Torrefaction and low-temperature carbonization technologies as a pretreatment for woody biomass have been gaining great attention these days since those processes generate high-quality biomass with lower water content, higher heating value and better grindability comparing to raw biomass. While development of torrefaction and low-carbonization technologies are progressing, there iare very few studies in gasification of carbonized biomass, especially tar production behaviors in gasification process. This research aims at investigating characteristics of carbonized biomasses with different carbonization temperature by comparing to that of raw biomass in lab-scale experiment. The results show that gasification of biomass torrefied at 300℃ produces the synthesis gas with higher heating value and less tar than that of raw biomass.

Alkali catalyzed hydrothermal treatment (HTT) can be used as pretreatment of biomass for catalytic gasification in an entrained flow gasifier. The main function of HTT is to prepare slurry feedstock which is pumpable, easily pressurized, has good atomization characteristics and contains alkali catalyst for downstream gasification process. This study investigates the effects of HTT process conditions, such as the temperature and the catalyst load, on the resulting slurry properties. It was found that a higher catalyst load resulted in a higher ash content, or catalyst content, in the slurry. In addition, a higher temperature promoted the liquefaction of the biomass making the slurry more homogeneous.

In this study, a small scale demonstration plant was manufactured to produce upgraded wood fuel by torrefaction. The plant consists of rotary-kiln type oven and ring-die type pelletizer, which were optimized for torrefaction based on the commercial models. We succeeded in 240h operation of the torrefaction oven and producing 2.2 t of torrefied chip from raw Japanese cedar chip without drying. The energy yield of the torrefied chip was 2 times higher than that of conventional charcoal chip. The average length of the torrefied pellet was 7.4 mm, which was shorter than that of the untreated wood pellet.

Dynamic and isothermal thermogravimetric (TG) analyses of Japanese beech (a hardwood) and Japanese cedar (a softwood) along with their delignified and ball-milled samples were conducted to understand the thermal reactivities of hemicellulose and cellulose in wood cell wall. As a result, both delignification and ball milling tended to increase the thermal reactivities of hemicellulose and cellulose in cell wall, but the influences varied depending on two wood species. These treatments tended to affect the reactivities of cellulose in cedar and hemicellulose in beech more significantly. These results are discussed in terms of the different hemicellulose chemical structures (sugar type, uronic acid and acetyl content) and assembly of hemicelluloses and cellulose crystallites in cell wall.

Aromatic solvents are known to stabilize levoglucosan (1,6-anhydro-β-D-glucopyranose), the major pyrolysis intermediate of cellulose, against thermal degradation including char formation. We investigated the pyrolysis of cellulose in aromatic solvents, which significantly delayed the thermal degradation of cellulose. In addition, the selectivities of the levoglucosan and 5-hydroxymethylfurfural (5-HMF) formations were greatly enhanced in the aromatic solvents. Accordingly, pyrolysis in aromatic solvent is a promising way to convert cellulose into chemicals such as levoglucosan and 5-HMF by suppressing their secondary reactions into char and other products through inhibiting the proton donation (acting as acid catalyst) by complexation with aromatic π electrons. Char formation mechanism via 5-HMF is also discussed in terms of the cell wall lamellar ultrastructure.

Levoglucosan is the major volatile intermediate in cellulose pyrolysis and gasification and known to be stable up to the temperatures as high as 500°C in the gas phase. To study whether this stability is characteristic of levoglucosan, the gasphase reactivity of α- and β-methyl glucosides (GlcαOMe and GlcβOMe) at 200-500°C (residence time 1.2-2.0 s) was studied in this paper. As a result, methyl glucosides were found to be rather more reactive in the gas phase than in the liquid phase. Interestingly, levoglucosan formed selectively from the gaseous methyl glucosides at relatively low temperatures of 200 and 300°C, and the fragmentation reactions started at the higher temperatures than 400°C. Thus, levoglucosan is a specially stable carbohydrate against heat and this special stability reasonably explains why large amount of levoglucosan is produced from the pyrolysis of glucose-based carbohydrates such as cellulose. This stability is also discussed at the molecular level in terms of the steric hindrance of 1,6-anhydrostructure.

