To increase the co-firing ratio of biomass in coal fired power plant, the evaluation of the particle size distribution of biomass is necessary for the stable operation of the roller mill. However, the measurement of the biomass content in coal and biomass mixture is difficult with traditional fuel analysis. Because the neutral sugars were only contained in biomass, the biomass content in the mixture can be estimated from neutral sugar content. In this study, the grinding test were performed using a test roller mill with coal and biomass (WP; wood pellet, TP; torrefied pellet) mixture. The neutral sugar analysis showed the main constituent of the mixture with a large particle size was derived from biomass. In addition, comparing the particle size distribution of coal and WP mixture with coal and TP mixture, the improvement of grindability of biomass by torrefaction was confirmed quantitatively.

Biomass power generation attracts attention as one of the power generation methods utilizing renewable energy. Among them, a method utilizing a spark ignition engine (SI-ICE) is proposed. A small downdraft gasifier was manufactured to produce bio-syngas from woody biomass. A SI-ICE was driven fueled with bio-syngas generated by the gasifier. On the other hand, reduction of NO emitted SI-ICE is essential. From this reason, the purpose of this study is to elucidate the generation mechanism of NO fueled bio-syngas. The experimental results showed that the generation process of NO was thermal NO. The in-cylinder temperature was dependent on hydrogen ratio in inflammable gas of bio-syngas.

In this study, we examined the gasification rate of grass biomass with that of woody biomass and clarified the gasification mechanisms. The gasification rate of grass biomass was approximately 10 times that of the woody biomass. The increased surface area of the pores on grass biomass-derived char (specific surface area) was less than 1/3 that of the woody biomass-derived char. The surface area of grass biomass-derived char was saturated near X=0.5. The grass biomass-derived char consisted mainly of leaf sheaths, which are aggregates of vents. Because gasification agents can easily pass through vents, the reaction mechanism in grass biomass-derived char was predicted to be similar to that on its external surface. The tube walls of the vents were as thin as several μm and the carbon structure of the grass biomass was more amorphous, then external surface rapidly eroded (including collapse). As a result, increases in the surface area of the pores on grass biomass-derived char were inhibited and the gasification rate constant K_p was higher than that of woody biomass.

Pyrolysis is a promising method to convert biomass-plastic mixture to useful chemical feedstock. In this study, for the purpose of effective control of pyrolysis products, co-pyrolysis experiments were conducted under high plastic mixing ratio and different particle size of cedar wood, and the synergy effect was examined. The reduction of the particle size promoted the diffusion to the molten polyethylene, thereby suppressing aggregation on the surface of the cedar wood and reducing the yield of char. Donating hydrogen from PE-derived volatile pyrolysates promoted the stabilization of the cedar-derived pyrolysites and the further degradation of PE-derived pyrolysites, thus significant gasification by co-pyrolysis was observed.

An auto-thermal small downdraft gasifier has received particular attention due to its easy fabrication, operation, and low tar content in producer gas. Therefore, it can efficiently couple with reciprocating internal combustion engines to generate high electric efficiency. However, one of the major problems prevented the development of small power generation is tar. The presence of tar in syngas cause many operational problems for the system machinery. In order to understand clearly about tar characteristics, this study has conducted the tar sampling and analysis. In this work, tar from producer gas have been sampled with air supplied 40 L/min and moisture content of pellet 1.5 w% used the small downdraft gasifier (auto-thermal type, 500mm height, and 120mm diameter). Additionally, the tar deposit inside the pump with the long-term operation also analyzed to investigate the condensation mechanism. The tar samplings have been characterized by gas chromatography-mass spectrometry (GC-MS, QP 2010 Plus). Results revealed that the abundant components of tar from raw producer gas are acetic acid, propanoic acid, phenol, and naphthalene. Moreover, the heavy tar substances are main compostions in the pump deposit tar.

