Bamboo forests mostly uncontrolled are spread nationwide in Japan and expanding the area with 3,000ha per year. Bamboo is growing rapidly but difficult to use as biomass because it contains harmful substances like potassium (K) and chlorine (Cl) which cause a fatal damage to boilers and a generation of carcinogenic Dioxins. HITACHI has developed an innovative reforming process, i.e. pulverizing and eluting to eliminate the above harmful substances which enables bamboo can be used as a typical wood-based biomass. And moreover, the waste liquid used for elution can be reused as a fertilizer realizing an environmentally friendly recycling scheme.

It is important to grasp the yield percentage in order to estimate the available amount of woody biomass resources. Previously it was estimated using a fixed yield percentage. However, it is pointed out that the yield percentage depends on tree species and forest age. Therefore, the yield of tree species was estimated from the log production data and the available amount of woody biomass resources was estimated. We compiled the production of logs and pulp from log production data of national forest and private forest. The yield percentage was estimated by dividing the result by the amount of logging. As a result, the yield percentage by tree type was 67% larch, 68% cypress, 58% cedar, 48% red pine. It is compared with estimation of woody biomass resources with fixed yield of 80%. Considering the yield percentage, the available amount of any tree species decreased.

In recent years, a variety of small scale gasification power generation processes less than 2 MW for FIT have been introduced from Europe and other countries overseas. However, due to differences in propeerties of biomass including tree species between Europe and Japan, and to ambiguities in fuel specifications presennted by manufacturers, the achievements in Japan are far behind those in Europe disturbed in many cases by unstable ooperation. In this research, we investigate the cause of the mismatch and propose a way to successful implementation of gasification process by quantifying the biomass fuel properties aiming at establishing a new guideline or a standaard that can be effective in non-European biomass conditions.

Bio-coke that does not cause melting of combustion ash after combustion is also important from the viewpoint of promoting effective utilization of biomass combustion ash. However, a technology for mass-producing bio-coke that can be used in a household compact combustor has not yet been established. As a result of working on improvement of batch type manufacturing process using six-hole molder system for the purpose of improving production capacity of small diameter bio-coke, the following results were obtained. (1) It was found that it is possible to increase the size per unit by 85% by optimizing the initial moisture content. (2) It was found that by shifting the molding process using two molding units, the manufacturing capacity per unit time can be improved by about 40%.

In this study, the grinding test were performed using a test roller mill with the mixtures of wood pellet and bituminous coal. As a results, in grinding test, the power consumptions of the mixture were higher than that of the coal. In addition, the differential pressure between inlet and outlet of the test roller mill were also increased. On the other hands, the neutral sugar content of samples in test roller mill were markedly increased from input. These results indicate that wood pellet was condensed in the roller mill. The condensation of biomass is a cause of an increased differential pressure in roller mill, even in low biomass mixing ratio.

The fluidization process has important role to create optimal contact between raw material and particle fluidization like silica sand and clay (bentonite) with a raw material. The addition of Potassium Chloride (KCl) as an alkaline compound was selected as representation of the highest inorganic element which is dominantly contained inside raw material from biomass having potential problem like slagging formation and defluidization condition inside reactor during pyrolysis at 700oC. By comparing the performance of particle fluidization against KCl addition showed that the use of bentonite particle gave better performance than silica sand to maintain fluidization condition.

BDF was widely used due to environmentally friendly use of subsidies because it is derived from waste edible oil and vegetable oil, but its use has been declining since the common rail system appeared in internal combustion engines. In the common rail system, high pressure spraying is possible by electronic control, but in BDF, dirt and deposits on the nozzle tip and the supply pump are generated and it is not usable. Therefore, using distilled BDF, we realized adaptation to common rail and clarified combustion characteristics by BDF-water emulsion fuel. As a result, BDF water emulsion fuel was able to reduce NOx concentration by about 30% and fuel consumption rate by about 14% compared to BDF.

