Biofuels are a renewable source of energy that has been around for decades. The two most popular versions of biofuel are biodiesel and ethanol, representing the first generation of biofuels. Other biofuels include biogas, butanol, methanol, and wood.
Bioengineers manufacture biofuels using plant materials and other feedstock, generally called biomass. They first convert biogas and liquid biofuels before using them as an energy source. However, solid biofuels such as wood and wood waste can be used directly as a fuel source without conversion.
Biofuels have a much lower impact on the environment than traditional sources of fuel, offering a renewable and sustainable source of clean energy. As a result, they are often mixed with regular gasoline to make them more efficient and sustainable.
Biofuels have different modes of production, depending on their composition and intended use. For example, the manufacturing process of ethanol begins with the cultivation of starchy plants like corn, wheat, or soybeans. After harvesting, bioengineers process the crops to obtain the oils and sugar used in making biofuels. This stage of processing biomass for fuel production is called conversion. The conventional method of doing this is fermentation.
Corn is ground and mixed with water to obtain a starchy mix. Enzymes are introduced to this mix to reduce their cellular structure to simple sugars and watery forms. These simple sugars are then fermented with yeast to produce ethanol. Any leftover water in ethanol must be dried and exhausted before it is used as fuel for car engines; therefore, it must first undergo dehydration and distillation to remove any water content before it is suitable for use.
In biodiesel production, transesterification is used in place of fermentation. Fatty acid methyl esters (FAMEs) are the primary chemicals present in biodiesel. Transesterification is the method of disintegrating the triglycerides in oil or fat so that all that remains are the FAMEs.
Sodium hydroxide acts as a catalyst on a mixture of oil or fat and an alcohol like methanol to complete this process. After completing this process, heating and agitating the by-product produces glycerin and FAMEs. The glycerin is discarded, and biodiesel is the liquid that remains after the entire process of transesterification.
Biogas is a common fuel source in most power plants. It is commonly used for the generation of heat and electricity. Its production is a result of a process called anaerobic digestion. During this process, organic matter is decomposed in the absence of oxygen. As a result, carbon dioxide, a mixture of methane and other gasses that can be used for energy production, is obtained.
Regardless of the mode of production, ethanol and biodiesel must be purified and blended with gasoline or diesel fuel before use in a car engine as fuel. They are not used as primary fuel sources in cars because their level of efficiency as a standalone fuel does not measure up to that of fossil fuels. Therefore, they are only used as an additive or mixed with gasoline to increase their octane levels. An example of an ethanol and gasoline mixture that is well known for its use is E10, which consists of 10 percent ethanol and 90 percent gasoline and can aid in the higher performance of internal combustion engines.
