The biomass is the biodegradable fraction of the products, waste and residues from agriculture, including vegetal and animal substances, from forestry and related industries, as well as the biodegradable fraction of industrial and urban waste. (Definition given in the Decision no. 1844 of 2005 on promoting the use of biofuels and other renewable fuels for transport).
Biomass represent the most abundant renewable resource on the planet. This includes all the organic matter produced by metabolic processes of living organisms. Biomass is the first form of energy used by humans since the discovery of fire. The energy integrated into biomass is recovered by various methods, which, ultimately, is the chemical process of burning (chemical transformation in the presence of molecular oxygen, a process by excellency exergonic).
Forms of energy recovered from biomass (biofuels):
• Direct burning with heat generation.
• Combustion by pyrolysis, with singaz generation (CO + H2).
• Fermentation, with the generation of biogas (CH4) or ethanol (CH3-CH2-OH) – in case of fermented sugar products, the biogas can be burnt directly, and the bioethanol, blended with gasoline, can be used in internal combustion engines.
• Chemical transformation of biomass by treating vegetable oil with alcohol and generating esters, eg methyl esters (biodiesel) and glycerol. In the next stage, purified biodiesel can be burnt in diesel engines.
• Enzymatic degradation of biomass to obtain ethanol or biodiesel. Cellulose can be enzyme degraded to it’s monomers, carbohydrate derivatives, which can then be then, fermented to ethanol.