Pyrolysis and gasification characteristics of oil palm residues were investigated with thermogravimetric analysis (TGA), pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) and ampoule pyrolysis. The characteristics of each compound differ based on their lignocellulosic chemical structures. In TGA , empty fruit bunch (EFB) and shell had relatively high cellulose degradation peak temperatures (369.8°C and 363.2°C, respectively), whereas the peak temperatures of trunk, frond and mesocarp were much lower (336.0°C, 327.2°C, and 344.2°C, respectively). Kernel cake exhibited the maximum weight-loss rate at as low as 287.4°C. Primary pyrolysis products observed in pyrolysis-gas chromatography/ mass spectrometry (Py-GC/MS) at 423°C were also different for these residues depending on the chemical composition. Although secondary reactions were very limited even at 764°C with Py-GC/MS, based on the results of the ampoule pyrolysis conducted at 600°C, secondary pyrolysis reactivities including gas formation were also discussed.

Xylan and glucomannan are the typical wood hemicelluloses, but the compositions are different depending on the species; xylan is the major hemicellulose in hardwood, whereas the contents of glucomannan are much greater in softwood. In the present study, thermal reactivities of polysaccharides in beech (hardwood) and cedar (softwood) cell wall were evaluated by comparing the reactivities with isolated polysaccharides. The reactivities were evaluated by obtaining the hydrolysable sugars remaining in the heated residues. As a result, cell wall ultrastructure had a significant effect on the reactivities of hemicellulose and the influences were different for cedar and beech. With these reactivities, thermogravimetric analysis (TGA) data were explained; although different shapes of DTG curves of softwood and hardwood are believed to originate from the reactivities of hemicellulose, the present results rather suggest the cause of different cellulose reactivities.

Wood consists of heartwood and sapwood, and the extractives content of heartwood is higher than sapwood to increase the resistance against the deterioration caused by microorganisms. Such difference may affect the pyrolysis behaviors of the major components (cellulose, hemicellulose and lignin), but this has not been fully clarified. Pyrolysis behaviors of heartwood and sapwood samples were studied using pyrolysis-gas chromatography-mass spectrometry (Py-GC/MS) and thermogravimetric analysis (TGA). The successive extractions with n-hexane, methanol, and acetone/water (70/30, v/v) were also conducted to study the chemical compositions of the extractives and the influences of the removal of extractives on the pyrolytic reactivity of the major components. Extractives were found to accelerate the pyrolysis of major components especially in the heartwood. The majority of the heartwood extractives directly evaporated without suffering from the degradation reactions, while not for those in the sapwood.

In the previous study, we found that the yield of 5-hydroxymethylfurfural (5-HMF) and solid carbonized products were in the trade-off relationships in the pyrolysis of cellulose in various aromatic solvents. These results suggest that 5-HMF has a crucial role in cellulose carbonization forming. In the current study, we investigated the mechanisms of benzenering formation via 5-HMF by using ¹³C-labeled 5-HMF derivatives that were formed in situ during the pyrolysis of ¹³Clabeled glucoses. As a result, the furan-ring of 5-HMF was suggested to be cleaved into the smaller reactive fragments before reconstructing the benzene-rings. Role of water in this process is also discussed.

Pyrolysis of biomass produces useful compounds such as biochar, bio oil and syngas, but low thermal conductivity of biomass is a big issue to achieve efficient heat transfer. In this study, microwaves with high electric field density are input into a single mode cavity using high coherence microwaves generated by a semiconductor oscillator. Pyrolysis of cellulose and rise straw were performed by directly heating biomass wiuthout using microwave susceptor. The maximum heating rate of rice straw attained 330°C/sec by using the present microwave set-up.

Pellet stoves use wood pellet as fuel. The wood pellet is made from sawdust which occurs when making wooden products. So wood pellet is carbon neutral and useful for solving the environmental problems such as depletion of fossil fuel and global warming. It is a good idea to use pellet stoves instead of devices which use fossil fuels. However, pellet stoves have some problems. For example, the exhaust gas from pellet stoves contains much heat. It also contains soot, CO₂, CO and some gas which is harmful for human health. So it is important to solve these problems. In this research, we considered about mass balance and energy balance. In addition, we studied soot amount which is contained in exhaust gas from pellet stove.

