Page 278 - Low Temperature Energy Systems with Applications of Renewable Energy

264 Low-Temperature Energy Systems with Applications of Renewable Energy

Fig. 7.5 Classification of biofuels by generation.

9. Upgrading of the biogas to biomethane via amine gas treatment.
10. Delivery of the biomethane to the public gas supply pipeline grid.
Classification of biofuels by first and second generations is given in Fig. 7.5.
The raw materials of the First Generation are agricultural crops with a high content
of fats, starch and sugars. Vegetable fats are processed into biodiesel, while starches
and sugars are converted into ethanol. Non-food remains of cultivated plants, grass
and wood are called the Second Generation of raw materials. Such raw materials
contain cellulose and lignin; these can be directly burned (as traditionally done with
firewood), gasified (producing flammable gases), and processed by means of pyrolysis.
Biofuel of the Third Generation refers to specially grown species of biomass.
The annual requirement of world energy is about 14 billion tonnes of oil equivalent.
In Africa, the use of biomass for energy purposes is about 60% of total energy con-
sumption; in Asia it is up to 40%; in Latin America it is about 30%. In many cases
in these places, the biomass is likely firewood for heating and cooking. Owing to
health and environmental impacts, this use of biomass is not a desired approach and
should be distinguished from the more environmentally friendly applications described
in this section.

7.2 Technical description of bioreactor processes

Bioconversion is a technological process that involves the treatment of organic mass
for the purpose of obtaining high quality heat or fuel, as well as environmentally
friendly organic fertilizers. Bioconversion is one of the most important renewable