A loop seal is installed between a pair of fluidized beds to isolate individual fluidized bed reactor and to control particle circulation rate between the reactors by aeration. Advantages of the pneumatic loop seals are simple structure and high durability. Design of loop seals were empirically carried out so far because particle circulation rate passing through a loop seal was easily adjusted by particle hold up in fluidized beds. Detailed understanding of relationship between particle circulation rate and loop seal operation condition, therefore, was considered not to be important. However, to establish a more stable loop seal structure and/or operation or to realize an advanced multi-column circulating fluidized bed system detailed behaviors of loop seal should be required. In this study, a back pressure difference term was introduced into a correlation equation of particle circulation rate under atmospheric pressure. It was found that differential bed height of fluidized beds connected by a loop seal was adjusted by back pressure difference term like follows.

A process to produce carbonized solid fuels from woody biomass by carbonization/torrefaction accompanied by tar recovery with the produced char itself was proposed. The experiments of continuous carbonization/torrefaction and tar recovery processes were performed using the two furnaces, the carbonization furnace (lower, 300 to 500 °C) and tar recovery furnace (upper, 100 °C) aligned vertically. Thirty cylindrical pieces of Japanese cypress were moved upward through the two furnaces and the volatile matters emitted from the lower pieces were recovered by the upper pieces which were already pyrolyzed. As the furnace temperature increased, the mass yield of the tar-containing char decreased and the heat value increased. As a result, the energy yield was highest at the furnace temperature 350 °C. And also, the grindability of the tar-containing char produced over 350 °C was satisfactory. The study demonstrated that the energy yield could be increased up to over 90 % by tar recovery with the produced char itself even in the case of torrefaction.

These days, the amount of domestic waste is decreasing in association with the depopulation and the need for small scale garbage disposal plant is growing among local governments. In this research, we imitated the power generation from biomass resources that includes domestic waste. We gasified woody biomass by using mixed gas of nitrogen as an oxidizing agent and measured the composition of the bio-syngas, temperature in the reactor and so on. Consequently, the bio-syngas produced low heat value. It is believed that the carbon conversion efficiency and the cold gas efficiency decreases when the flow rate of an oxidizing agent increases or the quantity of supplied oxygen into the reaction field decreases.

The decomposition behaviors of lignin in various lignocellulosics as treated by two-step hot-compressed water (1st stage: 230°C/10 MPa/15 min, 2nd stage: 270°C/10 MPa/30 min) were compared. As a result, the delignification from monocotyledons such as nipa (Nypa fruticans) frond, rice (Oryza sativa) straw and corn (Zea mays) cob were higher than those from woody biomass such as Japanese cedar (Cryptomeria japonica) and Japanese beech (Fergus crenata), especially during the 1st stage, in which most of hemicellulose were decomposed. According to the analysis of their lignin structures, it was found to have a stronger correlation between the delignification and cinnamic acids contents compared to their phenylpropane structures.

Supercritical water gasification (SCWG) for biological effluent holds promise as a technology to convert biological effluent into valuable, environmentally, and substitute energy for Fossil fuel. The improvement of the equipment utilization efficiency of the SCWG facility on-site is important. 24 h continuous SCWG operation with pilot plant (treatment capacity = 1 t-wet/d) was succeed. However, SCWG plant appropriate operation is considered as DSS (daily start and stop on weekday), because of the shochu distillers’ daily work schedule. Therefore, 60 h DSS tests were conducted with difference feed rate conditions and the influence for tar formation at heat exchanger by temperature rising rate of gasification feedstock slurry was confirmed. As the result,

We carried out the decomposition of oil palm empty fruit bunch (EFB) as a lignocellulosic biomass at 300 °C in water using metallic iron. As a result, we found that water-soluble fraction (WS) and water-insoluble fraction (WI) were obtained in high yield while suppressing by-production of char. Moreover, we demonstrated that the catalytic cracking of WS fraction using HZSM-5 zeolite resulted in improving the yield of light olefins (C₂–C₄). We suggest that the WS was upgraded by the reduction ability of metallic iron in water.

