Chandra Mohan Sinnathambi

Krittika Chandran

Smita Krishnan

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Journal of Applied Science and Agriculture, 9(18) Special 2014, Pages: 245-248 
 
AENSI Journals 
Journal of Applied Science and Agriculture 
ISSN 1816-9112 
 
Journal home page: www.aensiweb.com/JASA 
 
   
Corresponding Author: Chandra Mohan Sinnathambi, Universiti Teknologi PETRONAS, Department of Fundamental and 
Applied Sciences, Bandar Seri Iskandar, Malaysia. 
                                          E-mail: chandro@petronas.com.my 
Application of Different Groups of Demulsifier In Water-In-oil Emulsion  
 
Krittika Chandran,  Smita Krishnan  and Chandra Mohan Sinnathambi 
 
Department of Fundamental and Applied Sciences, Universiti Teknologi PETRONAS Malaysia. 
 
A R T I C L E  I N F O   A B S T R A C T  
Article history: 
Received  25  July  2014 
Received in revised form 
8 July  2014 
Accepted  15  September 2014 
Available online 17 October 2014 
 
Keywords: 
Crude oil  Demulsifier Emulsion 
 
 
 
 Crude oil is always produced with water. This association causes many problems during 
oil production, arising from the formation of emulsion. To overcome this issue, a 
synthetic surfactant, aka demulsifiers, is formulated to break the emulsion. Emulsion, a 
mixture of liquids with no mutual solubility between them is usually present as droplets 
of one liquid distributed in other continuous phase. Demulsifiers acts as an emulsion 
breaker, where they are able to separate the water-oil emulsions to their respective 
phases. There are many types of demulsifiers formulation where they may be divided 
into four main type of group for the oil and gas industries. This include; polymer, 
amines, alcohol and polyhydric alcohol. Demulsifier main function is to reduce the 
interfacial tension properties of the emulsion. This in turn helps break the emulsion into 
their respective phases.  Demulsification formulation is also dictated by the properties 
of the crude oil. Demulsification formulation is tailor made for individual type of crude. 
Therefore, choosing the right demulsifiers formulation is important to give an effective 
separation of emulsion in crude oil processing. The objective of this review is to 
examine the different groups of demulsifiers used as surfactant for the 
removal/breakdown of emulsion from crude oil processing. Polymeric demulsifiers are 
found to be more suitable for water-in-oil emulsion, while the other 3 mention above 
are suitable for oil-in-water emulsion. 
 
 
© 2014 AENSI Publisher All rights reserved. 
To Cite This Article: Krittika Chandran., Smita Krishnan and Chandra Mohan Sinnathambi., Application of different groups of demulsifier 
in water in oil emulsion. J. Appl. Sci. & Agric.,  9(18): 245-248, 2014 
 
INTRODUCTION 
 
Crude oil is natural and unprocessed oil found under the earth’s surfaces. During the production of crude 
oil, water will be produced along with the oil in the form of an oil-and-water emulsion (Abdel-Azim et al., 
2010). Emulsion is defined as the mixture of liquids that have no mutual solubility between them, where one 
liquid is present as droplets and distributed throughout the other (Abdurahman, H.N., and M. Nuraini, 2010). 
Emulsion is an undesirable substance, which increases the operational and capital cost in pipelines and 
processing equipment. Consequently, an effective and efficient demulsifier is needed to separate the oil and 
water, destabilize and break the emulsion to produce oil without any water. The demulsifiers need to be 
analyzed and formulated precisely to ensure it meets the requirements in separating the emulsion. Demulsifiers 
acts as an emulsion breaker, where they are able to separate the water-in-oil into their respective phases (Adel, 
S.H., et al., 2003). 
However, it has been found that the interfacial barrier (boundary between the oil and water phase) is the 
main cause of the formation of the water-oil emulsion. The interfacial boundary divides the oil and water 
phases. Due to its close proximity reaction between oil and water takes place. This creates interfacial barriers 
which prevent the coalescence between the oil and water phase from taking place. As a result, oil-water 
emulsion is formed. Adding the demulsifier will interrupt this interfacial barrier by destabilizing and breaking 
the emulsion to segregate the oil and water phase.  Addition of demulsifiers needs to be carefully administrated 
as wrong formulation might make the emulsion more stable and difficult to break. A correct formulation is a 
must to ensure it meets the necessary requirements in breaking the emulsion.                                                                                                                                                                                     
 
