A comprehensive approach to tank design and tank equipment selection

Global AST Solutions Provider Since 1978 www.hmttank.com

A Comprehensive Approach to Tank Design and Tank

Equipment Selection

Andrew A East Director

HMT International Business Development Group


Core objectives of a comprehensive approach

• Through proper tank design and consideration of all key factors, we believe we can achieve:

– Greater than 80% reduction in emissions

– Nearly 10% increase in working capacity

– Upwards of 70% reduction in unusable inventory (adding back more than € 300k to working capital)

– Between € 250K and € 400k per tank in reduced maintenance costs every 30 years

– Improved tank safety

– Reduced risk of unplanned maintenance

– No increase in up-front capital cost


Core design considerations

• In order to design the ideal tank, key performance factors need to be considered:

– Emissions and product loss reduction (impacts on financial and regulations)

– Safety of the tank and its appurtenances

– Working capacity of the tank

– Inventory utilization in the tank (usability of your working capital)

– Maintenance considerations (to minimize both planned and unplanned)

– Up-front capital cost of the tank and tank products


Emissions Factors


Background information: Tools available to estimate emissions

• Modelling programs – Provide the capability to build virtual tanks to estimate emissions based on

AP-42 equations and loss factors – Helpful for calculating emissions of future assets for permit application – Helpful for evaluating different tank equipment options – May also be used by regulators for compliance audits

– Tanks 4.0.9d • The latest version of the EPA’s tank emissions estimation software – widely used in U.S.

– TankESP • Additional functionality over Tanks 4.0.9d, and more up-to-date with AP-42

• Physical observation and accurate surveys/measurement – Good for finding leaks; not good for annual-average extrapolation

EMISSIONS / PRODUCT LOSS SAFETY WORKING CAPACITY /

INVENTORY UTILIZATION MAINTENANCE & DURABILITY




Factors that influence tank emissions:

• Wind – Average wind speed and whether the tank is covered with a fixed roof or dome

• Floating roof penetrations and seams – Type, quantity, size and method of sealing

• Floating roof seals – Type and quality

• Temperature factors – Average temperatures on site, as well as tank color (effect of solar gain)

• Tank diameter / height

• Operational factors – Product stored, cycles per month, etc.




Capture the benefits of a fixed roof over your floating roof • A fixed roof over your floating roof eliminates the

evaporative effect of the wind, greatly reducing emissions from seals and all roof penetrations

Example of the Benefits

For a 36.6m (120’) diameter tank, storing gasoline RVP 10 in Houston, the difference between a covered and an uncovered tank is nearly 6 metric tons per year.




Self-supporting roofs yield more benefits, by eliminating column penetrations in the floating roof

• No columns means elimination of the principle floating roof emission source

• More significant impact on larger diameter tanks (due to the elimination of more columns)


For a typical 36.6m (120’) diameter IFRT with 7 columns, storing gasoline RVP 10, column well emissions account for approximately 1.4 metric tons per year (approx. 193 kg) per column)




Further reduce your emissions by eliminating leg penetrations • No leg penetrations means no leg emissions

• Fixed legs (not adjustable) can achieve this because they do not penetrate the roof.

• A suspended roof can also achieve this while still reducing inventory (heel)


For a typical 36.6m (120’) diameter tank, storing gasoline RVP 10, the difference between a leg-supported steel IFR and a cable-suspended welded aluminum IFR or one piece roof is another 1.4 metric tons per year (approx. 32 kg per leg).




Further reduce your emissions by eliminating leg penetrations • No leg penetrations means no leg emissions

• Fixed legs (not adjustable) can achieve this because they do not penetrate the roof.

• A suspended roof can also achieve this while still reducing inventory (heel)


For a typical 36.6m (120’) diameter tank, storing gasoline RVP 10, the difference between a leg-supported steel IFR and a Deckmaster GRE one piece roof is another 1.4 metric tons per year (approx. 32 kg per leg).




Common questions about full-contact roofs

Question 1: By eliminating the vapor space, are deck seam emissions eliminated? – No. Only through completely eliminating seams through seal-welding or one-piece

construction are deck seam emissions eliminated. FC roofs which use bolts, fasteners or adhesives to join components still have deck seam emissions according to AP-42 and all industry-accepted modeling programs

Question 2: If the roof panels are factory welded, does this mean I can use the welded construction loss factor – Only through completely field-welding all seams between the panels (resulting in a

single contiguous roof) does an IFR qualify as welded construction per AP-42

Question 3: Why is there a different model in TANKS 4.0.9d for IFRT and DEFRT? – Due to the way EFR penetrations are constructed, a covered external floating roof

emits less than typical steel IFR construction. For example, longer leg sleeves on a typical EFR result in lower emissions. Be sure to choose the right tank type to model.