Tar steam reforming enhanced by CaO particle was demonstrated by using a biomass gasification / tar reforming facility. The facility was mainly contained with a rotary kiln gasifier and a CaO particle bubbling fluidized bed tar reformer. It was confirmed that, biomass gasification tar was nearly completely reformed to H₂ and CO with a less 10.7mg-tar/Nm³ in the product gas after reforming.

Dehydrocyclization-cracknig of methyl oleate (OM), one of FAME model compounds, into hydrocarbons, especially aromatics, which includes hydrocracking of OM and dehydrocyclization of alkyl fragments formed, was investigated using ZnZSM-5-Al₂O₃composite-supported NiMo sulfide catalysts in a fixed bed flow reactor. The effects of loading amounts of NiMo, the mixing ratio of ZnZSM-5 to alumina and temperature on the catalytic activity and the product selectivity were examined. At 450oC almost all catalysts exhibited 100% of conversions and the product distributions could be changed by choosing the appropriate amounts of NiMo loading and the mixing ratio of Zn-exchanged ZSM-5 to alumina. Using 9.3NM/Zn(13)Z(24)35A catalyst, the yield of aromatics reached 20 wt% at 450°C.

A novel bioethanol production process from lignocellulosics via acetic acid fermentation has been proposed in our laboratory. The hydrogenation reaction of acetic acid into ethanol was slowed down, when the reaction temperature reached 280-300°C in a flow-type reactor at 10 MPa. In the present paper, the slowdown mechanism was studied by investigating the reactivity of acetaldehyde as the intermediate. As a result, the Cannizzaro-type reaction, oxidation, and gasification were found to occur as the competitive side reactions along with the desired hydrogenation into ethanol. In addition all these three side-reactions were found to be catalyzed by this Ni-Sn/TiO₂ catalyst. The selectivities of these reactions at each temperature were determined, and the careful comparison with the data of acetic acid hydrogenation revealed that the oxidation of acetaldehyde into acetic acid that becomes significant at >300°C plays the most important role in the slow-down mechanism.

A bioethanol production process from lignocellulosics via acetic acid fermentation has been proposed in our laboratory as a more efficient carbon utilization method than the conventional process based on alcohol fermentation. Direct hydrogenation of acetic acid into ethanol is highly desired. Aqueous solution of commercial acetic acid (model acetic acid) and acetic acid obtained from fermentation of the hot-compressed water treatment products of Japanese cedar (fermentation acetic acid) were used. Ru-Sn/TiO₂ and Ni-Sn/TiO₂ were employed for the hydrogenation in a batch reactor. Catalytic activities were compared for both catalysts for bioethanol production. Those catalysts were successfully converted model acetic acid to ethanol in high yields, while the fermentation acetic acid solution had the lower reactivity, particularly for the Ni-Sn/TiO₂ catalyst. In this study, the negative effects that may be caused by the action of the impurities existing in the fermentation acetic acid solution are presented. Characterization of the spent catalysts that were recovered after hydrogenation with the hydrogenation reactivity, XRD, and SEM-EDX will also be presented.

In the previous study, we have proposed a two-step process for monounsaturated fatty acid (MUFA) conversion to hydrocarbons as renewable gasoline. As an extension of the previous work, the hydrocarbon production from polyunsaturated fatty acids (PUFA) was conducted with the same method. By oxidative cleavage with KMnO₄, linoleic acid was cleaved into 90 mol% hexanoic and 53 mol% azelaic acids; and linolenic acid was cleaved into 60 mol% azelaic acids. Hexanoic and azelaic acids were further decarboxylated to yield 73.5 mol% n-pentane and 73.1 mol% nheptane, respectively. Combination of the previous and current results will deliver a comprehensive understanding for further application of real plant oil as feedstock, which contains MUFAs and PUFAs.