Development of different groups of demulsifier: 
  Before the 1940’s, the chemicals that were obtained from condensation, such as sulphuric acid, sulphated 
caster oil, polyamines and polyhidric alcohols were used directly as demulsifiers (Auflem, I.H., 2002).  
However, in the early 1940’s, with the development of the condensation of alkylene oxide technology, majority 
246                               Krittika Chandran,  Smita Krishnan, Chandra Mohan Sinnathambi 2014 
Journal of Applied Science and Agriculture, 9(18) Special 2014, Pages: 245-248 
 
of the demulsifier components were made up of condensation products such as ethylene-, propylene- and 
butylene- oxides, which are derived  from the alkoxylated polymer group.                                                                                         
After 1950, new classes of nonionic detergents were developed through condensed polyether, which were 
made possible by the large-scale production of ethylene and propylene oxides (Amir Mosayebi, Reza Abedini., 
2013). The condensation products of ethylene oxide were found to be water-soluble (hydrophilic), whereas 
propylene oxide gave poly condensation products that tended to be oil soluble (hydrophobic).                                                                                     
At present, the polymer widely used in demulsification industry is a surfactant which consists of both the 
hydrophilic and hydrophobic groups. This means that the polymeric surfactant has both a hydrophilic and 
hydrophobic group. The hydrophilic part is able to locate itself to the water molecule and the hydrophobic to the 
oil molecules present at the interface. Alkoxylated material was found to be the best polymeric surfactant.                                                                       
In water-in-oil emulsion, the most effective demulsifiers are oil-soluble or hydrophobic demulsifiers. This 
is because; oil is the continuous phase while water is the dispersed phase. Therefore, the surfactant will absorb 
directly into the continuous phase without any resistance in its optimum temperature. Oil soluble demulsifiers 
are usually formulated only in the organic solvents, such as toluene, xylene, dioxane, or even in co-solvents 
comprising of organic solvents and water, where the organic solvent usually consists of ethylene diamine, 
diethylene triamine or ethanolamines (Becker, J.R., 1997). 
 
Objective: 
The objective of this review is to investigate the different groups of demulsifiers that have been used as 
surfactants for breaking water-oil emulsion from crude oil. 
 
RESULTS AND DISCUSSION 
 
Most common groups of demulsifiers used in oil and gas industries is either water-in-oil or oil-in-water. 
The main surfactant species can be basically be divided into 4 groups namely; amine, polymeric, alcohol and 
polyhydric alcohol. The grouping of the different surfactant species are summarized in Table 1 below 
 
Table 1: Grouping of demulsifiers based on surfactant species 
Amines Pentylamine  
Hexylamine  
Octylamine  
Dioctylamine 
Polymeric Polyethylene Oxide 
Polyethylene block 
Alcohol Methanol  
Ethanol  
Propanol  
Butanol 
Polyhydric Alcohol Polyethylene glycol 
Ethylene glycol 
Propylene glycol 
 
The separation rate of water-in-oil emulsion is influenced by the addition of a chemical breaking agent aka 
demulsifier, into the emulsion. Demulsifiers are strained from a wide range of chemistries. With the right 
formulation, the demulsifiers are able to treat all kinds of emulsions under the most challenging field conditions, 
such as in high turbulence or high water content. This is due to its ability, affinity and properties to locate the 
interfacial section of the oil-water emulsion. Apart from its swift action, a successful demulsifier formulation 
needs to have a water separation efficiency of 80% separation, a sharp and clear interface, and the separated 
water phase must be clear to the naked eyes.                                                            
According to previous study done by (Kim, Young-Ho, 1995), polymer group demulsifiers give drier oil, 
cleaner water and a sharper interface. Moreover, the polymer group demulsifiers provide outstanding 
performance in heavy oils and low temperatures. This is because the polymeric molecule has high molecular 
weight, and is able to flocculate the large number of sub-micron water droplets dispersed in the crude oil. 
Therefore, water droplets are concentrated at the base of the oil column due to the coalescence action, and the 
oil is dehydrated above the settling level of the flocculated water droplets.                                                
Amine group demulsifiers are frequently used in crude oil emulsion studies because it provides good results 
in separating the emulsion. According to the study of Nuraini et al (2011), oil soluble demulsifiers are the best 
for water-in-oil emulsion. Amines are highly surface active and are able to absorb on the oil-water interface, 
because it will directly absorb into the continuous water phase. However, the disadvantage of the amine group 
demulsifiers is that they are capable of changing the pH or salinity of the aqueous phase of the emulsion. This 
property will enhance emulsion stability and decreases the demulsification efficiency of the applied demulsifiers 
(Merchant, Jr. and M.L. Sylvia, 1988). 
247                               Krittika Chandran,  Smita Krishnan, Chandra Mohan Sinnathambi 2014 
Journal of Applied Science and Agriculture, 9(18) Special 2014, Pages: 245-248 
 
