FRONT END ENGINEERING DESIGN (FEED)
PIPELINE GAS DARI PELABUHAN BENOA KE PLTG PESANGGARAN - BALI
PIPELINE STABILITY AND BOUYANCY CALCULATION
BENOA - PESANGGARAN
Document No:
PEL-PL-CAL-003
0
17 FEBRUARY 2015
ISSUED FOR BID
BM
MI
B
9 FEBRUARY 2015
ISSUED FOR REVIEW
BM
MI
A
2 FEBRUARY 2015
ISSUED FOR REVIEW
BM
MI
PREP’D
CHK’D/
APP’D
REV.
DATE
DESCRIPTION
APP’D
PT. LAPI ITB
PT. PEL
STATUS CODE: IFR = Issued for Review, IFI = Issued for Information, IFA = Issued for Approval, IFB = Issued for Bid
Total or partial reproduction and/or utilization of this document are forbidden without prior written authorization of
PT Pelindo Energi Logistik.
DOCUMENT NUMBER
REVISION
STATUS
PEL-PL-CAL-003
0
IFB
FEED GAS PIPELINE
FROM PORT BENOA TO PLTG PESANGGARAN - BALI
DOC. TITLE
Pipeline Stability and Bouyancy Calculation
Benoa - Pesanggaran
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PEL-PL-CAL-003
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TABLE CONTENT
1.
INTRODUCTION ..................................................................................................... 3
2.
OBJECTIVE ............................................................................................................. 3
3.
DEFINITIONS .......................................................................................................... 3
4.
CODES, STANDARD AND REFERENCES ............................................................. 3
5.
DESIGN ................................................................................................................... 4
6.
CALCULATION ........................................................................................................ 7
APPENDIX A .................................................................................................................... 9
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FROM PORT BENOA TO PLTG PESANGGARAN - BALI
DOC. TITLE
Pipeline Stability and Bouyancy Calculation
Benoa - Pesanggaran
1.
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INTRODUCTION
PT. Pelindo Energi Logistik (PEL) plans to build gas pipeline from Port Benoa to PLTG
Pesanggaran Indonesia Power. Gas transported is coming from LNG regasification
plant at Port Benoa and will be utilized to provide fuel gas for PLTG Pesanggaran,
which is belong to PT Indonesia Power. This project will include construction of new
pipeline from Port Benoa to PLTG Pesanggaran complete with metering station at
PLTG Pesanggaran.
2.
OBJECTIVE
This document presents pipe concrete coating thickness calculation for stabilize pipe
with weight and buoyancy equation force based on code ASME B31.8 Gas
Transportation and Distribution Piping System. In this calculation will be calculated
concrete thickness for pipeline area from Benoa to Pesanggaran.
3.
DEFINITIONS
The definitions contained in this document are as follows:
a.
CLIENT, refers to PT Pelindo Energi Logistik (PEL) as the ultimate user and
owner.
b.
CONSULTANT, refers to PT. LAPI ITB as the party providing the technical
consultation services "Front End Engineering Design (FEED) Gas Pipeline from
Port Benoa to PLTG Pesanggaran - Bali".
c.
CONTRACTOR, refers to company selected by COMPANY, which may provides
services to perform part of the contract scope of work on behalf Client.
d.
VENDOR/MANUFACTURER, refers to the company selected by COMPANY or
CONTRACTOR, which is responsible for the purchase agreement specification.
e.
MIGAS, is Indonesian Government body which is responsible for issuing licenses
and permits oil and gas facilities.
4.
CODES, STANDARD AND REFERENCES
The project specifications and the applicable codes and standards as follow:
FEED GAS PIPELINE
FROM PORT BENOA TO PLTG PESANGGARAN - BALI
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Pipeline Stability and Bouyancy Calculation
Benoa - Pesanggaran
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Code & Standard
ASME B31.8
: Gas Transportation and Distribution Piping System
API 5L
: Specification of Line Pipe
PEL-PRO-GEN-001
: Process Design Basis
PEL-PL-CAL-001
: Pipeline Wall Thickness Benoa – Pesanggaran
PEL-PL-SPC-001
: Specification Pipeline
PEL-PL-SPC-002
: Specification External Coating
PEL-PL-SPC-007
: Specification for Concrete Coating
5.
DESIGN
5.1
Methodology of Buoyancy Calculation
Analysis of buoyancy and hydro-dynamic stability needs to be done considering survey
result due to proposed new pipeline against hydrodynamic force. Criteria required in
the ASME B31.8 standard are total weight ratio of the pipe and its contents against the
bouyancy force of fluid (mud) is transferred by a pipe buried at a minimum marsh is 1.1
(W / B = 1.1) to obtain the effect of negative buoyancy so that the pipe is stable in the
marsh and not float when immersed.
Figure 1 Separated Free Body Diagram Pipe Due to Buoyancy Effect
Buoyancy analysis conducted to determine how much the minimum force necessary to
counteract the effects of buoyancy. We calculate the buoyancy force generated by the mud,
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Benoa - Pesanggaran
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and calculating a weight force generated by the pipe and fluid. When the weight of the fluid
produced by the pipe and its contents cannot resist buoyancy force, it is necessary to design
concrete weight (ballast) to be installed on the pipe to resist buoyancy forces. The
configuration of the coating is shown in Figure 2.
