Storage Tank Farm Piping

TANK FARM PIPING

Raju Pundra

Tank• Tank is used to store the fluids.• Tanks are classified based on

-Nature of the product to be stored (atmospheric, low pressure & Medium Pressure)

- Operating Temperature (ambient & Low Temperature)

- Type of construction (above ground or under ground & double wall)

The basic Tank designs are

• Fixed roof (vertical & Horizontal)

• External floating roof

• Internal floating roof

• Domed external (covered) floating roof

• Medium Pressure

• Fixed roof tank Used to store products which are not vaporize at

ambient temp. Roof is of Cone or Dome shaped. Used when True Vapor Pressure (TVP)<1.5 psia at tank operating temp.

Ex. Gas oil, Lubricating oil This is mainly 3 types (a.) Non-pressure fixed roof tank – used for

storage at atmospheric pressure and provided with open vent.

(b.) Low pressure and (c.) high pressure used for storage at low and high internal pressure or vacuum respectively and fitted with pressure/vacuum relief valves (breather valve).

• Floating Roof - No space for evaporation for liquid. TVP < 11.1 psia . Ex. Light products, kerosene & crude oil.

• External Floating Roof –works at atmospheric pressure. Normally preferred only for dia of tank is >=15m

-consists of open topped cylindrical steel shell equipped with a float roof which is having deck, fittings & rim-seal system. Floating decks are pontoon and double deck type.

• Internal Floating roof tank protect the floating roof from external elements

like Snow, Rain, Air, Lightning

• Domed External Floating roof tank

• Medium Pressure Tank

Spherical shaped storage tanks are used to store products with high vapor pressure in very large capacity, 10 times larger than bullet tanks [(horizontal) which are large cylindrical pressure vessel used for LPG .Working pressure 1-70 bar.

• Mounting 1. Form establishing to the grounds a. Earth (Compact Fill) Foundation -It minimizes the tank settlement. b. Concrete Foundation c. Concrete ring wall d. Concrete slab Foundation 2. Form that lay under the ground a. Underground laying b. Wearing ring laying

GROUPING

• Class A and/or class B petroleum products can be stored in same dyked enclosure. If class C petroleum is stored with class A and/or class B all safety stipulations applicable for class A and/or class B shall apply.

• Excluded petroleum shall be stored in a separate dyke enclosure.

• Tanks shall be arranged in maximum two rows so that each tank is approachable from road surrounding the enclosure. For 50,000 cu. m. capacity and above shall be laid in single row.

TANK HEIGHT• - Height from tank bottom to top kerb angle

for cone roof tanks• - Height from tank bottom to top of tank

shell for floating roof tanks• Tank Height shall not exceed One and Half times

the Dia of tank or 20 M whichever is less.

• Tank foundation height is more than 300mm and normally decided by the pump suction head line.

Capacity of tanks located in one dyked enclosure - For floating roof tanks 120,000 cu.m - For fixed roof tanks 60,000 cu.m -In case of combination of above two consider

as fixed roof tank only.• Dyked enclosure should be able to contain the

complete contents of the largest tank in tank farm.

• The height of dyke is in between 1 to 2 M above average grade level . However for excluded petroleum products min height is 600 mm.

• Dyke capacity = Maximum Tank's capacity + Each Tank's Foundation volume + (5-10% extra)

Sleeper tank piping arrangement

Slope

Sump pit

Cross over

• Piping that do not connect with Tank within Dikes must not pass Dike inner space.

• Available inspection designs so that do not pierce Dike except Pump Suction piping.

•  Pump Suction piping that pierce Dikes acts unreasonable Load by thermal expansion to Pump Nozzle , this is minimized by providing Flexible piping (expansion loop).

• The first valve that is laying pipes with Blind Flanges placed directly to Tank Nozzle.

• Emergency shut down valve should be close to tank.

HALL

HLL

LLL

LALL

Circular Stair way

• When calamity occurrence tank upper part is exploded, to minimize the  damage keep interval (gap) without Stair way or ladder should be in the connecting the platform and stair way.

• same direction of tank yard main aisle or road side.

Nozzle Orientation

Tank settlement

In case of settlement the following design should be consider

• Providing Horizontal Loop or L-form type arrangement

• Flexible Tube establishment (below 6“ & pressure below 15 ㎠ / ㎏ )

• Expansion Joint establishment (in case design pressure is high or large pipe Size )

• Adjustable Type Support establishment (first Support close to Tank Nozzle)

Thank You