Tankfarm Area Design
-
Upload
prasanna-kumar-subudhi -
Category
Documents
-
view
47 -
download
5
description
Transcript of Tankfarm Area Design
TANKFARM AREA DESIGN
I.Introduction:
The use of tanks is common in all kinds of plants found in oil & gas industry.
1. Process Plant
Refineries
Petrochemicals
Specialty chemicals
2. Terminals
3. Administration buildings
4. Material Handling Plants
Storage tank are containers used for storage of fluids for the short or long term. Cluster of tanks together in a
same are termed as “Tank Farms”.
II.Types of Tanks:Types of Tanks in Process plant depend on the product to be stored, potential for fire, and capacity to be
handled.
Cone roof tank: Used for countless products including Petroleum, Chemicals, Petrochemicals, Food
products & Water
Floating roof tank: The roof of tank rises and lowers with the stored contents thereby reducing vapour loss
& minimizing fire hazard. Commonly found in Oil refineries.
Low temperature storage tank: Tanks stores liquefied gases at their boiling point. Products found in such
tanks include Ammonia (-28 °F), Propane (-43.7 °F) and Methane (-258°F).
Horizontal pressure tank (Bullet): Used to store products under high pressure.
Hortonsphere pressure tank: Handles large capacity under high pressure.
Underground Tanks: Commonly used for drain collection of the plant at atmospheric pressure.
FRP Tanks: Commonly used for corrosive fluid at atmospheric pressure.
Fig Tank farms
Low Temperature Storage Tank
Underground Tanks
III. Design Considerations for Tankfarm Layout:
Below considerations are to taken into account while designing a Tankfarm for Process plants:
General considerations:
Local codes and regulations
Client specification
Topography
Adjacent process units
Neighbouring commercial and residential property
Maintenance and operation
Detail design:
Identification of storage based on fluid stored.
Safety considerations/Statutory requirements
General / Plot plan arrangement
General piping layout
Material of Construction.
Statutory and Safety Requirements:
Following are the key statutory requirements (India). However these are to be relooked based on
geographical location:
1. OISD -118 ( Plant Layout )
2. OISD -116 / 117 (Fire Fighting )
3. Fire Hydrant Manual & Spray Manual.
4. Factory Act of State. If Any
5. Petroleum Act 1934 (Act N0.30 of 1934) Along with The Petroleum Rules.
6. Static and Mobile Pressure Vessel (SMPV).
7. National Fire Protection Act (NFPA).
Apart from this, local rules and regulations pertaining to State and local industrial requirement should be
taken into consideration.
Safety ensures proper protection and safe operation- Lifetime.
Insurance Premium.
IV. Plot Plan Arrangement for Tankfarm Hydrocarbon processing and handling plants are inherently hazardous involving large and complex
processes and substantial risk potential; hence a careful consideration shall be given while developing a plot
plan.
Plot plan is a spatial arrangement of equipment considering proper flow sequence, system grouping, safety,
statutory requirements, maintenance, operation, erection and construction with logistical economy.
General classification of petroleum products for storage.
1. Class – A: Flash Point below 230 °C
2. Class – B: Flash Point of 230 °C & above but below 650 °C.
3. Class – C: Flash Point of 650 °C & above but below 930 °C.
4. Excluded Petroleum class: Flash Point of 930 °C & above.
5. LPG doesn’t fall under this classification but form separate category.
Grouping of petroleum products for storage shall be based on product classification.
Classification based on capacity and diameter:
1. Larger installations: Aggregate capacity of Class A and Class B petroleum product is more than 5000 cu.m
or diameter of Class A or Class B product tank is more than 9m.
2. Smaller installations: Aggregate capacity of Class A and Class B petroleum product is less than 5000 cu.m
or diameter of Class A or Class B product tank is less than 9m.
The storage tanks shall be located at lower elevation, wherever possible.
The storage tanks should be located downwind of process units.
Due to risk of failure of storage tanks and primary piping systems, means must be provided to contain the
spills. The containment for petroleum storage tanks is in the form of Dykedenclosures.
Tank farm
V. Dyke Enclosure
Aggregate capacity in one dyke enclosure:
1. Group of Fixed roof tanks: Upto 60,000 m3
2. Group of Floating roof tanks: Upto 120,000 m3
3. Fixed cum floating roof tanks shall be treated as fixed roof tanks.
4. Group containing both Fixed roof tanks & Floating roof tanks, shall be treated as fixed roof tanks.
Class – A and / or Class – B petroleum products :- Same dyked enclosure
Class – C: – Preferably separate dyked enclosures.
Tanks shall be arranged in maximum two rows. Tanks having 50,000 m3 capacities and above shall be laid
in single row.
The tank height shall not exceed one and half times the diameter of the tank or 20 m whichever is less.
The minimum distance between a tank shell and the inside toe of the dyke wall shall not be less than half
the height of the tank.
Dyked enclosure for petroleum class shall be able to contain the complete contents of the largest tank in the
dyke in case of any emergency.
1. Height of Dyke (H): 1m < H < 2m
2. Width of Dyke (W): Minimum 0.6m (Earthen dyke) Not Specific (RCC dyke)
Dyke enclosure
Dyke enclosure
Separation distances between the nearest tanks located in separate dykes shall not be less than the
diameter of the larger of the two tanks or 30 meters, whichever is more.
All process units and dyked enclosures of storage tanks shall be planned in separate blocks with roads all
around for access and safety.
In a dyked enclosure where more than one tank is located, firewalls of minimum height 600mm shall be
provided to prevent spills from one tank endangering any other tank in the same enclosure.