Figure 2 Concrete Weight Coating Configuration
5.2
Pipe Data
The design condition accordance to the document number PEL-PRO-GEN-001 shows at
Table 1.
Table 1 Design Data
Data
Benoa - Pesanggaran
Design pressure (psig)
223
Design temperature (oF)
151
The selected wall thickness and other properties of pipeline accordance to the document
number PEL-PL-CAL-001, PEL-PL-SPC-001 and API Spec. 5L shows at Table 2.
Table 2 Pipe Properties
Data
Specification - Grade
Benoa - Pesanggaran
API 5L – X42
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Benoa - Pesanggaran
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Data
Benoa - Pesanggaran
Nominal Pipe Size (NPS)
406.4 mm or 16 inch
Outside diameter
406.4 mm or 16 inch
Selected wall thickness
9.525 mm or 0.375 inch
Length per unit (L)
Plain-end weight per unit length
5.3
12 m or 39.37 ft
93.72 kg/m or 62.64 lb/ft
Anti-Corrosion Pipe Coating
The first layer applied in pipeline concrete coating is used in order to protect pipe material
from being corroded. According to document number PEL-PL-SPC-002, the anti-corrosion
layer coating is 3-LPE. Table 3 show the 3-LPE coating data.
Table 3 LPE Coating Data
Anti-Corrosion Coating
Total coating thickness
Coating density (common product data)
5.4
3 mm
(0.93 – 0.96) gr/cm3
Concrete
Concrete or cement is required for the manufacture of concrete weight is must follow
document number PEL-PL-SPC-007. The density stated in that document is 190 lb/ft3. The
concrete must be reinforced with mesh.
5.5
Mud Data
Based on the Benoa - Pesanggaran route of proposed pipeline, pipeline will go across mud.
CONSULTANT assume the average mud density. The value of average mud density is 1773
kg/m3.
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Benoa - Pesanggaran
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6.
CALCULATION
6.1
Bouyancy Force and Total Weight Formula
Weight of line pipe and it,s coating (W) must be higher than buoyancy forces (B). The ratio of
weight against of buoyancy forces (W / B) should meet the minimum requirements of the W /
B = 1.1. So that, the pipeline can not counteract the effects of buoyancy (Figure 3).
Figure 3 Buoyancy Uplift and Weight Force
𝑾 = 𝑾𝒑 + 𝑾𝒂 + 𝑾𝒄
With, Wp is bare pipe weight, Wa is Epoxy coating weight, and Wc is weight of concrete
applied in line pipe. These weight can be calculated by following formulas.
𝑊𝑝 = (𝑃𝑙𝑎𝑖𝑛 − 𝑒𝑛𝑑 𝑤𝑒𝑖𝑔ℎ𝑡 𝑝𝑒𝑟 𝑢𝑛𝑖𝑡 𝑙𝑒𝑛𝑔𝑡ℎ)(𝑙𝑒𝑛𝑔𝑡ℎ)(𝑔)
𝜋
𝑊𝑎 = ( 𝜌𝑎 × 𝐿 × ((𝐷 + 2𝑡𝑎 )2 − 𝐷 2 )) 𝑔
4
𝜋
𝑊𝑐 = ( 𝜌𝑐 × (𝐿 − 2𝐶) × ((𝐷 + 2𝑡𝑎 + 2𝑡𝑐 )2 − (𝐷 + 2𝑡𝑎 )2 )) 𝑔
4
Where,
𝜌𝑎
: Anti-corrosion coating density, kg/m3
𝜌𝑐
: Concrete density, kg/m3
L
: Pipe length/joint, m
C
: Cut off length, m (Figure 4)
D
: Outside diameter, m
tp
: Pipe wall thickness, m
ta
: Anti-corrosion coating thickness, m
tc
: Concrete coating thickness, m
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The buoyancy force depends on density of the mud/liquid on outer of the line pipe and
line volume includes the coating. Then, the buoyancy force will be calculated as
formula below.
Figure 4 Cut off Schematics
𝜋
𝐵 = ( × 𝜌𝑚𝑢𝑑 × (2𝐶 × (𝐷 + 2𝑡𝑎 )2 + (𝐿 − 2𝐶) × (𝐷 + 2𝑡𝑎 + 2𝑡𝑐 )2 )) 𝑔
4
Since,
𝑊
𝐵
= 1.1
then
𝑊𝑝 + 𝑊𝑎 + 𝑊𝑐 = 1.1 𝐵
6.2
Calculation Result
Based on bouyancy force and total weight calculation, CONSULTANT can extract
formula for calculating concrete thickness. The output of calculation can be shown in
Table 4 below.
Table 4 Calculation Result
No
1
Description
Buoyancy force
2
Total weight
3
4
5
6a
6b
Results
Symbol
B
Value
178.55
Unit
Kg/m
W
163.89
Kg/m
Bare pipe weight
Wp
93.23
Kg/m
Epoxy coating weight
Wc
3.70
Kg/m
Fluid Content
Wf
66.96
Kg/m
Concrete thickness
tc
48.724
mm
Concrete thickness
tc
2
inch
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APPENDIX A
BOUYANCY CALCULATION CHECK
Pipa NPS 16 Inch; API 5L-X42
NO.
