First Generation Biofuels

Posted by Bryan McCulloch

First generation biofuels are biofuels produced from edible foodstuffs, i.e. starch, sugar, vegetable oils and animal fat (tallow). These are called edible foodstuffs as they can be consumed by either humans or animals. There are a few main types of 1st generation biofuels, which are:

• Biodiesel
• Bioalcohol
• Biogas
• Vegetable Oil
• Syngas

Biodiesel

Biodiesel is produced from tallow and vegetable oils (including used cooking oil). The most common forms of vegetable oils used are rapeseed, soybean, sunflower and palm oil. These materials are converted into biodiesel using a process called transesterfication. This is a process whereby the vegatable oils and tallow are mixed with an alcohol in the presence of either a homogeneous or heterogeneous catalyst, depending on the content of free fatty acid (FFA) in the oil. What this does is converts the input into a product of fatty acid methyl esters (FAME), or biodiesel, and glycerol, which is produced as a by-product.  Biodiesel can be blended with mineral diesel in the forms B2 (2% biodiesel), B5 (5%) and B20 (20%). B100 is the name given to pure biodiesel.  Both pure and blended biodiesel can be used in any diesel vehicle without any major changes to the engine, the only thing which you may need to change are the fuel lines and other components made of rubber.

Bioalcohol

Bioalcohol is produced through the fermentation of sugar containing crops (sugar cane, sugar beet, fruit, etc.) or starch containing crops (wheat, barley, corn, rice, etc.). The fermentation process for bioalcohol is exactly the same as that for Whiskey, Vodka, Gin, Rum etc. The most common form of bioalcohol is bioethanol, although biobutanol and biopropanol can also be produced. The largest volume of biofuel at the moment comes from bioethanol production, with a lot of plants operating in the USA and Brazil. For use in vehicles, the bioethanol, like biodiesel, has to be blended into the gasoline. The most common mixtures for this are E5 (5% bioethanol) and E85 (85%). Some vehicles, however, are equipped to run on 100% bioethanol. Biobutanol has been reported to be a more energy efficient fuel and can be used in vehicles without any blending.

Biogas

Biogas is produced by anaerobic digestion of waste or crops. Anaerobic digestion is when anaerobic bacteria are used to breakdown the organic matter of the biomass in the absence of oxygen. This releases a mixture of 60-70% methane and about 30% carbon dioxide. This process occurs naturally on landfill sites, although the methane and carbon dioxide are of equal proportion and there are trace elements of oxygen and nitrogen from the atmosphere as well as some organic matter. The gases produced from a landfill site are called landfill gas, or LFG.  These gases then need to be refined to remove the carbon dioxide and other contaminants to leave the methane. This can then be used to power turbines, boilers, dryers, kilns etc.  Another method is to take the methane and turn it into a liquid fuel, methanol. Methanol can be used for similar applications to bioethanol. The waste from the process of anaerobic digestion can be sold on for use as fertilizer.

More to follow tomorrow