Many studies have been performed on the gasification rate of char for biomass-derived char. However, the gasification rate varies greatly with the experimental device and the type of biomass, even if the same gasification temperature is adopted. Further, the mechanism of pore development on the biochar surface has been barely studied. The present study investigated in detail the gasification rate of biochar (Douglas fir char) in the presence of water vapor (H₂O) or CO₂ using the same experimental device. The results showed that (1) the gasification rate of the biochar was approximately 10 times higher under the H₂O atmosphere than under CO₂, (2) the specific surface area of the microand mesopores on the biochar surface increased as the gasification proceeded, and the increase in the specific surface area during H₂O gasification was similar to that during CO₂ gasification, for the carbon conversion rates of 0.2 - 0.5, and (3) the active site between the gasifying agent and the carbon on the char surface resulted in a higher reactivity during H₂O gasification than during CO₂ gasification..

Microwaves has been used as an efficient pretreatment for lignocellulosic biomass as well as biomass conversion reactions. Previously, a frequencty at 2.45 GHz has been widely used for microwave reactions, however, the use of adequate microwave frequency is desired for more efficient microwae propagation to each reaction systems. In this paper, we report effects of six different microwave frequencies for conversion of model biomass subsrates (e.g. monosaccharides) with and without polyoxometalate catalysts. The reactions were conducted with waveguide-type (915 MHz, 2.45 GHz, and 5.8 GHz) and coaxial-type reactors (1.7 GHz, 2.0 GHz, 2.7 GHz) equipped with semiconductor microwave generators. The substrates were added to ionic liquid ([BMIM]Cl) or DMSO solvents and reacted under microwave irradiation. The distribution of products varied with different microwave frequencies due to frequency-depednet dielectric property of the catalysts as well as solvents.

There are five million tons of wasted wood building materials in a t ime span of a year in Japan. About 50% of the energy used in waste recycling factory is diesel oil for heavy machinery. The objective in this study is the investigation of the use of a nail, involved in the wasted wood building materials, for Fischer-Tropsch synthesis (FT-syn) catalyst to produce diesel oil. The mechanisms of the preparation of FT-syn catalyst from a nail and the FT-syn with the catalyst are clarified.

In this study, we investigated the catalytic activity of Ni-loaded chicken droppings for biomass tar reforming. The Ni-loaded chicken dropping catalysts showed the catalytic activity for decomposition of biomass tar derived from pyrolysis of Japanese Cypress, which is comparable to a commercially available 20 wt% Ni/Al₂O₃. The introduction of steam during biomass pyrolysis reduced carbon deposition and increased H₂ yield.

Municipal waste incineration facilities in Japan often use gasification melting furnaces due to their high environmental performance and ash volume reduction. This project tests bio-coke made from various types of biomass, fed into a furnace for several months as a substitute for coal coke. Bio-coke is considered to be a carbon-neutral fuel, and has been verified to reduce CO₂ emissions by at least 25% compared to conventional fuel.

Previous performance test of the diesel engine using Bio Diesel Fuel (BDF) has shown that the PM exhaust characteristic has been improved through increased net thermal efficiency with a larger fuel supply and a rise in fuel injection pressure. However, the NO_X density in the exhaust gas increased in that case as well with the rise of combustion temperature. In this research, effective EGR for NO_X decrease is applied and the effect on operation characteristics of the engine is investigated. The results make it clear that superior operating characteristics during BDF use can be obtained in comparison to the use of gas oil, in operating conditions with a decreased excess air factor.