Biodiesel generally refers to a mixture of fatty acid methyl esters (FAMEs). Solid precipitates are occasionally generated in biodiesel due to the presence of minor components, such as monoglycerides (MGs) and diglycerides (DGs). The effect of diglycerides to biodiesel cold flow properties was studied in the current study. Binary mixtures of FAME-DG and MG-DG and multi-component mixtures of FAME-DG-MG were prepared, and the melting temperature was measured by DSC. Two prediction models (ideal liquid and non-ideal liquid models) were then applied to the experimental result. It was found that the binary mixtures with DG followed the non-ideal liquid model. Deviations from the model were found only when the concentration of MG was low, or when MG was the first solidified component, which was likely due to the polymorphism of MG. Hence, DGs did not critically affect the cold flow properties of biodiesel, while MGs were critical for the solidification.

In bioethanol production derived from lignocellulose biomass, delignification process or acid hydrolysis of cellulose are important as pretreatment. On the other hands, about 10% of crude glycerol is produced from vegetable oil during biodiesel production, and the effective usage is expected. In our previous study, delignification using model glycerol, that is glycerol added sodium soap, was applied to various biomasses such as Japanese cedar, beech and bamboo. As the results, lignin was removed from biomass by model glycerol treatment at 250°C for 1h. Simultaneously, lignin dissolving glycerol usable to high calorific liquid fuel was obtained. In this study, by-product glycerol from rapeseed oil biodiesel production was applied for delignification of Japanese cedar. As the result, lignin content of Japanese cedar was decreased to 15% from 37% of native state when residual oil content in by-product glycerol was below 4 wt.%. Further, enzymatic saccharification of Japanese cedar whose lignin content was below 20wt% was succeeded.

We commercialize a system for on-site methane fermentation of food waste and kitchen wastewater generated in the building, but currently we are removing the oil upstream of the fermenter to prevent methane fermentation inhibition by the oil. From the past operation results, it has been confirmed that methane fermentation operates stably if the ratio of oil content to volatile solid content is below a certain level. Therefore, we examined the confirmation of oil processing capacity by continuous test and n-Hex / VS control by volatile solid supply from the outside of the system.

In this study, sunlight is converted into thermal energy by converging sunlight to one point by using Fresnel lens. The heat is used to evaporate Zn, superheated steam and Zn steam is used as a reaction medium perform oxidation reaction and hydrogen is generated. Thereafter hydrogen is recovered by a sampling bag connected to the downstream portion of the apparatus. Furthermore, we calculate the thermal energy stored in hydrogen by measuring the hydrogen concentration and aim to evaluate the conversion efficiency of energy in this experimental apparatus. The result showed that we acquired 830mL of hydrogen for 2320mL of gas. The energy conversion efficiency was 0.689%.

Hydrogen production methods without CO₂ emission by using thermochemical water-splitting have been investigated. Although the current techniques of thermochemical water-splitting required a temperature higher than 800°C, The sodium (Na) redox cycle was able to be operated below only 500°C. The sodium redox reactions consists of three reactions, which are hydrogen generation by the NaOH and Na reaction, metal separation by thermolysis of Na₂O, and oxygen generation by hydrolysis of Na₂O₂. However, there is a serious corrosion problem in the metal separation reaction between Na₂O and reactor materials. In this work, corrosion properties of Na-oxides for various materials such as pure metals, carbides, and oxides.

Hydrogen is paid attention as clean energy because it does not emit CO₂ when converted to electricity. Among others, MgH₂ is one of the promising hydrogen storage materials because of its high volumetric and gravimetric hydrogen densities and abundance. However, Mg expands and shrinks during the hydrogen absorption and desorption, respectively. The MgH₂ powder pulverizes during the hydrogen absorption and desorption cycles. In the tank filled with the MgH₂ powder, pulverized powder drops and accumulates with high density at the bottom of the tank resulting in the deformation of the tank during the cycles. In this research, to accommodate the volume change of the MgH₂ powder holding the pulverized powder during the cycles, the MgH₂ particles were retained in carbon nanotube (CNT) films. The MgH₂ powder and CNTs were co-dispersed in N-methyl-2-pyrrolidone, then the MgH₂-CNT composite was fabricated by a vacuum filtration of the dispersion. The structure of the MgH₂-CNT composite was maintained after the hydrogen ab/desorption, however, the hydrogen desorption rate of the composite was lower than that of the MgH₂ powder. To improve the desorption rate keeping the structure, the MgH₂-CNT composite was wrapped in a stainless mesh and pressed to support the film structure. With this structure, the desorption rate improved and the film structure maintained during the hydrogen ab/desorption cycles.