Waste food oil can be regenerated to biodiesel BDF(Biofuel Diesel Fuel) by methyl esterification, but it costs 30 to 60 yen / L, and SVO(Straight Vegetable Oil) attracts attention . In recent years, high pressure spraying and multistage spraying are adopted for the purpose of improving combustibility. In this research, in order to improve applicability in the future, we attempt to generate SVO as a whole use of waste food oil, targeting multi-stage spray combustion, and clarify the combustion characteristics of SVO as an alternative fuel to BDF. In addition, we adopted water emulsion fuel as a method of SVO and expected ion decomposition and radical treatment

Microalgae are potential biomass to produce biofuel due to the high yield. In large-scale production, polyculture-based microalgae in open raceway pond were promising. However, bringing the concept to the business of microalgae is challenging because the cultivation to the down-streaming process of microalgae consists of several complex activities and unique combination. The detail and structured evaluation in one framework were essential to optimize the production as a beginning step to achieve the profit. This research proposed the business evaluation framework using the economic cost-based analysis (CBA). The business evaluation framework was developed and implemented to the microalgae in an open raceway pond and used to evaluate the cost based on 10 ha cultivation. Based on the analysis, the production cost of bio-crude oil between 391.1 - 1,815.5 JPY kg^-1 by utilizing the wastewater as a nutrient.

Mass cultivation of microalgae by closed type light illumination cultivator is superior to open type outdoor cultivator in the following points with previous report¹⁾. Algal mass concentration can be made around 100 times. Energy conversion efficiency is high. Microbial contamination from the outside is small. With this report, wetted-wall tower type bioreactor is introduced that is easy control of light intension, CO2 dissolution and the nutrient medium density and that structure is simple. Gas exchange system for thermal power station using this bioreactor is also introduced.

Transgenic strains of M. thermoacetica in which aldehyde dehydrogenase gene (aldh) was introduced and pduL2 or both of phosphotransacylase genes, pduL1 and pduL2 were eliminated were constructed. Although all strains harboring aldh produced ethanol using fructose as a substrate, they didn’t produce ethanol from H₂-CO₂. However, a pdul2 deletion mutant produced formate, suggesting that insufficient ATP supply caused poor metabolism of H₂-CO₂.

This paper presents global transition from the conventional fuel to the sustainable biojet fuel and key triggers by actor-network theory. Biojet fuel is made from sustainable sources and is also similar to kerosene, a hydrocarbon from C8 to C18. It can be used in existing jet engines without modification. The process of the transition from the conventional fuel to the biojet fuel was historically analyzed and visualized by actor-network theory which was originally methodology of Latour and Callon, anthropologists. The result revealed that D7566 certification of American Society for Testing and Materials International（ASTM International）was established for introduction of alternative jet fuel including biojet fuel into society, and biojet fuel of D7566 annex 2 HEFA was starting to be blended in conventional jet fuel. The trigger of transition was also shown to be mainly both push and pull mechanism of intervention. Push mechanism meant subsidies for research, development and demonstration from government and pull mechanism meant procurement of airlines and US military services. The issue in Japan was indicated that there was push mechanism of government such as funding of New Energy and Industrial Technology Development Organization, however, there is not pull mechanism.

Nanocellulose has the characteristic that it is five times stronger than steel and 1/5 light. Utilizing its characteristics, the development of high-strength materials by combining with plastics has attracted attention. However, if it sticks to nano size, practical materialization becomes difficult. We are developing technologies that produce nanocellulose from various raw materials by various methods and clarifying the characteristics of nanocellulose that is optimal for the purpose of use. As application development, we are currently aiming to apply it to a wide range of fields from daily necessities to functional foods.

In order to build a sustainable society and to counter global warming (reduction of CO₂), it is expected to utilize woody biomass with carbon neutrality. The demand for wood plastic composite (WPC) has been increased using woody biomass as a filler in recent years. Although WPC is high strength, light weight, and has excellent corrosion resistance, weather resistance, white ant durability, it has a problem with fire resistance. Thus, it is considered necessary to make flame retardant (or incombustible) for expanding the applications. In this study, therefore, we aimed to develop novel flame retardants for WPC using woody biomass.

