Читать книгу Encyclopedia of Renewable Energy - James Speight G., James G. Speight - Страница 174

First-generation biofuels are biofuels produced from sugar, starch, vegetable oil, or animal fats using conventional technology. The oil is obtained using the conventional techniques of production. Some of the most popular types of first-generation biofuels are: biodiesel, vegetable oil, biogas, bioalcohols, and synthesis gas.

Biodiesel has a composition similar to fossil/mineral diesel except that components in biodiesel include animal fats and oils from soy, mustard, flax, and sunflower seeds. The oil or animal fat is reacted with an alcohol through a process called transesterification to create the fuel. Vegetable oil is most often used in the production of biofuels, but there are cases where straight vegetable oil is being used as a fuel.

Biogas is created when organic matter breaks down anaerobically (that means without any oxygen). It can be produced from gunk like manure, sewage, and municipal waste. Some types of biogas, such as landfill gas, contain something called volatile organic compounds that are restricted by environmental regulations. Synthesis gas (syngas) is a mix of carbon dioxide and hydrogen. It is created when biomass is combusted with a measured (limited) amount of oxygen. Syngas can be used to produce diesel and can also be converted into methane.

Bioalcohols are produced through the fermentation of starches and sugars. Ethanol is the most common bioalcohol, although there is also methanol, propanol, and butanol. Some bioalcohols can be used directly in gasoline-powered engines.

The basic feedstocks for the production of first-generation biofuels are often seeds or grains such as wheat, which yields starch that is fermented into bioethanol, or sunflower seeds, which are pressed to yield vegetable oil that can be used in biodiesel. These feedstocks could instead enter the animal or human food chain, and as the global population has increased, their use in producing biofuels has been criticized for diverting food away from the human food chain, leading to food shortages and price rises.

The most common first-generation biofuels are bioalcohols, biodiesel, biogas, and vegetable oil.

See also: Bioalcohols, Biodiesel, Biofuels From Synthesis Gas, Biofuels – Second Generation, Biofuels – Third Generation, Biogas, Methanol, Ethanol, Vegetable Oil.