February 16 2016 Lorri Grainawi Director of Technical Services Steel Tank Institute Who and What is STISPFA Trade association of 186 fabricating and affiliate companies of steel construction products ID: 935142
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Storage TanksMaintenance & CorrosionFebruary 16, 2016
Lorri GrainawiDirector of Technical ServicesSteel Tank Institute
Slide2Who and What is STI/SPFA?Trade association of 186 fabricating and affiliate companies of steel construction products STI members build a significant majority of shop-fabricated underground and aboveground fuel storage tanks
Slide3What does Steel Tank Institute do?UST & AST tank technologiesIndustry standards, RP’sQC of tank fabricators Information resourceTankTalk, Tank MishapsCertification of Testers & Inspectors
Slide4Who & Where is the Typical Steel UST Fabricator?Family owned2nd & 3rd generation commonLocated throughout North America62 tank factories in US
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Slide6History of Storage TanksAll Single Wall, Steel, No Corrosion protection1969 – sti-P36
Slide7History of FuelsLeaded Gasoline, Diesel fuel composed 5000 ppm sulfur No Biofuels7
Slide8History of RegulationsUS Clean Air Act, 19631st federal vehicle emission standards1968EPA UST regulationsEffective 1988Corrosion protectionSpill & overfill
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Slide9History EnginesGone are the days of big engines, low gas mileage and high emissions!9
Slide10All UST’s have Corrosion Protection
Slide11All USTs - Secondary Containment11
Slide12About changing fuels:ethanol blended gasoline Nearly all gas today is blended with ethanolEPA approved E15 in cars 2007 and newerAbout 1% of today’s cars run on E85 (85% ethanol/15% gasoline)
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Slide13Engines TodayHigh pressure fuel injectorsFuel injected into cylinders 35,000 psiHigher pressureFiner fuel mist Lower emissions13
Slide14Regulations Today ULSD – 2006BiofuelsEPA UST regs require maintenance equipment14
Slide15Fact or Fiction?ULSD holds more water?15
Slide16Fact or Fiction?ULSD holds more water?Fiction!The manufacturing process used to make ULSD results in a diesel fuel that actually holds less water in suspension than “older” higher sulfur fuels.
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Slide17History Corrosion Related to ULSD2006- ULSD2007 – PEI forum2008 – 2009 ASTM committees2010 – Clean Diesel Fuel Alliance17
Slide18History2012 – Battelle Report2014 – CRC2015 – EPA study and report (hopefully!)18
Slide19Fact or Fiction?ULSD is more corrosive than higher sulfur diesel fuels.19
Slide20Fact or Fiction?ULSD is more corrosive than higher sulfur diesel fuels.Fiction! Any petroleum fuel is noncorrosive to metals. In order for corrosion to occur, a conductive material like water must be present in the fuel system. In addition, fuel additives, contaminants, etc., may react with components and create a corrosive situation.
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Slide21Problem exists!21
STP column pipe inside FRP tank
Slide22In service less than one year STP Column Pipe
Slide23Pump connection corroded thru
Slide24CDFA hires BattelleAPIFord Motor Co.RailroadsPEINATSOPMAA and others24
Slide25Battelle Investigation - 20126 FRP tanks Tank age: 14- 14 years oldThroughput: 6500 gallons – 29.000 gallons Capacity: 6000 gallons to 17, 265 gallons 25
Slide26Inspection ProcessVapor Sampling: SKC TubesTested for carboxylic acids and formic acid analysis by GC-MS (CAS Method 102)
Slide27Water Bottom Sampling~1-2 Liters of water bottom sample/siteBottom sedimentConsolidated from multiple risersBacon Bomb triggered by bottom of tank
Slide28Inspection ProcessFuel Sampling1 gallon of diesel sample/siteConsolidated from multiple risersBacon Bomb with string to trigger collection within fuel column
Slide29Inspection ProcessDisassembled SystemCollected scrape, wipe, o-rings, and other corrosion samplesFouling investigation process by 2 labs
Slide30Site NY-2 (Feb 18)
Slide31Site CA-3 (Feb 23)
Slide32Liquids and Vapor SummaryLow biodiesel levels3 fuels failing NACE ratingsSulfur content 5.9 – 7.7 ppmpH 3.5 to 5.33 NACE failures had pH of 3.5 – 3.8
Slide33Liquids and Vapor SummaryTrace amounts of ethanol at 4 sitesAcetate (dominant acid) and formic acid detected in all water and vapor samplesGlycolic and other acids foundAcetobacter dominant organism found at 3 sites
Slide34Other elements found Significant levels of sodium and chlorides (4 of 6)Significant level of potassium (3 of 6)Significant level of magnesium (4 of 6)Others:Methyl vinyl ketone, phthalate, glycol and dioxane
Slide35Conclusions of Battelle ReportBattelle hypothesize: Acetic acid was created by Acetobacter microorganisms and ethanol, thus causing the corrosion.
