Biodiesel Fuel Additives

Biodiesel Fuel Additives

Biodiesel, known also as B100 and fatty acid methyl esters –- or FAME — is an alternative transportation fuel. It is usually synthesized in a process called trans-esterification by combining certain lipids, such as animal fat, with an alcohol. Biodiesel has several distinct advantages over its standard petro-diesel counterpart. It produces fewer pollutants when it undergoes combustion, it does not require engine modification for use in many standard diesel vehicles and it can be made from widely available sources.

Despite these benefits, there are circumstances when manufactured bio-diesel requires enhancement through additives. Typically, B100 is susceptible to water haze, low-temperature flow problems and issues arising from oxidation. These can all impact the efficiency of the fuel. During periods of cold weather, biodiesel (like petro-diesel) clouds as small crystal of wax form. This wax can create engine system clogging. As the temperate drops even further, biodiesel begins to colloid becoming gel-like. Eventually, it refuses to flow altogether – clearly a problem! Biodiesel made from recycled oils and fat clog more readily at low temperatures. In order to improve the fluidity of biodiesel at low temperature it becomes necessary to introduce an additive. A quick and easy way to improve fluidity is to blend with petro-diesel. Although petro-diesel also suffers a similar outcome at very low temperature, it can resist the cold better than biodiesel and is easily winterized with standard additives or as standard. Introducing 20-30% petro-diesel should free up flow issues with biodiesel, although the environmental benefits are lost.

Alternatively, and perhaps preferable, one can choose from one of the numerous specific biodiesel anti-gelling agents available. Wintron XC30 and Wintron XC40 are typical cold flow additives that help winterize biodiesel. Operability of biodiesel is also heavily dependent on oxidation. As soon as it is produced, biodiesel begins to degrade as it comes in to contact with oxygen in the atmosphere. Water in storage or transit media in addition to the degree of care taken to preserve biodiesel can also further accelerate degradation. The residues created when biodiesel reacts with oxygen can impair engine performance and in untreated instances can lead to corrosion damage, gumming and plugging. A range of antioxidant additives is available to reduce the effects of oxidation and keep biodiesel fuels fresh and fully operable.
Exposure to air, and water in storage units of engine systems can lead to another degradation vector, namely microbes. Once introduced, micro organisms will rapidly take root and soon break down biodiesel. Anti-microbial additives (biocides) will eliminate microbe infestation and prevent recurrence. These additives dissolve the contaminants which are then burnt off via the engines regular combustion cycle leaving no discernible trace.

Further additives commonly available for biodiesel engines include: fuel catalysts which can reduce emissions, improve fuel economy and aid combustion, and fuel booster additives which increase the fuel cetane number (reducing the fuel’s ignition delay.)

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