Autopsia Membrana de RO - [PDF Document] (2024)

American Water Chemicals, Inc. 9203 King Palm Dr. Suite A, TampaFL 33619

Tel: 1-813-621-3932 Fax: 1-813-621-4085WWW.MEMBRANECHEMICALS.COM

Membrane Autopsy Report

Date Nov/19/2008

Tests performed for Minera Yanacocha

Tests Performed by Di Yu

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Table of Content Table ofContent................................................................................................................2Introduction.......................................................................................................................3

Membrane information...................................................................................................3 Membranes autopsy tracking information..................................................................3 Background information.............................................................................................3

Procedure ofautopsy.......................................................................................................5 Shipping and Package:.....................................................................................................6 External inspection...........................................................................................................7

Fiberglass wrap...............................................................................................................7 Brine Seal and Anti Telescoping Device (ATD)............................................................ 8

WeightTest......................................................................................................................10 ATD and FiberglassRemoval........................................................................................11 Membrane Sleeves and Spacer Inspection...................................................................12 Dye Test...........................................................................................................................13 Fujiwara Test..................................................................................................................14 Foulant and ScalantCollection......................................................................................15 Advanced foulant/scalant analysis................................................................................16

SEM imaging and EDS analysis...................................................................................16 FTIR analysis................................................................................................................19

Results Discussion...........................................................................................................20 Findings and discussion................................................................................................20 Conclusion andrecommendation..................................................................................20

Release ofLiability..........................................................................................................21 Attachment......................................................................................................................22

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Introduction A membrane that was severely scaled duringoperation was submitted for autopsy analysis.

Membrane information

Membranes autopsy tracking information Element manufacturer: HWProcess Technologies, Inc. Model: HWATFE 8040 SN: 8008519 Clientand client address: Minera Yanacocha SRL, Lima Peru. Client ContactPerson: Gustavo Escobar Client Contact Phone Number: +51-1-215-2600Client Contact E-mail: [emailprotected] Date AutopsyInitiated: Nov. 19th 2008 Date Shipped: Nov. 7th 2008 DateReceived: Nov. 14th 2008 Carrier: Senores International MilleniumCargo AWC Lab Reference Number: 20081119MA Autopsy performer: DiYu

Background information 1. Describe the feed water source for theRO Unit in question?

See AWC water chemistry projection attachment.

2. List the equipment in the Pretreatment System in the orderthey appear in the process. Make the description as specific aspossible. Provide chemical manufacture and dosage level ifpossible. Merrill Crowe plant press filter barren tank Antiscalantdosing Nalco 9714 Bag filter hp pump for RO membrane system.

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3. Describe the configuration of the RO system:

1st Stage 2nd Stage 3rd Stage Array, number of pressure vessel36 24 12

Pressure drops (PSI) -13 6 -2

Elements per pressure vessel 6 6 6

Types of membrane elements in each vessel and stage

HWATFE 8040 HWATFE 8040 HWATFE 8040

Insert a chart of the RO system configuration if necessary. 4.Describe the position of the membrane element sent for autopsy:

RO Skid: Stage: Position:

5. Describe the problem of the membrane (pressure build up,performance degrading, reduced production, increased maintenancecost, etc.): Pressure build up and reduced production.

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Procedure of autopsy Based on the pre-diagnosis, certain autopsytests will be determined to be performed at the AWC Laboratory.This section contains a brief description of the tests; the ones tobe performed on this specific autopsy report are marked with .Photographs are taken throughout the autopsy to record theprogress. Any sign of abnormal condition of the membrane elementwill be reported on this document.

1. Examination of the shipping container for damage incurredduring shipment. 2. Examination of the external construction of theelement, including the

fiberglass shell, ATDs, and brine seal, for damage incurredduring operation and/or shipping.

3. Weight measurement and bubble test to estimate scale problemand integrity. 4. Examination of the feed and concentrate ends ofthe element before and after

removal of the ATDs. 5. Removal of the fiberglass shell. 6.Examination of each individual membrane sheet for evidence ofchanneling,

fouling, and/or manufacturer defects. 7. Examination of gluelines. 8. Measurements of active membrane area, for comparisonagainst the

manufacturers specifications. 9. Testing of three membranesamples with flat sheet testing setup, representing

the feed, middle, and concentrate portions of the element, fordetermination of membrane damage.

10. Perform dye testing to verify the integrity of the membranesample 11. Perform Fugiwara tests for membrane samples to identifychlorine damage if

such damage is suspected. 12. Perform SEM, EDS and FTIR analysisfor samples of the membrane sheet if

ordered by customer. 13. Collect and extract foulant and/orscalant found on the membrane surface. 14. Perform at least but notlimited to, acid test, SEM, EDS, XRD and FTIR

analysis for the foulant and/or scalant. 15. Perform BART(Biological Activity Reaction Test) for the foulant materialsto

determine presents of bio-fouling..