The influence of alcohol and polyhydric alcohol demulsifiers towards water-in-oil emulsion was also 
studied. The efficiency of this group of demulsifiers depends on the water solubility and the molecular weight of 
the demulsifier. Alcohol is a low molecular weight demulsifier, which is also known as a water-soluble 
demulsifier. In general, demulsifiers with lower molecular weight chemistries cause increase in the interfacial 
adsorption rate and decrease in the interfacial activity. Therefore, lower molecular weight demulsifiers have a 
faster initial effect, but it will   not be effective in the overall demulsification.            
Producing a workable demulsifier formulation for a demulsification purposes is a complicated 
process/method. The most important challenge in producing a novel demulsifier to match the characteristics of 
the crude oil investigated. This is because, not all the crude oil has the same composition or properties. One 
demulsifier formulation suitable for one type of crude might be risky for another. In the water-in-oil emulsion 
system, the key factor of a demulsifier mechanism is breaking the stable interfacial film (Mosayebi, A., 
Abedini., R., 2013). The mechanism of the demulsification process should be examined carefully in order to 
understand the molecular interaction between the demulsifiers and interfacial active agents, such as asphaltenes, 
resins and waxes, which exist in crude oil. It is likely that the demulsifier interacts differently with some crude 
oil components, which causes differences in the demulsification performance. Demulsifier bases give 
outstanding performance in resolving a range of crude oil emulsions and are mostly effective when used in 
heavy crude formulations (Monson, L.T., 1969). This is because as the density of the crude increases, its density 
approaches the density of water. The interface attraction between the water and oil molecules increases as a 
result a correct demulsifier formulation at an optimum temperature is able to increase the thinning of the 
interface barrier, resulting in better separating of the two phases.    
If the demulsifier is prepared based on the needs of the particular emulsion, it will ensure that the excess 
water in the oil be removed or treated before disposal. Further work in selection of the surfactant for a particular 
application is essential to provide a better understanding of the mechanisms involved, in order to help in the 
development of a demulsifier formulation that could serve its applicable in the industry. 
To further illustrate the above statement, experiment conducted by Mosayebi is given in Figure 1. The 
experiment investigates the amount of water separated from water-in-crude oil emulsion versus time using 
different demulsifiers on artificially prepared water-in-oil emulsions. All the demulsifiers were used under 
similar condition and matrix, at different solvent concentration. Results shows that in the first 200 minutes, the 
amount of water separated by EO/PO Block Copolymer (polymer group) hexyle amine, pentyl amine (amine 
group) and ethylene glycol (polyhydric alcohol group) was 7, 7, 2, and 0 % respectively. There was no water 
separation from 1000 minutes until 2200 min. After 2200 minutes, EO/PO Block Copolymer had separated the 
highest percentage of water which was approximately 55 %, followed by hexyle amine with 34 %, pentyl amine 
with 29 %, and ethylene glycol at 22% respectively (Kim, Young-Ho, 1995).        
Thus, the polymer-group (EO/PO) demulsifiers provided a better result in separating the emulsion in crude 
oil. This is because the polymer-group demulsifier is able to decrease the interfacial tension gradient, and 
accelerates the coalescence of crude efficiently. This occurs when the displacement of the natural stabilizers 
(from demulsifier), which is present in the interfacial film around the water droplets occurs, creates an 
interfacial tension gradient, whereby it is high on the inside of the film and low on the outside the film. 
Subsequently, when the demulsifier molecules are adsorbed, the interfacial tension is decreased, causing an 
increase in the rate of film thinning by inducing sharper interface resulting in droplet coalescence and better 
separation (Salam, K.K., et al., 2013). 
 
 
Fig. 1: The effect of polymer and amine demulsifiers on crude oil emulsion (Kim, Young-Ho, 1995) 
248                               Krittika Chandran,  Smita Krishnan, Chandra Mohan Sinnathambi 2014 
Journal of Applied Science and Agriculture, 9(18) Special 2014, Pages: 245-248 
 
Conclusion: 
The results from the findings demonstrate that the stability of the crude oil emulsion depends on the type or 
group and concentration of surfactant and solvent used. For oil-in- water, water soluble demulsifier such as 
amine and alcohol surfactant group are favored. For water-in-oil, polymeric surfactant group is recommended as 
the continuous phase is oil. Properties of the crude also play an important part in breaking oil-water emulsion. 
Therefore, having selected surfactant group laboratory and industrial experiments need to be carried out to select 
the best group, solvent and their optimal concentrations. 
 
ACKNOWLEDGMENTS 
 
The author would like to thank Universiti Teknologi PETRONAS for the encouragement & studentship 
from the Enhance Oil Recovery, mission oriented research division and MyBrain 15 for its tuition fees support. 
The author would also like to express her sincere and honest gratitude to colleagues from UTP and  PRSB, who 
have given guidelines and assistance throughout the study. 
 
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Application of Different Groups of Demulsifier In Water-In-oil Emulsion

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Application of Different Groups of Demulsifier In Water-In-oil Emulsion

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