Effective utilization of biomass resource rapidly has been promoting since the government adopted the ‘Biomass Nippon’ strategy at a cabinet meeting in 2002. Especially, the energy conversion technology of applying biomass has been expected from a point of view of environment and resource conservation. However, the energy conversion technologies are developed only for woody and herby biomass, and not for all of biomass. A stable supply of large quantity of biomass will be pressed in the future because the conversion technology must expand to use a variety of biomass. This study is to consider ways by various quantitative correlation analyses between the atomic composition and thermal decomposition of various biomass samples. The results found that thermal decomposition analyses of various biomass resources have correlations between atomic composition properties and exothermic properties.
This paper reports on the pyrolysis process of various biomass materials in a thermobalance. In particular, the primary yields of total volatiles, tar and non-condensable gases, together with the composition of non-condensable gases, are measured as a function of temperature. The use of a high-intensity infrared heating source, in conjunction with a non-absorbing carrier gas (viz. argon), is reported to reduce the significance of secondary gas-phase pyrolysis reactions. The results indicate that the pyrolysis process of wood and grass biomass (tar and gas evolution process) is greatly affected by the main composition (cellulose, hemicellulose and lignin) and the linear trends with atomic H/C ratio are observed in the tar yield, total volatile yield CO, CO2 and CH4 yields. The volatile yields of wood and grass biomass are predicted based only on the values of ultimate analysis of the biomass.
An epoch-making incineration plant, which is equipped with a pressurized fluidized-bed combustor coupled to a turbocharger, for the recovery of the energy contained in sewage sludge is proposed. This plant has three main advantages. (1) A pressure vessel is unnecessary because the maximum operating pressure is 0.3 MPa (absolute pressure). The material cost for plant construction can be reduced. (2) CO2 emissions originating from power generation can be decreased because the FDF (Forced Draft Fan) and the IDF (Induced Draft Fan) are omitted. (3) Steam in the flue gas becomes a working fluid of the turbocharger, so that in addition to the combustion air, the surplus air is also generable. Therefore, this proposed plant will not only save energy but also the generate energy. The objective of this study is to elucidate the fundamental combustion characteristics of the sewage sludge using a lab-scale pressurized fluidized bed combustor (PFBC). The tested fuels are de-watered sludge and sawdust. The temperature distribution in the furnace and N2O emissions in the flue gas are experimentally clarified. As the results, for sludge only combustion, the temperature in the sand bed decreases by drying and pyrolysis, and the pyrolysis gas burns in the freeboard so that the temperature rises. On the other hand, the residual char of sawdust after pyrolysis burns stably in the sand bed for the co-firing of sludge and sawdust. Thus the temperature of the co-firing is considerably higher than that of the sludge only combustion. N2O emissions decreases with increasing freeboard temperature, and are controlled by the temperature for all experimental conditions. These data can be utilize to operation the demonstration plant.
In order to promote the utilization of unused woody biomass such as forestry biomass and pruned branch of fruit, the utilization of woody biomass has come to attract attention as a fuel at the pulverized-coal fired power plant. When the woody biomass in the forestry region is utilized, it is necessary to examine and reduce the energy consumption for collecting of resources, preprocessing such as comminuting and drying and transportation . In the present study, effect of semi-carbonization pyrolysis on comminution energy and assessment of transport property of woody biomass is investigated. The results obtained are as follows. Empirical correlations of work index in Bond′s Law are presented for both woody and semi-carbonization regions. The comminution energy can be estimated by the present empirical correlations within an accuracy of ±30 percent. To evaluate the effect of semi-carbonization process on the energy reduction of transport and comminution, an analysis of energy consumptions is conducted. From the result of analysis, it is found that the energy consumption ratio is the minimum at a mass yield condition of 0.6 for the same transport distance.
The impact welding has been carried out using the projectile with the diameter of 11 and 5 mm. The large projectile with the slenderness ratio L/d (L is Length and d is diameter) of 1 to 5 was welded to the stainless steel target. However, only the small projectile with the slenderness ratio less than 1.2 was welded to the same stainless steel target. In order to clarify the effect of the diameter of the projectile on the weldability, the temperature elevating process in the cylindrical projectile subjected to a longitudinal impact is evaluated numerically using LS-DYNA. The slenderness ratios used in the analysis were 1.0, 2.0 and 3.0. The coefficient of friction used in the analysis was 0.2. The constitutive equation used in the analysis was Cowper-Symonds type. Those numerical results indicated that the deformation mechanism of the projectile with the slenderness ratio less than 2.0 is different of that of the projectile with the slenderness ratio more than 2.0. It was clarified from those results that the temperature of the small projectile with the slenderness ratio less than 1.5 arrives at the bonding temperature by the difference of the deformation mechanism regardless of the small kinetic energy.