ASTM D6807-17 Standard Test Method for Operating Performance of Continuous Electrodeionization Systems on Reverse Osmosis Permeates from 2 to 100 μS cm.pdf

1、Designation: D6807 17Standard Test Method forOperating Performance of Continuous ElectrodeionizationSystems on Reverse Osmosis Permeates from2 to 100 S/cm1This standard is issued under the fixed designation D6807; the number immediately following the designation indicates the year oforiginal adoptio

2、n or, in the case 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 covers the determination of the oper-ating characteristics

3、 of continuous electrodeionization (CEDI)devices, indicative of deionization performance when a deviceis applied to production of highly deionized water from theproduct water of a reverse osmosis system. This test method isa procedure applicable to feed waters containing carbonic acidor dissolved si

4、lica, or both, and other solutes, with a conduc-tivity range of approximately 2 to 100 microsiemens-cm-1.1.2 This test method covers the determination of operatingcharacteristics under standard test conditions of CEDI deviceswhere the electrically active transfer media therein is predomi-nantly rege

5、nerated.1.3 This test method is not necessarily indicative of:1.3.1 Long term performance on feed waters containingfoulants or sparingly soluble solutes, or both;1.3.2 Performance on feeds of brackish water, sea water, orother high salinity feeds;1.3.3 Performance on synthetic industrial feed soluti

6、ons,pharmaceuticals, or process solutions of foods and beverages;or1.3.4 Performance on feed waters less than 2 S/cm, par-ticularly performance relating to organic solutes, colloidal orparticulate matter, or biological or microbial matter.1.4 This test method, subject to the limitations described,ca

7、n be applied as either an aid to predict expected deionizationperformance for a given feed water quality, or as a method todetermine whether performance of a given device has changedover some period of time. It is ultimately, however, the usersresponsibility to ensure the validity of this test metho

8、d for theirspecific applications.1.5 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.6 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user o

9、f this standard to establish appro-priate safety, health, and environmental practices and deter-mine the applicability of regulatory limitations prior to use.1.7 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the

10、 Decision on Principles for theDevelopment of International Standards, Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2D513 Test Methods for Total and Dissolved Carbon Dioxidein WaterD859 Test Me

11、thod for Silica in WaterD1125 Test Methods for Electrical Conductivity and Resis-tivity of WaterD1129 Terminology Relating to WaterD1293 Test Methods for pH of WaterD2777 Practice for Determination of Precision and Bias ofApplicable Test Methods of Committee D19 on WaterD4194 Test Methods for Operat

12、ing Characteristics of Re-verse Osmosis and Nanofiltration Devices3. Terminology3.1 Definitions:3.1.1 For definitions of terms used in this standard, refer toTerminology D1129.3.1.2 For descriptions of terms relating to reverse osmosis,refer to Test Methods D4194.3.2 Definitions of Terms Specific to

13、 This Standard:3.2.1 cell, nan independently fed chamber formed by twoadjacent ion exchange membranes, or by a membrane and anadjacent electrode.1This test method is under the jurisdiction of ASTM Committee D19 on Waterand is the direct responsibility of Subcommittee D19.08 on Membranes and IonExcha

14、nge Materials.Current edition approved Dec. 15, 2017. Published February 2018. Originallyapproved in 2002. Last previous edition approved in 2009 as D6807 02 (2009).DOI: 10.1520/D6807-17.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at servicea

15、stm.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 StatesThis international standard was developed in accordance with

16、internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.13.2.2 continuous electrodeionization (CEDI)

17、 device, nadevice that removes ionized and ionizable species from liquidsusing electrically active media and using an electrical potentialto influence ion transport, where the ionic transport propertiesof the active media are a primary sizing parameter.3.2.2.1 DiscussionCEDI devices typically compri

18、se semi-permeable ion exchange membranes and permanently chargedion exchange media. Examples include continuousdeionization, electrodiaresis, and packed-bed or filled-cellelectrodialysis.3.2.3 current effciency, nthe ratio, expressed in percent,of the net transfer of ionized and ionizable solutes pe

19、r unit cellwithin a CEDI device, expressed in chemical equivalentstransferred per unit time, to the number of coulombs trans-ferred from an external DC power source to each electrodepair, expressed in faradays per unit time.3.2.3.1 DiscussionCalculation of current efficiency is de-scribed in 9.2.4.

