Rizaldi_pipeflow

8/3/2019 Rizaldi_pipeflow

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Pipe Flow : Philosophy, sizing, and

simulation

Presenter: Rizaldi


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PT. TRIPATRAENGINEERS AND CONSTRUCTORS 1

Module objectives

By the end of this module you will: Have knowledge whats behind the flow

Recognize and identify parameter, criteria, and properequation for pipe sizing

Get Brief introduction Hydraulic simulation (pipephaseas case study)


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Introduction

Proper design and fullyaccomplish consideration

should be taken in order tooptimize performance andavoid undesired event


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Fluid Behaviour

Newtonian Fluid : viscosity is proportional torelative movement rate/shear stress

Non newtonian Fluid : viscosity is not proportionalto relative movement rate


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Reynold Number

At low flowrate pressure drop is proportional tothe flowrate, but as flowrate increase until certainpoints, the relationship between two become non-linear

Re = momentum/viscous shear stress

Re = .v2/(.v/D)

Re = .v.D/


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Reynold Number

Flow Regime based on Reynold number :

a. Re < 2000 = Laminer :

fluid elements moved in smooth layers

relative to each other with no mixingb. Re > 4000 = Turbulence :

unstable flow pattern, characterized by highdegree of mixing of fluid elements


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Conservation of mass

For steady state :


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Conservation of momentum

(bernouli eq)


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Conservation of Energy


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Bernouli Equation (derivation form)

for liquids :

For gas : modified Bernoulli


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Sizing and Hydraulic Evaluation

What do we need to know ?What are the critical Parameter?

Which correlation/equation to be used?

What are the outputs?


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What do we need to know?

Phase : Single phase Liquid, Single phase gas, two phase,slurry (not to be discussed).

Phase determine the characteristic of fluid and to beconsider to derive proper equation

Flowrate : Quantity of the fluid, in volumetric rate or inmass rate.Consider maximum and minimum conditionwhich will happen during operation

Process condition : Temperature, Pressure.

Fluid properties : Viscosity, density System arrangements (elevation, fittings, pipe length)


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What do we need to know (summarize)

PhaseFlowrate

Temperature

Fluid viscosity

Fluid density

Elevation change

Fittings

Pipe length


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Critical Parameter

Velocity (max, min, erosion velocity, sonicvelocity, entrainment velocity, noise velocity)

Pressure drop

Select diameter in which will give satisfiedparameter value


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Velocity

Limit between certain values to attain economical and safeoperation

Erosion velocity :

Commonly used as parameter for two phase flow, velocity atwhich erosion or excessive wear on elbows will start to occur

identified by equation : C/(m^0.5)

Where C = empirical constant,

= 100, if continues solid free

= 125, for non-continues solid free service

= 150 200, for continues solid free(employing corrosion resistant alloy)

Where m = density of liquid-gas mixture


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Velocity

Noise velocity :Velocity at which will cause noise above the noise limit(commonly 85 dB - 90dB). API 14 give identification above60 ft/s

Sonic velocity :

The maximum velocity that a compressible fluid flowing ina pipe of uniform cross-section can achieve is limited bythe maximum velocity of pressure wave travel in the pipe,which equivalent to speed of sound. Noise and vibrationincrease when sonic velocity approached. Can occur in

liquid called chocked flow


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Typical velocity and Pressure DropLimitation (fluor daniel)


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Typical velocity and Pressure DropLimitation

Two phase flow velocity limit:min : 10 ft/s (API 14 E)

max : erosion velocity


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Pressure Drop Equation

Proper equation shall be use for spesificcase/phase :

a. Single phase liquid flow

b. Single phase gas flowc. Two phase flow


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A. Single Phase Liquid Flow

Straight pipe, using Darcy Equation :

Elevation loss :

Fitting Loss :


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Fitting loss can also be obtained using equivalentlength method :

Friction factor ( f) obatined using moody/darcyfriction factor :


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For liquid with Re > 2000 , using ColebrookEquation:

Where f = friction factor

d = pipe diameter

E = pipe roughness


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Gravity Flow

Mechanical Energy Balance :

(V12/2g+ H1 + 144 P1/d) W1 (V22/2g+ H2 + 144 P2/d) W2 = E

Friction Lost : E = W (V2/2g) (k1 + fL/D+ k2)

D = (W0.5) (1.78 + fL/D)0.25 / (150.6 d0.5 X0.25)

since; constant mass flow & no pipe size change, V= V1 = V2

k1 and k2 are K factors for pipe entrance and exit

L is total equivalent pipe length excluding the entrance and exit effect in ft

Dis pipe diameter in ft

dis the liquid density

fis Darcy friction factor WequalsW1 or W2

A is the pipe cross sectional area in ft2

Xis the gravity flow driving force in ft

gis gravitational constant, 32.174 ft/sec2


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General Equivalent Length (GPSA)


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B. Single Phase Gas Flow

Two models :a. Isothermal

straight pipe loss :


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Fitting loss :


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B. adiabatic flow (use in many simulationsoftware)


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C. Two Phase Flow

Flow regime :Horizontal vs Vertical

Horizontal : Bubble, Plug, Stratified, Wavy, Slug,

Annular, Mist/Spray Flow.

