Storage Tank Maintenance for
Todays New Fuels
Lorri Grainawi
Director Technical Services
Steel Tank Institute
STEEL TANK INSTITUTE/STEEL PLATE FABRICATORS ASSOCIATION
Who and What is STI/SPFA?
Association of 186 fabricating and affiliate companies
of steel construction products shop-fab tanks, field
erect tanks, pipe, pressure vessels and other special
fabricated products
STI members build a significant majority of shopfabricated underground and aboveground fuel
storage tanks
What does Steel Tank Institute do?
UST and AST tank
technologies
Industry standards, RPs
Quality control of tank
fabricators who build
tanks to STI specifications
Information resource
TankTalk, Tank Mishaps
Certification
Over 350,000 STI Labeled USTs
STI AST Technologies
Fuel Cleanliness Important
Newer
Engines
Changing Fuels
Govt
Regulations
Industry Practices
Fuels
New
Engines
Revised
Standards
Industry
Practice
Regs
Result
Increased
Need for
Storage Tank
Maintenance
Fuels
New
Engines
Revised
Standards
Industry
Practice
Regs
Air Quality
To produce cleaner burning fuel oxygenates
were added to gasoline
To produce cleaner burning fuel, sulfur was
removed from diesel
Note changes were for Air Quality, not fuel
quality
10
Gas Mileage
Automobile
manufacturers
required to increase
overall mileage
Regulation resulted
in engine changes
State Regulations
Some states, like
MO, regulate
water bottoms in
tanks
1 inch maximum
water allowed
Fuels
New
Engines
Revised
Standards
Industry
Practice
Regs
Clean Air & Newer Engines
Engine exhaust must be cleaner to meet
EPA Clean Air regulations
Now achieve > 95% reduction in overall
exhaust emission levels
Significant design modifications
Fuel injection systems instead of carburetors
Reduced clearances injection system
Greater timing precision required
14
Clean Air & Newer Engines
Particulates can clog injectors
On-board filtration systems now include
water separators and filters to 2 microns
Clear and bright just starting point
Total water of 200 mg/kg
Total particulate count 18/16/13
Filters should have Beta ratio
2 means filter removes 50% particles
15
Fuels
New
Engines
Revised
Standards
Industry
Practice
Regs
Fuel Production & Distribution
US terminal capacity reduced, while fuel
consumption increased.
Therefore, more fuel moves distributed at
faster rate = less time to settle out
before final delivery.
Industry moving to shared delivery
infrastructure, so individual companies
have less control over product.
17
New Fuels
Biodiesel
Ethanol
ULSD
Additives
Future
Fuels
Changing Fuels
Changing to ULSD (Ultra Low Sulfur Diesel)
significantly changed fuel:
Had a significant impact on solids formation
Peroxide formation is more of a problem
Wax precursors and solids propagators more
pronounced
What does all this mean? Generally, there may
be more particulate and sediment in ULSD
compared to LSD
About changing fuels:
ethanol blended gasoline
Nearly all gas today is
blended with ethanol
EPA approved E15 in
cars 2007 and newer
About 1% of todays
cars run on E85 (85%
ethanol/15% gasoline)
20
Fuel Additives Are They Necessary?
Gasoline and diesel fuel contain many additives
essential for good fuel quality and necessary for
good fuel stability and performance:
14
Stability additives -- prolongs fuel life, limits
oxidation/degradation and metal interaction
reactions;
Corrosion inhibitors -- protects metal in fuel
systems;
Conductivity improvers lessens static
electricity, prevents fires/explosions;
Fuel Additives Are They Necessary?
14
Lubricity improvers provides needed
lubrication in diesel injection systems;
Biocides preventive use minimizes bugs
which may lead to corrosion;
Anti-foulant additives counteract fuel
degradation & contaminant interactions that
lead to filter/injector plugging
Additives generally added at terminals
May get used up along the way
Fuel Degradation
Water is fuels
enemy and must
be managed
Stability additives
slow degradation
Biocides kill bugs
Corrosion
inhibitors
Fuels
New
Engines
RevisedSt
andards
Industry
Practice
Regs
ASTM International - American
Society for Testing and Materials
ASTM is the primary
organization in the
US for developing
fuel standards
Other international
organizations exist in
Canada, Europe (ISO,
BSI, etc.)
Consensus Organizations
Members work together to produce Fuel
Specifications such as ASTM D975 for diesel fuel
and ASTM D4814 for gasoline.
Standard Test Methods (STMs) are needed so
testing for properties is done consistently
D7548 STM for Determination of Accelerated
Iron Corrosion in Petroleum Product
Majority vote required, and all concerns and
negative votes are thoroughly discussed.
Consensus process can be lengthy!
ASTM requirements
ASTM requirements intended to be met
at terminals
Some discussion on developing a
standards for fuel that is fit for use
New proposals emphasize industry
practice:
A good industry practice is to drain any free
water from a storage tank before the fuel is
transferred further
Water and Sediment limits
D975
Diesel fuel shall be visually free of undissolved
water, sediment, and suspended matter.
Max 0.05% dissolved water & sediment
4806 Ethanol
Visibly free of suspended or precipitated
contaminants (clear & bright)
Factors Affecting Water & Sediment
Temperature
Water drops out at higher temperatures
Sediment can also form at different temps
Humidity
Biofuels absorb water from air
Factors Affecting Water & Sediment
As fuels age,
degradation
occurs and
sediment forms
Cleanliness Emphasized
One ASTM proposal to update
informational language on water and
sediment states,
Water is virtually everywhere and
exists in multiple forms from solid, to
liquid, to vapor
it is critically important that fuel be as
free from water (and particulates) as
possible prior to its introduction into
the engines fuel system.
