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Emulsification vs. Demulsification to Control Water in Diesel Fuel
Diesel Fuel has a few issues; the presence of water is one of them. If there is water present in the fuel, it will negatively affect a machine. Hence, all suppliers strive to minimize the effect of water on Diesel Fuel. This is possible either with the process of emulsification or demulsfication.
The big issue with Diesel Fuel
One of the properties of Diesel is that it attracts and holds water. This can become a major issue for storage tanks since diesel with presence of water will lead to corrosion of such tanks. Besides which, it also leads to a decrease in level of lubrication and forms ice crystals when put to use.
It is possible for emulsifiers to encapsulate water droplets. It is then allowed to pass through the fuel system as usual; Advantage being they will be vaporized and expelled during a combustion cycle.
The demulsifier can also cause water to precipitate out of the fuel. It is possible to separate it mechanically or by other means.
Pros & Cons of using Emulsifier for Diesel Fuel
- Fuel Emulsification: The aim of emulsified fuel is to reduce pollutants. The presence particulate matter (PM) and nitrous oxides (NOX) in fuel causes lot of pollution which emulsified fuel (water in diesel) can fix. The way it works is that emulsified diesel is created as a mix of diesel fuel, water and other additives which can efficiently reduce the emissions of several pollutants and also prevent water from affecting the engine.
- Bio diesel: Bio-diesel also has a hygroscopic property, it has an ability to hold more emulsified water that pure petro-diesel. It also has better lubrication property that petro-diesel.
- Ultra Low Sulfur Diesel (ULSD): There is a risk of water damaging in fuel components and result in a reduction of lubrication as well. However, it is possible to use additives that helps restore lubricity. ULSD has enhanced surfactant property which help improve propensity in emusified water in the fuel. Thus, it is possible to control separation of water from diesel.
- Unfiltered Water: Fuel filter is useful in protecting the systems from water using hydrophilic filter elements. However, it often happens that some of the emulsified water manages to find its way in the fuel system which can harm the fuel system. Several heavy vehicles have a special indicator for this to alert a driver. However, this sensor is not very efficient in detecting water in untreated emulsified water.
- Mechanical Separation: If there is any water in the fuel as free water or coarsely emulsified water, it is possible to separate using mechanical separators and filters.
- Reduction of Energy: Water tends to reduce energy level of the fuel in the combustion chamber. The reason being, the presence of water in fuel means there is a lower volume of fuel thus reducing power output. This affects all vehicles by reducing the power output and mileage.
Vehicles using diesel fuel that has water contamination is a big issue for all diesel vehicle owners. It affects the overall performance and can also damage the vehicle in the long run.
The use of additives has an ability to cancel out the effect water in diesel fuel. Emulsifiers and demulsifiers are the most popular additives for diesel fuel. Emulsifers are useful since they are more hygrosocpic and hence can ensure that water remains in a nanoscale state. On the other hand, Demulsifier can help prevent large scale water contamination by making use of a mechanical water separator.