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International Journal of Mechanical Engineering and Technology (IJMVolume 9, Issue 13, December 201

Available online at http://www.iaeme.com/ijmet/issues.asp?JType=IJMET&VType=9&IType=13

ISSN Print: 0976-6340 and ISSN

© IAEME Publication

DRAG REDUCTION OF IR

FLOW IN PI

University of Kerbala, Petroleum Eng. Dept.

Akram Jassim Jawad, Auda J.Braihi

Unviersity of Babylon, Faculty of Materials Engineering,

Polymers an

ABSTRACT

In this work, a Drag Reducing Age

of Iraqi crude oil using Poly Vinyl Pyridine (PVP) at different concentrations (0, 500,

750, 1000, 1250 and 1500 ppm). Results show that a significant decrease in flow index

values has been achieved at a concen

lowest value is obtained at a PVP concentration of 1000 ppm. This has been clarified

by obtaining flow indexes of less than unity indicating the sample shear thinning.

Thus, using a DRA concentration of 1500 ppm

for a pipeline capacity, pipe diameter and length of 0.02 m

respectively. In addition, a maximum drag reduction of 35.1 % has been achieved at

the highest concentration (1500 ppm). Therefore, th

power and increases the produced flow by 35.1 % and 27.5 %, respectively.

Keywords: Drag reduction,

power.

Cite this Article: Farhan Lafta Rashid, Auda J.Braihi, Ahmed Hashim, Akram Jassim

Jawad, Drag Reduction of Iraqi Crude Oil Flow In Pipelines by Polymeric

International Journal of Mechanical Engineering and

1049-1060.

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IJMET/index.asp 1049 [email protected]

International Journal of Mechanical Engineering and Technology (IJMET) 2018, pp. 1049–1060, Article ID: IJMET_09_13_110


ISSN Online: 0976-6359

Scopus Indexed

DRAG REDUCTION OF IRAQI CRUDE OIL

FLOW IN PIPELINES BY POLYMERIC

ADDITIVES

Farhan Lafta Rashid

University of Kerbala, Petroleum Eng. Dept.

Akram Jassim Jawad, Auda J.Braihi


Polymers and Petrochemical Industries Dept

Ahmed Hashim

University of Babylon

In this work, a Drag Reducing Agent (DRA) has been employed to reduce the drag



values has been achieved at a concentration range of (750-1500 ppm) in which the



Thus, using a DRA concentration of 1500 ppm decreases the pressure drop by 35.7 %

for a pipeline capacity, pipe diameter and length of 0.02 m3/s, 0.0508 m and 10 m,


the highest concentration (1500 ppm). Therefore, the DRA addition saves the pumping


Drag reduction, polymeric additive, rheological characterization

Farhan Lafta Rashid, Auda J.Braihi, Ahmed Hashim, Akram Jassim

Jawad, Drag Reduction of Iraqi Crude Oil Flow In Pipelines by Polymeric

ernational Journal of Mechanical Engineering and Technology, 9(13), 2018, pp.


[email protected]

110


AQI CRUDE OIL

PELINES BY POLYMERIC


nt (DRA) has been employed to reduce the drag



1500 ppm) in which the



decreases the pressure drop by 35.7 %

/s, 0.0508 m and 10 m,


e DRA addition saves the pumping


rheological characterization, pumping

Farhan Lafta Rashid, Auda J.Braihi, Ahmed Hashim, Akram Jassim

Jawad, Drag Reduction of Iraqi Crude Oil Flow In Pipelines by Polymeric,

, 9(13), 2018, pp.


Drag Reduction of Iraqi Crude Oil Flow In Pipelines by Polymeric

http://www.iaeme.com/IJMET/index.asp 1050 [email protected]

INTRODUCTION

Flowing liquids in pipelines can be occupied by high friction losses, especially in the case of

turbulent flow. Therefore, drag reduction is essential to reduce these losses using a small

quantity of additives (DRA). This would be crucial in many applications to reduce the

required pumping energy (head of the pump). So, a drag reducing agent is added to crude oil

transmission pipelines to achieve this goal [1, 2]. This can provide several benefits in pipeline

systems such as saving pumping power, reducing consumption of energy, enhancing flow rate

and decreasing pump sizes [3].

The drag reduction phenomenon was firstly observed by Mysels [4-6]. Mysels compared

the pressure of gasoline and gasoline thickened with aluminum di-soaps flow through the

same pipe. In 1948, Toms [7] also observed the drag reduction phenomenon, while he was

investigating a polymer degradation. He discovered that the use of polyxdcc methyl

methacrylate in mono-chlorobenzene causes a decrement in the turbulent skin friction drag up

to 80 %. It is also found that the flow rate could be raised due to the addition of the tasted

polymer at a constant pressure gradient.

