Technoeconomic Feasibility of a Sunflower Husk Fast Pyrolysis Value Chain for the Production of Advanced Biofuels.

Biofuels are required to reach the target set out by the European Commission's Transport mandate in the RED II (Renewable Energy Directive) for 2020-2030. To avoid indirect land use change, waste biomass resources such as sunflower husks can be used for advanced biofuel production. A process simulation and technoeconomic assessment of three fast pyrolysis plant scenarios were conducted. The nature of the waste feedstock has an effect on the value chain configuration, fast pyrolysis, and upgrading process design. Considering the difficulties with the transport and storage of biogenic waste due to low bulk density or hazardous and pathogenic content in case of transporting untreated sunflower husks, it is recommended to use a hub-and-spoke type of decentralized value chain configuration. The fast pyrolysis plants are located close to the feedstock, and the fast pyrolysis bio-oil (FPBO) is transported to a single upgrading facility, colocated at an existing refinery. The upgraded FPBO is then cofed into an FCC (fluidized catalyst cracker), where partially green biofuels such as gasoline and diesel are produced. For the fast pyrolysis process design, Scenario 2, treating 10 t/h of dry biomass with electricity and steam as coproducts, has the most favorable economic results with a total capital investment (TCI) of 78 million Euro and operating expenses (OPEX) of 6 million Euro.

Valorization of Eucalyptus, Giant Reed Arundo, Fiber Sorghum, and Sugarcane Bagasse via Fast Pyrolysis and Subsequent Bio-Oil Gasification.

Fast pyrolysis of giant reed Arundo (Arundo donax), fiber sorghum (Sorghum bicolor L.Moench), eucalyptus (Eucalyptus spp.), and sugarcane bagasse (Saccharum officinarum) was studied in bench-scale bubbling fluidized bed reactor. Product yields were determined, and detailed physicochemical characterization for produced fast pyrolysis bio-oils (FPBOs) was carried out. The highest organic liquid yield (dry basis) was observed with sugarcane bagasse (59-62 wt %), followed by eucalyptus (49-53 wt %), giant reed Arundo (39 wt %), and fiber sorghum (34-42 wt %). After the pyrolysis experiments, produced FPBOs were gasified in an oxygen-blown autothermal catalytic reforming system for the produced synthesis gas. The gasifier consists of a partial oxidation zone where the FPBO is gasified, and the raw syngas is then reformed over a fixed bed steam-reforming catalyst in the reforming zone. The gas production (∼1.7 Nm3/kg FPBO) and composition (H2 ∼ 50 vol %, CO 20-25 vol %, and CO2 25-30 vol %) were similar for all FPBOs tested. These results show that the combination of fast pyrolysis with subsequent gasification provides a technically feasible and feedstock flexible solution for the production of synthesis gas.

Evaluation of Analysis Methods for Formaldehyde, Acetaldehyde, and Furfural from Fast Pyrolysis Bio-oil.

Fast pyrolysis bio-oil (FPBO), a second-generation liquid bioenergy carrier, is currently entering the market. FPBO is produced from biomass through the fast pyrolysis process and contains a large number of constituents, of which a significant part is still unknown. Various analytical methods have been systematically developed and validated for FPBO in the past; however, reliable methods for characterization of acetaldehyde, formaldehyde, and furfural are still lacking. In this work, different analysis methods with (HS-GC/ECD, HPLC, UV/Vis) and without derivatization (GC/MSD, HPLC) for the characterization of these components were evaluated. Five FPBO samples were used, covering a range of biomass materials (pine wood, miscanthus, and bark), storage conditions (freezer and room temperature), and after treatments (none, filtration, and vacuum evaporation). There was no difference among the methods for the acetaldehyde analysis. A significant difference among the methods for the determination of formaldehyde and furfural was observed. Thus, more data on the accuracy of the methods are required. The precision of all methods was below 10% with the exception of the HPLC analysis of acetaldehyde with an RSD of 14%. The concentration of acetaldehyde in the FPBO produced from the three different biomasses and stored in a freezer after production ranged from 0.24 to 0.60 wt %. Storage at room temperature and vacuum evaporation both decreased significantly the acetaldehyde concentration. Furfural concentrations ranged from 0.11 to 0.36 wt % for the five samples. Storage and after treatment affected the furfural concentration but to a lesser extent than for acetaldehyde. Storage at room temperature decreased formaldehyde similarly to acetaldehyde; however, after vacuum-evaporation the concentration of formaldehyde did not change. Thus, the analysis results indicated that in FPBO the equilibrium of formaldehyde and methylene glycol is almost completely on the methylene glycol side, as in aqueous solutions. All three methods employed here actually measure the sum of free formaldehyde and methylene glycol (FAMG).