Production of fine particles from biomass chips is usually performed using milling machines under drying condition that consume large amount of energy. To overcome these problems, we proposed a novel milling method by utilizing the thermal energy, so called self-steam (self-SE) explosion method. Different from conventional steam explosion method that directly supplies steam into reactor, self-SE method indirectly heat-up the reactor and utilizes the moisture content in biomass as steam resource. In this study, we focused on the possibility of our proposed method to produce fine particles with a size below 1 mm from wet wood chips. Sakura (Prunus spp, hardwood) chips with a size of 5-10 mm were used in this study. The effects of treatment conditions on the biomass size reduction were investigated in detail. The energy consumption of our proposed was also calculated and compared with that of the conventional mechanical mill (cutter mill). We found that self-SE method not only can effectively reduce the size of wood chips into fine particles (<1mm), but also can improve the properties of product such as higher heating value and high hydrophobicity. Self-SE is also more energy-efficient than the conventional mill.

Mass production of sweetpotatoes by a cheap cultivation method was achieved with small pots by optimizing the elongation space of the roots and the hygroscopic condition of the soil. In Okinawa we planted vine of sweetpotato in October, and harvested in April. The amount of sweetpotatoes cultivated in the winter months was reached to 7.3 kg/m², which was three times the national average to grow in the summer. The result showed that annual production of 20kg/m² sweetpotatoes is feasible by further optimizing the growth condition. For the purpose to use sweetpotatoes as fuel, technological issues of the methane fermentation and the gas power generation system were investigated.

Biogas from sewerage sludge and food waste, which are collected by a local government, have a large potential as renewable energy resource. A conceptual study on a small scale DME production process from biogas is conducted. Slurry phase direct DME synthesis process is applied and the process scheme is simplified from a large scale plant. The cold gas efficiency from feed biogas and the thermal efficiency including electricity are estimated 68.6% and 55.5%, respectively. A modular type plant is designed and the main equipment such as reformer and DME synthesis reactor is sized so as to be set in several ISO containers. The total plant area is 70m long and 35m wide.

Biomass has attracted attention as a carbon neuteral resource in recent years. In Japan, utilization of biomass has been promoted in various places, but the entire flows of biomass have not been well understood in a systematic way. In this study, we estimated life-cycle material flow of agricultural biomass in order to identify its energy potential. Based on the estimated material flow, total amount of byproduct/waste and its total energy potential were estimated at 22 million t/year and 38000 TJ/year in 2013. There were gaps between our estimates and literature, which need further consideration. However, we believe that the mass balance principle adopted in this study can reach more accurate estimation of the potential and the results can be used for evaluation of resource use efficiency improvement.

Finding viable alternative crops for bioethanol production is a major challenge for the biofuel industry. To that end, the current work embarks on assessing the potential of palm saps as bioethanol feedstock. The availability and chemical composition of palm saps were investigated. Bioethanol yields were determined based on the following parameters: palm density, ratio of productive palms, sap yield per day, tapping duration, sugar content, and fermentation yield. As a result, the prospective annual bioethanol yields from palm saps ranged from 4,550 to 19,000 L/ha/yr, which are higher than those from traditional sugar and starch crops. Overall, palm saps show advantages as promising feedstocks for sustainable bioethanol production.

It is important to construct 2^nd bioethanol system that various cellulosic waste can be used. Waste mushroom bed is one of such hopeful feedstock for ethanol production. Steam explosion was adopted as the pretreatment technology for enzyme hydrolysis which can be applied to the various cellulosic waste. Steam explosion is a thermo-mechanicochemical pretreatment which allows the breakdown of cellulosic biomass components by the action of heating, formation of organic acids, and shearing forces resulting in the expansion of the moisture. Steam explosion at 180, 190 and 200 °C for 10 and 20 min was applied to waste mushroom bed in a pilot scale reactor. All pretreatment conditions led to high enzyme hydrolysis, with the maximum achieved at 200 °C, 10min.