20、Summary of Test Method4.1 This test method is used to determine performancecapabilities of CEDI devices with regard to extent of ionremoval, pressure/flow relationships and electrical power con-sumption at standard or nominal operating conditions, electri-cal current characteristics, and the relativ

21、e ability of the deviceto remove ionized and ionizable species when fed reverseosmosis permeate water. On this type of feed, there is consid-erable water splitting and ion-exchange resin regeneration,causing certain species to become ionized within the device,either by the electromotive force or a l

22、ocalized pH shift. Thistest method is applicable to both new and used devices.4.2 Pressure loss data is obtained. This information providesinformation relating to possible particulate plugging, fouling,or internal damage of the device. Deionization performance,extent of silica and dissolved carbon d

23、ioxide removal, concen-trating stream pH, and applied voltage are determined at apredetermined level of electrical current transfer. The ohmic(electrical) resistance is determined. This information in com-bination with concentrating stream pH provides basic designand performance information.5. Signi

24、ficance and Use5.1 CEDI devices can be used to produce deionized waterfrom feeds of pretreated water. This test method permits themeasurement of key performance capabilities of CEDI devicesusing a standard set of conditions. The data obtained can beanalyzed to provide information on whether changes

25、may haveoccurred in operating characteristics of the device indepen-dently of any variability in feed water characteristics oroperating conditions. Under specific circumstances, this testmethod may also provide sufficient information for plantdesign.6. Apparatus6.1 Description:6.1.1 The test apparat

26、us is schematically represented in Fig.1. Feed water to the apparatus may be passed through a heatexchanger or other accessories to modify or control feed watertemperature as desired. Alternately, data obtained from theoperation of the apparatus may be normalized for temperatureif normalization fact

27、ors are known.6.1.2 Feed water to the apparatus enters a holding tank(open or vented) of volume sufficient to maintain good controlof water level and solute concentrations. The tank isunpressurized, ported to be capable of occasional cleanings orsanitizations, and incorporates needed safety features

28、 such ashigh temperature and overflow protection. The tank alsoincorporates a drain valve. During operation of the apparatus,the drain valve may be used in combination with a valvecontrolling the rate of feed water to the apparatus to aid incontrol of solute concentrations, water level, and temperat

29、urewithin the tank. The tank supplies water to a recirculationpump designed to feed water to the CEDI device at a flow rateand pressure consistent with the ratings of the CEDI device. Arecirculation line with shut off valve from the pump dischargeto the tank may be incorporated as required for prope

30、r pumpoperation.6.1.3 Adjustment of feed water solute concentration is notrequired.Adjust feed water pH as required by the manufacturerof the CEDI device. Feed water to the CEDI device must bemonitored for solute concentrations, pH (Test MethodsD1293), and temperature. Solute concentration may be mo

31、ni-tored via electrical conductivity or resistivity (Test MethodsD1125) in combination with silica (Test Methods D513) andcarbon dioxide (Test Method D859) concentrationmeasurement, or alternately may be monitored for individualionic species and dissolved carbon dioxide and silica, depend-ing on the

32、 feed water supplied to the tank and the solutes ofinterest.6.1.4 Feed water provided to the CEDI device should beplumbed as specified by the supplier, with appropriate flow andpressure controls, internal recirculations, drains, interlocks,safety controls, and other features as required. Pressure at

33、 theinlet and outlet and flow rates of each the streams of interestmust be monitored (for example, deionized water stream,concentrate stream, and electrode feed stream).6.1.5 The CEDI device should be powered as specified bythe supplier, with equipment and wiring to provide appropriatesupply DC volt

34、age and amperage, controls, interlocks,grounding, and safety features. Supply voltage and supplyamperage to the CEDI device should be monitored at positionswithin the device or device assembly as specified by thesupplier.6.1.6 Streams leaving the CEDI device may be returned tothe tank via return lin