In order to improve the economical and energetic efficiencies of glucose production from eucalyptus, the effect of solid concentration during the hydrothermal pretreatment on the subsequent enzymatic production of glucose was investigated. The hydrothermal pretreatment was conducted at 200 °C with various solid concentrations (9.1–50.0 wt%). The subsequent enzymatic hydrolysis was performed at 50 °C for 72 h. It was found that the glucose yield increased with increasing solid concentration during the hydrothermal pretreatment. In the case of concentration of 50.0 wt%, especially, the glucose yield reached to 91.1%. The concentration of acetic acid generated during hydrothermal pretreatment increased with increasing the solid concentration. It is thus considered that the efficient removal of hemicellulose was achieved in high solid concentration because acetic acid accelerates decomposition of hemicellulose by autohydrolysis. Consequently, enzyme access to the cellulose surface during enzymatic hydrolysis should be improved and the high glucose yield was eventually observed.

Supercritical water gasification is expected to be the next-generation wet biomass conversion technology. In Chugoku District, this technology has been studied in the framework of Chugoku District Supercritical Water Gasification Research Group, and 1 t/d pilot plant has been built and operated. During the development the importance of rapid heating has been determined, and addition of radical scavenger has been proposed. The development of this technology is reviewed in this presentation.

Seaweeds have attracted the attention as a promising candidate of a renewable feedstock as 3^rd generation biomass because they can be produced with a similar or higher yield compared to terrestrial energy crops and are less resistant to degradation than terrestrial lignocellulosic feedstocks. However, for developing energetically, economically, and environmentally feasible process for biorefinery of seaweed, integrated research approach including not only deep-understanding and improvement of elemental technology but also the process optimization in consideration of industrial use is needed. Hence, several key technologies for complete utilization of macroalgae were developed including efficient pretreatment, biofuel and valuable chemical production with zero-emission of hazardous materials.

Koji is a traditional fermentation culture product, based on mold strains, which is commonly used in the manufacture process of Japanese fermented products such as soy sauce, miso, and sake, and promote enzymatic degradation. Koji is usually prepared by culturing a mold on cereals such as wheat flour, soybean, or rice, but that cultured on seaweeds has not been developed yet. This study prepared the koji by culturing Aspergillus oryzae on moisture-conditioned pieces of Pyropia yezoensis (nori), Saccharina japonica, and Sargassum horneri. The obtained koji products showed enzymatic activities in amylase and protease as well as traditional soy sauce koji and rice koji but not in agarase. This kind of seaweed koji, if prepared with a mold strain showing agarase activity, is expected to be utilized for solid saccharification of seaweed biomass coupled with bioethanol production. This study also reviews on the recent progress in seaweed fermentation technology.

Because of the accident at Fukushima Daiichi Nuclear Power Plant occurred in 2011, radioactive cesium was dispersed over a wide range of eastern Japan including forest area. In March 2018, decontamination of residential areas has been completed, whereas the forest areas have hardly been decontaminated. The forest decontamination should be implemented in an integrated manner: 1) the wood chips as feedstock of gasification CHP, and 2) Cs immobilization in a pollucite for stable storage of concentrated radioactive cesium. In this study, effect of Cs₂CO₃ addition to feedstock on enhancing H₂ and CO generation has been clarified enhancing during wood gasification.

One of the problem in biomass gasification technology is the emergence of tar which will reduce the efficiency of the biomass system performance. This research present on experimental of tar formation in the small downdraft gasifier with 500 mm length and 120 mm in diameter, in order for achieving a better outcome in syngas production. The research was done using wood pellet due to the easiness of availability. This experiment was conducted with the variation of moisture content on the condition 2%, 4%, 6%, 8%, and 10 % because of the limitation on wood pellet drying and the limitation of humidity. The occurrence of tar needs to be reduced because it will disrupt the performance of other systems. In addition, the effects of initial moisture contents on the yields of tar formation products from wood pellet were studied. The result showed by increasing moisture contents, the tar formation products indicated increased too as well as for chemical substances as acenaphthylene, acenaphthene, fluorene. The research had been carried out, and the result is differentiation on moisture content will affect the tar composition.