Wang et al. [8] carried out a direct simulation of numerical study using a model of spring-

dumbbell to examine the inhomogeneous phenomena of polymer molecules during drag

reducing in a flow channel using polymer additives. Results show that the concentration of

polymer additives and elongation in buffer layer are highest, and most molecules of polymer

are parallel to the direction of streamwise and vertical to the direction of spanwise. Because of

the elastic effect of polymer, the balance of turbulent kinetic energy varies dramatically.

Hassanean et al [9] studied the effect of a DRA on the flow lines of crude oil production

in the Egyptian western desert. The DRA used in their study is poly alpha olefin of a high

molecular weight. The obtained results showed that this DRA has a significant effect on the

pressure drop and fanning friction factor. Thus, the pressure drop is decreased by 36% at a

pipeline capacity of 18,804 bbl./day when a 60 ppm of the DRA is added. So, the fanning

friction factor and shear stress are decreased by 47%.

Niccolo et al. [10] investigated three types of poly(acrylamide-co-NaAMPS) and pure

PHPAAm as polymers induced a drag reduction and a mechanical polymer degradation in 1"

horizontal bore circular cross-section pipe. It is found that the existence of NaAMPS groups

can increase the ability of PHPAAm to reduce the frictional drag while the sensitivity to

mechanical degradation remains unchanged.

DeGroot et al. [11] conducted a Computational Fluid Dynamics (CFD) simulation using

k–ω shear-stress transport (SST) as a turbulence model to simulate the effect of a macroscale

surface modification in terms of longitudinal grooves shape on the drag reduction in laminar

and turbulent channel flows. Results show that the approximate drag reduction can be

specified by evaluating the geometry drag reduction employing the first Fourier model of a

grooved geometry.

Jacob and Mei [12] performed a numerical study to simulate the drag coefficient and

vortex shedding for a two-dimensional bluff body and a Reynolds number range of (1-4x106).

They reported that the drag coefficient is reduced by 75% at maximum actuators power input.

So, an increase in Strouhal number for each successive increase in actuator power is observed.

The objective of the present work is to investigate the effectiveness (%DR) of drag

reducing agent (PVP) on drag reduction of Iraqi crude oil. This can be accomplished by

studying the effect of different additive concentrations on Rheological characterization,

pressure drop (or head loss), pumping power saving and flow increase.

Farhan Lafta Rashid, Auda J.Braihi, Ahmed Hashim, Akram Jassim Jawad


EXPERIMENTAL PART

LIQUID

Iraqi crude oil was used in this test as a flowing liquid which is supplied from Al-Najaf

refinery–Iraq. The physical properties of the crude oil at 25 oC are: viscosity =27.5 cp,

specific gravity =0.885, and API=32.36.

DRAG REDUCING AGENT

Poly vinyl pyridine is soluble in polar solvents such as water. It is also soluble in various

alcohols, such as ethanol and methanol as well as in more exotic solvents such as the heavy

eutectic solvent created by choline chloride and urea. So, it has prime wetting properties and

can form films [13, 14]. In the present work, poly vinyl pyridine is used at different

concentrations 500, 750, 1000, 1250 and 1500 ppm.

DESCRIPTION OF CIRCULATING FLOW LOOP SYSTEM

The test rig used in present work consists of a crude oil reservoir of dimensions (0.75 x 0.75 x

0.75 m) and a pump (flow rate =30 L/min., maximum head=30 m, maximum power =0.74

hp). This pump is used to circulate the treated crude oil from the reservoir through the pipe. A

flow meter is also used to measure the flow rate (flow rate=8 m3/h) of the treated crude oil

through the system. Tow pressure gauges are fixed at two different point on the pipe to

measure the pressure drop. A stainless-steel pipe of 10 m in length and inside diameter of

0.0508 m is used. A schematic diagram of the test rig is shown in Fig. (1). In addition, a

viscometer and density tester are used to measure the viscosity and density of the crude oil as

shown in Fig. (2) and Fig. (3), respectively. After the experimental apparatus is built, the

crude oil treated with different PVP concentrations is circulated through the flow loop system

to measure different affecting parameters.