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Shipping and Package: Description of the shipping and packagecondition: Delivery date and time: Nov. 14th afternoon Packagematerials: paper box Packaging Description: Box was broken andmembrane was exposed. Sealing: A plastic cover wrapped themembrane. Part of the plastic cover was broken. Is the membrane wetor dry? : Half dry Additional observations (appearance, damageobserved, etc):

Membrane package was broken as delivered.

Membrane was wrapped with a plastic cover.

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External inspection

Fiberglass wrap 1. Manufacturer, Model and SN:

Element manufacturer: HW Process Technologies, Inc. Model:HWATFE 8040 SN: 8008519

2. Gel coat (crack or deformation observation): Gel coat crackedon feed side.

3. Finish (Fiberglass manufacture quality) Fiberglass surface iscovered with scale.

4. Additional note (attach photos if available)

Fiberglass close to feed side cracked Fiberglass close toconcentrate side cracked

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Membrane fiberglass was partially covered with scale.

Brine Seal and Anti Telescoping Device (ATD) 1. Brine Sealcondition (sign of degradation and leakage):

Brine seal is dirty with badly scaled surface.

2. Upstream ATD (integrity and make) Upstream feed side ATDcracked. The element sleeves formed telescope from the feedside.

3. Downstream ATD (integrity and make) Dent in two places andcracked in one area.

4. Odor and touch Light smell, dry to touch.

5. Additional notes (attach photos if available)

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Crack on feed side ATD Crack on concentrate side ATD

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Weight Test 1. Testing condition Dry/Wet:

Half dry

2. Testing results in Pound or Kg 85 lbs or 38.5 Kg

3. Additional notes (attach photo if available) Clean membraneshould have a weight of approximately 35 lbs or 19.5 Kg.

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ATD and Fiberglass Removal 1. Remove upstream and downstreamATDs.

See attached photo.

2. Inspect the feed side and concentrate end of the element.Heavily scaled and telescoping is visible.

3. Remove fiberglass wrap. See attached photo.

4. Additional notes. (attach photo if available)

Feed side ATD removal Concentrate side ATD removal

Fiberglass was partially removed

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Membrane Sleeves and Spacer Inspection 1. Number of sleeves andspacers

20 sleeves and 20 spacers

2. Condition of the sleeves Severely scaled

3. Condition of the spacers Severely scaled

4. Active membrane area and glue line (check the glue linecondition and measure the glue line width, estimate active membranearea)

The glue line is not uniform.

5. Additional notes (smell, touch, foulant, scale, attach photoif available)

Severely scaled membrane surface Severely scaled spacer

Scale collection from spacer Uneven membrane sleeve glueline

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Dye Test Three sections of membrane were cut from the feed end,middle and concentrate end of the element. Each was tested with adye solution to determine if the membrane had been damaged. A bluegreen dye solution is applied to the feed side of the membranesheet. If the membrane is damaged, dye color can be observed fromthe permeate side of the membrane. Photos of the dye at feed sideand permeate side are provided for comparison.

The dye was applied to the feed side of membrane samplescollected from feed, middle and concentrate end.

The dye was observed from the permeate side of the membrane. Thepenetration of the dye indicated structural damage of the membrane;this is probably caused by growth of scale to a thickness exceedingthe available space between the membrane leaves thereby prying themapart and tearing into the membrane.

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Fujiwara Test A sample of the membrane was subjected to aFujiwara test. A positive reaction indicated halogen damage to themembrane surface. Examples of Halogens are chemicals such aschlorine and bromine. The tests are carried out for samples fromfeed end, middle and concentrate end of the membrane element. Thephotos of the test results are insert below and all the tests werecarried out with a blank (test tube with colorless solution) forcomparison.

Tube A is 100% negative results with blank, tube B is 100%positive results, tube C is the membrane sample which has negativeresults, tube D is a virgin membrane sample with negative resultsfor comparison. The Fujiwara tests showed no chlorine damage.

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Foulant and Scalant Collection 1. Record the procedure ofcollecting foulant and/or scalant.

Large amount of half dry salt deposited on the surface ofmembrane sleeve and spacer.

2. Appearance of foulant and/or scalant Yellow color drysolids

3. Odor of the foulant and/or scalant No strong odor.

4. Viscosity of foulant The scale is solid and dry and notviscous.

5. Additional notes (attach photos if available) Collected scaledid not dissolve in 10% HCl. Neither did it dissolve in 10% NaOHsolution. However, it was dissolved in a special cleaning procedurethat adopted AWC products that specifically designed to removeCaSO4 scale.

