Chemistry and Action of Demulsifiers on Other Solvents
The separation of water combined in the crude oil can be handled using several different techniques. These can be mechanical, thermal, chemical, or even electrical. Manipulation of the hydrogen and hydroxide ions can also be used. Mechanical methods include filtration, heat treatment techniques and even membrane separation.
Action of Demulsifiers in Enhancing Quality of Crude Oil
Determination of the characteristic of the emulsion is important to knowing the best method to use. All other methods have proved difficult to use in the oil field due to hardware installation and especially in the North Sea. The best and most economical method is the chemical demulsification process.
For water in crude demulsification process, acceleration of the coalescing process is done as well as boosting the film rupturing process. The drops coalescing process is determined by the van der waal forces while the reuniting process is referred to as the maragoni effect.
Chemical Properties of Oil and Water Based Emulsifiers
Crude oil demulsifiers are basically molecules that assist in the separation of oil and water at low concentrations. Some are polymers while others have structures resembling non ionic emulsifiers. They are surfactants useful in breaking up emulsions.
The basic process of demulsification is the dispersing of the water from the oil molecules and the coalescence of the water droplets together to create a distinct water and oil layer. This process occurs in three distinct steps which are flocculation, coalescence, and solids wetting.
- Flocculation; Small water droplets are joined together in the emulsion and appear as clusters or bunches.
- Coalescence; this is the rupturing of the bonding film and the joining of the water molecules.
- Solids wetting is the process by which physical separation occurs and water settles out at the bottom.
Factors affecting the demulsification process
These include;
- Sufficient quantity of the emulsion breakers and adequate mixing and agitation.
- Sufficient heat to resolve the emulsion
- Sufficient settling time to allow settling of the demulsified water and impurities.
The management of oil wells must ensure that these requirements are met for successful demulsification.
General use and application of emulsion breakers
There is wide spread use of demulsifiers in separation of water from oil based solutions and even purification of solvents. In the oil wells these are critical chemicals because they affect the quality of petroleum as well as reduction of corrosion to the piping and settling tanks
Cost benefits analysis of demulsifiers.
Chemical demulsification is the best way to go in purification of crude. The cost of using physical separation such as filtration or even heat treatment is so high that the profit margins will be affected.
The cost of setting up the infrastructure and maintenance is also high and chemical demulsification is the best option.
Availability of demulsifiers in the global market
Due to the growing demand of demulsifiers, manufacturers have managed to place these products on the market and they are now readily available .Currently oil soluble demulsifiers are available online and can be shipped directly to buyer’s premises.
Conclusion
Demulsification is the process of separation of water from oil or vice versa .The process can be done in various ways but the best and the most cost effective is the use of demulsifiers. Chemically this process occurs in three main stages which are flocculation, coalescence and solids wetting. Demulsifiers are widely available with different properties that will suit your refinery needs.
This article has been written by Govind Patel.