Utilize a welded-seam or one-piece IFR to eliminate all deck seam emissions • Deck seam emissions refer to the product that escapes at the seams in

skin-and-pontoon roofs or the seams in bolted panel roofs • Seal-welded joints between panels completely eliminate this source • One-piece construction completely eliminates this source as well

Bolted construction Emissions from seams between sheets on either a pontoon roof(shown above) or bolted panel type Full contact roof

Welded construction No seams, no seam emissions

(Full contact welded aluminium roof shown above)

One-piece construction No seams, no seam emissions

(One Piece GRE roof shown above)




The impact of eliminating deck seams Skin & Pontoon

Sheet-construction

(Bolted)

Zero Deck Seam Emissions

Full Contact Panel-construction

(Bolted)

Any Welded or One-piece IFR

Emissions along each deck seam

2,334 kg/yr* 3,852 kg/yr* 0 Kg/yr

Assumptions: 36.6m x 14.6m tank, 600mm freeboard, Gasoline RVP 13, Houston, 24 turnovers/year

* Deck seam emissions only; these figures do not include emissions for seals or other appurtenances




Emissions Comparison (kg/year) for Various Tank Configurations and Various Major Markets

Assumptions • All tanks are 36.6m diameter x 14.6m high with 13.4m of working capacity (3,722,518 gal) • Stored product is gasoline, RVP 10 • Each IFR equipped with primary mechanical shoe seal and rim-mounted secondary seal • Each IFR with the exception of the welded IFR is equipped with adjustable deck legs • Emissions based on 24 tank turnovers per year • Bolted panel based on a 5’ (1.5m) x 12’ (3.66m) panel; bolted sheet is 5’ (1.5m) wide • All deck fittings “Typical” except the suspended IFR, which has no leg penetrations • Cone roofs have 7 columns

Location EFRT Domed EFRT

Cone Roof, Steel IFR, Adj Legs

Cone Roof, Aluminum

Bolted Panel IFR, Adj Legs

Cone Roof, Aluminum

Skin & Pontoon IFR,

Adj Legs

Dome, Welded or

One-piece IFR, Suspended (no legs)

Houston 9,478 820 3,646 6,542 5,879 664

Los Angeles 8,029 739 3,264 5,852 5,259 602

Chicago 8,607 552 2,379 4,251 3,822 450

Rotterdam 15,179 573 2,478 4,430 3,983 464

Moscow 5,305 447 1,882 3,351 3,014 365

Lagos, Nigeria 14,028 1,163 5,268 9,480 8,514 941

Singapore 8,544 1,061 4,787 8,608 7,732 858

Saudi Arabia 18,679 1,146 5,191 9,340 8,389 933


Utilize tight-fitting seals (that remain tight throughout the service life of the tank!)

• As defined in: – API Manual of Petroleum Measurement Standards (1997) – Chapter 19, Section 2 (Evaporative Loss Measurement) – 5.2.1 – Rim-seal Loss Factor

• Defined as: “The loss factors for average-fitting seals are applicable for

typical rim-seal conditions and should be used except when a rim-seal is known to be consistently tight-fitting (that is, when there are no gaps more then 1/8 in. (3mm) wide between the rim seal and the tank shell), in which case the loss factors for tight-fitting seals are applicable”




Utilize tight-fitting seals (that remain tight throughout the service life of the tank!)

• Poorly performing seals can be a major source of emissions as well as a safety risk


For a typical 36.6m (120’) diameter tank with a primary shoe seal, storing Gasoline RVP 10, the difference between tight fitting and average fitting seals can be a 33% reduction in rim seal emissions.

Rim Seal Factors as per API Chapter 19.2 (1997)




Impact of Emissions Savings Single-tank Comparison

Traditional Tank – 36.6m(120’) x 14.63m(48’)

with Cone Roof

– Leg-supported steel IFR

– Gasoline RVP 10, Houston

• Emissions per tank: 3,646 kg/yr

Reduced Emission Tank – 36.6m(120’) x 14.63m (48’) with Dome

Roof

– Chain-suspended, welded or one-piece IFR

– Gasoline RVP 10, Houston

• Emissions per tank: 664 kg/yr

82% lower emissions per tank through proactive design




Emissions Comparison EFRT vs Dome + Aluminator FC system

75% Reduction in Emissions This example is based on a 135’ Crude Tank in Salt Lake City, Utah. EFRT has standard deck fittings

and adjustable legs. Suspended Aluminator FC has standard deck fittings. 24 turnovers per year.