This study aims to analyze the regional biomass energy system. Three systems that the woody biomass distributed in the target region is utilized to heat, power, or combined heat and power (CHP) are compared based on the fossil fuel substitution rate. The heat produced from the biomass resource by heat only boiler (HOB) or CHP is distributed in the district heating system (DHS). In this study, the district heating network is designed using Prim’s method based on the linear heat density [GJ/m]. As a case study, the target area is Koriyama city. 968 buildings are selected as district heating demand based on the drawn heat density map. The designed district heating network length is 21.2 km, and the linear heat density is 10.4 GJ/m. The fossil fuel substitution rates are 0.86 for HOB, 0.61 for power, and 1.03 for CHP.

In this research, we are developing "village clinical records" that summarize basic information on energy supply and demand in terms of settlements and the evaluation results of the possibility of introducing energy systems utilizing forest biomass resources. We propose the basic framework of the data structure to become clinical records, and investigate and collect information on villages in Mishima-town, Fukushima Prefecture, and actually prepare charts. Furthermore, we will evaluate the village clinical records from the viewpoint of the accumulation and sharing of data and the effectiveness for the actual policy planning process.

In this research, effective utilization of locally existing woody biomass energy within the municipality area was studied. A mass and heat equilibrium simulation model for a plant that supplies heat to local agriculture using bark material discarded at neighbor sawmills was constructed. Using the simulation model, energy evaluation and exergy evaluation of the above woody biomass heat supply plant were carried out. In this study, investigation was made on the production of dry woody fuel using boiler surplus heat generated in the system and the possibility of supplying the produced dry woody fuel as energy feed material to the other boilers or co-generation systems in the local area.

Energy conversion technology of woody biomass (WB) has attracted because of its low CO₂ emission. On the other hand, the energy use of WB is not advanced sufficiently since the cost of power generation by WB is higher than that of grid. Costs, CO₂ emission, and technological performance and improvement have been discussed in the previous studies. However, those reports tend to be limited to present technologies, and not to include the cost of CO₂ capture and sequestration. Moreover, they have not discussed requirements of new technologies for wide-spread use. In this study, we evaluated economic and environmental advantages of chemical looping combustion (CLC) which is one of the promising energy conversion technologies from carbon fuels based on the cyclic reduction and oxidation of metal oxide particles and with reduced energy for CO₂ capture, to clarify the technological problems and the influence of the improvement on power generation cost. We propose the innovation pathway based on designing each power generation process and calculation of the energy efficiency and power generation cost by the detailed bottom-up approach. Then, we found that sales of CO₂ and / or carbon pricing were more effective method to reduce power generation cost of CLC with the improvement of steam cycle conditions and the cost reduction of WB itself.

This study extracted production forests and estimated the availability of unused materials for woody biomass power generation in Tochigi and Ibaraki prefectures. Production forests were extracted as sub-compartments where expected revenues surpassed all costs—from planting to final harvesting—for a 55-year rotation. Annual availabilities were 53, 1,212, and 2,697 tons for Nakagawa, Mibu, and Hitachioota of which demands were 35,000, 30,000, and 65,000 tons, respectively. In order for the annual availability to meet their demands, prices of unused materials should be increased to JPY9,000/ton, JPY10,188/ton, and JPY11,750/ton, respectively.

In this study, we aim to design sustainable forestry policy models focusing on forest resource data and forestry machine operation. For analysis, we use spatial information analysis and design optimal forestry machine placement. Analysis was carried out for the west area of Mishima Town, as a Case Study, in the Oku Aizu area in Fukushima Prefecture. As a result of evaluating the labor productivity of the forest with a slope of 20°or more, the average labor productivity was 10.16 [m³/man-day]. It is considered to be able to contribute to forest roads and planning of forest maintenance.

