floating roof tanks - different aspects
DESCRIPTION
Different aspects of floating roof designsTRANSCRIPT
Types of Tanks
CONE ROOF TANKS (CR)
FLOATING ROOF TANKS
DOME ROOF TANK
IFR EFR
(a) Advantage of Floating Roof Tanks
MINIMIZING VAPOR SPACE: (a) ELIMINATES FILLING LOSS
CONE ROOF TANKS
FLOATING ROOF TANKS
MINIMIZING VAPOR SPACE: (b) REDUCES BREATHING LOSS
FLOATING ROOF TANK
CONE ROOF TANKS
MINIMIZING VAPOR SPACE: (c) PROVIDES EFFECTIVE FIRE PROTECTION AND LIGHTING SAFETY, IT ALSO INHIBITS ROOF AND
SHELL CORROSION
FLOATING ROOF TANKS
CONE ROOF TANKS
(b) Type of Floating RoofThere are a variety of deck options that may be exercised depending on the service conditions of the stored product.
• Single Deck Pan Type• Single Deck pontoon Type• Double Deck
Selection of a specific type of roof and tank depends on the intended service conditions, such as the petroleum liquid being stored, its vapor pressure and corrosive nature, and the anticipated weather and loading conditions.
General Industry Trends in selection
• Double deck floating roofs for large diameter tanks above 60 m dia. forcrude oil service (to conserve lighter end products) or otherwise andvery small diameter tanks less than 15m
• Single deck floating roof tanks for most intermediate range tank diameters
• Internal floating roof tanks for volatile, highly inflammable or value addedProducts – based on economics of advantages vs costs On the aforesaidguidelines, a thumb rule classification of roof selection for various serviceconditions may be made. A final selection would require a more detailedinvestigation of process conditions during tank service and relative vaporloss advantages gained by the use of various deck options.
• Available in standard sizes from 15 – 91.5 m diameter
• Provides a cost effective solution, compared to the double deck, except inthe larger and very small sizes
• Greater water carrying capacity while afloat
• Prone to weldseam fatigue cracking from extended exposure to high windconditions
• Sufficient pontoon volume to keep deck afloat with any two pontooncompartments punctured
• Pontoon area varies from 35% on small diameter roofs to 20% on largediameter roofs
• Pontoon underside slopes upward toward centre of roof to hold temperaturegenerated condensible vapors
SINGLE DECK (PONTOON TYPE) EXTERNAL FLOATING ROOF TANKS
SINGLE DECK EXTERNAL FLOATING ROOF TANKS (EFR)
Shell
Rim
Roling ladder
(typ)
Deck Plate
Single Deck Pontoon Type Floating Roof Tank
Pontoon
Curb Angle
• Available in standard sizes from 9 – 122 m diameter
• Most efficient solution, double deck provides good insulation over entireliquid surface, most stable and maintenance free option for larger sizes
• Limited water carrying capacity while afloat, water allowed to passthrough deck
• Reduces impact of high winds on product, stable performance of deck undersuch conditions
• Emergency drains provided to accommodate 10” of rainfall in 24 hours
• Roof designed to float directly on product, and stay afloat with any twocompartments punctured. Deck flexibility allows temperature generatedcondensible vapor to be contained under center of deck
DOUBLE DECK EXTERNAL FLOATING ROOF TANKS
DOUBLE DECK EXTERNAL FLOATING ROOF TANKS (FR)
• Provides additional protection against wind and rain
• Combines the all-weather performance of a cone roof tank with theevaporation saving and fire protection qualities of a floating roof tank
• Maximum protection against exposure or rim fires
• Floating roof simultaneously combats corrosion and product deterioration
• No drainage system required – this eliminates maintenance of this item andfloating roof may be operated to lower levels
• In lieu of pan type construction, special pontoon type decks can be providedfor more positive floatation and increased stability.
• Shell/Roof vents provided for venting air-vapor mixture between the floatingdeck and fixed roof during product pump in
DOUBLE DECK INTERNAL FLOATING ROOF TANKS (IFR)
DOUBLE DECK INTERNAL FLOATING ROOF TANKS (IFR)
DOUBLE DECK EXTERNAL FLOATING ROOF TANKCENTER DRAIN PROFILE
DOUBLE DECK EXTERNAL FLOATING ROOF TANKREVERSE SLOPE PROFILE
Pipe Support
Roof Drain
Roof Drain
PARTS OF ADJUSTABLE / FIXED PIPE SUPPORT
DECK MANWAY
• Deck manway is use to enter the tank bottom from top of deckby using internal ladder and also use as vent.during maintanance when tank is empty.
PONTOON MANWAY
• Pontoon Manway is use during hydrotest of pontoon.Water is inlet from pontoon manway.
• Generally size of Pontoon Manway is 20” NB.• Each compartment one & for big tank two required.• Pontoon manway is use to excess in pontoon for welding of
radial & circumferencial bulkhead to bottom deck also.
PARTS OF DECK MANWAY PARTS OF PONTOON MANWAY
An Example of Deck Layout of Floating Roof Tank Size is
92m ID x 20M HT.EFR Tank for
Crude Oil Storage
PARTS OF CONE ROOF TANKS
Lifting the Roof/Shell section of the tank.
The Roof and Top shell Section is Fit and being tacked from the Inside.
Dome Roof Knuckle Profile
Looking down on Knuckle