This research work is focused at determining the best combined factors (temperature, concentration & salinity) for the most stable O/W Emulsion and consequently considering the effect the factors have on the amount of oil content recovered after transportation through the piping system at the minimal pressure drop possible. In order to achieve this, the formulation of emulsion using stabilized alkaline solution according to the specific formulated factorial combination was done. Pumping of the formulated emulsions through a pilot scale pipe-system was considered. Also, thermal demulsification of emulsion transported to measure the oil content recovered, in order to ascertain the best yield under the best conditions was carried out. Data obtained from the experiments performed shows that run 8 with highest factorial level (75C, 1wt. %, 0.1M) has the most stable emulsion with no phase separation, higher flowability and very reduced pressure drop. Similar trend was also seen in run 4 with the least pressure drop. The observed properties of emulsions formed can be attributed to the effect of (i) concentration of the aqueous phase (ii) salinity of the aqueous phase and (iii) emulsification temperature.

1. SUMMARY OF PROJECT REPORT ON THE EMULSION
TRANSPORT OF NIGERIAN HEAVY OIL
Olanrewaju, Adebayo Bamidele
Department of Chemical Engineering,
Obafemi Awolowo University, Ile-Ife, Osun State, Nigeria.
Email: adebayoolanrewaju206@gmail.com Contact: +234 (0) 7037710839
ABSTRACT
This research work is focused at determining the best combined factors (temperature, concentration &
salinity) for the most stable O/W Emulsion and consequently considering the effect the factors on the
amount of oil content recovered after transportation through the piping system at the minimal
pressure drop possible. In order to achieve this, the formulation of emulsion using stabilized alkaline
solution according to the specific formulated factorial combination was done. Pumping of the
formulated emulsions through a pilot scale pipe-system was considered. Also, thermal demulsification
of emulsion transported to measure the oil content recovered, so as to ascertain the best yield under
the best conditions was carried out.
Data obtained from the experiments performed shows that run 8 with highest factorial level (75oC,
1wt. %, 0.1M) has the most stable emulsion with no phase separation, higher flowability and very
reduced pressure drop. Similar trend was also seen in run 4 with the least pressure drop.
The observed properties of emulsions formed can be attributed to the effect of (i) concentration of the
aqueous phase (ii) salinity of the aqueous phase and (iii) emulsification temperature.
1.0 INTRODUCTION
Nigeria is a country rich in mineral wealth, with petroleum and natural gas as the country’s major
mineral resources. Nigeria’s economic growth primarily comes from the country’s oil sector. Natural
bitumen in place, estimated to be not less than 38 billion barrels, is located in southwestern Nigeria,
in the Ghana Basin. A large portion of Nigeria reserves of crude oil consists of heavy and extra heavy
crude (Ashimiyu, 2013).
As the reserves of conventional crude oil continue to decline, heavy oil and bitumen are becoming
increasingly important sources of hydrocarbon liquids. A major challenge associated with the
exploitation of these heavy oil resources is the difficulty inherent in its pipeline transportation to the
market/refinery due to its very large viscosity. To curb this problem, the operation of transporting
such oil has to be economical so as to keep costs in line with the market realities. Methods such as Oil-
in-water (O/W) emulsions, heating and dilution with lighter petroleum fractions such as kerosene,
diesel etc. could be used to reduce the viscosity level of the oils for their ease of transportation through
conventional pipelines.
An emulsion is a dispersion of droplets of one liquid in another one with which it is incompletely
miscible. In emulsions, the droplets often exceed the usual limits for colloids in size (Israelachvili,
1994). All emulsions, perhaps with the exception of micro-emulsions, are thermodynamically
unstable. However, the destabilization may take considerable time, and a stable emulsion is unable to
resolve itself in a defined time period without some form of mechanical or chemical treatment
(Schramm, 1992).
From the previous work on emulsion transport of Nigerian Heavy Oil, the following observations have
been made:

2.  Emulsifying Temperature: Emulsion Prepared between 10-20oC resulted to a decrease in
droplet size and amount of resolved water. The properties remained constant at temperature 30 -
60oC. On the other hand, at 20-60oC, the apparent viscosity of the emulsions was observed to
decrease linearly. However, it was observed that higher temperatures could promote stabilization
effects derived from the increased Brownian motion and mass transfer across the interface.
 Treatment Combinations for Factorial Runs: The emulsification temperatures were made
to vary from 30 to 80oC, the concentration of the NaOH used at pH of 13 varied from 0.1M to 1M
while the weight of the NaCl salinity substance of the emulsion was found to vary between 1 to 4
wt.%. The highest yield was observed at the lowest combination of 30oC, 0.1M NaOH
concentration (pH of 13) and 1wt% NaCl which confirmed Adewusi’s work of 1989 on Nigerian
Heavy Oil.
 Heavy Oil-Caustic System: The Heavy Oil-Caustic System used were in the ratio of 60%:40 %,
57.14%:42.85% and 50%:50%. From the results obtained the combination of 60%:40% was found
to be more stable at 100% pump power input.
1.1 Modifications
Improvement on the stability of O/W emulsion before transportation with maximum oil recovery after
transportation via pipeline system could be enhanced by applying the following modifications to the
flow system;
Emulsifying Temperature: First, from Lawal (2013), that higher temperature can promote
stabilization effect on O/W emulsion. This thus leads to a proposition of higher emulsifying
temperature of about 25-75oC with 10oC increment as compared to 20-60oC of the work to be
modified.
Treatment Combinations For Factorial Runs: Since the highest O/W emulsion yield
was observed at the lowest combination of 30oC, 0.1M NaOH concentration (pH of 13) and 1wt%
NaCl, further lowering the combination conditions to about 25oC-75oC, 0.07M to 0.1M NaOH
concentration (pH of 13) and 0.5wt% to 1wt% is also proposed.
Heavy Oil-Caustic System: Since the result obtained the combination of 60%:40% was
found to be more stable at 100% pump power input and, recalling Ashrafizadeh et.al.(2010) that the
stability of crude oil-in-water emulsion slightly decreases with increasing oil content of the emulsion
up to 60 vol. %, beyond this critical value, the stability of the emulsion experiences a significant
decrease; afterwards the stability continues to increase with increasing oil content until it attains 70
vol.% where phase inversion occurs. This means that at immediately above 60 vol.% the stability of
O/W emulsion will decrease slightly but increasing it to say 65-67 vol. % restore better stability.
Hence, proposition of 65-67 vol.% oil content in oil-in-water is made.
Gravitational Settling (Application of Natural Gravitational Force): This would be
adopted over centrifugal settling (the use of centrifugal force) to test the level of phase separation over
a reasonable period of time, in order to validate the stability of the O/W emulsion before
transportation.
2.0 METHODOLOGY
2.1 Experimental Apparatus
2.1.1 Mechanical Stirrer
Mixing was done with the aid of a variable speed mechanical stirrer (App No 07B 9369 B) with
operating frequency of 50Hz, voltage range of 220-240 V and 1 Amp.

3. 2.1.2 Electric Stove
Electric Stove (model- ES-1020) with operating frequency of 50 Hz, voltage of 230 V and power of
1000 W was used for heating at various stages of work.
2.1.3 Digital weighing balance
The weighing balance used in the experiment is the Metler Toledo model PB 153.
2.1.4 Centrifugal pump
Centrifugal pump of gear type (Viking HLI4) with operating frequency of 50 Hz, pump power of 0.5
hp and maximum flow rate of 35 L/min was used in this research work.
2.1.5 Pilot plant pipe system
The pilot pipe-system used in this study of a horizontal cylindrical stainless steel tube, 320 cm long
and 1.77 cm internal diameter. It is made up of a centrifugal pump attached to one end of the pipe
system to pump the emulsion prepared, pump-filter to filter dirts from the emulsion to be pumped
and two cylindrical tanks placed at both ends of the pipeline, one the reservoir for emulsion before
pumping and the other to receive the pumped emulsion. It is also fitted with four pressure guages
placed at different position to record the pressure drop across the pipe-system, a control valve to
control flow rate and pump support to give the pump appropriate stability.
2.2 Experimental Materials/Chemicals
1. Heavy oil samples obtained from Agbabu village, Ondo state.
2. Caustic Solution: Two solutions of Sodium Hydroxide (NaOH) of 0.1M and 0.07M respectively
which acts as the alkaline medium.
3. Stabilizer: Sodium Chloride (NaCl),
4. Co-surfactant: Butanol ( ).
5. Distilled water.
2.3 Preparation of Emulsion

