Alaa-pipeline Mechanical Design

7/22/2019 Alaa-pipeline Mechanical Design

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Pipeline mechanicaldesign


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Stages of pipeline design:Fluid types determination.

Design conditions determination.

Stress analysis.

Selection and sizing of pipeline components.


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Fluid types can be transported in pipeline:Liquid

Crude Oil- Petroleum Products-Water

liquefied

LNG-LPG

gas

Natural Gas.

Slurries.


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Design conditions:Pressure:

Internal design pressure.

Maximum operating pressure(MOP).

External design pressure.

- Due to backfill pressure(buried pipeline).

- Due to water head(submerged pipeline).

backstatic PPPsteady )frictionovercome()state(Pmax


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Design conditions:temperature:

It is the temperature of line pipe metal.

Material properties changes with temperature various.

Temperature study is important at

- Low ground temperature.

- Low atmospheric temperature.

- Transient operating conditions.


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Design conditions:Ambient Influences:

Fluid Expansion Effects.

-We must withstand or relive increased pressure due tofluid expansion.

Dynamic effect.

- Impact.

-Wind.- Earthquake.

-Vibration.

-

Waves and currents.


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Design conditions:Weight effect:Live loads

-Liquid transported weight.

-Extraneous materials that adhere to the pipe(ice) weight.

- Impact of waves & wind.

Dead loads

-Pipe weight.

-Components weight.

-Coating weight.

-Backfill weight.

-Unsupported attachment to the pipeline.


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Design conditions:Thermal Expansion and Contraction Loads.

Relative Movement of Connected Components.- It must be taken into account in design of piping

and pipe support elements.


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Major pipeline components:Components required to ensure effective

operation:

Line pipe

strainers

Couplings

Meters

Valves


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Line pipe


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Line Pipe Selection ParametersThickness and Grade Selection

Handling and Transportation (d/t ratio)

Type of Line Pipe

Installation Requirements


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analysis:tressWall Thickness Calculations according to

pressure.

Expansion and flexibility.

Pipeline anchoring and support.

Anti-Buoyancy Measures.


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Wall ThicknessCalculations


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Wall Thickness Calculations:tepPipe wall thickness is

primarily driven by the need

for pressure containment.

Design for internal pressure

is based on consideration ofhoop stress in pipe wall.


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Wall Thickness Calculations:tepLIQUID PIPEL INE (ASME B 31.4, Cl. 404.1.2)

Given:

Selected:

Required:

Design formula:

0.72factorDesignFtable).mfactor(frojointweldE

C120TC30-pipelineofdiameteroutsideDpressuredesigninternalP

o

pipe

o

i

ssthicknet wall

*2

p FE

D

tS

strength.yieldminimumspecifiedS


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:Wall Thickness Calculations.tepGAS PIPELINE (ASME B 31.8, Cl. 841.11)

Given:

Selected:

Required:Design

formula:

table)mfactor(frorating-deuretemperatT table)mfactor(froDesignF

table).mfactor(frojointweldEpipelineofdiameteroutsideD

pressuredesigninternalPi

thicknesst wall

*2

p FETD

tS

strength.yieldminimumspecifiedS


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Thickness Calculations:WalltepDesign factor, f


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Expansion &flexibility


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and flexibility.ExpansiontepExpansion stress :

Thermal expansion occur due to temperature change or

due to any event that could cause relative displacement

between anchor points.

That causes excessive stress in the piping material and

Impose excessive forces or moments on equipment orsupports.


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:Expansion and flexibility.tepIf restrained pipel ine:

Pipeline is said it restrained if it cant

expanded in longitudinal direction.

That occur when it is fixed supported or

buried pipeline.


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:Expansion and flexibility.tepIf restrained bu ried pipel ine:

Given:

Req.