In dilute sulfuric acid process, cellulose in wood is hydrolyzed into glucose which is a raw material for bio-fuel and chemical production. One of the problems of this process is that the obtained lignin can not be used as functional chemicals because of its low reactivity and solubility to solvent. In this study, we conducted dilute sulfuric acid hydrolysis of wood meal coated by p-cresol to obtain reactive lignin as well as useful chemicals from cellulose and hemicellulose. As a result of p-cresol coating, we successfully extracted lignin with THF or by soda cooking in a higher yield. It was expected that p-cresol grafted to lignin during hydrolysis and excessive polymerization by condensation reaction was prevented. In this hydrolysis process, we can obtain sugars, furfurals, organic acids and lignin which would be useful for resin, gel or film production.

The cloud point (CP) of biodiesel refers to the temperature at which crystallization begins on cooling. However, solid precipitates often form even above the CP. Such precipitates are known to consist mainly of monoglycerides (MGs), which have high melting points. MGs have several polymorphic forms with different melting points (α < β′ < β), and this fact makes the solidification behavior of biodiesel complicated. In this study, the behavior of MGs in biodiesel is discussed using 1-monopalmitin and methyl oleate mixtures as a model biodiesel fuel. The CPs measured without agitation were close to the solid–liquid equilibrium (SLE) temperatures of α-type monopalmitin. On the other hand, the CPs measured under ultrasonic treatment were close to the SLE temperature of the β′ form. This indicates that the β′ form crystallization causes a risk of precipitation even at temperatures higher than CP.

In our previous experiments, Bi₂O₃ photocatalyst prepared using urea showed hydrogen generation activity under ultraviolet irradiation, although it did not show the activity under visible light irradiation. Therefore, in this study, inexpensive iron oxide as a transition metal oxide was added to bismuth oxide in order to obtain response to visible light, Fe₂O₃-Bi₂O₃ catalyst was prepared by the sol-gel method, and the effect of Pt loading was investigated. Pt/Fe₂O₃-Bi₂O₃ with appropriate amounts of platinum and Fe₂O₃ showed high photocatalytic activities under both ultraviolet and visible light irradiation.

In this work, we focused on thermal decomposition of Na alloys to understand the fundamental physical properties. Na15Sn4 was selected as typical Na alloy and the decomposition reaction was carried out in various conditions. As a result, the decomposition reaction hardly occurred in the closed system. On the other hand, the reaction occurs at 300-500 °C in the open system, and then Na is generated and evaporated from the reaction field. Furthermore, the decomposition temperature is decreased to 150 °C under higher vacuum condition. It was found that the thermal decomposition temperature can be decreased by controlling the vapor pressure of the liquid Na which was the product of the reaction.

We investigated ethanol steam reforming for H₂ and CH₄ production over noble metal catalysts at 673K. The Ru/SiO₂ and Rh/SiO₂ catalysts showed higher activity for CH₄ production than Pt/SiO₂ and Pd/SiO₂ catalysts. As the amount of Ru/SiO₂ catalyst was increased from 5 to 20 g, production of H₂ was suppressed and production of CH₄ was increased. The experimental results suggest that H₂, CO, and CO₂ are firstly produced in the reactor by ethanol steam reforming, followed by the reduction of the CO and CO₂ to CH₄. The effect of support material on Ru catalyst was also investigated. The Ru catalysts supported on SiO₂ and CeO₂ show higher activity for CH₄ production than any of the Ru catalysts examined.

The two-step water splitting reaction with perovskite type manganese metal oxide (La_xSr_1-xBO_3-δ or La_xCa_1-xBO_3-δ, B=Mn, Co, Cr, Al) is investigated for solar hydrogen production. The various samples were prepared by modified Pechini method. The maximum amounts of evolved H₂ and O₂ gases were obtained at the La_0.5Sr_0.5MnO_3-δ in the La_0.5Sr_0.5BO_3-δ and La_0.5Ca_0.5BO_3-δ samples. The tolerance factor of La_0.5Sr_0.5MnO_3-δ is very close to 1, it is suggested that the perovskite structure of the compound is most stable. Also, the huge amount of O₂ gas evolution was obseved with La_0.7Ca_0.3CoO_3-δ, however, the reactivity of the reduced sample was decreased in the H₂-generation reaction because of eliminating stability of the sample.