In our previous paper, we tried to formulate the relationship between unit cost or environmental load such as CO₂ emissions and energy consumption per amount of logging residue and transportation distance. Generally larger scale transportation modes have an advantage over smaller scale transportation modes. The mode transfer from smaller scale to larger scale can be accomplished with an investment such as a setting of intermediate landing. In this report, the obtained formulation is applied to infrastructure development, i.e., improvement and/or construction of forest road network, and broad-leaved tree harvesting. Three mode of extraction was set: manual, winching, simple cable system. The levels of infrastructure development were assumed as two: one with 2m width road network for small-scaled system, and the other with 2.5m width road network for 0.20m³ class excavator based machines. Required data for calculating threshold harvesting volume have been identified.

Disaster risks that disturb harvesting logs make decline the profitability of forestry and change optimal forest management. In this paper, the profitability indicator of forestry involving the risks which can be used for detecting optimal harvesting schedules in region level is formulated. There are two types of disasters: subject forest stand is reparable / irreparable for wood production after a disaster (e.g., wind damage / land slide); both types were considered separately. The indicator is derived as a continuous formula, developing Bright and Price (2000)’s discussion. Since the derived indicator is continuous, fast and accurate detection of optimal rotation ages will be possible. The indicator will be convenience for wide-area profitability-based prediction of biomass production in this regard.

Composition analyzes of fly ash and bottom ash occurring in chicken feces boilers, identification of crystalline phases, heating tests, chicken feces droppings clinker composition analysis and analysis of element distribution were carried out. As a result, the composition ratio of clinker and fly ash was fairly close but the crystal structure was different. It was suggested that clinker is generated by changing fly ash. Also, when analysis the element distribution of clinker, the part with many sulfur and the part with many chlorine appear alternately, forming a striped pattern. From this, it was considered that clinker adhered stepwise from the heat exchanger.

In the previous studies, we analyzed the gasification performance for producing hydrogen fuel (Bio-H₂) from biomass feedstock. This time, for reducing heat loss from the reformer, the partial oxidation process was argued. In the pyrolysis process, not only the pyrolysis gases but also a solid mainly consists of carbon are generated in a pyrolyzer. This substance is used for generating the heat, and the residue reacts with CO₂ and/or H₂O. Therefore, for the improvement of the process simulator of Bio-H₂ production, we measured the rates of char-gasification using a random pore model. Consequently, the gasification rates due to CO₂ and H₂O were obatained.

In recent years, biomass fuel demand for domestic power / heat production is increasing. For a stable woody bioresource supply, herbaceous perennial energy-crop such as Erianthus arundinaceus (Erianthus) is a promising option. Erianthus (JES1) grew about 14 t/ha in Nasu-shiobara, Japan; it stands dead, causing small drying cost. In this study, pyrolysis characteristics and kinetic constants, and the suitable blend to Japanese cedar (JC) in gasification was revealed via the continuous gasification apparatus. The DTG for Erianthus showed a two-step peak derived from intermolecular dehydration of hemicellulose. The pyrolysis rate for Erianthus was 9.05×10² s^–1, which is the half of that for JC (1.35×10⁵). The cold-gas-efficiency for 10 wt% Erianthus continued to be the same level as pure JC, despite the smaller LHV for Erianthus (18.4 MJ/kg) than JC (20.8 MJ/kg) by 12%.

High energy and long reaction time are generally required for pyrolysis of lignocellulosic biomass due to its poor thermal conductivity. We applied microwave heating for pyrolysis of biomass for direct and rapid heating cellulosic biomass from within. In this study, fast pyrolysis of lignocellulosic biomass was carried out by single-mode microwave reactor equipped with semiconductor microwave generator. The pyrolysis of crystalline cellulose was accomplished in shorter time as compared to conventional heating at low microwave power level. Furthermore, carbon ratio of biochar was higher than that obtained by conventional heating. This result suggested that microwave irradiation promote carbonization of biomass.

The demand of wood chips increases along with the expansion of woody biomass use. However, wood as a resource has finitude. So, it is required to utilize the calorific value of wood as efficiently as possible. Therefore, focusing on thedrying process as a means for it, and a test using a batch type drying facility was conducted. The test facility was a convective heat transfer system in which wood chips of about 8 m³ were filled in containers and warm air was applied from the bottom. Comparative study was conducted by changing the main test factors as air volume per 1 cubic meters chip and existence of heat recovery system using exhaust air from wood chip surface. As a result, it was confirmed that the heat recovery system increases drying efficiency by about 10%.