Step1:hoop stress

Longitudinal stress

(P.D)/(2t)h

S

)(. 12L TTESS ch

restraintofat timemperatureAmbient teTretemperatuoperatingMaximumT

expansionthermaloftcoefficienLinearsteelofelasticityofmodulusColdE

ratiosPoisson,,

1

2

c

tPD

)( sstrengthyieldcheck


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:Expansion and flexibility.tepIf restrained bu ried pipel ine:

Design formula:

*9.0h TSSS l


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:Expansion and flexibility.tepIf restrained supported above ground pipeline:


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:Expansion and flexibility.tepIf restrained supported above ground pipeline:

Design formula:

Where:

absolute resultant value of beam bending stresses

planeofoutrefer toiplaneinrefer toi

modulus.sectionZmoment.tionaltorM

moment.planeofoutM moment.planeinM

o

i

t

o

i

TSSSS Bl *9.0h

ZMMiMiS tooii /75.075.05.0

222

B


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:Expansion and flexibility.tepIf un restrained

pipel ine:

Design formulae:

Dead load

Live loadSSSS

LDBL

)(E

SSS DB *45.05.0 )(H

SSS LDBL *85.0)(


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:Expansion and flexibility.tepIf un restrained pipel ine:

Where:

Z

MS

Z

iMSSSS tt

bbtbE

&&

stressthermalcombinedSloading.liveanddeadbothfrom

stressbendingallongitudinofvalueabsoluteSPD/4tstressallongitudinS

loads.deadfromresultingstress

ncompressiobendingbeamofvalueabsoluteS

5.022

E

L)B(D

l

BD


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:Expansion and flexibility.tepIf the pipeline in transi t ion fromful ly restrained to un restrained:

1. longitudinal deflection calculated.

2. We decide if we will use anchor or no.

3. anchor sizing obtained.


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:Expansion and flexibility.tepHow do we overcome expansion stress:

Using flexible pipeline:

If we cant use material satisfy previous conditions we can

use one of the next system.

Expansion loop.

Expansion of fset .

Mechanical jo ints .

Coupl ing .

Bends.


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:Expansion and flexibility.tep Expansion loop:


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:Expansion and flexibility.tepSizing an expansion loop:


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Given:

Required:

table)mfactor(frorating-deTPa)strength(MyieldminimumspecifiedS

feet(m)anchorsbetweendistanceinch(mm)pipetheofexpansionltherma

inch(mm)sizepipenominal

uY

D

feet(m)loop,expansionofwidthw


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Design formula:

where:

cA

E

S

UL

DY 30

2

factorfatiguecyclingthermalmax temp.at*67.0Smin temp.atT*S0.67S

)S0.25S(1.25rangestressallowableS

psi(MPa),elasticityofmodulusinch(mm)loop,oflengthh

H

c

Hc

A

fTS

fS

E

A

c


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For ferrous material :

Answer : 2/)( uLw

)(3.208

)(03.02

unitsSIor

impricalUL

DY


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:Expansion and flexibility.tep Expansion loop capaci ty


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:Expansion and flexibility.tepExpansion of fset :


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:Expansion and flexibility.tepSizing an expansion offset:


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:Expansion and flexibility.tepSizing an expansion offset :

Where:

)(3.208

)(

2

2

348

unitsSI

impricalS

h

DYEAh

DYE

c

c

cycle7000cyclesofNoif1factorfatiguecyclingthermal

factor.rating-destressTmax temp.at*67.0Smin temp.atT*S0.67S

)S0.25S(1.25rangestressallowableS

psi(MPa),elasticityofmodulusinch(mm)loop,oflengthh

inch(mm)anchor,ofntdisplacemelthermainch(mm)sizepipenominal

H

c

HcA

f

TS

fS

E

YD

A

c


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Pipeline anchoring&supports


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:Pipeline anchoringtepCase1: no anchor


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:Pipeline anchoring .tepCase1: no ancho r

Given:

Req.

Step1:

expansionthermaloftcoeffecien

pipetheofareasectional-crossA strength.yieldminimumS p

.AatstressallongitudinS/2SBatstressallongitudinS

LA

HLB

TESH

regions.restrainedunand restrainedfullybetweenpipeoflengthL


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anchoring :PipelinetepCase1: no ancho r

Stress and strain between A&B

-Point A has zero longitudinal stress.


