Transfer Conditions《测定传热条件下冷却水腐蚀和结垢性的标准试验方法》.pdf》由会员分享,可在线阅读,更多相关《ASTM D4778-2015 Standard Test Method for Determination of Corrosion and Fouling Tendency of Cooling Water Under Heat Transfer Conditions《测定传热条件下冷却水腐蚀和结垢性的标准试验方法》.pdf(5页珍藏版)》请在麦多课文档分享上搜索。
1、Designation: D4778 15Standard Test Method forDetermination of Corrosion and Fouling Tendency ofCooling Water Under Heat Transfer Conditions1This standard is issued under the fixed designation D4778; the number immediately following the designation indicates the year oforiginal adoption or, in the ca
2、se of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method provides directions for fabricating andoperating a test apparatus to simu
3、ltaneously monitor thecorrosion and fouling tendency of real and pilot cooling watersystems under heat transfer conditions.1.2 Interpretation of the results of this test method must beleft to the investigator. Many variables are involved which maynot be easily controlled or fully understood. Variati
4、ons indesign and operating conditions may produce results that arenot comparable from unit to unit.1.3 The values stated in inch-pound units are to be regardedas standard. The values given in parentheses are mathematicalconversions to SI units that are provided for information onlyand are not consid
5、ered standard.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 of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2
6、. Referenced Documents2.1 ASTM Standards:2D1129 Terminology Relating to WaterD2331 Practices for Preparation and Preliminary Testing ofWater-Formed DepositsD2777 Practice for Determination of Precision and Bias ofApplicable Test Methods of Committee D19 on WaterG1 Practice for Preparing, Cleaning, a
7、nd Evaluating Corro-sion Test SpecimensG16 Guide for Applying Statistics to Analysis of CorrosionData3. Terminology3.1 Definitions:3.1.1 For definitions of terms used in this standard, refer toTerminology D1129.3.2 Definitions of Terms Specific to This Standard:3.2.1 corrosion, nthe deterioration of
8、 the metal by reac-tion with its environment.3.2.2 fouling, ndeposition of organic matter or inorganicmatter, or both, on heat transfer surfaces that result in the lossof heat transfer efficiency.3.2.3 heat flux, nheat transfer per unit area per unit time.4. Summary of Test Method4.1 Water from the
9、system to be tested flows across a heatedtube of the desired metallurgy at a constant flow rate and heatflux. Corrosion rate is determined by weight loss while foulingtendency is determined by the deposit weight.5. Significance and Use5.1 Deposits on heat transfer surfaces reduce efficiency ofthe he
10、at exchanger affected. A method for easily determiningthe corrosion and fouling tendency of a particular water underheat transfer conditions will allow the evaluation of changes inthe various system variables such as heat flux, flow velocity,metallurgy, cycles-of-concentration, and treatment schemes
11、 onheat exchanger performance.6. Apparatus (Fig. 1)6.1 Test SpecimenA metal tube of38 or12 in. (9.5 or 12.5mm) outside diameter with sufficient inside diameter to snug-gly accommodate the cartridge heater. The tube should be cutto a length sufficient to extend12 in. (12.5 mm) from each endof the tes
12、t assembly. If both corrosion and deposition are to bedetermined, metallurgy of the test specimen should match thatof the heat exchanger being modeled.6.2 Cartridge HeaterA14 or38 in. (6.2 or 9.5 mm)diameter. Heated surface should be 4 to 8 in. (10 to 20 cm) longwith a minimum power rating sufficien
13、t to provide 110 % ofthe heat load required (see Eq 7, 8.2.2). The heater should have1This 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 an
14、d Process Use,On-Line Water Analysis, and Surveillance of Water.Current edition approved June 1, 2015. Published July 2015. Originally approvedin 1988. Last previous edition approved in 2010 as D4778 10. DOI: 10.1520/D4778-15.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orco
15、ntact 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, West Conshohocken, PA 19428-2959. United States1an unheated section o
16、f sufficient length to allow the center ofthe heated section to be placed consistently in the center of thetest specimen.6.3 Power ControllerA device to set and control thepower to the heater, such as a variable transformer, is used toadjust the heat flux in order to maintain the surface temperature
17、of the test specimen consistent with the heat exchanger beingmodeled. The power controller should be rated to maintain atleast 120 %, but not more than 400 % of the power required.6.4 Flow ControlA flow meter or a flow control devicesuch as an orifice, or both, is recommended to maintain aconsistent
18、 flow rate during the test period.6.5 Safety EquipmentA pressure or flow sensor/controlleris necessary to cut power to the heater in the event of a flowinterruption. A high temperature cutoff is recommended foradded protection.6.6 Test AssemblySee Fig. 2.7. Materials7.1 Vapor Phase Inhibitor PaperEn
19、velopes constructed ofvapor phase inhibitor paper.8. Procedure8.1 Installation of Test Device:NOTE 1All pipe is threaded 1 in. (25 mm) PVC. Heater should befused and grounded in accordance with local electrical codes.FIG. 1 Test Apparatus and Parts ListParts List:(1) test specimen (6) acrylic tube,
20、10 in. (25 cm) long by 1 in. (25 mm)outside Diameter(2) tube fitting; nylon (no metal parts) (7) Cartridge type heater (not shown)(3) reduci ng bushing, PVC(4) tee, 1 in. (25 mm) PVC(5) tube fitting, 1 in. (25 mm) tube by 1 in.(25 mm) male pipe thread stainless steelFIG. 2 Test Assembly and Parts Li
21、stD4778 1528.1.1 Placement of the test device with respect to thecooling water system is an important factor in monitoringfouling and corrosion in interpreting the test results. Foulingand corrosion are both affected by temperature. In the case ofcorrosion, the higher the water temperature, the grea
22、ter will bethe corrosivity of the water. Fouling, however, is a far morecomplex phenomenon, involving one or more of several typesof foulants, namely, particulate matter, precipitates, biomass,corrosion products, and contamination. There are five phasesinvolved in the fouling phenomenon: initiation,
23、 attachment,removal, transport, and aging.8.1.2 Several of the foulants are temperature sensitive.Precipitates, such as calcium carbonate, tend to precipitatemore rapidly as temperatures increase. Most biomasses, on theother hand, would agglomerate more rapidly at temperaturesbetween 90 and 105F (32
24、.2 and 40C).8.1.3 The test device may be installed to take its inlet waterfrom one of three locations: cold water supply to a heatexchanger, a heat exchanger outlet, or warm water return to thecooling tower. The choice of location is a function of the typeof fouling problem(s) experienced with the p
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