Torrefaction is mild thermochemical pretreatment technology that enhances biomass by changing its physico-chemical characteristics to produce a high-quality solid biofuel.The present study evaluated the performance of...Torrefaction is mild thermochemical pretreatment technology that enhances biomass by changing its physico-chemical characteristics to produce a high-quality solid biofuel.The present study evaluated the performance of a continuous screw-auger-type torrefaction system for upgrading agricultural residues rice husk(RH)and wheat straw(WS)into energy-dense,hydrophobic biomass suitable for cofiring applications.Torrefaction experiments were conducted at three temperatures of 250℃,275℃,and 300℃ with a total residence time of 12 minutes.The results revealed that the mass yield decreased with temperature,from 85.60%to 75.00%and from 83.20%to 70.80%for RH and WS,respectively.Higher heating values increased significantly with torrefaction severity,reaching 19.26 MJ/kg for RH and 20.25 MJ/kg for WS when torrefied at 300℃,representing a 22%-25%improvement over raw biomass.Moisture uptake dropped substantially from 38.6%to 1.9%and from 41.5%to 2.1%for RH and WS,respectively,indicating the enhanced hydrophobicity.Combustion indices have also showed desirable trends;the fuel ratio increased to 0.54 and 0.57,and the volatile ignitability exceeded 15 MJ/kg for both biomass samples torrefied at 300℃,indicating improved ignition characteristics suitable for cofiring.Techno-economic analysis revealed a net profit of 138520 Indian rupees/year,with a payback period of 5 years and a benefit-cost ratio of 1.27,supporting the economic feasibility of the system.Overall,the study confirms that torrefied biomass presents improved fuel characteristics and combustion behaviour,making it a viable solution for clean-energy transition and sustainable waste management.展开更多
文摘Torrefaction is mild thermochemical pretreatment technology that enhances biomass by changing its physico-chemical characteristics to produce a high-quality solid biofuel.The present study evaluated the performance of a continuous screw-auger-type torrefaction system for upgrading agricultural residues rice husk(RH)and wheat straw(WS)into energy-dense,hydrophobic biomass suitable for cofiring applications.Torrefaction experiments were conducted at three temperatures of 250℃,275℃,and 300℃ with a total residence time of 12 minutes.The results revealed that the mass yield decreased with temperature,from 85.60%to 75.00%and from 83.20%to 70.80%for RH and WS,respectively.Higher heating values increased significantly with torrefaction severity,reaching 19.26 MJ/kg for RH and 20.25 MJ/kg for WS when torrefied at 300℃,representing a 22%-25%improvement over raw biomass.Moisture uptake dropped substantially from 38.6%to 1.9%and from 41.5%to 2.1%for RH and WS,respectively,indicating the enhanced hydrophobicity.Combustion indices have also showed desirable trends;the fuel ratio increased to 0.54 and 0.57,and the volatile ignitability exceeded 15 MJ/kg for both biomass samples torrefied at 300℃,indicating improved ignition characteristics suitable for cofiring.Techno-economic analysis revealed a net profit of 138520 Indian rupees/year,with a payback period of 5 years and a benefit-cost ratio of 1.27,supporting the economic feasibility of the system.Overall,the study confirms that torrefied biomass presents improved fuel characteristics and combustion behaviour,making it a viable solution for clean-energy transition and sustainable waste management.
