syngas cleaning system should be optimized for selected crop residue. Syngas is an
excellent chemical feedstock for the production of ammonia, methanol, and other
derivatives through suitable chemical catalytic conversion, i.e., Fischer–Tropsch
synthesis.
6.4
Biofuels Production from Agricultural Residues
6.4.1 Solid Biofuels
The low bulk density biomass materials can be converted into high-density biomass
fuel by briquetting technology. Biomass briquette is a solid biofuel and used to
replace firewood in steam boilers. However, briquetting technology is an energyintensive process. Moreover, charcoal is a solid fuel produced from agro-residues
through the pyrolysis/carbonization process. The quality of charcoal depends on
biomass type and pyrolysis conditions (Zubairu and Gana 2014). The charcoal yield
from residues is strongly influenced by lignin content and also biomass
compositions.
6.4.2 Liquid Biofuels
Bioethanol and biobutanol are produced from fermentable sugars using appropriate
fermentation technology. For the production of liquid biofuels from any agroresidues, biomass pretreatment is a necessary step to separate lignin and also
improving the hydrolysis process. Bio-oil is also derived from agro-residues through
a fast pyrolysis process. Nevertheless, the yield and composition of bio-oil depend
on factors including but not limited to composition of biomass and the operating
parameters of pyrolysis process.
6.4.3 Gaseous Biofuels
Syngas and biogas are produced from biomass via gasification and anaerobic
digestion process, respectively. The major combustible gases present in syngas are
carbon monoxide, hydrogen, and methane, whereas methane accounts for a significant share in the biogas composition. Both these biofuels require the cleaning
process to remove impurities for further usage in engines.
6 Sustainable Biorefinery Technologies for Agro-Residues: Challenges and. . .
109
excellent chemical feedstock for the production of ammonia, methanol, and other
derivatives through suitable chemical catalytic conversion, i.e., Fischer–Tropsch
synthesis.
6.4
Biofuels Production from Agricultural Residues
6.4.1 Solid Biofuels
The low bulk density biomass materials can be converted into high-density biomass
fuel by briquetting technology. Biomass briquette is a solid biofuel and used to
replace firewood in steam boilers. However, briquetting technology is an energyintensive process. Moreover, charcoal is a solid fuel produced from agro-residues
through the pyrolysis/carbonization process. The quality of charcoal depends on
biomass type and pyrolysis conditions (Zubairu and Gana 2014). The charcoal yield
from residues is strongly influenced by lignin content and also biomass
compositions.
6.4.2 Liquid Biofuels
Bioethanol and biobutanol are produced from fermentable sugars using appropriate
fermentation technology. For the production of liquid biofuels from any agroresidues, biomass pretreatment is a necessary step to separate lignin and also
improving the hydrolysis process. Bio-oil is also derived from agro-residues through
a fast pyrolysis process. Nevertheless, the yield and composition of bio-oil depend
on factors including but not limited to composition of biomass and the operating
parameters of pyrolysis process.
6.4.3 Gaseous Biofuels
Syngas and biogas are produced from biomass via gasification and anaerobic
digestion process, respectively. The major combustible gases present in syngas are
carbon monoxide, hydrogen, and methane, whereas methane accounts for a significant share in the biogas composition. Both these biofuels require the cleaning
process to remove impurities for further usage in engines.
6 Sustainable Biorefinery Technologies for Agro-Residues: Challenges and. . .
109