Impact of Emissions Savings Total Tank Farm Expansion

9 Traditional Tanks Total Tank Farm Emissions: 32,814 kg/yr

49 Reduced Emission Tanks Total Tank Farm Emissions: 32,536 kg/yr

444% more tanks under the same permit




Safety Factors


Safety Benefits of Ideal Tank vs. EFRT

• Suspended systems eliminate the risk of spiral collapse during maintenance


Safety Benefits of Ideal Tank vs. EFRT • Eliminate snow and ice

hazards on EFR • Eliminate drain hazards

• Recent failures: Ohio Pennsylvania Alberta Also a maintenance benefit


Utilize Chain Suspension for Major Safety Benefits

• Best available suspension technology

• Non-kinking, high-strength alloy chain

• Tight lay pattern

• Eliminates potential snagging




Chain Suspension Safety Benefit 1: Eliminate Confined Space Entry Risks

• Easy-access dome hub cover allows pinning from the top of the dome

• Simply allow the product to drain to maintenance level, then pull up the slack and pin before draining tank

• After maintenance, re-pin in low operating position any time after IFR is floating

• Eliminates confined space entry




Chain Suspension Safety Benefit 2: Set Maintenance Position at Optimum Height

• Choose optimum height - chain provides pinning flexibility

• Set maintenance position above working height to give workers full ergonomic access




Chain Suspension Safety Benefit 3: Eliminate Bottom Repair Hazards

• Not necessary to jack up IFR to get a tractor inside

• No risk of the tractor damaging support legs

• Clear and open; no obstructions to work around




If using a full-contact panel-constructed IFR, ensure it can be certified gas-free

Open-cavity panel design

• Completely open internal cavity does not impede vapor detection

Traditional Metallic Sandwich/Honeycomb Panel

• Internal cavity filled with partitions or fillers • Internal materials may impede vapor detection




Utilize a seal that can be certified gas-free



• Foam log or bag seals are prone to wear and punctures, and can trap product, creating a hazardous environment, and problems with disposal of saturated foams.

• Shoe seals or other mechanical seals comprised of stainless steel, fabrics and other materials which cannot retain or become damaged by product are preferred


Working Capacity and Inventory Utilization Factors


Factors that contribute to working capacity:

• Type of fixed roof (impacts max fill level)

• Type of internal floating roof (impacts max fill level)

• Whether IFR has legs (impacts minimum fill level)

• Whether tank utilizes a drain-dry sump or plateau bottom (impacts minimum fill level)

Through proactive tank design and careful selection of tank products,

working capacity can be maximized




Factors that impact working capacity:

EMISSIONS / PRODUCT LOSS

ENGINEERED SAFETY

WORKING CAPACITY

INVENTORY UTILIZATION

MAINTENANCE & DURABILITY

1. IFR travel constraints at the top of the tank (max fill height)

2. Depth of the Floating Roof System

3. IFR travel constraints at the bottom of the tank (min fill height)


Working Capacity Factor 1: Conditions at the top of the tank


ENGINEERED SAFETY

WORKING CAPACITY



Steel cone roof Rafter clips consume 6-8” of capacity

Aluminum Dome Mounted flush to top angle, consuming no tank capacity

Top Angle

Elevation

High-fill interference from rafters

No high-fill interference

below top angle


Capture capacity through the use of a low-profile internal floating roof

• Steel internal floaters are typically 500mm in pontoon & rim depth

• Low-profile aluminum or GRE roof depth is only 230mm or less



Recapture 270mm of working capacity using a low-profile Aluminum or GRE Full-Contact Roof

500mm

230mm


Benefits of Working Capacity Gains

• Financial Impacts – Increase income-generating capability of tank – Hold more product when you want in order to optimize market conditions

• Maintenance Flexibility – Take a different tank out of service with less worry of storage constraints

• Operational Efficiencies – Take larger deliveries at one time, reducing transactional costs per barrel

• Deferred Capital Costs in the Future – Each additional barrel of storage you capture from this asset defers the

need for future storage as you grow


ENGINEERED SAFETY

WORKING CAPACITY




• A bottom-fill system with suspended IFR allows roof to be lowered to within 300mm of the floor

• Recaptures 760mm of capacity (800m3 in a 36.6M tank)

• 6% increase in capacity


ENGINEERED SAFETY

WORKING CAPACITY



Working Capacity Factor 3: Conditions at the bottom of the tank

Assumes no mixers or diffusers; however, capacity gains can still be achieved with these in place


Utilize a “plateau” bottom and suspended roof to gain capacity and reduce inventory

• A mesa bottom displaces the majority of remaining product inventory when the IFR is in the low position (product that is normally unusable and ties up valuable working capital)

• Ideal for use when perimeter mixers or other equipment prevents the IFR from being lowered completely to the bottom




Cone roof structure impedes travel of IFR to high position by 300mm (150mm structure and 150mm safety clearance)

Dome roof only requires 150mm of safety clearance

Low-profile FC roof is only 230mm of roof

depth plus 300mm of

secondary seal

Traditional steel roof is approximately 500mm of pontoon depth and 300mm of secondary seal