Vertical : Bubble, Slug, churn(froth), annular


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C. Two Phase Flow

Bubble Flow :

Plug Flow :


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C. Two Phase Flow

Stratified Flow

Wavy Flow


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C. Two Phase Flow

Mist/spray Flow

Slug Flow


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C. Two Phase Flow

Pressure Drop Calculation :a. Duikler Taitel

b. Beggs and Brill


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C. Two Phase Flow

A. Dukler Taitel


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C. Two Phase Flow

Dukler Taitel Maps


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C. Two Phase Flow

Beggs and Brill


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C. Two Phase Flow

Beggs and Brill


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C. Two Phase Flow

Beggs and Brill


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C. Two Phase Flow

Beggs and Brill Maps


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C. Two Phase Flow

Other Methods (summary)No. Methods FlowMap LiquidHoldup

Flow DirectionHorizontal Vertical Inclined

Upw. Downw.1 Mandhane (Dukler / C&M/ L&M) Yes Yes Yes No No 62 Eaton-Dukler No Yes Yes No No 63 Dukler-Taitel 1) Yes Yes Yes 2) 2) 64a Beggs & Brill Yes 3) Yes Yes 4) 4) 4)4b Beggs & Brill / Palmer Yes 3) Yes Yes Yes Yes Yes5 KSLA - Oliemans Yes Yes Yes Yes Yes 5)6 Eaton - Oliemans No Yes Yes No No 67 BJA-2 No Yes Yes No No 68 Mukherjee / Brill Yes Yes Yes Yes Yes Yes9 Orkiszewski Yes Yes No Yes No No10 Gray No Yes No Yes No No11 Hagedorn-Brown No No 6) No Yes No No12a HTFS Homogeneous Flow No No Yes Yes Yes Yes12b HTFS with Slip No Yes Yes Yes Yes Yes13 Duns and Ros Yes Yes No Yes No No


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C. Two Phase Flow

Mandhane The Mandhane method is a hybrid horizontal flow correlation, which is a combination of other

existing correlations. These are selected based on the flow regime predicted by theMandhane flow map.This method gives better matching results with test data than any of the methods used on its

own.Holdup predictions for the Annular, Annular-mist flow regime, however, are not satisfactoryby any of the methods. A new correlation has to be developed.For inclined lines (less than 6degrees upwards or downwards) the pressure drop is calculated as for horizontal lines. Thepressure recovery is calculated using the two-phase density.


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C. Two Phase Flow

KSLA-Olemans For the calculation of holdup and pressure losses, however, this method can only be used for

horizontal and inclined lines up to 10 degrees, upwards and downwards and for vertical lines,in between 70 90 degrees. For all other inclinations, the results have to be treated withcare. The liquid holdups are systematically 13% over-predicted. A test facility was made foran 8 line at 75 bar and the results from the field tests were confirmed by the method. Theliquid loadings were increased to give other flow regimes than stratified wavy flow. Thepressure drop is calculated using the two-phase density for upward and for downward flow,except for stratified downward flow, where the gas density has been used


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C. Two Phase Flow

BJA-2 This method has been specially developed for large diameter, high-pressure gas /

condensate pipelines with low liquid volumes of 1% or less. The pressure-losscalculation procedure is similar in approach to the Oliemans method, butaccounts for the increased interfacial shear resulting from the liquid surfaceroughness. These correlations appear to give consistently more reliable holdupand pressure drop predictions than the other correlations tested and have been

used in the design of several large pipeline and gas gathering systems in theNorth Sea. Baker Jardine and Associates (BJA) have developed this method

from pipeline operating data


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C. Two Phase Flow

MULHERJEE-BRILL The prediction of flow pattern is based on experimental data on air-kerosene and

air-lubricating oil mixtures in a 3.81 cm ID pipe, working at about 8-9 barg. Flowregime maps were drawn for different inclination angles, including horizontal andvertical flow. Different empirical equations for the flow regime transitions areproposed that are functions of inclination angle for both upflow and downflow. Ingeneral, the flow regimes and their transition for upflow were similar to thoseproposed by Duns and Ros for vertical upflow. For downflow, the flow regimes andtransitions conformed more to the Mandhane et. al. type of flow regime map. The stratifiedflow regime in downflow was bound to be affected appreciable by the angle of inclination. Fordownhill flows, this method normally overpredicts the pressure drop with 10 40% for1 to45 degrees inclined lines. All other pressure drop calculations for other line inclinations are

very well matching


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C. Two Phase Flow

ORKISZEWSKI The Orkiszewski method is a hybrid vertical flow correlation, which is a combination of other

existing correlations, with the contribution of one himself. Measurements were done on oilwells with oil-gas and oil-water-gas mixtures in 3 8.75 lines. Do not use this method forlines larger than 10. Instead use a 10 diameter pipe and recalculate the loadings, so thatthe line velocity stays the same. This will give reasonable results


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C. Two Phase Flow

GRAY The Gray method has been especially developed for gas condensate wells, and should not

be used for horizontal pipes. The recommended ranges for use are:

Angle of inclination 70 degrees

Velocity 15 m/s

Pipe diameter 3.5 inches

Liquid condensate loading 50 bbl / MMSCF (280 m3/106 Nm3)

h l


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C. Two Phase Flow

HAGEDORN-BROWN This correlation is not flow regime dependent and basically their calculation method is the

extended homogeneous case, assumed for the total pressure gradient . Hagedorn andBrowns major contribution is their holdup correlation for vertical flow. They did not measureholdup experimentally, rather they measured the pressure gradient and calculated the holdupnecessary for the total pressure gradient to give the observed value. They used a very largeamount of data, collected for pipe between 1 and 2 diameter

d li Si l i ( i h d )


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Hydraulic Simulation (Pipe phase case study)

Modelling both single phase and two phase flowinside pipeline and piping networks and includesstandard industrial compositional and non-compositional PVT predictive methods.

H d li Si l i (Pi h d )


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Calculation module : Network and Single link


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H d li Si l ti (Pi h t d )


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Pressure Drop Correlation method can beselected

Heat transfer model can be selected

Using source and sink method. Data on one ofside shall be completed to run the iteration.

Pipe arrangements can be modeled



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Calculation method



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Pressure Drop Calculation method

Other hydraulic simulation used by


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