RESULTS AND DISCUSION

In this work, equations (1-4) are used to predict the flow Reynolds number (Re), percentage

of the flow increase (%FI), percentage of the drag reduction (%DR), and Darcy friction factor,

respectively [15, 16]:

�� = �� (1)

% � = � 11 − ��%�� .�� − 1� �100 (2)

%�� = ∆� − ∆�!∆� (3)

# = 2�∆�$��% (4)

where v is the linear velocity, � is fluid density, � is dynamic viscosity, � is pipe diameter,

Δ�b and Δ�a are the pressure drop before and after the DRA is added, respectively and $ is the

pipe length.



RHEOLOGICAL CHARACTERIZATION

PVP polymer is added to the crude oil as a drag reducer at different concentration (0, 500,

750, 1000, 1250 and 1500) to investigate their effect on the flow characteristics of the Iraqi

crude oil. Fig. (4) shows that the density of the crude oil increases as the concentration of the

PVP increases. On the other hand, the viscosity

Relationship between shear stress and shear rate of the crude oil treated with different

concentrations of the DRA (0, 500, 750, 1000, 1250 and 1500 ppm) is illustrated in Fig.6. It is

observed that at concentration of 0 ppm (pure crude oil), almost a linear increase in the shear

stress is shown with the shear rate. This concentration exhibits the highest values of the shear

stress at all values of the shear rate compared with other concentrations. In addition, a

considerable decrease in the shear stress is obtain by adding the DRA to the crude oil. This

reduction varies as the concentration of the DRA varies and the highest decrease (lowest shear

stress) is observed at a concentration of 1500 ppm. It is also observed that the shear stress at a

concentration of 750 ppm is higher than that at 500 ppm.

Figure (7) shows the viscosity–shear rate relationship for the tested crude oil treated with

different concentrations (0, 500, 750, 1000, 1250 and 1500 ppm) of the DRA (PVP) at a

constant temperature of 25 oC. From this figure, it is shown that adding the DRA reduces

significantly the viscosity of the crude oil and the reduction depends on the DRA

concentration in the crude oil. Consequently, the lowest and highest reduction is obtained at

750 and 1500 ppm, respectively. This means that the influence of the tested DRA in reducing

the pipeline pressure drop is not attributed to its effect on viscosity but it is attributed mainly

to its effect of reducing the degree of turbulence energy inside the pipeline network, thereby

reducing gradually the shear stress which is clearly presented in figure (8).

CONSISTENCY INDEX AND FLOW INDEX

The Power law model can be used to describe any material behavior that obeys the power law.

In this model, if the power law index (flow index) is greater than unity (n>1), this means that

the sample is shear thickening, n<1 denotes that the sample is shear thinning and n=1 shows a

Newtonian, viscous behavior. This would normally be apply on the data that show

monotonically shear thinning behavior, rather than on the data areas that show plateaus, i.e.

the zero shear and infinite shear viscosities. After the log shear stress versus log shear rate is

plotted for the obtained experimental data, the power law trend line is fitted to obtain a

formula representing the data. The model is:

Shear stress = KDn

Where K = consistency index, D=shear rate, and n = power law exponent (flow index)

Figures (9, 10, 11, 12, 13 and14) present the shear stress vs shear rate with different PVP

additive concentrations (0, 500, 750, 1000, 1250 and 1500 ppm), respectively. For all these

figures, the flow indexes are less than unity which means that the sample is shear thinning and

the values of flow index are clearly decreased by adding the PVP at concentration of (750 to

1500 ppm). In addition, the minimum value of the flow index is obtained at a PVP

concentration of (1000 ppm).

CRUDE OIL FLOW CHARACTERSTICS

Figure (15) shows variation of pressure drop with different concentrations of the PVP. It is

shown that the pressure drop decreases with increasing the PVP concentration. This is

because that the addition of DRA (PVP) reduces the viscosity and therefore the Reynolds

number will increase which leads to decrease the friction factor, thereby the pressure drop

decreases. Accordingly, the head loss decreases as shown in figure (16).


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Figure (17) manifests the PVP concentration effect on the process of drag reduction. This

figure shows that the %DR increases with increasin

%DR is regarded to the increase in the associated additive molecules in the drag reduction

process. A maximum drag reduction of 35.1% is achieved at the largest concentration (1500

ppm). Therefore, the DRA addition

(18).

Another benefit of the DRA addition is increasing the flow as shown in figure (19). the

maximum flow increase is found to be 27.5 % which is obtained at PVP concentration of

(1500 ppm).