ASTM D975 Appendix
Available fuel additives can improve the
suitability of marginal fuels for long-term
storage and thermal stability,
Most additives should be added at the
refinery or during the early weeks of
storage to obtain maximum benefits.
Contamination levels in fuel can be
reduced by storage in tanks kept free of
water,
Water monitoring
Operations and maintenance procedures
for water monitoring and removal have
been a recommended practice for over
thirty years.
33
Fuels
New
Engines
Revised
Standards
Industry
Practice
Regs
INDUSTRY RPS
Coordinated Research Council
Diesel Fuel Storage & Handling Guide, #667
www.crcao.org
Clean Diesel Fuel Alliance
Guidance for Underground Storage Tank Management
at ULSD Dispensing Facilities www.clean-diesel.org
Petroleum Equipment Institute
RP900: UST Inspection and Maintenance
www.pei.org
US EPA
http://www.epa.gov/oust/pubs/ommanual.htm
Industry standards: biodiesel
NREL, Biodiesel Handling and Use Guide
Higher concentrations = reduced stability
Check for compatibility (steel is compatible)
36
STI R111, Storage Tank Maintenance
STI R111, Storage Tank Maintenance
Recordkeeping
Changing Fuels
How to Monitor Tanks
How to Remove Water and
Contaminants
Change of Service
Verify Monitoring Eqpt Operational
Checklist
Todays factors affecting tank
maintenance
Common installation and maintenance
procedures contribute to water
accumulation:
Open vents
Low fill areas
Sloped tank installations
39
What works Best?
Microbial contamination
Reddish, scaly, gritty deposits: corrosion
and/or silt in tank
Black or brown deposits: water
contamination has degraded the fuel
Work with your
supplier to test
fuel/water and
determine treatment.
41
Microbial Contamination
As microorganisms grow and thrive, they
form a slime
Over time, sludge is formed from the
slime
Clogs may not be visible, unlike mold
growth
Sludge breaks off and clogs fuel filters and
small openings throughout entire system
42
Microbial warning signs
Short filter life or flow slowed to 3-5 gpm
Erratic tank gauge readings
Frequent replacement of valves, hoses, etc.
Rotten-egg odor from digestion of fuel by
microorganisms
Chemically-altered fuel
components attack:
Rubber
Fiberglass reinforced
plastic
Tank linings & coatings
Metal
43
Contamination
Contaminants like
salts in water may:
Degrade fuel
chemical structure,
yielding substances
detrimental to system
components
Cause fuel additives
to leave fuel and
enter water
44
Monitoring tanks: all fuels
Inspect tanks at least monthly
Check for water as often as possible
If water is present, remove within 30 days
Best monitoring: automatic tank gauging (ATG)
system
Some floats may not work with alcohol fuels
Simpler, less expensive: appropriate water paste
on gauge stick
Water-sensitive filters and watch for slow
fueling
45
Monitoring tanks: ethanol
When ethanols water absorption capacity
is reached, excess water separates, causing
two distinct layers of product:
Top layer: lower octane gasoline, possibly out of
spec
Bottom layer: ethanol/water mix, dispose of
Resulting water bottom:
Storage system exposed to ethanol
concentrations greater than 10%
46
Monitoring & detection methods
Tank bottom sampling
Bacon bombs collect
samples from tank bottom
47
Monitoring & detection methods
Fuel filters
Use water absorbing filters to detect slowed
fuel dispensing; filters expand when absorbing
water
48
Monitoring & detection methods
Fuel samples from nozzle
Visual evaluation by examining fuel caught in
clear glass container
Clear & Bright test
49
Monitoring & detection methods:
Biofuels
Use recommended inspection and
maintenance schedules
Daily monitoring of tanks with ATGs and
water level sensors
If gauge shows water one day but not the
next, may indicate water has been absorbed
into ethanol-blend or biodiesel fuel
If ATG records are inconsistent, test with
water paste or bottom sample
50
How to remove water and
contaminants from storage tanks
Multipoint water pumping
Fuel filtration/polishing
Non-entry tank cleaning
Physical entry tank cleaning
51
Leak Detection & Monitoring
NWGLDE, National Work Group on
Leak Detection Evaluation
Independent group consisting of 11 state and
federal EPA employees
New protocols for leak detection
In future, leak detection equipment will
have to be rated for ethanol use
Preparing tanks for changes in fuel
type
Tank and related dispensing equipment
must be thoroughly cleaned
53
STI R111s monthly inspection
checklist
Inspect tanks monthly
Checklist on pages 1213 of R111 document
Covers all inspection
recommendations
Your record of tank
inspection and
maintenance
54
Inspection and Maintenance of
Tank Systems
STI Webinar
February, 2015
www.steeltank.com
Tank Talk STI Publication
August 2014, Todays New Engines, R Gault
Thank you!
Lorri Grainawi
STI/SPFA
944 Donata Court
Lake Zurich, IL 60047
Web: www.steeltank.com
Phone: 847/550-3831
E-Mail: lgrainawi@steeltank.com
AUGUST 2010
STI/SPFA
SLIDE 57