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:Pipeline anchoring :tepCase1: no ancho r

Step2:

Step3:

Step4:

We can use higher thickness at this section.

S

LALB

F

SS

pAL)(

)(D0.0813soilavaragueofresistance(KN/m)

2

o mFs


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:Pipeline anchoring :tepCase2: with anchor


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given:

Req.: force at anchor block.

Result :

For caped

end p ipe:

expansionthermaloftcoeffecienpipetheofareasectional-crossA

strength.yieldminimumS

p

pLALB ASS )(F

pi ATE

t

PDDP)

2

(

4

)(F

2


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Stress and strain between A&B


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Step3:Pipeline support:


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Buoyancy control


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Step4:Buoyancy control. When does pipeline

subject to buo yant force?

1. when they encounter

freestanding or flowing

water.2. when buried in saturated

soils.


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Step4:Buoyancy control.Saturated soil under water


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Step4:Buoyancy control. Methods of Buoyancy Contro l:

Backfill .

Using heavy pipeline.

Density anchors.

-

Set-on weight- Bolt-on weight

- Continues concrete coating

Mechanical anchors.


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:Buoyancy control.tepMethods of Buoyancy Contro l:

Backf i l l

High density soil

Deep ditch

Using heavy pipeline

By using low yield strengthmaterial


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Dens i ty anchors

Bolt-on

weights

Cont inues

conc rete coat ing

Set-on

weights


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:Buoyancy control.tepSet-on weigh ts


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:Buoyancy control.tepbol t -on weights


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:Buoyancy control.tepCont inues concrete coating


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Mechanical anchor:


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Valve assemblies


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Valve assembliesValve types

Valve sizing

Valve selection


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Valve types


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Valve Types and function

Gate

GlobeBall

Butterfly

plugdiaphragm

Isolation Modulating/throttling

Non-return

globe

BallButterfly

Swing check

Lift check

Specialvalves

PRESSUREREDUCING

VALVES

Relief valve

Anti-cavitationvalve

Air-valve


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Gate Valve

A double-disk parallel-seat

type.

Wedge-shaped-gate type

with an inclined seat.


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Gate ValveThey are suitable for the toughest applications in high

pressure and high temperature systems.

A gate valve cannot throttle or operate partially open.

The pressure drop through these valves is about equal

to that in a pipe of the same length

It is used at Infrequent operation.


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BALL VALVES

Ball Valve - WithFloating Ball

Ball Valve TrunnionMounted


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BALL VALVES


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BALL VALVESIts application is limited to temperatures that have little

effect on its plastic seats.

They are compact.

When the valve is closed, pressure in the line helps to keep it

closed.

The fluid can flow through it in either direction.

Most ball valves are quick acting.

The pressure drop across the valve in a fully open position is

minimal for a full-port design.


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Globe valves


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Globe valvesThe amount of flow restriction observed with a globe valve

is a function of the valve disk location relative to the valve

seat.

In most cases, the higher pressure fluid stream connected

to the pipe side above the disk, which helps to maintain a

tight seal when the valve is fully closed.

The direction of fluid flow through the valve changes

several times, which increases the pressure drop across the

valve.


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Return Valveson


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Non-Return Valves

Non return valves are used for:

Minimizing reverse flow.

Keeping lines full of fluid.

Prevention of loss of fluid when the system is not in

operation.

Prevention of reverse rotation of pumps.

Prevention of outflow of fluid from vessel.


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PRESSURE REDUCING VALVES


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Relief Valvesan automatic pressure-relieving

device suitable for use as either a

safety or relief valve, depending

on application.

Used to protect piping systemfrom excessive pressure


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cavitation systemntiAnt cavitation orifice.

CLA-VAL 100-45 anti cavitation valve.

Lincoln Log anti cavitation valve


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cavitation orifice.nti


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cavitation orifice.ntiStage 1:

High pressure is reduced as it passes through the first

restriction.Stage 2:

Flow through the first restriction is directed towards the

center of the pipe. An additional pressure drop is created as

the f low converges.


