Contamination Of Biodiesel Fuel
Biodiesel, although immiscible with water may contain small but problematic quantities of water as biodiesel fuel contaminants. It is like ethanol, hygroscopic and absorbs water from atmospheric moisture. Let us study the contamination of biodiesel fuel in detail on this page.
As a result of inappropriate processing, mono and diglycerides are left over from an incomplete reaction. This is one of the reasons biodiesel can absorb water. These molecules of mono and diglycerides can act as an emulsifier and allow water to mix with the biodiesel thus promoting pollution of biodiesel fuel. Moreover, there may be water as a residual of processing or it may be the result of storage tank condensation.
The contamination of biodiesel fuel due to the presence of water is a problem as:
• Water decreases the heat of combustion of the bulk fuel, which means more smoke, harder starting, less power.
• Water as biodiesel fuel contaminants may lead to corrosion of essential fuel system components
• Water & microbes can lead to the failure of the paper element filters in the system, which in turn result in untimely failure of the fuel pump due to ingestion of large particles.
• Water can freeze to form ice crystals near 0 °C (32 °F) and these crystals can offer sites for nucleation and speed up the gelling of the residual fuel.
• The presence of water leads to biodiesel fuel contamination as it promotes the growth of microbe colonies, which can plug up a fuel system. Biodiesel users with heated fuel tanks face a year-round microbe problem.
• In addition, water can be the source pitting in the pistons on a diesel engine.
Earlier, contamination of biodiesel fuel by measuring the water amount had been difficult. However, today by using water-in-oil sensors, it is now easy to gauge the water content. Biodiesel fuel contamination due to water is also a potential problem while using certain chemical catalysts, which are involved in the production process.
Free glycerin may be present in biodiesel as a result of improper processing, for instance,
insufficient separation of the glycerin phase or inadequate washing by water after eparation. Glycerin may also be present as biodiesel fuel contaminants when distillation is used as the primary mechanism for its removal. Free glycerin is suspected to contribute to deposit formation in the engine. Since free glycerin also has a high affinity for water if it is present, it is suspected that it will selectively attract these compounds.