Slide36Fact or Fiction?ULSD requires good lubricity and corrosion inhibitors to prevent unacceptable engine wear
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Slide37Fact or Fiction?ULSD requires good lubricity and corrosion inhibitors to prevent unacceptable engine wearFact! As necessary, additives to increase lubricity and to inhibit corrosion are added to ULSD prior to being distributed.
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Slide38EPA Research - 2015Concern about possible releasesOverfill limiters, automatic shut-offs and otherWorked with CRC members to develop test planSimilar approach to first Battelle study38
Slide39Changes from Battelle R&D 2007, RFS expandedEPA considered ethanol and biodiesel as possible causes, while not eliminating other possibilities39
Slide4042 sites- 24 FRP, 18 STEEL40
Slide41Diverse populationAGE: 1 to 29 yearsCAPACITY: 5,000 – 20,000 gallonsOWNERS: Gov’t, retail and fleetNUMBER SITES OWNED: One to multiple41
Slide42Vapor TestingAcids, humidity
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Slide43Fuel Testing43
Water content
Acids
Particulates
Biofuel
Conductivity
Corrosion Rating
Chromatography
Slide44Water Bottom TestingWater bottoms tested for: ethanol, methanol, glycerinacids, cations
pH level44
Slide45Equipment AnalysisIf equipment was removed, it was visually examined and photographedPristine condition!
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Slide46What did they find?EPA report is not yet finalizedAcids: formic, acetic, propionic and lacticMethanol, ethanol and glycerolHumidity levels relatively high – average 68%Failed NACE ratings on percentage of fuelsGasoline
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Slide47What did they find?47
Slide48Regulatory requirementsThe corrosion is not a violation of federal UST requirements.UST owners and operators must ensure the corrosion does not impact the functionality of equipment, or lead to releases into the environment. Contact your state implementing agencies, which may impose additional requirements that may be more stringent.
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Slide49Fact or Fiction?ULSD requires good lubricity and corrosion inhibitors to prevent unacceptable engine wear
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Slide50Fact or Fiction?ULSD requires good lubricity and corrosion inhibitors to prevent unacceptable engine wearFact! As necessary, additives to increase lubricity and to inhibit corrosion are added to ULSD prior to being distributed.
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Slide51Steps ForwardCRC – Coordinating Research CouncilVoting members are major oils and automotive groupsMy sense - Solidarity Enough field tests51
Slide52Lab Test – Isolate VariablesCorrosion inhibitorsOxygen levelsHumidityWater absorption52
Temperature
Fungi
Bacteria
Biocides
Slide53Ethanol Concerns53
Slide54Ethanol studiesIntermediate Ethanol Blends Infrastructure Materials Compatibility Study, M. Kass, ORNL TM-2010/326, 2010. Preliminary Compatibility Assessment of Metallic Dispenser Materials for Service in Ethanol Fuel Blends, ORNL/TM- 2009/286. Elastomer Compatibility to a Gasoline Standard Containing Intermediate Levels of Ethanol, M Kass et al., 21st International Fluid Sealing Conference, 2010. Dispensing Equipment Testing with Mid-Level Ethanol/Gasoline Test Fluid
, Document No. 10807, NREL/SR-7A20-49187. Boyce and Chapin, 2010.
