In the production of bioethanol in Asia, developed countries such as Japan have the problems of high cost and a lack of resources, while Southeast Asian countries have substantial biomass production and export potential. The purpose of this study is to optimize the international supply of bioethanol in East Asia. A linear model is developed to estimate costs, energy consumption, and carbon emissions in three processes: cultivation, conversion, and international transport. In order to consider the regional characteristics of producing countries, biomass price, electric power generation, fertilizer usage, agricultural machine usage are incorporated into the model. Optimization based on linear programming is carried out with two objective functions: minimizing cost and minimizing carbon emissions. For each objective function, the amount of supply, economic efficiency, and carbon emissions are quantitatively analyzed in three cases. One is domestic supply case where each country supplies bioethanol to domestic market. Another is Asia supply case where Asian countries supply bioethanol with international supply. The other is Asia-Brazil supply case where Brazil is included in bioethanol supply in Asia. The average supply cost of bioethanol in Asia supply case with the objective function of minimizing cost is a quarter of that in domestic supply case. The carbon emissions reduction increases by international supply. Brazil has more than 50 % share in bioethanol production in both objective functions and contributes to the reduction of carbon emissions.
Ru catalysts were investigated for the synthesis of Fischer-Tropsch (F-T) fuels in a biomass-to-liquid (BTL) plant operation using biomass-derived syngas. Bio-syngas was produced from woody biomass in a BTL gasification plant, and H2/CO ratios of 0.8 and 2.2 maintained by a BTL water-gas shift reactor were used. With a bio-syngas feed, Ru/Mn/Al2O3 showed high catalytic activity, selectivity, and stability for F-T synthesis under the BTL plant conditions, whereas Ru/Al2O3 exhibited very poor performance. Characterization results revealed that the addition of a small amount of Mn to the Ru/Al2O3 catalyst influenced an increase in the concentration of the active Ru species on the catalyst surface, resulting in high catalytic performance for F-T synthesis. Under the BTL plant operation conditions (T = 550 K, P = 4 MPa, W/F = 1.5 g h/mol and H2/CO = 2.2), Ru/Mn/Al2O3 showed 87% CO conversion where the production rate of F-T fuels was about 17 L/d (1879 g/(kg h)) when using biomass-derived syngas.
Lignophenol is a lignin-based polymer which highly conserves the native lignin structure. Through simple adsorption experiments between Trichoderma reesei cellulase and softwood lignophenol synthesized from Hinoki cypress and p-cresol, several ideas were obtained on non-productive cellulase binding to lignin expected during enzymatic saccharification of cellulosic substrates. Cellulase is promptly bound to lignin within 10 min. The adsorption reaches a saturated value, indicating that cellulase adsorption on lignin is not multi-layered. Maximum adsorption is observed at around the isoelectric point of cellulase and, at the same time, phenolic hydroxyl groups in lignin seem to enhance cellulase binding. Cellulase bound to lignin maintains its enzymatic activity and probably functions as an immobilized cellulase in saccharification liquor.
In Tochigi prefecture, some facilities to demand woody biomass resources such as the biomass power plant, chip production factories, and the pellet plant are located. These raw materials are mainly supplied by sawmill residues and construction wastes. However, since the number of entrepreneurs who set up the biomass power plants as a measure against climate change, it is worried about stringent supplies of those materials. Therefore, unused materials such as logging residues must be harvested and used near the future. In the previous study, we developed a method to estimate the harvesting volumes and costs of logging residues from subcompartments with plus balances, including both timber and logging residue harvesting at Sano city, Tochigi prefecture. In this study, we estimated the harvesting volumes and costs of logging residues for all cities and towns in Tochigi prefecture. Three factories in Sano city, Kanuma city, and Nasu-shiobara city, Tochigi prefecture were assumed as destinations, and set of the harvesting operation system based on each forestry cooperative. In addition, the previous study estimated these volumes and costs in whole city of Sano, but this study estimated these volumes and costs using forest management records. This could estimate these volumes and costs based on actual forest operations in this area. The model estimated these volumes and costs in the following order. 1) Selecting subcompartments conducting pre-commercial or commercial thinning operations from forest management records, 2) Setting extracting rates for timber and logging residues, 3) Estimating harvesting volumes of timber and logging residues, 4) Estimating logging distances, transporting distances, and inclinations of operation sites, 5)Estimating total expenses, 6) Estimating incomes, 7) Estimating economic balances, 8) Estimating harvesting volumes from subcompartments with plus balances. The amount of logging residues from subcompartment with plus balances were 581 ton on the price of logging residues in this area: 3,000 yen/ton. If Feed-in Tariff (FIT) was established, the price of logging residues would be 10,000 yen/ton and the amount of logging residues from subcompartment with plus balances would be 134,198 ton/year which were almost equal to the demand of this area. The whole tree logging system may be more advantageous than the cut-to-length system for extracting logging residues.