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cavitation orifice.ntiStage 3:

Pressure is dropped further as it passes through the second orificeplate.

By creating a series of small pressure drops the potential for a

fluid vapor condition (cavitation) is minimized.

Stage 4:

Flow passing through the second orifice plate is directed away

from pressure boundary surfaces.

Cavitation bubbles collapse in the fluid further reducing the

chances of cavitation damage to components.


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anti cavitation valve.500ALLA


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anti cavitation valve.500ALLAFlow enters through the slot detail

of the seat. The slot orientation

directs flow towards the center of

the chamber where flowconverges.

Flow exits trough the disc

guide slots are angularly

oriented to direct flow away

from the valve body.


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anti cavitation valve.500ALLA


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Valve selection


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Purpose of valves in pipelineIso lat ion o f sect ion s

Flow contro l

Pressu re contro l

Reverse f low prevent ion

De-aeration


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Sectionalizing Valve Purpose:

Sectionalizing valve assemblies are used to

isolate sections of mainline or long laterals

when isolation is required in the event of a line

break or if maintenance in a section of the line

is necessary.


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Sectionalizing Valve Requ ired components:

A gate or ball valve the size of the mainline to

allow passage of pigs.

Two blow-downs (gas only) for equalizing the

pressure on both sides of the block valve.

A riser on each side of the block valve.


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Sectionalizing Valve Spacing

ASME B 31.8 for Gas pipelines

ASME B 31.4 for Liquid Pipelines

Gas Pipelines

Location Class 1 32 km (20 miles)





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Sectionalizing Valve LPG Pipelines

Industrial, 12 km (7.5 miles)

Locat ion

Pollution Concerns

Statutory Requirements

Prevention of Inventory Loss

Approachability of Valve Station


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Sectionalizing ValveSelection of ball and gate valves

Ball valve Gate valve

sealing

infrequent operation Fail-safe

Hot tap isolation

High speed

Repair ability

Cost

Space limitation

Hydraulically operated


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CRYOGENIC VALVE


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CRYOGENIC VALVEApplication: Specialty Gas, Food Processing,

Chemical, Dry Cleaning, Electronic.

Cryogens: Nitrogen, Oxygen, Hydrogen,Helium, Argon, Fluorine, Methane

Pressure Range: Vacuum to 70 bar (1015 psig)

Temperature Range:-269C to 100C

(-452F to 212F)


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CRYOGENIC VALVE All the cryogenic valves have an extended bonnet with

a mounting pad.

The extension prevents cryogenic liquids from

reaching the stem packing by enabling the liquids toboil and convert to gas.

The balls have a pressure relief hole on the upstream

side to prevent overpressure of the body cavity from

thermal expansion.

The valve is uni-directional with an arrow showing flow

direction.


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Valve selectionConveyed fluid Nature of fluid Valve function Type of disc

LiquidNeutral

(Water, Oil, etc)

On/Off

Gate

Rotary ball

Plug

Diaphragm

Butterfly

Plug gate

Control valve,modulating

GlobeButterfly

Plug gate

Diaphragm

Needle


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LiquidCorrosive

(Acid, alkalineetc.)

On/Off

Gate

Plug gate

Rotary ball

Plug

Diaphragm

Butterfly


GlobeDiaphragm

Butterfly

Plug gate


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gasNeutral

(Water, Oil, etc)

On/Off

Gate

globe

Rotary ball

Plug

Diaphragm


Globe

Butterflygate

Diaphragm

Needle


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gas

Corrosive(Acid vapors,chlorine etc.)

On/Off

Butterfly

Rotary ball

PlugDiaphragm


Globe

Diaphragm

Needle

butterfly

vacuum On/off

Gate

Globe

Rotary ball

butterfly


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Valve sizing


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Flow Calculation Principles valve flow coefficient is determined by testing the

valve with water at several flow rates


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Flow Calculation PrinciplesThe principles of flow calculations are illustrated by the

common orifice flow meter.

Alaa-pipeline Mechanical Design

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