Metal hydrides such as magnesium hydride (MgH₂) and titanium hydride (TiH₂) are attractive materials for chemical heat storage because of high enthalpy change of the hydrogen desorption. On the other hand, although the hydrogen absorption of Mg and Ti is exothermic reaction, thermal activation at generally several hundred °C is necessary for the reaction progress. In this work, suface modification of Ti is carried out to improve the kinetcs for hydrogen absorption. On the basis of knowdelge for Mg, various kinds of additive are dispersed on Ti, and the hydrogen absorption properties are investigated. However, additive with significant catalytic effects are not found. On the other hand, when the hydrogenation is immidiately perfoemd after the hydrogen desorption from pristine TiH₂, hydrogen can be absorbed even at near room temperature. The above results indicate that the hydrogenation of Ti is prevented by surface oxide layers, and any catalysts are not necessary for Ti with fresh surface.

We constructed 100 MPa class High Pressure Hydrogen experimental facility for Metal hydride compressor. The facility consists of a hydrogen compressor, a 200-liter high-pressure tank, a 100 MPa high-pressure high-temperature reaction vessel, a flow rate control device, and pressure reducing valves. Using this facility, pressurization by Metal hydride was confirmed.

Thermodynamics of BCC alloys, which are expected to be an incombustible material, are researched by pressure-composition-isotherm (PCI) measurement as a metal hydride compressor (=MH compressor). Although V-Ti-Fe alloy has large hystelysis in its initial ab/desorption cycle, the hystelysis degreases by the following cycles. Then, thermodynamic parameters of V-Ti-Fe alloy are estimated to discuss its application to MH compressor.

Anodic performance of a Fe-CeO₂/ScSZ anode is evaluated. Net power output is negligible for the cells with 0CeO₂, 10CeO₂ and 80CeO₂ anode catalyst. Whereas anodic performance comparable to Ni/ScSZ are obtained for the anode catalyst between 20 mol.% and 70 mol.% ceria content, and the anode with 30CeO₂ electrode catalyst shows the best anodic performance in the range experimental condition. CeO₂ addition to Fe electrode catalyst presumably enhances reducibility of electrode catalyst from Fe₂O₃ to Fe during discharge. However excessive addition causes to reduce electric conductivity of the anode. These are the main reasons why these complex behavior is observed.

In order to reduce CO₂ emissions economically, “Photovoltaic Power Generator (PV) integrated with Electric Vehicle (EV) and Smart system” has been proposed and the effects of the system have been clarified. However, this system has an issue that the energy supply and demand adjustment between seasons has difficult. In this paper, some new energy systems which are combined with PV, EV, Heat Pump Water Heater (HP) and Hydrogen have been studied. As the results, these systems are able to reduce a large quantity of CO₂ emissions in comparison with the conventional system. The advantages and disadvantages of the new systems were clarified.

In order to reduce CO₂ emissions, an energy system which is combined with Photovoltaic Power Generation and Battery-powered Electric Train has been proposed. However, the air-conditioning energy consumption is about 30 percent of the whole of train energy consumption. Therefore, it is important to improve the energy efficiency of the air-conditioner for trains. In this paper, Air-conditioner Integrated Battery-powered Electric Train has been proposed. As the results, the proposed system is able to reduce CO₂ emissions by 61% compared with the conventional system using diesel trains.