Cu-ZnO/Al₂O₃ catalyst is widely used for methanol synthesis, methanol steam reforming reaction and so on. Cu-ZnO/Al₂O₃ catalyst is usually synthesized by co-precipitation method and the surface are of the catalyst is not high.

We had developed a new method to synthesize Cu-ZnO/Al₂O₃ catalyst with high surface area which value is more than twice of ordinal co-precipitation one. In this new method, ammonia gas is applied to precipitation agent and contact with metal ions only limited liquid-gas interface. Then, agglomeration must be limited and catalyst with enlarged surface area is obtained.

From SEM observation, the catalyst particles, synthesized by a new method, have round shape and diameter is around 3μm. EDX study shows metal localization is not observed with the catalyst prepared by a new method.

Direct carbon fuel cells (DCFC) are fuel cells utilizing solid carbon as fuels. We proposed a novel DCFC system using tubular type cells which enables continuous supply of solid fuels. This study investigated basic characteristics of tubular type molten carbonate DCFC (TMC-DCFC). A tubular cell was inserted into the mixture of activated carbon and molten carbonate. Continuous power generation was achieved for 24 hours with 100 mA cm^-2 at 800°C. Most of CO₂ generated by anode reaction was presumed to react with carbon and changed to CO by reverse Boudouard reaction. From the calculation of the energy balance for the continuous power generation test, it is revealed that TMC-DCFC generate both electricity and CO with effective utilization of solid carbon.

A single phase, dense PdCu membrane was prepared by one-step electroplating. The electroplated alloy was easily delaminated from the SUS electrode by cutting around the edge, and the single PdCu membrane was collectable. The crystal structure, surface texture, and alloy compositions were determined by XRD, SEM, and EPMA & XPS. The plated membrane before and after hydrogen permeation measurements consisted of a single fcc (α phase) and an ordered bcc (β phase), respectively. The atomic ratios of Pd and Cu were 49 and 51 at%, respectively; thus the Pd and Cu contents were slightly higher and lower than Pd₄₇Cu₅₃, which shows the highest hydrogen permeability among binary Pd-Cu systems. The as-plated membrane had high mechanical property. The hydrogen permeability of the plated PdCu (the β phase) was almost the same as that of the rolled film and the values reported in literature. In addition, porous Ni support prepared by electroplating is also reported in this study.

To generate hydrogen from water at low power consumption, a plate type plasma membrane reactor has been developed, which can generate hydrogen from superheated steam by plasma discharge power. In this study, effects of the applied voltage on the hydrogen generation behavior was investigated. To change the plasma state, argon gas was mixed into superheated steam. The hydrogen flow rate was increased with an increase in the applied voltage, which was the first observation in hydrogen production by atmospheric plasma.

An efficient device for hydrogen production from ammonia has been developed, which is an original pulsed plasma reactor with a hydrogen separation membrane. For commercial uses, an increase in hydrogen production rate of the plasma membrane is desired; therefore, a packed bed plasma reactor was developed in this study. Effects of dielectric particles on the hydrogen permeation rate were investigated for six different types of zeolite. The hydrogen permeation flow rate was significantly increased by the packed zeolite, because the stability of the plasma was strongly improved by the packed zeolite. It found that SA-600 zeolite had the best activity for an increase in hydrogen permeation rate.

In the author's laboratory, the new wave power generation system called oscillating was proposed. The mechanism of power generation is described below. A floating body of rectangular solid containing water and a turbine floats on the sea. Then, the floating body swings to the left and right when getting over the waves. At the same time, the water in the floating body reciprocates. So, the water power cause the turbine to rotate. However, the coupled motion of the floating body and the water is very complicated. Therefore, in this research, I thought that it was necessary to understand the behavior of the floating body and water against waves, and tried to model the oscillating motion and reciprocating flows.