Slide55Ethanol studiesAnalysis of Underground Storage Tank System Materials to Increased Leak Potential Associated with E15 Fuel, EPA report Compatibility Assessment of Metallic Dispenser Materials for Service in Ethanol Fuel Blends up to E85, ORNL Technical Memorandum Analysis of Steel Underground Storage Tank failure storing Ethanol, 2013Compilation of failure reports, ASTSWMO, 2013
Slide562013 study: DW FRP tank, 23 years
“UST fibers exposed due to chemical exposure.”
Slide57“The tanks were so brittle that they split in two when lifting lugs were used.”
2013 study: 23-year old FRP tank storing E10
Slide58DNV studySteel and ethanol: CompatibleExposure time 2 months at ambient temperature.95% Fuel grade ethanol (FGE) - nitrogen purge: corrosion rate: 0.008 to 0.02 mm/y90%gasoline-10% FGE, nitrogen purge: 0.0025 mm/yearCorrosion below detection limit70% gasoline-30%FGE, air purge90% gasoline-10% FGE, air purge 95% FGE , air
purge
Slide59ORNL ethanol study All materials which could be in UST system were testedMetals: negligible corrosionElastomers (gaskets, seals, etc.): some not compatible with E15.Found that increased swelling caused important property loss.Plastics included older and newer FRP resinsResins exhibited 7%-25% swell Volume swell corresponds to material softening
Slide60“Evaluated
four resin types representative of those used in legacy and modern FRP UST construction:
“The pre-1990 resin was severely damaged from exposure to CE25a, along with one of the post-1990
resins.
“The
addition of glass to the test samples may prevent swelling
.”
ORNL ethanol study, cont.
Slide61ORNL ethanol study, cont.Residual fuel in the polymer is likely responsible for the material softening.Even after drying at 60°C for 65 hours, some level of fuel was retained within the plastics. “The highest property changes observed were for nylon 11, nylon 12, PETG, PP, and vinyl and polyester resins” “Volume
& softening of acetals, nylons, PBT, PETG, & thermoset resins increased to varying degrees with exposure to ethanol”. “…mild steel…and stainless steel were found to be essentially immune to corrosion…”
Slide62“The study showed negligible corrosion of either steel or aluminum immersed in either CE10a or CE17a.” (Aggressive blend of 10% and 17% ethanol.)
ORNL ethanol study, cont.
Slide632010 study
Testing with mid-level ethanol/gasoline:“In this study, there was no noted effect on metallic parts of equipment.”
Slide64Corrosion in sumps
Slide65Steel tank interior – E85
Slide66Exterior mold on ethanol tanks
Slide67Close-up area
Slide68Best management practice:IMPROVE STORAGE TANK MAINTENANCE
Available
at www.steeltank.com
Keeping Water Out of Your Storage System
STI R111, Storage Tank Maintenance
Slide69Check for water69
Determine lowest end of tank
Use stick with paste
Frequency?
Keep records!
Look for trends
Remove water and
Test for microbes
Slide70Microbial contamination signsErratic tank gauge readingsFrequent replacement of valves, hoses, etc.
Rotten-egg odor70
Slide71Monitoring: BiofuelsDaily monitoring of tanks with ATGs and water level sensorsIf gauge shows water one day but not the next, may indicate water has been absorbed into ethanol-blend or biodiesel fuelIf ATG records are inconsistent, test with water paste or bottom sample71
Slide72Microbial contaminationDegradation can occur:
Fiberglass reinforced plasticTank linings & coatingsRubberMetal
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Slide73Visually check Fuel73
Clear
& Bright
Slide74Contamination Contaminants like salts in water may:Degrade fuel Cause fuel additives to leave fuel and enter water
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Slide75Monitoring & detection methodsTank bottom sampling“Bacon bombs” collect samples from tank bottom75
Slide76Keep Spill Box Clean & DryUS EPA regulationsWalk through inspectionEvery 30 daysAll spill prevention eqpt76
Slide77EPA RegulationsInspect spill prevention Inspect overfill preventionEvery 3 yearsStarting Oct 13, 201877
Slide78Inspect Fuel FiltersIf changed frequently (< 6 month intervals), Check for white “hair-like” fibersThese are signs of fiberglass degradation. If you suspect degradation, have your filters analyzed by a laboratory.
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Slide79Thorough cleaning may be required79
Slide80Lorri GrainawiSTI/SPFAlgrainawi@steeltank.com(847) 550-3831February 16, 2016
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