The objective of this study is to analyze, from a comprehensive perspective, the economic and environmental effects induced by constructing and operating hydrogen utilization systems presented by METI’s roadmap. We focused on a marine transport system for hydrogen produced offshore, hydrogen gas turbine power generation, fuel cell vehicles (FCVs) and hydrogen stations, as well as residential fuel cell systems (RFCs). In this study, using an Input-Output Table for Next Generation Energy Systems (IONGES) with newly established renewable energies and hydrogen-related sectors, we evaluated the induced output, labor and CO₂ from construction and operation of these hydrogen technologies using a uniform approach. Initial investments in facilities based in foreign countries that produce hydrogen, transport it through organic hydride, and supply it to a power station of 1 GW capacity yield an induced production of 2.7 times. This investment can exploit a new opportunity for the utilization of unused renewable energy sources that are abundantly available in foreign countries and reduce significant CO₂ emissions. Additional investments in domestic hydrogen supply systems, FCVs, and RFCs yield an induced production of 2.6 times each. From a comprehensive point of view, the construction of a hydrogen utilization system may result in cost and CO₂ reductions.

It is important for overtopping wave power generators to clarify the relation of the wave power and the water feeding from reservoir for irregular wave on the sea. In this paper, the simulation of the wave power and wave feeding for various irregular waves is presented. It may become a favorable current by inertia force also when tank inside water level is lower than tank outside water level. This result may raise the efficiency of wave overtopping type wave power generation equipment.

In the previous research, the authors proposed a system that can utilizes the energy of both vertical (up and down movements) and horizontal movements of waves. The experimental results on the basic performance of waves energy had been presented at last year’s conference. This system is based on the combination of waves motion with the reciprocating motion between the horizontal flat plates, and at the same time, by using the sloshing phenomenon, the reciprocating motion in the flow channel is sustained for the next incoming waves. However, in order to gain electrical energy, a high efficiency turbine that can converts this reciprocating motion in one direction rotation is necessary. In this research, a turbine that applicable to such a reciprocating motion of water flow was studied. Three different types of turbines were installed in the water tank for sloshing experimental purpose which were, Savonius turbine, Cross-flow turbine and Gyro-mill turbine. Based on the output of hydraulic turbine that was estimated from the rotation speed and torque generated by the reciprocating movement, it was found that Savonius turbine can realize the conversion of one direction rotation with highest efficiency. As the experimental results, the maximum efficiency of Savonius turbine based on the reciprocating motion of water flow to one direction rotation was about 70%.

A simple computational model for a wind power generation system that consists of a wind turbine, a generator connected directly with turbine and a load is investigated. In this report, the system model is enhanced for unsteady wind speed that is required to analyze characteristics of the system for actual field conditions. As the results, it is investigated that some response delay of the power of turbine and generator compared with change of wind speed are shown by the model and some phase difference between the power of turbine and the power of generator are also shown with sinusoidally changed wind speed.

The possibility of using liquid electrolyte of vanadium redox flow battery for sensible heat storage is discussed. The proposed redox flow battery that simultaniously stores electricity and thermal energy is used in connection with phtovoltaic and thermal hybrid solar collectors. The effect of operating temperature on the voltage efficiency was measured with a small scale cell (5cm²) from the temperature range from 25°C to 80°C. As the result of examining the electrochemical performance and the stability of the electlyte solution, the redox flow battery is expected to operate under the condition of 50°C or lower with acceptable electrochemical performance. The thermal storage system with the redox flow battery can be effective equipment aiming for off-grid solar power houses and facilities.

In the present study, copper-zinc oxide–based catalyst coated by porous silica for hydrogenation of carbon dioxide into methanol was fabricated. A commercial catalyst was coated with silica by a sol-gel method. In this process, cetyltrimethylammonium bromide (CTAB) was added as an organic template for formation of porous silica during the coating process. The amount of CTAB influenced in morphology and physicochemical properties of the catalyst. The results from TEM images and N₂ sorption measurement indicated that both the coated silica particles and the catalyst particles with highly dispersed and porous structure was obtained by appropriate amount of CTAB added in the coating process of silica. The silica-coated catalyst prepared with appropriate amount of CTAB displayed a high activity at high temperatures, indicating that silica-coated catalyst showed stable catalytic activity.

