This paper presents a new method for predicting the gas release characteristics of various species in pyrolysis of wood and grass biomass. The pyrolysis experiment of various biomass samples were carried out, and the gas release process in pyrolysis was measured. Large amount of CO2 and CO were released at first. CH4 was subsequently released. Additional CO was released at more than 700°C in the pyrolysis of lignin and lignin-rich biomass. Finally, H2 release was increased. This gas release Characteristics indicate that the pyrolysis mechanism of biomass was almost same with that of coal. Based on these experimental results, biomass-CPD model was modified to divide the reactions of intact bridge, side chain and aromatic cluster for predicting the gas release process of various species. In the first reaction, H2O, CO and CO2 were released from intact bridge and side chain. Next reaction was the release of CH4 from intact bridge and side chain. Further CO release from intact bridge and side chain occurred at high temperature only in lignin pyrolysis. Finally, H2 was released from intact bridge, side chain and aromatic cluster. Kinetic parameters of those reactions were determined from values of the conventional pyrolysis model both of coal and biomass. Consequently, the gas release process of various species was well predicted by using above mentioned new biomass-CPD model.
The introduction of renewable energy has been stagnant in Japan in spite of its growing need as the effective measures to reduce CO2 emissions globally. The New Energy Foundation carried out a survey from the financial aspect, subjects of which included photovoltaic generation, wind power, biomass, geothermal energy, small and medium-sized hydropower and snow-ice heat. It is pointed out that a corporate-finance scheme is adopted in many projects in addition to government subsidies while a project-finance scheme is found only in the large-scale wind power. Based on this survey, a cash-flow model for the finances of power generation project making use of scrap wood thrown out in a lumber mill is made. Its plant size is assumed to be 75 ton/day and 70% of generated electricity is used for in-house consumption and the rest for selling to a electric company in order to save money and to increase cash inflow. The financial performance of the model for 16 years is evaluated by the indices of recoverable period of time for investment, debt service coverage ratio and internal rate of return on investment. Sensitivity analysis is made assuming the variation in the amount of subsidy, the amount of material input, the proportion of outsourcing of material, quality of material and the rate of electricity sold to power company. According to the results, more than 50 ton/day of scrap wood used and less than 40% of the rate of outsourced material are found to be required as the condition for the achievement of a profit. In-house supply and consumption of scrap wood makes the project profitable.