4. Emulsions were prepared by weighing the required amount of heavy oil (1.3kg) and the stabilized
alkaline solutions in a suitable container according to the desired emulsion formulations (see table
3.1) to prepare the oil-in-water emulsion. The oil/water ratio of the emulsion prepared was 65:35. This
is to aid maximum oil content recovery with the best stability possible. The emulsions were
homogenized with the aid of the variable speed mechanical stirrer provided.
The solutions made were found to be visually uniform and free of un-dissolved particles after
15minutes of mixing time. Additional mixing of solution was avoided to prevent shear degradation.
Measured volumes of each emulsion were transferred into suitable containers for transportation.
Some samples of each emulsion prepared were taken to test for their stability by watching-out for
phase separation after 6-7 days of preparation.
2.4 Emulsion Transportation
The heavy oil-water emulsions prepared were pumped through a pilot plant pipe-system previously
described. The flow rate of the emulsions was regulated by means of a variac connected to the
centrifugal pump. Flow rate was calculated based on the volume pumped over in a given time taken.
Pressure heads were measured by means of the pressure gauges attached to the pipeline. Reynolds
number, Friction factor, and head loss due to friction, Pressure drop along the pipe, were calculated
for each experimental run.
3.0 RESULTS AND DISCUSSION
3.1 Results
3.1.1 Emulsification of Heavy Oil
Eight heavy oil-in-water emulsions were prepared for this research. The heavy oil / alkaline solution
systems are presented in Table 3.1. The table shows the respective system, the formulations and
observed properties of the emulsions formed.
3.1.2 Pumping of Emulsion through the pipe System
Table 3.2 shows the fluid properties of the emulsion prepared on transportation. It shows that run 8
has the highest flow rate and velocity. It is among the runs with the least pressure drop, and has the
least viscosity hence the highest flowability. All these are responsible for the ease of flow and pumping
rate of run 8. These properties of run 8 make it the best emulsion for transportation.
3.1.3 Oil Content Analysis
To further process the emulsified oil, it has to be recovered from the emulsion using one of the readily
recognized procedure for demulsification. Samples were taken after pumping for thermal
destabilizing. Table 3.3 shows the volume and weight % of the emulsion transported prior to
demulsification while table 3.3 shows the data obtained from the thermal destabilizing method
adopted.

5. Table 3.1: Heavy oil/Alkaline solution systems (factorial combination)
S/No Temp. of mixing
(oC)
Heavy oil feed
(wt/wt.%)
Brine
(wt/wt.%)
Caustic solution
concentration
(M)
Butanol
(Vol.)
Remarks
1
2
3
4
5
6
25-35
75
25-35
75
25-35
75
65-67
65-67
65-67
65-67
65-67
65-67
0.5
0.5
0.5
0.5
1.0
1.0
0.07
0.07
0.10
0.10
0.07
0.07
106.25
106.25
106.25
106.25
106.25
106.25
Most stable emulsion
No phase separation
Relatively high viscosity
Very high pressure drop
Relatively stable emulsion
No phase separation
Reduced viscosity
Reduced pressure drop
Transient stability
Phase separation occurred
Reduced flowability
High pressure drop
Stable emulsion
No phase separation
High flowability
Reduced pressure drop
Transient stability
Phase separation occurred
Reduced flowability
High pressure drop
Stable emulsion
Partial phase separation
High flowability
Reduced pressure drop

