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 chemical families.
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., 2006)
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.