DESCRIPTION
Data - Pipeline
1
Nominal Pipe Size
SYMBOL
UNIT
CASE 1
CASE 2
CASE 3
NPS
inch
16
16
16
2
Pipe Outside Diameter
OD
inch
16
16
16
3
Wall thickness
t
inch
0.375
0.375
0.375
4
Coating Thickness
t coating
mm
3
3
3
5
Pipe Length per unit
Lp
m
12.00
12.00
12.00
6
Specified Minimum Yield Strength
SMYS
psi
42000
42000
42000
7
Modulus of Elasticity
E
3.00E+07
3.00E+07
3.00E+07
8
Pipe Density
ρ Steel
psi
kg/m 3
7850
7850
7850
9
Coating Density
ρ coating
kg/m 3
960.00
960.00
960.00
ρ mud
kg/m 3
Data - Field
10 Mud Density
1337
1337
1337
11
Gas Density (Operation gas)
ρ gas
kg/m 3
9.10
9.10
9.10
12
Water Density (for Hydrotest)
ρ water
kg/m 3
1000
1000
1000
Weight in The Air
13 Bare Pipe Weight per meter
Wp
kg/m
93.23
93.23
93.23
14
Pipe Coating weight per meter
Wc
kg/m
3.70
3.70
3.70
15
Fluid Content per meter
Wf
kg/m
0.00
1.07
117.84
16
Total Weight (Wp+Wc+Wf)
W
kg/m
96.93
98.00
214.77
B
kg/m
178.55
178.55
178.55
W/B
kg/m
0.54
0.55
1.20
NOT OK!
NOT OK!
OK!
Buoyancy check --> Min W/B = 1.1
17 Buoyancy
18
Buoyancy Check
Status
Noted
1) CASE 1 : Empty Condition
2) CASE 2 : Operation Condition (Pipe weight + gas content weight )
3) CASE 3 : Hydrotest Condition (Pipe weight + Water content weight )
REMARK
Sch 40
Case 1 & 2 need concrete weight
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APPENDIX B
CONCRETE COATING CALCULATION
INPUT DATA
No
Description
Symbol
Value
Unit
1 Length
L
2 Gravitation
g
12.000
9.810
3 Epoxy coating density
ρa
930.000
m/s2
kg/m3
ta
0.003
meter
5 Outside diameter
O.D.
0.406
meter
6 Concrete density
ρc
3043.508
kg/m3
7 Mud density
ρmud
1337.000
kg/m3
8 phi
π
9 Pipe density
ρp
7850.000
kg/m3
tp
C
0.010
0.3
m
m
Total epoxy coating thickness
10 Selected wall thickness pipe
11 Cut off
meter
3.143
OUTPUT DATA
No
Description
Symbol
Value
Unit
1 Buoyancy
B
3251.788
kg
2 1.1 Buoyancy
1.1 B
3576.967
kg
3 Bare pipe weight
Wp
1118.715
kg
4 Coating weight
Wc
2523.815
kg
5 Epoxy coating weight
Wa
44.44997
kg
6 Total weight
W
3686.98
kg
7a Concrete thickness
tc
0.050067
meter
7b Concrete thickness
tc
50.06658
mm
7c Concrete thickness
tc
1.971125
inch
7d Concrete thickness
tcselected
2
inch
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APPENDIX C
CONCRETE WEIGHT CALCULATION
CONCRETE WEIGHT DESIGN
Pipa dalam kondisi kosong (case 1) dipilih sebagai acuan dalam merancang concrete weight
No
Description
SYMBOL
UNIT
CASE 1
REMARKS
CAPTION
Data - Pipeline
Nominal Pipe Size
NPS
Inch
Outside Diameter
OD
Inch
16
16
Wall thickness
t
Inch
0.375
Total Weight (Pipe + Fluid Content)
W
kg/m
96.93
Total Pipe Length at Swamp and Ricefield Area
Ltotal
m
1740
Buoyancy concrete weight
B
337.81
Concrete Density (ρcon)
ρcon
kg
k g/m 3
3043
d = 0.2032 m
Clearence
CL
m
Length (Cross Section)
f
A
m
m2
e = 0.412 m
Area
0.0029972
0.81
0.31
A1
m2
0.50
f = 0.8128 m
A2
m2
0.04
A3
m2
0.07
A4
m2
0.09
3
0.25
a = 0.412 m
Sch 40
b = 0.2032 m
Concrete Weight - Calculation
c = 0.412 m
Volume
V
m
Concrete Weight
ms
kg
Concrete Weight - Bouyancy
ms
kg
Minimum Less Weight per meter
kg/m
Minimum Less Weight per unit pipe
kg
Quantity of concrete weight per unit pipe
Quantity of concrete weight per unit pipe selected
Total quantity of concrete weight
Length between concrete weight
m
g=2m
h=4m
769.05
431.24
99.47
1193.64
2.77
3
402.00
4