Fig

han Lafta Rashid, Auda J.Braihi, Ahmed Hashim, Akram Jassim Jawad

IJMET/index.asp 1053 [email protected]


figure shows that the %DR increases with increasing the PVP concentration. The increment in



ppm). Therefore, the DRA addition increases the saving in pumping power as shown in figure



Figure (1): Circulating flow loop system

Figure (2): Viscometer cone-plate

han Lafta Rashid, Auda J.Braihi, Ahmed Hashim, Akram Jassim Jawad

[email protected]


g the PVP concentration. The increment in



increases the saving in pumping power as shown in figure





Figure (3) Density tester decreases with increasing of the concentration as shown in Fig. (5).

Figure (4): Variation of crude oil density with PVP concentration

Figure (5): Variation of crude oil dynamic viscosity with PVP concentration



Figure (6): Shear stress-shear rate variation for the tested crude oil treated with different

concentrations (0, 500, 750, 1000, 1250 and 1500 ppm) of the PVP

Figure (7): Viscosity-shear rate variation for the tested crude oil treated with different concentrations

(0, 500, 750, 1000, 1250 and 1500 ppm) of the PVP



Figure (8): Shear stress-viscosity variation for the tested crude oil treated with different

concentrations (0, 500, 750, 1000, 1250 and 1500 ppm) of the PVP

Figure (9): Analysis plot power law for pure crude oil (0 ppm PVP)

Figure (10): Analysis plot power law for crude oil with addition of (500 ppm PVP)




Figure (15): Variation of pressure drop with different concentrations of PVP

Figure (16): Variation of head loss with different concentrations of PVP



Figure (17): Variation of the drag reduction (%) with different concentrations of PVP

Figure (18): Variation of the pumping power with different concentrations of PVP

Figure (19): Variation of the flow increase (%) with different concentrations of PVP

CONCLUSIONS

The drag reduction effect is very important in many applications such as petroleum flow in pipeline

systems. The drag reduction behavior of PVP has been studied. It is concluded that adding a small

amount of PVP concentration can provide a significant impact on the characteristics of the fluid flow

in the turbulent flow. So, it is proven that the PVP is an effective drag reducing agent in the fluid

turbulent flow, especially, at relatively high concentration of the PVP. The percentage of the drag



reduction also increases due to the reduction of the crude oil viscosity. Besides that, pressure drop (or

head loss) also decreases as the PVP concentration increases. Accordingly, the pumping power and the

flow can be optimized. Thus, the PVP additive is found to be an efficient drag reducing agent for the

Iraqi crude oil.

ACKNOWLEDGMENT

We would like to express our deep thanks and respect to all members of (Faculty of Materials

Engineering, Polymers and Petrochemical Industries Department) for their cooperation.

REFERENCES

[1] Zakin, J., 2005, “Some recent developments in surfactant drag reduction,”

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Heat and Mass Transfer 51(2), pp. 835-843.

[3] Lixin, C., Dieter, M., Andrea, L., 2007, “Boiling Phenomena with Surfactants and

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[4] Mysels, K., 1971, "Early experiences with viscous drag reduction," Chem. Eng. Prog.

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[5] Mysels, K., 1949, “U.S. Pat.,” 2(492), pp.173-179.

[6] Mysels, K., Agoston, G., Harte, H., Hottel, H., Klemm, W., Pomeroy, H., and Thompson,

J.,1954, "Flow of gasoline thickened by napalm," Ind. Eng. Chem.,46, pp. l0l7-1019.

[7] Toms, B., 1949, “Some observations on the flow of linear polymer solutions through

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[8] Wang, Y., Yu , B., Xuan, W., Peng, W., 2012, “POD and wavelet analyses on the flow

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Heat and Mass Transfer , 55, pp. 4849–4861.

[9] Hassanean, M., Awad, M., Marwan, Bhran, A., 2016, “Studying the rheological

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[10] Niccolo, L., Brun, I., Zadrazil, L., Norman, Alexander, B., Christos, N., 2016, “On the

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[11] DeGroot, C., Wang, C., Floryan, J., 2016, “Drag Reduction Due to Streamwise Grooves in

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[12] Jacob, T., Mei, Z., 2016, “Active Flow Control Schemes for Bluff Body Drag Reduction,”

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[13] Wohlfarth, C., 2010, "Thermodynamic Properties of Polymer Solutions," Landolt-

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[14] Sapir, L., Stanley, C., Harries, D., 2016, "Properties of Polyvinyl pyrrolidone in a Deep

Eutectic Solvent," J. Phys. Chem. A., 120, pp.3253–3259.

[15] Darby, R., 2001, “Engineering Fluid Mechanics,” Marcel Dekker, New York, NY, USA,

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[16] Holland, F., Bragg, R., 1995 “Fluid Flow for Chemical Engineers,” Edward Arnold,

London, UK, 2nd edition.

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