Steel roof legs limiting vertical travel of IFR to within 1100mm of tank bottom

Suspended roof and plateau bottom

eliminate majority of

unusable inventory

Increase of 1,150m³ in working capacity Or 27,600m³ per year at 24 turnovers (over 170,000 barrels)

13,050m³ working capacity

Working Capacity Comparison 1 Traditional Tank vs. Dome + Suspended Roof + Plateau Bottom





Cone roof structure impedes travel of IFR to high position by 300mm (150mm structure and 150mm safety clearance)

Dome roof only requires 150mm of safety clearance

Low-profile FC roof is only 230mm of roof

depth plus 300mm of

secondary seal

Traditional steel roof is approximately 500mm of pontoon depth and 300mm of secondary seal

Steel roof legs limiting vertical travel of IFR to within 1100mm of tank bottom

Suspended roof and

drain-dry sump allow IFR to travel

to within 300mm of

tank bottom

Working Capacity Comparison 2 Traditional Tank vs. Dome + Suspended Roof + Drain Dry Sump



Increase of 1,280m³ in working capacity Or 30,720m³ per year at 24 turnovers (over 190,000 barrels)




• Re-capture lost working capital by eliminating unusable inventory

Inventory reduced by 672m³ (over 4000 barrels)

Inventory Utilization Comparison 1 Traditional Tank vs. Dome + Suspended Roof + Plateau Bottom

1,120m³ unusable inventory

448m³ unusable inventory




• Re-capture lost working capital by eliminating unusable inventory

Inventory reduced by 800m³ (over 5000 barrels)

Inventory Utilization Comparison 2 Traditional Tank vs. Dome + Suspended Roof + Drain Dry Sump



1,120m³ unusable inventory

320m³ unusable inventory


Impacts of gained capacity

• To achieve the same cumulative working capacity, a tank farm owner could operate 12 traditional tanks or 11 ideal tanks.

• Or, using the same number of tanks, the owner could increase its cumulative working capacity by over 15,000m³ (over 90,000 barrels)

• An owner building a new tank farm could spend only 92% of the capital to achieve the same working capacity.

Traditional Tank Farm Ideal Tank Farm




Maintenance Factors


Eliminate painting and coating on your fixed and floating roofs

• Aluminum domes require no painting

• Aluminum or GRE IFRs require no painting


A steel cone roof and IFR located in a coastal zone (such as Houston ship channel), will typically require painting of the cone roof and IFR every 10 years. For a 36.6m (120’) tank, this could cost approximately € 75,000




Eliminate structural steel repairs on your fixed roof

• Domes require only moderate maintenance on elastomers every 20 to 30 years (estimated € 10-15k)


A steel cone roof located in a coastal zone (such as Houston ship channel), will typically require structural repairs every 20 years. For a 36.6m (120’) tank, this would cost approximately € 150,000.




Full-Contact IFR Durability Factors

• Extruded aluminum rim section (not welded) or one-piece GRE structure – Flexibility to handle turbulence without loss of strength

• Designed to handle more than minimum API loading criteria – Built for high flow rates, turbulence, pigging operations and other

unanticipated operational loads and stresses




Seal System Durability Factors

• All stainless steel moving parts

• No springs or weights that wear

• Correctly specified hardened stainless steel for spring retention and centering of the roof, eliminating many sources of potential seal damage

• Consideration of tank verticality and out-of-roundness

• Quality fabrics

• Materials that are truly compatible with the stored product




Summary


Summary Comparison

Traditional Tank

Ideal Tank A (Dome + suspended FC + plateau bottom)

Ideal Tank B (Dome + suspended FC + drain dry sump)

Tank dimensions 36.6m(120’) x 14.6m(48’)

36.6m(120’) x 14.6m(48’)

36.6m(120’) x 14.6m(48’)

Emissions (lbs per year) 3,646 kg/yr 664 kg/yr 664 kg/yr

Maintenance cost €250 - €450k per 30 year period €10-15k every 30 years $15-20k every 30 years

Safety --- Improved over Traditional Tank

Improved over Traditional Tank

Working capacity 13,050m³ 14,200m³ 14,330m³

Additional capacity --- +1,150m³ +1,280m³

Unusable inventory 1,120m³ 448m³ 320m³

Inventory reduction --- -672m³ -800m³

Capital Cost (new tank) --- Similar to Traditional Tank Similar to Traditional Tank

36.6m x 14.6m IFRT, Storing Gasoline (RVP 10), in Houston, Texas Equipped with primary mechanical shoe seal and rim-mounted secondary seal. Annual turnover of 24 cycles.


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Date post:	07-Aug-2015
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A comprehensive approach to tank design and tank equipment selection

Education