We researched the power generation factors that are important in promoting the development of the wave overtopping type wave power generator. In order to grasp the power generation system, we set variable resistance from 10 Ω to 100 Ω and acted irregular waves on the multistage water tank of the model and confirmed the output power from the generator. Moreover, although the output was low, the power generation efficiency was also calculated. From now on, in order to obtain larger output power, it is necessary to construct the same system in the 2nd to 4th multistage water tanks where the potential energy is large, and to study the power generation elements in detail.

A simple computational model for a small wind power generation system that consists of a wind turbine, a generator connected directly with turbine and a load is investigated. In this report, a numerical wind turbine model developed by QBlade, an open source wind turbine analysis system, is investigated as an alternative to enhance the model applicability for new wind turbine that has seen never before. As the result the applicability of the wind turbine model from QBlade has insufficient ability for the system though the basic behavior of the turbine power to the wind speed is simulated to some extent.

In recent years, floating offshore wind turbine（FOWT）power generation which is expected to have relatively easy instalment and stable power generation receives attention. Critical understanding on the dynamic oscillation characteristics of waves and wind acting on the facility and stable attitude control is required for designing FOWT. Therefore, in this study an experimental investigation on the wind force characteristics acting on the wind turbine was done. From the experiments conducted in this study, it was found that the way forces acted on the blade differ depending on the inclination of the wing. Besides, the difference in the rotational speed caused the difference in the drag acting on the generator. Therefore, by controlling the number of revolutions with an electrical system and combine it with mechanical parts equipped with a pitch controlling system, a higher of power generation efficiency may be achieved, possibly lead to the suppression of the fluctuation phenomenon. Next, we will study in more detail the relationship between rotational speed and the characteristics of the wind forces added to the generator. Furthermore, combination of the electrical controlling system with pitch controlling system will also be done simultaneously.

The high-temperature concentrated solar-driven thermochemical reacting system for hydrogen and syngas production has been considered as an effective alternative to fossil fuels and reduce the CO₂ emissions. So, various thermochemical reactors have been developed in the past few decades. In solar fluidized bed reactors, thermal transport and fluid flow characteristics have significant impacts on hydrogen production efficiency. Computational fluid dynamics (CFD) modeling is one of the appropriate tools to understand the particulate flow and heat transfer behavior of the reactor. In this study, a transparent fluidized bed experimental setup has been developed to obtain the particle flow characteristics and validate the numerical model. Experiments were performed for various flow rates and the flow characteristics and pressure differences were obtained. Simulations were performed for the same operation conditions and the difference between the experimental and numerical results have been compared. A reasonable agreement has been found between the experimental and numerical results.

The thermochemical production of solar fuels uses concentrated solar energy as a high-temperature heat source to drive endothermic chemical reactions. The temperature in a solar thermochemical reactor can reach higher than 1200 K, and the heat is transferred to the reacting particles predominantly by radiative heat transfer. In order to understand and enhance the performance of the reactors, various numerical and experimental studies have been carried out in the past few decades. In this investigation, a numerical model has been developed for a packed bed solar thermochemical reactor and the radiation transfer equation has been solved by the Discrete Ordinate (DO) radiation model. To validate the model, the simulation results have been compared with reported experimental results. A good agreement has been found between the experimental and numerical results. Then, the influence of operating parameters on the thermal performance of the reactor has been investigated. Moreover, the comparison of numerical results predicted by the surface to surface (S2S) and DO model have been presented.

Economic effectiveness of electric thermal energy storage power (ETES) is described. Intermittent renewable power or un-adjustable nuclear power is converted to thermal energy and stored. The stored thermal energy is converted to electricity when required. ETES is effective when stabilizing interval is relatively long since thermal energy storage is very cheap. Effectiveness of rotating synchronous heater is also described. This rotating heater is cheaper than resistive heater and has synchronous inertia, which is essential to stabilize power grid.