In order to use the tar produced from waste wood building materials, containing arsenic, as an alternative to regenerative additives of recycled asphalt, the pyrolysis of arsenic-containing wood pellet was carried out. A recycled asphalt performance after the addition of the tar and the arsenic behavior in the pyrolysis were investigated.

Recently, depletion of phosphorus resource and its impact on economics has become a serious problem. Thus, recovery of inorganic phosphorus from sewage sludge using hydrothermal treatment is proposed as the effective solution for this problem. However, detailed reaction characteristics of organic phosphorus contained in sewage sludge have not been elucidated. Therefore, the purpose of this study is to examine the characteristics of mineralization and gasification in hydrothermal treatment of DNA as the major organic phosphorus in sewage sludge. As the result, DNA was mineralized around 200 °C. Meanwhile, carbon gasification efficiency at 400 °C was approximately 0.2.

Hydrothermal treatment is a promising option for wet organic waste, due to its low energy consumption. Hydrothermal treatment can also be used as resource recovery method. When considering the recovery of phosphorus from sewage sludge by hydrothermal reaction, organic phosphorus is mineralized and get precipitated, while the carbon content is gasified and recovered from other part. We report the process of efficiently recovering phosphorus based on the experimental runs in the range of 375 to 600 °C under 25 MPa.

Hydrothermal reaction field is often employed for biomass conversion, but due to its high temperature and pressure, it is not easy to detect the chemical species in the reactor. Products are often analyzed after cooling down and depressurization, but the possibility of reaction during these steps cannot be denied. Thus, in-situ mass spectrometry has been proposed to directly analyze the chemical species in the reactor. However, so far this technology can be applied only to temperature lower than 250 °C. In this study, we improved the operation so that analysis from the reactor temperature or 400 °C is successfully conducted. Decomposition of formic acid was observed.

The amount of liquid waste from palm oil production in Indonesia is increasing every year as the production capacity increases. Phosphorus in palm oil mill effluent (POME) could be the important potential phosphorus resource, considering the depletion of phosphate rock due to over exploitation. Supercritical water gasification (SCWG) technology could convert POME into valuable gas coming along with phosphorus recovery. To acquire a good understanding about behavior of POME conversion in SCWG, a set of experiments were developed. Here, variation of temperature (500-600 °C) and residence time (5-50 s) with controlled pressure at 25 MPa were employed in a continuous reactor. A reaction model of conversion of organic phosphorus in POME to inorganic phosphorus was also proposed. As the results, the organic phosphor could be converted into inorganic phosphorus and precipitation took place in the reactor. The rate was faster at higher temperature. The reaction followed first order kinetics, and the model was found to fit well with experimental data.

In this study, the effect of the metal wall catalyst on product distribution of guaiacol as a model compound of lignin under supercritical condition was investigated. To demonstrate this, a stainless steel 316 reactor containing Fe, Ni and various metals, which acts as the catalyst for gasification of guaiacol, was employed. The experiments were performed in a continuous flow reactor at 600 °C, 25 MPa and fixed the residence time at 90 s with different internal diameters of the reactor (2.17, 4.35 and 9.40 mm). The results indicated that the carbon yields of TOC, solid, and gas was not affected by the internal diameter of the reactor.

In this study, we measured the packed bed temperature and gas generation amount at the time of torrefaction using bamboo powder and bamboo blocks, in order to investigate the influence of the sample on the torrefaction. As a result, as the sample size increased, the packed bed temperature reached the maximum temperature earlier and the maximum value of the gas generation amount became larger. This may be because heat generated by pyrolysis of xylan was not released due to heat storage effect of bamboo and thermal decomposition was promoted. However, since the heat storage effect depends on the smallest side, there is a limit to the improvement of the heat storage effect by enlarging the sample size

Cellobiose, which is one of the decomposition products from cellulose, was treated under hydrothermal condition at 240 °C for 0-240 min holding, for obtaining carbonized solid products. The carbonized solid was produced with the extended 30 min holding time. However, elongation of the reaction time did not lead to the increase of the carbonized solid yield. On the other hand, carbon concentration of the produced solids was also the constancy, not depending on the holding times. The holding time of the reaction might affect the degree of polymerization of the produced solid.

