Thermochemical biorefinery

There are four main biorefineries biosyngas-based refinery, pyrolysis-based refinery, hydrothermal upgrading-based refinery, and fermentation-based refinery. Biosyngas is a mrrltifimctional intermediate for the production of materials, chemicals, transportation fuels, power and/or heat from biomass. Figrrre 3.4 shows the gasification-based thermochemical biorefinery. 

Main type of conversion processes applied thermochemical biorefineries, biochemical biorefineries, two platform concept biorefineries. 

For example, in a (thermochemical) biorefinery, biomass is converted into energy carriers such as transportation fuels (e.g., ethanol), heat, and power and/or chemicals. In terms of energy content, the amount of biomass for (transportation) fuels and CHP (e.g., by combustion) is much higher than the amount used for the production of chemicals. However, in terms of added value, chemicals can provide a significant contribution to the overall cost effeaiveness of the refinery. When the main product of a biorefinery is (hemi) cellulose bioethanol, the lignin ends up in a residue that mostly is used as a fuel to generate heat. The economics of the biorefinery will benefit much from the valorization of this lignin-rich residue to value-added aromatic chemicals. 

Figure 8.2 An example from the 1920s of a thermochemical biorefinery the flow sheet for the Ford continuous wood distillation plant, Iron Mountain, Michigan, USA. ...

The University ofWaterloo continued the development in greater detail and showed from an economic evaluation that the process is an interesting alternative for the conventional production of ethanol. " In 1999, they compared the cost of producing ethanol from ceUulosic biomass via the hybrid thermochemical biorefinery approach, to acid hydrolysis and enzymatic hydrolysis technologies. The results indicate that the production cost of ethanol via the fast pyrolysis-based concept is competitive with the production cost via the conventional approaches. 

Lignocellulosic Feedstock Biorefinery 10- Syngas Platform Biorefinery (Thermochemical Biorefinery)... 

Biochar in thermal and thermochemical biorefineries—production of biochar as a coproduct... 

Besides converting wet biomass into hydrochar, the HTC process is also capable of coproducing chemicals, which include phenolic compounds, 2,5-HMF, and aldehydes (acetic, lactic, propenoic, levulinic, and formic acids) that can potentially be used in biorefineries (Axelsson et al., 2012 Hoekman et al., 2012 Oladeji et al., 2015). The formation and concentration of these chemicals can be controlled by adjusting the HTC process conditions (Libra et al., 2011 Xiao et al., 2012), such as temperature, pressure, and residence time. Therefore the HTC process could be a useful part of biological and thermochemical biorefineries, processing wet residues, and coproducing chemicals and hydrochar. 

Besides production of biochar as an intended or unintended coproduct during conversion of biomass to biofuels and chemicals in thermochemical biorefineries, biochemical biorefineries also provide opportunities for production of biochar as a standalone process, valorizing residues resulting from biological treatments. Various residues can be left behind after enzymatic, microbial, and other treatments in biorefineries, mainly constituting recalcitrant fractions high in lignin and mineral matter. Both of these streams can be used in biochar production, as discussed below. 

---