35、es.Alternately, one or more of the streamsmay be sent either completely or partially to drain viaappropriate valving if such operation provides easier control ofdesired feed water conditions. The outlet deionization stream ismonitored for the same solutes as for the feed water. The outletconcentrati

36、ng stream is also monitored for the same solutes asfor the feed water. Control of temperature is not required. ForCEDI devices with internal recirculation and “feed and bleed”features, solute concentrations must be measured at locationsthat are indicative of conditions within the CEDI module priorto

37、 mixing of recirculation flows.D6807 172FIG.1ProcessFlowSchematicD6807 1736.1.7 Feed water to the tank of the test apparatus shall beprepared using reverse osmosis apparatus. The pretreatmentrequirements for the RO are optional depending on theapplication, but should, at minimum, conform to the manu

38、fac-turers specifications for the particular system.6.2 Installation:6.2.1 Materials of construction shall be as specified by thesupplier of the CEDI device and in conformance to standardengineering practice.6.2.2 Controls and monitors should be calibrated and main-tained according with suppliers re

39、quirements and standardengineering practice.7. Reagents7.1 Specific chemical reagents are not required for this testmethod. However, chemical modification such as pHadjustment, addition of trace solutes, and the addition ofdissolved carbon dioxide may be applicable under certaincircumstances. Unless

40、 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 specifications are available.3Other grades may beused, provided it is first ascertained that the reagent is ofsufficiently hi

41、gh purity to permit its use without lessening theaccuracy of the determination.8. Procedure8.1 Start Up:8.1.1 Ensure that the tank and reagent feed reservoirs aresufficiently full, with adequate feed water rate to accommodateany losses of water caused by the positioning of the variousdrain valves. C

42、ontrol valves to the CEDI device should beclosed and the device should be unpowered.8.1.2 Turn on the recirculation pump and then slowly openthe feed water throttling valves and various valves and recir-culation devices on the CEDI device until the device isoperating at nominal or supplier recommend

43、ed flow condi-tions. Modify throttling valves to adjust inlet and outletpressures of the various device streams in accordance withsupplier recommendations.8.1.3 Operate the system with no DC power applied for asufficient time to ensure adequate removal of any residual airfrom the piping and device.

44、During this time, flows, pressures,feed solute concentrations, and temperature, should be adjusteduntil a desirable steady state device feed water condition hasbeen attained.8.2 Electrical Property and Deionization PerformanceMeasurements:8.2.1 Turn on the DC power supply to the CEDI device,beginnin

45、g at a low voltage. Raise the applied DC voltage untilDC amperage between electrode pairs attains a pre-determinedelectrical current efficiency, typically below 20 %, but do notapply a voltage or amperage that exceeds suppliers recom-mendations (consult supplier for recommended values). Cur-rent eff

46、iciency should be calculated as described in 9.2 using asNdi the total combined normality of all ionized and ionizableconstituents (for example, including all ionized species, anddissolved carbon dioxide as monovalent bicarbonate ion anddissolved silica as monovalent bisilicate ion).8.2.2 As the int

47、ernal media electroregenerates, pH shifts andnon-steady state concentrate concentrations should be ex-pected. Therefore, recirculation flows, flows to drain, andvoltage should be controlled so as to avoid exceeding suppli-ers recommended operating parameters and to speed theattainment of steady stat

48、e conditions.8.2.3 Continue to operate until steady state is achieved,including applied voltage, concentrate stream electricalconductivity, deionization performance, silica and carbon di-oxide concentrations at the deionizing and concentratingstream outlets, and deionizing and concentrating stream f

49、lowsand inlet and outlet pressures. Since electroregeneration of theactive media can be a gradual process, it will typically take 4to8htoreach steady state. Pressures should be expected tochange as the internal media electroregenerates. Do not exceedsuppliers specifications for pressure differentials.8.2.4 Measure and record DC voltage, DC amperage, devicefeed water temperature, deionizing stream inlet and outletconductivity or resistivity, and deionizing stream flow rate.Also, measure and record feed pH, feed and deionizing streamand concentrating stream outlet silic