In recent years, co-combustion of torrefied biomass with coal in coal-fired power generation has been studied. The properties of torrefied materials greatly vary depending on the temperature of the torrefaction. In this study, softwood or hardwood pellets were torrefied at 250-280 °C and the torrefied samples were analyzed by thermogravimetric analysis (TGA) to 400 °C under nitrogen to study reactions during torrefaction. Although the torrefaction yield and the yield after TGA of the torrefied samples differed between the softwood and hardwood, those obtained by multiplying both yields were similar at each temperature. As the temperature of torrefaction increased, the residual yield after TGA of torrefied samples increased. It was expected that the higher temperature is, the more thermally stable substance is created regardless of the species.

Torrefaction of oil palm fronds (leaves and stems) were carried out in combustion gas of wood pellets at 473 K for 30 min. For comparison, torrefaction of the same samples were carried out in nitrogen gas. The solid products were characterized by elementary and proximate analyses and calorific value measurement. Combustion gas resulted in higher carbon content and higher calorific value than nitrogen gas for both the stems and leaves. This trend may be attributed to the oxidative effect of combustion gas since it contained several percent of oxygen. Meanwhile, leaves showed higher carbon content and calorific value than stems before and after torrefaction regardless of atmosphere during torrefaction.

Importance of energy source supply is known for biomass power generation. Torrefaction is an effective method for the improved energy source supply because it saves the cost related to transportation and improves the energy density of raw material. In this study, torrefaction by fermentative and oxidative heating was investigated in order to improve the energy source supply. Sawdust temperature was increased up to 70°C using fermentative heating by composting. It was also increased up to more than 300°C by oxidative heating under more than 180°C of reactor temperature. It could keep 300°C under 180°C of reactor temperature and 0.2 L/min of aeration rate. In the future, the control of oxidative heating from 70°C will be investigated.

BDF is a research and development and commercialization as an alternative fuel for gas oil by methyl esterification. This is one how to use of biomass, it is reduced than diesel oil about SOx, CO₂ and black smoke (PM) in exhaust gas, and the raw material (biomass) of plant origin, carbon neutral and regarded. However, there is a concern that the fame is the main component. In this study, we try to generate water emulsified fuel using BDF and clarify the odor characteristics in exhaust gas by water content.

Microalgal biocrude was produced by hydrothermal liquefaction (HTL) of native microalgae slurry using a bench-scale continuous flow tubular reactor. The native algae was harvested in an open raceway pond in Minamisoma city, Fukushima prefecture. The slurry of native algae was continuously injected to a tubular reactor by high-pressure pumps, and the temperature was increased gradually through preheating tubes. The slurry eventually reached the reaction tube, which was held at 350 °C and 19.5 MPa, where it was kept for 6 min. The yield of biocrude recovered in a tank No. 1 was 43.0 wt%. The higher heating value (HHV) of biocrude was 29.1 MJ/kg-dry (34.5 MJ/kg-daf) calculated by the chemical elements using Dulong's formula.

The green microalga Botryococcus braunii was expected as a biofuel resources since this colony-forming microalga produces hydrocarbons and stores the hydrocarbons in the extracellular matrix. In this study, relationship between colony size and growth rate of Botryococcus braunii was evaluated.

Hydrothermal carbonization is a treatment method for heating a biomass in high pressure water to obtain a char product. In this study, hydrothermal carbonization of microalgae was carried out using ethanol and water. Ethanol boiling point is lower than that of water. So, it was expected that when mixed with water, the critical point moved to a lower temperature as compared with water alone. However, addition of ethanol is also considered to reduce reactivity. Therefore, in this experiment, the mixing ratio of ethanol during hydrothermal carbonization was changed, and the influence on char was confirmed.