Economic effectiveness of electric thermal energy storage power (ETES) is described. Business profitability will appear when the amount of renewable energy introduced increases in the future. Also, development of technologies that contributes to cost reduction are considered to boost that.

It is necessary to establish a suitable solar panel arrangement and control method to avoid crop quality degradation and yield reduction in the agrivoltaic system. We investigated effects of solar panel control methods on solar radiation on the ground under the solar panels by the developed simulation model taking into consideration the shading rate by the panels, the sun tracking control and the orientation of the panel surface (east to west, north to south). The results showed that the east-west oriented sun tracking control was superior in terms of spatial uniformity of solar radiation under the panels. The validity of the developed simulation model was verified by comparison with the measured results

This paper describes development of hydrogen energy utilization system for buildings. This system consists of a water electrolyzer, hydrogen storage using metal hydride tanks, fuel cell and renewable energy. The developed hydrogen energy system was controlled by BEMS and demonstration operation was carried out. Using weather prediction, it was possible to control the system optimally. BEMS can operate this system fully automatic using weather forecast. In March 2019, we moved this system to the actual business site from our institute. We plan to demonstrate “Bring-in-Hydrogen” and rapid filling operation.

NFPA flammability of NH₃ is low because of high flash point. The category of the flammability increases with decreasing of the flash point, approaching to constant value 4. However, Japanese GHS flammability of ammonia is high, because the classification of flammability is defined by explosive (combustible) range in air. NFPA health hazard of NH₃ has high value 3. The ratio of NH₃ accidents divided by the high pressure gas accidents is about 10%. The water solubility of NH₃ is high, although NH₃ vapor concentration and NH₃ concentration in the water solution have similar high values at 298 K. NH₃ storage materials for the vapor concentration (vapor pressure) and the nitrogen concentration in water lowering will be required to reduce the negative effects on the environment.

Ammonia is carbon free and has high energy density. As the demand for ammonia increases, it is necessary to ensure safety. We focused on proton-based solid acid as an ammonia removal material and evaluated its ammonia absorption properties. In this study, we used zirconium phosphate, zeolite, and impregnated activated carbon as proton-based solid acids. We also used activated carbon, mesoporous silica, and sepiolite as references. Ammonia absorption properties of these samples were evaluated in the water solution. The ammonia absorption capacity of zirconium phosphate was 10.2wt%, which is the highest value among the studied samples. The proton concentration in the samples was determined by titration experiments using NH₄HCO₃. The ammonia absorption capacity corresponds to the proton concentration, indicating that NH₃ reacts with H⁺ to form NH₄⁺ in the solid acid.

I investigated characterization of ignitability for flame-retardant plastic used by automotive battery case. First, I did characterization of combustibility by using UL94V test. Therefore I grasp combustibility of plastics. Second, I did TG/DTA in order to measure the temperatures of H₂ generation, CH₄ generation，CO₂ generation，CO generation. By using this date, I simulate elementary reaction of ignition behavior, and I compared UL94V with simulation.

We manufactured a small scale downdraft gasifier and operated the Spark Ignition Internal Combustion Engine (SI-ICE) with produced gas (bio-syngas). The effects of composition change on the operating stability was verified. The operating stability got worth with the extension of the initial combustion duration (ICD). So the effects of combustible substance (hydrogen, methane, carbon monoxide) in the bio-syngas on the ICD were considered. For the ICD, the conclusion was made that the increasing of the methane vlume ratio in the combustible substance prolong the ICD.

In this study, a Rapid-Compression Machine was used to simulate combustion in a gas engine. The Rapid Compression Machine was equipped with a pre-chamber with a volume equal to 3.4% of the clearance volume. The pre-chamber and the main chamber are connected through an orifice. The effect of changing the connecting orifice diameter on the methane combustion characteristics was evaluated considering two diameters: 3 and 5 mm. Longer duration of the initial combustion period, larger values for the pressure rise due to combustion and higher values for the combustion efficiency were found for a connecting orifice diameter of 3 mm than for 5 mm. It is believed that reducing the connecting orifice diameter increases the momentum of the flame jet and increases the turbulence in the main chamber.

