TANKSWhat is a Tank?Tank is a container used to receive and store the liquid materials.Normally made out of metallic plates.

TANKSTanks are Storage vessels. In Industries tanks are used toReceive materialStore materialSupply material when needed

Tanks are important for continuous operation without interruption.

TANKSTanks are generally atmospheric vessels.

They are designed to withstand mild pressure and vacuum conditions.

For handling high volatile and low flash material low pressure tanks are used.

TANKSPetroleum products classification

Products are classified based on flash point

Class A < 5 CClass B> 5 and < 35 CClass C > 35 and 65 CUnclassified > 65 C

TANKSType of tanksFixed roof tanks Used for Class C and Unclassified materials2. Floating roof tanksUsed for Class B materialsInternal float roof with fixed roof tanksUsed for Class A material

TANKSFixed roof tank Tank shell with a roof on it, is called Fixed roof tank

Fixed roof tanks also called Conical roof tanks

Used to store material with less volatility

TANKSFixed roof tankMan holeOutletInletFoam injectionTank level gauge/dipPV valveWater sprinkler

TANKSFixed Roof TankAdvantages:- Fixed roof tanks are less expensive - Less maintenance.Disadvantages:- Breathing loss- Explosive mixture of air and hydrocarbon between the liquid surface and tank roof

TANKSFloating roof tankUsed to store liquid products with high volatility.Tank roof floats on liquid surface.

There is contact between roof bottom and liquid surface.

Tank roof will move as the level in the tank increases and decreases.

TANKSOutletShellSealBleed valveManholeRoof drainInletTank gaugingFoam InjectionRoof support legs

TANKSFloating roof tankAdvantages:- No vapor space, hence no breathing loss- less Hydrocarbon vapors are vented to atmosphere.Disadvantages:- Expensive -High maintenance cost.

TANKSInternal floating roof tank

Floating roof tank with fixed roof on top of it. The vapor space between fixed roof and conical roof is buffered with inter gas.

These tanks are used to handle highly volatile materials which are hazardous in nature.

TANKSInternal floating roof tankMan holeOutletInletFoam injectionTank level gauge/dipPV valveWater sprinklerN2 injectionFloatshell

TANKS

Advantages:Compatible with all products, including 100% aromatics.Reduce emissions of Volatile Components

Disadvantages:ExpensiveHigh maintenance cost.

TANKS

In GFPC we use;

Fixed roof tanks - Paraffin, LAB, HAFloating roof tanks KeroseneInternal floating roof Benzene, Slop oil

TANKS

TerminologiesTank nozzles ManwayGauge hatchPVRVNitrogen purge controlPump out pitRoofPontoon Roof drainRoof legsDatum plateLevel indicatorsSprinkler systemFoam pourerDyke wall

TANKSTank Nozzles:These are flanged connections provided at the tank bottom to connect the incoming and outgoing pipelines.

Manways:These are the openings provided in the tank bottom shell and roof. They are used for entry in to the tank for any inspection and maintenance.

TANKSGauge Hatch:Provided at the tank roof. It is a pipe running up to the bottom of the tank. This is used to check the level in the tank and to collect sample from the tank.PVRV:Pressure and Vacuum Relief Valve mounted on the tank roof to relieve both pressure and vacuum.

TANKSNitrogen purge control:Fitted at the tank roof to maintain inert atmosphere by that stored material quality not deteriorated. Also by maintain slight pressure vaporization of stored product is prevented.Pump out pit:Small pit built inside the tank for pumping out all stored material during tank emptying when required for tank maintenance

TANKSRoof:It is a top cover of the tank fitted either on fixed position or floating position to maintain the quality of the stored products.It also prevents loss of vaporization of material and stops contamination like rain water and foreign materials.Pontoon:Fitted at the roof periphery of floating roof, uniformly divided compartments (boxes) to achieve good buoyancy while roof floats also create good effective insulating layer against suns heat.

TANKSRoof drain:To drain out accumulated water (rain water) from the tank roof a special roof drain is providedRoof legs:Also called roof supports fitted at the roof to rest incase of tank maintenance repair.Normal operation these legs move along with roof.

TANKS Datum plate:Is a plate welded at bottom plate of the tank where the reference height of the tank is calculated.Reference height means measured height between datum plate and the maximum filling level of the tank.

Level indicators:Device fitted in tanks for indicating the liquid level as well as alarms like low & high levels. It estimates the volume of stored liquid and available volume for filling.

TANKSSprinkler system:A fire fighting device fitted around the tank peripheral to spray water in order to cool down in the event of adjutant (near by) tank fire.

Foam pourer:Fire fighting device fitted at floating roof tank rim in order to provide access to blanketing foam in the event of fire.There are other foam injection systems used in fixed roof tank.Sub surface ----------- Injected at tank bottom.Top injection ---------- Injected at top of the tank.

TANKS Dyke wall:Also called bund wall to retain the oil incase of fire and sudden release of liquid during tank burst or boil over.Dyke walls normally made around grouping of tanks or individual tanks depends on material stored.

TANKSTank GaugingDIP TAPEA device with graduated tape with hook at the end to measure the depth of the liquid level to check or compare the automatic gauge system reading.DIP BOBA device which is attached to the hook at the end of the gauge tape to weight the tape ands carry it through the product.

TANKSDip:The measured distance from bottom of the tank to the surface of the oil by using dip gauge.Ullage (outage):The measured distance from the surface of the oil to a reference mark at the top of tank. By subtracting the Ullage (measured height) from the tank reference height the volume can be determined.

TANKSTerminologies used Initial gauge (opening gauge):The gauge reading of a tank before receiving or discharging of product.

Final gauge (closing gauge):The gauge reading of a tank after receiving or discharging of a product

TANKSTerminologies used Reference mark:A fixed point or mark on the gauging hatch which is used for measuring purposes.Reference height:The distance between reference mark and the bottom of the tank.

TANKSTerminologies used Water paste:A paste applied on the dip tape to find out the water interface in oil product tanks.Oil finding paste:A paste applied on the dip tape to find out the level of colorless liquid oil (kerosene).

TANKSLiquidDip (depth)UllageGauge hatchReference heightDatum plateReference marks