From Left to Right: Left: scale was added in 2%C238 solution atnatural pH and 45 degree C. Middle: scale was stirred overnight inthe solution and was dispersed by C238. Right: then 2%C239 wasadded and the pH was adjusted to 12.5, the dispersed scaleparticles were dissolved.

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Advanced foulant/scalant analysis

SEM imaging and EDS analysis SEM (Scanning ElectronicMicroscopy) is used to determine topography, morphology andcrystallographic orientation of a sample. The SEM shows verydetailed images at magnifications up to 200 thousand times. EDS(Energy Dispersive Spectroscopy) analysis is a standard procedurefor identifying and quantifying elemental composition of a sample.The material is bombarded with electrons from a SEM and the X-raysproduced are measured by an X-ray dispersive spectrometer. Everyelement has its own characteristic wavelength and can be identifiedaccordingly. The scale collected from the membrane is examined withSEM and EDS analysis. SEM images and EDS spectrums, together withcomposition reporting tables are attached in the section.

Minera Yanacocha scale image at 5000X magnification.

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Minera Yanacocha scale image at 200X magnification.

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EDS spectrum showed the elementary compositions of the MineraYanacocha scale. Element Wt % At % C 9.89 18.47 O 37.11 52.01 Na0.64 0.62 Si 1.84 1.47 S 18.86 13.18 Pd 2.06 0.43 Ca 22.98 12.86 Fe0.71 0.29 Au 5.9 0.67 Total 100 100

The quantitative ratio of the elements in the scale The scale ismainly CaSO4 with small amount of Si and Fe.

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FTIR analysis Fourier Transform Infrared spectrometer (FTIR) isa powerful tool for identifying types of chemical bonds (functionalgroups). The wavelength of light absorbed is characteristic of thechemical bond. The spectrum of an unknown material can beidentified by comparison to a library of known compounds. FTIR testis carried out for the scale after it was dried at 80 degree C for3 hours. FTIR analysis indicates functionality associated with ahydrated metal salt or oxide exclusively. The sample is thereforelikely mainly a hydrated calcium and sulfur salt. The spectrum isshown below:

FTIR spectrum of scale dried at 80 degree C for 3 hours.

FTIR spectrum of a CaSO4 standard

4000.0 3000 2000 1500 1000 600.015.820 25 30 35 40 45 50 55 6065 70 75 80 85 90 95

100.0

cm-1

%T 3391.76

2209.35

1681.91

1617.87

1425.47

1097.26

666.31

4000 6503500 3000 2500 2000 1500 1000

101

25 30

40

50

60

70

80

90

cm-1

%T

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Results Discussion The customer of Minera Yanacocha had a verysevere membrane scaling problem. The membrane was autopsied at AWCand the composition of the scale was identified.

Findings and discussion The scale was mainly CaSO4. The scalehad grown so severely that the membrane sleeves had been damagedmechanically as shown in dye testing. This particular membraneelement was scaled and damaged beyond the limits of repair. Thecause of CaSO4 scale growth was that the antiscalant in use was notable to control the formation of CaSO4 scale. Tube testing in thelab of AWC antiscalants showed successful control of CaSO4 scalewhen dosed as recommended in the antiscalant projectionprogram.

Conclusion and recommendation The tested membrane was severelyscaled and damaged. If the membrane elements were scaled to suchextend, it should be replaced with new membrane elements. To cleanthe elements with less scale and damage, combination of AWC C238and C239 can be an efficient method. For future operation, acidshould be added to reduce LSI - due to the excessively high feed pHof the system, it is not possible to operate without acid dosing.AWC antiscalant A104 should be used to control CaCO3 and CaSO4scale formation for the RO system. Reviewed by Mohannad MalkiTechnical Director

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Release of Liability The Membrane Autopsy Service (The Service)was performed in accordance with the standards of care, skill, anddiligence normally provided by a professional in the performance ofsimilar services. American Water Chemicals, Inc. makes no warrantyof any kind with the respect to The Service and will not be liablefor any damages resulting from the use or misuse of The Service. Inno event shall American Water Chemicals, Inc. have any liabilityfor The Service, including, but not limited to, special, indirect,incidental, consequential, or other direct damages whether suchliability arises in contract, negligence, strict liability, orotherwise, and the Client hereby agrees to release and indemnifyAmerican Water Chemicals, Inc. against same.

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Attachment AWC antiscalant projection program report:

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