In this research, the effect of the compression ratio on the combustion of a simulated biogas in a SI engine was investigated. Experiments were conducted in a single-cylinder, 4-stroke, 412 cc, air-cooled gas engine using compression ratios of 20.3, 16.5 and 13.7. Biogas was simulated mixing H₂ and CH₄. Results show that as the compression ratio increases, combustion duration becomes shorter. The highest thermal efficiency obtained was 22%, for a compression ratio of 13.7 and a H.S.R. of 0.28.

In the study, we discuss the effect of heat transfer enhancing method on the high temperature side of alkali metal thermoelectric conversion (AMTEC) devices. The use of high porosity porous metal to promote heat transfer has been proposed. The performance degradation due to the increase of pressure drop of sodium vapor and the performance improvement due to the increase of temperature were compared and discussed. For the cell operating at 950K-500K, the output power is approximately doubled and the efficiency is calculated to increase from 11% to 18%. It was also shown that using the container wall as a current lead is effective for improving the efficiency.

In recent years, research using induced flow generated by plasma has been advanced as a control method of jet flow. Partial premixed combustion is a combustion technology that is easy to handle industrially and is expected to be used in the future. In this research, control of the main jet using partial premixed air was performed by the burst drive of a coaxial DBD plasma actuator（=DBD-PA）, and combustion continuation of the flame was maintained under specific conditions. We will clarify what kind of change the burst drive brings about the behavior of the partially premixed flame.

The Flamelet and Flamelet/Progress-Variable (FPV) models were applied to the numerical simulations of a laminar counterflow diffusion flame. Although the numerical results of the Flamelet and FPV models were in good agreement with the solutions based on the detailed chemistry in the temperature and mass fractions of major species, the accuracy with the Flamelet model becomes lower than that with the FPV model in mass fractions of the polycyclic aromatic hydrocarbons (PAHs). This is because progress variable used as a key parameter in the FPV model can trace the pathway of PAHs formation. Thus, the FPV model performed well to predict the PAHs formation compared with the Flamelet model.

The primary objective of our study is to clarify the droplet disintegration process in the secondary atomization phenomena during droplet burning of emulsion. Iterative droplet combustion experiments have been carried out about a n-hexadecane/water emulsion droplet, which was suspended at the tip of a quartz filament, in a quiescent air environment. The results showed that the dispersion rate for occurrences of micro-explosion increase with an increase of droplet lifetime. Disintegration process of a droplet depends on the radial position of initial bubble nucleation depends. It is guessed that an increase of droplet temperature affects on the dispersion of droplet.

We focused on a homogeneous charge compression ignition (HCCI) engine. HCCI engine can realize high efficiency and clean combustion. But it has a problem that restraint of steep combustion in the high load and control of the combustion phasing are difficult. In this study, a gaseous fuel blend was used with the aim of expanding the high load operating region. The results revealed that the region of high load operation can be suitably combining a high boost level, high exhaust gas recirculation, low compression ratio and a change in the fuel blending ratio.

This study aimed to investigate removal of chelated heavy metal ions from aqueous solution by adsorption on layered double hydroxides (LDHs). LDH with Mg and Al intercalated with carbonate ion was synthesized and calcined at 500°C for 3 hour. Ca. 50% of EDTA-chelated copper ion was removed by the calcined LDH from 500 mg-Cu/L aqueous solution. Recover of copper from the LDH subjected to the adsorption was carried out by calcination at 500°C, dissolution into nitric acid and precipitation by hydrogen sulfide gas. Addition of 20 wt% of NaOH to the solution accomplished restructuring of the LDH.

Removal of dusts on the boiler heating surface is effective to improve the efficiency of power generation in municipal solid incineration plants. A steam injection type sootblower has often been used in order to remove dusts on boiler tubes, however, it uses steam for power generation and causes erosion on tube surface by steam and drain. Additionally, it is difficult to streamline the placement of sootblowers for radiation chamber. To solve these problems, we developed new boiler cleaning systems. As results, these systems removed dusts well on the radiation and convection chamber.