Mitaka Koki Co., LTd., Miyazaki prefecture, Miyazaki University and Niigata University build a beam-down (BD) solar concentrating system in August 2012 at Miyazaki University for solar demonstration of the receiver/reactor. Both universities started an R&D joint project since 2011 to demonstrate the up-scaled receiver/reactor under a concentrated solar radiation. Niigata University has a 30 kW sun-simulator for testing of solar reactor. In this study, the first results of the receiver/reactor using 30 kW sun-simulator are reported. Quartz sand is used as a fluidization particle to examine performances of the receiver/reactor, while air is used as a passing gas. The temperatures of air and quartz sand are shown in the paper. In addition, cerium oxide powder is used as a fluidization/reaction particle to perform thermochemical two-step water-splitting cycle. The oxygen and hydrogen production are reported in this paper.

Solar hydrogen production via thermochemical water-splitting cycle by concentrated high-temperature heat has extensively investigated in a world. In this study, a thermochemical two-step water-splitting using redox material of Mn doped-ceria powder was examined in consecutive thermal reduction-decomposition steps by thermogravimetric reactor. Thermal reduction temperatures were performed at 1300, 1350 and 1400°C, while water-decomposition temperature were done at 1200°C. The reactivity of Mn doped-ceria powder with 5-30 mol% Mn doping was evaluated for various reaction temperatures in this study.

Perovskite-type metal oxides were synthesized by Pechini method. Then, they were examined its reduction/oxidation reactivity by thermogravimetric analysis. After TGA testing, high redox-capacity materials were selected, and its reaction enthalpy was measured by DSC analysis. These results showed that the redox reactivity was improved by decreasing Lanthanum ion activity and increasing Barium ion concentration of samples. It was revealed that Ba-containing samples are potential thermochemical energy storage application.

Numerical simulations of pulverized coal combustion were performed to investigate the effect of coal type on phenomena in blowpipe. Anthracite, low- and high-volatile bituminous coals were employed as the tested coal types. The temperature distributions in blowpipe were different with coal types. Comparison of the difference of temperature distributions with anthracite and low-volatile bituminous coal suggested that the thermal property of volatile matter has significant impacts on the temperature. The conversion of high-volatile bituminous coal char, which has the highest gasification reactivity, was higher than those of the other coal chars. Therefore, it is indicated that the char gasification occurs even the residence time of coal is remarkably short, and gasification of pulverized coal is important factor to improve current operating conditions.

The primary objective of our study is to clarify the statistical characteristics of occurrences of micro-explosion in secondary atomization processes of Mixture/water emulsions. Droplet combustion experiments were carried out for n-hexadecane/OME/water emulsion. Weibull analysis was applied to discuss the occurrence characteristics of micro-explosion events. The results showed that distribution function of waiting time for micro-explosion is correlated with the mixed type Weibull distribution. Waiting time distribution of test emulsions has been composed early failure type and chance failure type. Effect of OME addition on distribution function has been also revealed.

In the experimental researches associated with liquid spray, the spray cheracteristics were currently evaluated from a finite number data of droplets obtained by the optical measuring devices. In the present study, the number of data were studied statistically which was required to evaluate reliablely the mean droplet diameter and the outline of drop-size distribution, using the sets of high quality pseudo-random numbers generated by the mersenne twister method.

In this research, the influence of N₂ or CO₂ dilution on the characteristics of the stratified-combustion of methane was investigated by using a rapid-compression machine (RCM). In addition, by creating a model that estimated the mixture concentration distribution in the cylinder, the influence of the dilution of nitrogen and carbon dioxide on the distribution of the air-fuel mixture in the cylinder was quantitatively evaluated. Nitrogen dilution decreased the maximum NO_x concentration. Dilution mainly affects the uniformity of the mixture distribution.

To elucidate fundamental combustion behaviors of some solid combustible wastes under isothermal conditions, the isothermal combustion experiments are carried out, using an electrically heated vertical batch furnace. The effects of the furnace temperature and the oxygen partial pressure in the reaction atmosphere on the combustion behaviors are studied experimentally and kinetically. As a result, the completion period of the overall combustion decreases with increases of both the furnace temperature and the oxygen partial pressure.