1.1 Background of the Study
Water-in-oil emulsions stability is
always encountered at many stages during the production and processing
of crude oils. These emulsions formation is always or generally caused
by the presence of resins and asphaltenes which play the main role of
"natural emulsifiers", and also caused by wax and solids that accompany
the crude. These components can organize and form rigid films at the
oil/water interface Effective separation of oil and water is essential
in order to ensuring the crude oil quality and low cost of the oil
production. Chemical demulsification forms the most important step in
breaking of water-in-crude oil emulsions. Various techniques are used to
break these emulsions, among which the most widely used consists of
adding small amounts of demulsifiers. These surface-active molecules
adsorb at the oil-water interface and accelerate the phase separation
(Krittika et al, 2014)
Among the most critical aspects of
petroleum production, no matter what the production system is,
separating produced crude from water and basic sediments. Your profits
depend on doing so efficiently. But at the same time, dealing
with produced water in an efficient and environmentally
sustainable way is equally important. The most important
objective of any oil production facility is the separation of
water and other foreign materials from the produced crude. The
breaking of these crude oil and water emulsions constitutes one of the
challenging problems in today’s petroleum industry (Laurrier, 1992).
The present day oil production contains
water as one of main unavoidable associate or byproduct. Nearly 90% of
crude contains oil/water emulsions. The gradual entry of water in to
oil-bearing formations and the arrival of secondary and tertiary
recovery methods have led to the development of new technologies that
can be used to break crude oil and water emulsions.
Following series of investigation
and confidence results, the breaking of water-in-petroleum
emulsions is not yet completely understood, particularly as far as the
added chemical Demulsifiers role is concerned, and much research is
still required (Miguel et al., 2006). Hence Demulsifiers
performance has to therefore be improved, from the application as
well as from the environmental point of view. Recently made
formulations must be less toxic and at least as efficient as classical
Crude oil is most often produced as a
water-in-oil emulsion and the water must be removed (down to a level of
<0.5%), in a process that is usually called Demulsification or
dehydration, which consists of forcing the coalescence of water
droplets and producing their separation by settling (Miguel et al.,
In order to properly separate the water
from water-in-oil emulsion, demulsifiers are used as process aids. The
processes involve in the breaking of these emulsions is carried out by
using synthetic surfactants (Demulsifiers) which are added to
water-in-oil emulsion. The function of the demulsifiers consists in
Demulsification and prevention of re-emulsification by breaking the
protective film which is formed on the surface of water drops, by the
emulsifying agent. The demulsifying chemical is injected into emulsion
and mixed with it. After that water is removed from oil by sedimentation
(Koshelev et al., 2000). It is of great necessity to properly
de-hydrate water-in-oil emulsion; failure to carry out this process will
result in the following:
ü Cost of pumping will increase
ü There will be high pressure drop in flow line
ü Corrosion of downstream processing equipment.
Demulsifiers are typically polymeric and interfacial active. Demulsifiers may have the following disadvantages;
ü Most are specifically designed to treat particular crude and may not be effective in treating other crude oil emulsion.
ü Many are toxic to the environment, traces of which are left behind in the discarded water residue
ü Many requires huge amount of
mixing energy and thus take a long time to accomplish the
separation of water from the crude
ü Incomplete water removal from the
emulsion, leaving the problem of environmentally disposing of
oil-containing effluent water at sea.
Separation of the water-in-crude
emulsion is a technically big challenge in the petroleum industry.
Making use of an effective demulsifier in demulsification process can
save millions of Naira every year in operation cost. An increase in
water content in oil of one percent can result in transportation costs
increase by three to five percent (3-5%) for each transfer. The use of a
demulsifier can also reduce oilfield corrosion (Loumer, 1992).
Making a Green demulsifier is
reasonable not only due to the fact that it is environmentally
non-toxic, knowing its position as a biodegradable agent does not
require a lot of expenses, or at least reduces the cost of
clean-up and disposal of waste containing it. Therefore the desire
to create “environmentally friendly” chemicals is a step in a right
direction as it can actually lead to significant cost savings (Christine
and Christine, 2001).
1.2 Statement of the Problem
Chemical method, which is mostly used in
demulsification can be of threat to all the living organism in the
environment where crude demulsification is being perform ( i.e. in the
refinery or oil producing field ) because most of the chemicals used for
crude oil emulsion breaking, such as phenol group are toxic. To avoid
these toxic or environmental non-friendly emulsion breaking chemicals,
other non-toxic crude emulsion breaker called “green demulsifier” have
to be prepared. This is the main purpose of this work.
1.3 Aim of the Work
The aim of this work is to prepare a green demulsifier from naturally occurring substances.
1.4 Objectives of the Work
The objectives of this work are as follows:
ü To determine physical properties of
the substance (Crude Palm Kernel Oil, Citric Acid, Bio-ethanol, Fatty
Acid, Turpentine) that will be used as the demulsifier component.
ü To evaluate their demulsification potential when combined
ü Determination of the API of the given crude oil emulsion
ü Determination of water/oil separation from emulsions using bottle test and centrifugal method (ASTM D96).
1.5 Significance of the Work
This work will focus on finding natural
chemicals to replace toxic chemicals used as crude demulsifier, in crude
demulsification or emulsion breaking process. If we succeed in
obtaining a natural product as a demulsifier, it therefore means that in
the course of solving emulsion problem, we would not be creating
another problem; in environmental and health.
1.6 Scope of the Work
The scope of this work will require
buying the natural chemical substances, obtaining fresh crude oil
emulsion from any nearby flow station, and conducting demulsifier bottle
test of the natural chemicals in a laboratory.