12inch pipe x 500mt per hr c3@ 10deg.c

7/29/2019 12inch Pipe x 500MT Per Hr C3@ 10deg.C

1/13

LPG Cargo line sizing, pressure drop and TDH

Propane only

1. Find the Frictional Head Loss and the Total Dynamic Head in a12ND Pipe from Jetty manifold (at breakaway coupling) up to the

inlet of Bullet Tank #1. Do manual & computerized calculations.

2. Given data:

Flowrate, Q = 500MT/hr refrigerated Propane. (500,000 kg/hr)/(515

kg/m3) = 971 m3/hr

Pipe size / ID = 12ND Sch. 40 / 11.938 inches (303.3mm)

Pipe roughness factor = 0.04572 (for new pipes)

Operating Temp., T = 10

0

C (50

0

F)

assumed average pipeline operatingtemp. Refrigerated Propane temp. inside ship = - 420C. It is discharged

from the ship to the Jetty manifold where then, the pipeline drops down

to seabed and therefore, pick up heat from the seawater. From there, for

a preliminary ball park figure and ease of calculation, an operating temp.

of 100C is assumed throughout the length of the pipeline. It has lots of

insulation hence, minor heat was considered negligible. From the

pipeline, Propane will reached the storage tank where I assumed a worst

case scenario when the product temp. will eventually be in equilibrium

with the ambient temp. of 250C during summer.

Viscosity @ 100C (500F) , cP = 0.135 (ref. App. 1) = 0.000135Newton-

sec/m2

Specific Gravity, SG @ 100C (500F) = 0.515 (ref. App. 2)

Density @ 100C (500F) = 515 kg/m3

3. Pipe lengths, Valves and fittings:

Pipe lengths (ref. Site Development Plan Sht 1/1 and isometric dwgs PP2 &

PP3 Scheme 49).

Total Str. Pipe length (horizontal and vertical) = 2,300 + 6 + 13 + 453.33 =

2,772.33m

Equivalent length of valves & fittings:

FROM JETTY MANIFOLD (at Breakaway coupling) to inlet of Bullet Tank #1


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Fittings

No. of

Valves &

Fittings

Ref. App. 3

Calculation

for 12ND, ID =

0.3033m

Le, (m)

Ball Valve 6 3D6 x 3 x 0.3033

5.46

Gate Valve 1 13D1 x 13 x 0.3033

3.94

Check Valve1 135D

1 x 135 x

0.3033 40.94

Tee Equal 1 65D1 x 65 x 0.3033

19.71Elbow: 90,

R=1.5D 4 20D

4 x 20 x 0.3033

24.26Elbow: 45,

R=1.5D 10 16D

10 x 16 x

0.3033 48.52

Entrance 1 32D1 x 32 x 0.3033

9.70

Exit 1 64D1 x 64 x 0.3033

19.41

Total171.94

m

Total Str. Pipe length + Equivalent length = 2,772.33 m + 171.94 m = 2,944

4. Pressure Drop calculation

A. Manual calculation

Total Dynamic Head, TDH = Static Head + Pressure Head + Velocity Head

+ Friction Head

= (Zd - Zs) + (hpd - hps) + (hvd hvs) + (hfd - hfs)

= (Zd - Zs) + [(Pd - Ps)/ ] + (hvd hvs) + (hfd - hfs)

A.1 Static Head, = (Zd - Zs) where: Zd = static discharge head = 25 m

(given)

Zs = static suction head = 15 m (given). Ship

at sea is below grade level therefore, this

is static suction lift = - 15m.

= 25m ( - 15m) = 40 m

A.2 Pressure Head = (Pd - Ps)/where: Pd = vapor pressure of Propane at 25

0Cinside bullet = 10.2barg = 148psig =


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162.7 psia. (ref. App. 4). Note: It is safeto assume a worst case scenario (durinsummer) where the temperature insidethe bullet could reached, and will be inequilibrium with an ambient

temperature of 250

C. The vapor pressuof Propane at 250C = 148psig.Ps = vapor pressure of Propane at 10

0C inpipeline = 6.1barg = 88.5psig =103.2psia. (ref. App. 4)

= SG in metric units = 0.515kg/m3

Pressure head, Ft = (Pd - Ps)/ = [(162.7 103.2) x 2.31]/0.515 =

267ft = 81.4m

A.3 Velocity Head = can be assumed as nil since flowrate and pipe size is

constant.

