Biodiesel is a kind of fuel made from diverse resources such as soybean oil and recycled cooking oil. It is a clean-burning fuel that is seen as a replacement fuel for existing diesel engines. As it is meant for use in standard diesel engines, it is different from the vegetable and waste oils that are used to fuel transformed diesel engines. Moreover, Biodiesel can either be blended in any proportions with petro-diesel or can be used alone.
The biodiesel color can range from golden to dark brown, depending upon its production method. It carries a low vapor pressure and a high boiling point, and it is slightly miscible with water. There is some sulfur content also present in Biodiesel, due to which it can be used as an additive to ultra-low-sulfur diesel too safely. Technically, Biodiesel is defined as a mono-alkyl ester.
Details of Biodiesel
Biodiesel is a vegetable oil or an animal fat-based fuel that is made by chemically reacting lipids with an alcohol producing fatty acid, esters and comprises of a long-chain of alkyl esters. There are strict industry guidelines and specifications to ensure proper grade and performance of the fuel-grade Biodiesel. There is stringent ASTM definition for Biodiesel itself, and more complex specifications for legal diesel motor fuel. As raw vegetable oil fails to meet these specifications, it cannot be considered Biodiesel.
The technical definition of Biodiesel is ” fuel that meets the requirements of ASTM D 6751 and is made of mono-alkyl esters derived from animal fats and vegetable oils.” The long-chain fatty acids must meet the designated B100 requirements. Biodiesel blends meet ASTM D 6751 and designated BXX, where the XX stands for the percentage of biodiesel fuel in the blend.
Biodiesel shows promising lubricating properties and higher cetane ratings when compared to low sulfur diesel. The higher lubricating fuels increase the usable life of fuel injection equipment under high-pressure. The calorific value of Biodiesel is about 37 MJ/kg, which is slightly lower than regular Petro diesel. The differences in biodiesel energy density relies on the feedstock used rather than how it is produced. Still, the Biodiesel is known to provide better lubricity and fuller combustion, thus increasing the engine energy output.
The most commonly used and distributed Biodiesel is a blend. The system of the “B” factor is used to state the percentage of Biodiesel in any blend of Biodiesel. For example, B100 refers to 100% biodiesel, while B2 refers to 2% biodiesel and so on. One should use the type of blend based on the modifications and specifications of the engine. For example, diesel equipment with minor modifications works on blends of 20% biodiesel. ASTM D7467 specifications cover the B6 to B20 blends. B100 is the pure form of Biodiesel, and although it can be used in the purest form, there might be a need to make certain modifications to the engine to avoid any performance related problems and maintenance issues.
Applications of Biodiesel
Biodiesel can be used in pure form or blended with petroleum diesel in any concentration based on the requirement and modifications. There are strict factory restrictions of B20 or B50 for most injection pump diesel engines, based on the manufacturer specifications. A nonreactive material to Biodiesel, FKM, prevents Biodiesel from degrading natural rubber gaskets and hoses in vehicles, and moreover.
Biodiesel is also known to break down residue deposits in the fuel lines, and as a result, the fuel filters may get clogged with particulates. Therefore, it is suggested to change the fuel filters shortly after first shifting to a biodiesel blend. The fuel efficacy of Biodiesel relies on the blend, quality, and load conditions. The thermal efficiency can vary because of divergent energy content of the various blends. Thermal efficiency relies on characteristics of specific density, viscosity and flash point, and thus can change with the quality of Biodiesel and its blends.
One of the main reasons that drive biodiesel production is energy security and fast depletion of natural resources on the planet. Today, biodiesel production has almost touched 4 million tons, and the majority of biodiesel production comes from the European Union. The biodiesel production capacity is on a rapid rise, and the industry is growing at a very fast rate The purpose is to lower the dependence of the world on oil and reduce greenhouse gas emissions.