6. Table 3.1: Heavy oil/Alkaline solution systems (factorial combination) contd.
7
8
25-35
75
65-67
65-67
1.0
1.0
0.10
0.10
106.25
106.25
Stable emulsion
No phase separation
Reduced flowability
High pressure drop
Stable emulsion
No phase separation
High flowability
Very low pressure drop
Table 3.2: Results of emulsion fluid parameters
Runs Volume
(m3) x 10-3
Time (s) Pressure
drop
pa x 103
Flowrate
(m3/s) x 10-4
Velocity
(m/s)
Head loss
(m4/s) x 10-3
Friction
factor
10-3
Reynold
s
number
Re x 103
Viscosity
Pa.s x 10-3
1
2
3
4
5
6
7
8
2.5
2.5
2.5
2.5
2.5
2.5
2.6
2.6
10
6
8
5
8
5
6
3
34.47
13.79
20.68
10.34
24.13
11.72
22.75
13.79
0.250
0.420
3.125
5.000
3.125
5.000
4.330
8.670
0.0796
0.137
0.995
1.591
0.995
1.591
1.379
2.758
429400
5.65
8.47
4.512
1.053
3.529
1.033
6.259
5421580.3
240.82
6.861
1.426
0.3328
0.1115
0.4344
0.06582
0.0118
0.2658
9.329
448.78
192.295
573.777
0.147
972.32
5.0802
0.7910
0.1636
0.05105
0.07448
0.05787
0.1296
0.03928

7. Table 3.3: Volume and weight % of emulsion transported.
Table 3.4: Oil content analysis
3.2 Discussion of Results
Design of Experiment (DoE) software called Quantum XL was used to analyze the results obtained
from the experiment. The following were deduced from the analysis.
3.2.1 Emulsification of heavy oil
Alkali (NaOH) solution of concentration 0.07M and 0.10M were used to study the various factors
affecting the viscosity and stability of heavy oil-in-water emulsion. Results in Tables 3.1 and 3.2 show
the amount of heavy oil feed emulsified in the system considered in this study and also, the observed
properties of respective emulsions formed. The result shows that run 8 with the highest level of
factorial combination has the highest flow rate and the least viscosity value hence the ease of flow of
the fluid. The low viscosity is responsible for the reduced pressure drop during transportation. Run 6
also shows similar trend but with a reduced flow rate when compared with run 8. Run 1 with the
lowest factorial combination gives the highest viscosity hence higher pressure drop and reduced flow
rate compared with the other combinations.
Runs Volume of emulsion
transported
(%)
Wt. of emulsion
transported
(%)
1
2
3
4
5
6
7
8
70.0
83.3
52.0
64.0
30.0
91.3
61.5
92.3
82.2
88.2
47.1
55.6
42.5
91.7
50
88.9
S/No Volume of oil content
before pumping
(%)
Volume of oil
content after
pumping
(%)
Loss of oil
content
(%)
1
2
3
4
5
6
7
8
65
65
65
65
65
65
65
65
60.7
62.1
52.0
50.1
48.7
62.6
57.2
63.3
4.30
2.90
13.0
14.9
16.3
2.40
7.80
1.70

