**3.1 Thermochemical process**

Thermochemical processes are based on the use of high temperatures to convert biomass into energy (**Figure 7**). These processes involve irreversible chemical *Valorization of Biomass as a Raw Material to Obtain Products of Industrial Interest DOI: http://dx.doi.org/10.5772/intechopen.104108*

reactions carried out at high temperatures and a wide range of oxidation conditions [12]. These technologies have the potential to produce mainly heat, electricity, and fuels. Thermochemical transformation processes comprise liquefaction, pyrolysis, gasification, and combustion (**Figure 8**) [11–15].

#### *3.1.1 Biomass liquefaction*

Liquefaction aims to maximize the production of liquids from biomass, with the use of low temperatures (250–400°C) and high pressures (5–20 MPa) in the absence of oxygen and presence of catalysts such as carbonates and metals (zinc, copper, nickel, ruthenium) during processing. In this process the complex molecules of cellulose and lignin are fragmented by heating with steam and carbon monoxide, oxygen

**Figure 7.**

*Thermochemical and chemical processes of biomass and its resulting products.*