A.4 Friction Head, hf= (hfd - hfs) = fLV2 / 2gD

where: hf = friction head loss (Darcy Eqtn)

L = total length = 2,944.27 m

V = Velocity, m/s

D = inside diameter = 0.3033 m (12ND

Pipe)

g = 9.81 m/s2

f = coefficient of friction

Velocity = Q / A = (971 m3/hr x 1 hr/3,600s) / [0.7854 x

(0.3033m)2]

= 3.7 m/s (this is OK vs. the allowable velocity of 3.0

4.6 m/s.

Reynolds No. = VDp/u where: Velocity, V = 3.7 m/s

Inside dia., D = 0.3033 m

density, p = 515 kg/m3viscosity, u = 0.135 cP

u= 0.000135 Newton-

sec/m2


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Reynolds No. = (3.7m/s x 0.3033 x 515) / 0.000135 = 4,281,023

turbulent

Relative roughness for commercial steel at 303.3mm pipe ID =

0.00015 (ref. App. 5)

At Reynolds no. = 4.3 x 106 and roughness factor of 0.00015,

Friction factor, f = 0.015 (ref. App. 6)

Friction Head, hf= fLV2 / 2gD

= 0.015 x 2,944.27m x (3.7m/s)2/ (2 x 9.81 m/s2 x

0.3033m)

= 102m

Check for allowable delta P on friction head:

Psi = ft x SG / 2.31 = (102m x 3.28ft/m x 0.515) / 2.31 =

75 psi

Delta P/100ft = [75/(2,944.27m x 3.28ft/m)] x 100ft =

0.78psi/100ft. This is OK compared to the maximum

allowable pressure drop of 1.5psi/100ft.

Total Dynamic Head, TDH = 40 m + 81 + 0 + 102m = 223m (731ft)

Total Dynamic Head in terms of press., Psi = ft x SG / 2.31 = 731 x0.515/ 2.31= 16psi

BHP = [GPM x TDH (in ft) x SG] / (3,960 x eff.) where: GPM of

971m3/hr = 4,275gpm

= [4,275 x 731 x 0.515] / (3,960 x 0.65)

= 625 HP


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B. Internet Online Spreadsheet calculation for friction head loss

countercheck.

Input data


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Results:

Total pressure drop for 500MT/hr Propane @ 100C = 4.52 bar = 66 psi

Friction head loss, Ft = psi x 2.31 / SG = (66 x 2.31) / 0.515 = 296ft =

90m vs. 102m in manualcalculation.

5. Pressure drop and velocity calculation remarks

12ND x 500MT/hr.

Propane @ 100C

Velocity, m/sPressure drop,

psi/100ft

Calculated 3.7 0.78

Allowable 3.0 4.6 1.5Remarks Passed Passed

Therefore, use 12ND Sch 40 Pipe


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6. Appendices:

1. Viscosity Chart API TECHNICAL DATA BOOK

2. Specific Gravity vs. Temp. Chart for petroleum Oil Cranes Technical Paper,page A-7

3. Equivalent Length of Valves & Fittings Table DEP 31.38.01.11

4. Characteristics of LP Gas Typical Properties

5. Relative Roughness of Pipe Materials _ Cranes Tech. Paper, page A-23

6. Friction Factor for Any Type of Commercial Pipe Cranes Tech. Paper, page A-24

7. Line Sizing Criteria Table


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Appendix 1

Viscosity Chart


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Appendix 2

Specific Gravity vs. Temperature Chart


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Appendix 3

Equivalent Length of Valves & Fittings


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Appendix 4

Characteristics of LP Gas Typical Properties


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Appendix 5

Relative Roughness of Pipe Materials


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Appendix 6

Friction Factor for Any Type of Commercial Pipe

12inch pipe x 500mt per hr c3@ 10deg.c

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