Tank farm arrangement
For larger installation, minimum separation distances shall be as specified in following tables.
Table 1: Inter unit Distances for large installations (D>9m or Agg. Cap > 5000cu.m)
Table 1
Table 4
Table T4: Tank to tank distance within same Dyke
Notes for Table 1:
Table 2: Interunit Distances for smaller installations (D<9m or Agg. Cap < 5000cu.m)
Tankfarm part 1 I. Dyke Wall Height Calculation:
Area of Dyke : 21582.5 M2
Height of Dyke Assumed : ‘H’ = 1.2 M
Height of Foundation ‘h’ which is 0.9M
Diameter of Foundation : ‘D’ = Diameter of Tank + 1.5 M
Number of Tanks : ‘n’
Fire wall dimensions : 200 MM Thk. X 600 MM High
Dyke enclosure vol. ≥ Working capacity of Largest tank + Dead volumes
A ≥ B + C
A) Dyke enclosure volume = Area of Dyke X Dyke Height
= 21582.5 X 1.2 =25899 M3
B) Working capacityof Largest tank = 17304 M3
C) Dead volume = All tanks foundation volume + Liquid volume of tanks (other than the largest
tank) upto the Ht. of the enclosure + Dead volume of Fire wall
1) All Tank foundation volume:
Volume of a tank foundation = π/4 D2 X h X n
Let ,
D1 : Fdn Dia of 300 tank = 37.5 M; D2 : Fdn Dia of 250 tank = 26.5 M; D3 : Fdn Dia of 210 tank = 22.5 M
n1 : Number of 300 tank fdns = 2 nos; n2 : Number of 250 tank fdns = 4 nos; n3 : Number of 210 tank fdns = 6
nos;
Volume of all tank foundations = π/4 D12 X h X n1 + π/4 D2
2 X h X n2 + π/4 D32 X h X n3
= π/4 X 37.52 X 0.9 X 2+ π/4 X 26.52 X 0.9 X 4 + π/4 X 22.52X 0.9 X 6
= 1988.04 + 1985.56 +2147.08
= 6120.68 M3 …………………………………………………..(1)
2) Liquid volume of tanks (other than the Largest Tank) above Fdn upto Dyke Ht:
Liquid volume of tank above Fdn upto Dyke Ht. = π/4 d2 X (H-h) X n= π/4 d2 X (0.3) X n
Where, d : Dia of Tank
n : Number of tank
Total Volume of all tanks (other than the Largest Tank) above Fdn upto Dyke Ht:
= π/4 d12 X (0.3) X n1 +π/4 d2
2 X (0.3) X n2+π/4 d32 X (0.3) X n3
= π/4 X (36)2 X (0.3) X 1 +π/4 X (25)2 X (0.3) X 4+π/4 X (21)2 X (0.3) X 6
= 305.36 + 589.05 + 623.45
= 1517.86 M3 …………………………………………………..(2)
3) Dead Volume of Fire wall = 0.2 X 0.6 X (56 + 199+ 77.5 + 77.5 + 77.5 + 77.5 + 77.5) = 77.1 M3
= 100 M3 (Min Dead Volume of Sleepers & Crossovers) ……………..(3)
C) Dead volume = (1) + (2) + (3)
= 6120.68 + 1517.86 + 100
= 7738.54 M3
B + C = 17304 + 7738.54
= 25042.54 M3
A = 25899 M3
A > B + C
Dyke height (1.2 M) assumed is OK.
As per OISD, 200 MM free board is to be added to Dyke height
Dyke Wall Height = 1.2 + 0.2
= 1.4 M
II. Piping layout for Tankfarm
Piping from / to any tank located in a dyked enclosure should not pass through any other dyked enclosure.
Piping connected to tanks should run directly to outside of dyke to the extent possible to minimize piping
within the enclosures.
Inside dyked area, earth shall be graded and gravel filled. H.P (High point) level inside the dyked area shall
be 300mm above the outside grade & shall slope towards the drain sump inside dyke.
In dyked area of tankfarm, arrangement shall be made to drain containment to either OWS or storm water
drain by providing two valves. Generally for the first 10 -15 mins of rainwater will be routed through the OWS
and subsequently through the storm water.
Pumps & its associated piping shall be located outside the dyke wall.
Pipes Crossing the dyke wall shall pass through a sleeve suitably sealed.
Piping elevation to be fixed considering settlement values.
Spiral stairways shall be provided on each tank considering ease of access and minimizing paving
requirement. Wind direction consideration should be taken into account
Pumps shall be provided in a curbed area (150 mm high) with proper provision for draining either to OWS &
storm water drain. Pump plinth shall be minimum 300mm high from finished floor level.
Typical tankfarm layout
Related Posts:
Tankfarm: Types, Design Considerations, Plot Plan… Tankfarm: I. Introduction: The use of tanks is
common in all ...
Pressure / Vacuum Relief Valve- Part 2 Sizing Of Pressure / Vacuum Relief Valves (AS PER API 2000)
A) ...
Underground Piping (U/G) and Types of Underground System-… Underground Piping (U/G) The piping
system is taken underground generally for ...
Pressure / Vacuum Relief Valve – Part 1 Table of contents: 1. Purpose of Pressure/Vacuum Relief Valves 2.
How Pressure/Vacuum ...
Underground Piping (U/G) Piping – Part 2 (adsbygoogle = window.adsbygoogle || []).push({}); While
developing &preparing the underground pipi
Link- http://www.piping-engineering.com/tankfarm-dyke-wall-height-calculation-piping-layout-for- tankfarm.html