8. 3.2.1.1 Effect of emulsifying temperature
The emulsifying temperature plays an important role in the emulsion formulation and preparation. It
has effects on the viscosity of the oil and water phases as it aids in the reduction of viscosity of the
emulsions. The results of the experiment show that the major contributory factor in reducing the
viscosity of emulsion is the emulsifying temperature. Figure 3.1 shows that at the highest level of
temperature highest volume of emulsion was transported. This means that the amount of emulsion
transported is directly proportional to the temperature value; also the more the temperature the lesser
the viscosity (see table 3.2). Table 4.2 also shows that all combination with the highest level of
temperature has lower viscosity and higher flow rate. T his proves the temperature-sensitive nature of
emulsion.
Figure 3.1: Volume of emulsion against the emulsifying temperature.
3.2.1.2 Effect of emulsifier concentration
It was observed that increasing the concentration of alkali medium (NaOH) from 0.07M to 0.1M
resulted in a slight increase in the viscosity of the emulsion, while the stability significantly increased.
An increase in concentration caused an increase in the amount of barriers between the two phases and
provides a better distribution of dispersed droplets in the continuous phase. Since increase in viscosity
reduces flowability and in turn, transportability of the emulsion, there was a slight reduction in the
volume of emulsion pumped. This is shown by figure 3.2. At the lowest level more emulsion was
pumped than at the highest level.
Thus increasing alkali concentration in the emulsion increases the viscosity of the emulsion (Eirong
and Lempe, 2006). At the same time, increasing the concentration would lower the interfacial tension
which would facilitate the breakage of droplets into smaller ones. The latter would result in a more
stable emulsion of higher viscosity.
Figure 3.2: Volume of emulsion against emulsifying temperature.
3.2.1.3 Effect of salt concentration (Salinity)
The influence of salt concentration in the water phase of the emulsion, on the viscosity and stability of
the emulsions was investigated. It was observed that, increasing the salt concentration increases the
viscosity of the emulsions formed. The ions would act as barriers among the oil droplets and the water
phase. Thus increasing the salinity of the aqueous phase, results in the enhancement of the emulsions
stability. Ahmed et al. (1999) reported the same observation, i.e. increase in the viscosity of the
emulsion due to increase in the aqueous phase salinity, and attributed this behavior to the lower

9. interfacial tension of the oil and aqueous phases at higher aqueous salinities. It is obvious that at
lower interfacial tensions, smaller droplets of dispersed phase would also form, which represents
higher stabilities.
Figure 3.3: Volume of emulsion against salinity and NaOH concentration.
3.2.2 Emulsion transportation
During pumping operation, parameters like pressure head and volumetric flow rate were measured, as
well as, Pressure drop, Head loss due to friction, Friction factor and Reynolds Number calculated for
the eight experimental runs. All measured and calculated data are shown in Tables 3.2.
From the results obtained in the eight experimental runs, it can be concluded that the emulsion flow
of runs 3, 4, 5, 6, and 8 are turbulent as shown by the high value of Reynolds Number obtained, Re>
4000.
4.0 CONCLUSION
The oil-in-water emulsions were successfully prepared using different concentrations of alkali
according to the factorial formulation (see table 3.1). Concentrated oil-in-water emulsions were
formulated using low-cost additives and were prepared through a low-energy procedure at laboratory
scale. These formulations and procedures were done to determine the best conditions to produce
emulsions with the most suitable properties (low viscosity and high stability) that enable it to be used
for pipeline transportation of Agbabu heavy oil.
The results shows that emulsion prepared under the highest level of factorial combination (see table
3.1) gives the highest flow rate, reduced pressure drop and the least viscosity value (see table 3.2). This
observation is exhibited by run 8. Also, run 4 gives similar trend having the least pressure drop during
transportation.
In general, runs 2, 4, 6 & 8 with the highest temperature gives reduced pressure drop, smaller
viscosity value and higher flow rate compared to runs 1, 3, 5 & 7. Figure 4.1 showing that the
emulsifying temperature has the highest effect on the volume of emulsion pumped. This conforms to
the result of runs 2, 4, 6 & 8.
Figure 4.1: Main and combined effect of temperature, salinity & concentration on
the volume of emulsion produced.

10. REFERENCES
Ahmed, N.S., Nassar, A.M., Zaki, N.N., Gharieb, H.Kh., 1999. Formation of fluid heavy oilin-water
emulsions for pipeline transportation. J. Fuel 78, 593–600.
Ashimiyu, M.A. (2013). ‘Emulsion Transport of Nigerian Heavy Oil.’ Unpublished B.Sc. Thesis,
Department of Chemical Engineering, Obafemi Awolowo University, Ile-Ife.
Ashrafizadeh, S.N., Kamram, M. (2010). Emulsification of heavy crude oil water for pipeline
transportation. Journal of Petroleum Science and Engineering 71, 205-211.
Israelachvili, j. Colloids and surfaces a: physicochemical and engineering aspects 1994,91, 1-8.
Schramm, L. L. Petroleum Emulsion. In.: Schramm, L.L. Emulsions Fundamentals and Applications
in the Petroleum Industry. American Chemical Society, Washington DC. 1-45., (1992).