IPCC was established in 1988, and published the Special Report on Global Warming of 1.5°C in 2018. Throughout these 30 years, human activities are considered to have caused global warming. For limiting global warming to 1.5°C by 2050, it would be required rapid and far-reaching transitions in social and industrial systems. So, we are working to foster so-called Green Innovation. In this context, efficient use of biomass resources is one of the important measures of that. I will explain Gunma Prefecture’s action plans on promotion of renewable energy and biomass utilization as an example of local governments’ works.

Torrefaction is a low temperature thermal treatment originally for lignocellulosic biomass. When lignocellulosic biomass undergoes thermal treatment at temperatures between 200 and 350°C, light carbonization of the biomass occurs, and bring several features to the treated biomass. Recently non- and low-lignocellulosic biomass started to be used for this treatment. This may lead to diversification of raw materials of torrefaction. The present paper aims to review torrefaction behavior of certain types of non- and low-lignocellulosic biomass (fruits, vegetables, crops, meats, some other types of food residues and their mixtures) by comparing them with lignocellulosic biomass, in terms of the mass yield, HHV ratio and energy yield.

Japanese forestry is now expected to supply with woody biomass for energy plant and heat demand. Current condition and problems of forestry and woody biomass supply in Chiba Prefecture where forestry industry is not active is examined. Now relatively abundant forest resource exists in Chiba, however, logging industry is not active and current amount of log production and forest management operations is small. Stock of forests damaged by tree diseases and a strong typhoon which hit Chiba in 2019 is also a potential resource of low-price woody biomass. Recently, a large-scale sawmill company in neighboring Tochigi Prefecture has increased log procurement in Chiba, selling woody biomass to nearby large-scale energy plants, and supporting local movements to collect woody biomass.

In the dimethyl ether (DME)-to-olefin (DTO) reaction, zeolite catalysts that could allow the efficient synthesis of n-butene, such as 1-butene, trans-2-butene, and cis-2-butene, were investigated using a fixed-bed reactor. A screening of ten available zeolites indicated that the ferrierite zeolite with NH₄⁺ as a cation type showed the highest n-butene yield. The effect of the temperature of calcination as a pretreatment method on the catalytic performance was studied using three zeolites with promising topologies. The ferrierite zeolite showed the highest n-butene yield at a calcination temperature of 500°C.

To produce biofuels and biochemicals from biomass, the separation and recovery method of chemical components from biomass is important. In this study, a separation and recovery method using liquefied ammonia (NH₃(l)) was proposed. To evaluate the effectiveness of NH₃(l) treatment for biochemical conversion of biomass, sorghum biomass was treated using NH₃(l) and saccharified using enzyme cocktails. NH₃(l) treatment greatly dewatered from sorghum sample. NH₃(l) selectively extracted organic acids which are used as a feedstock of chemicals. In contrast, neutral sugars which are used as fermentation substrates remained in solid part without over-decomposition after NH₃(l) treatment. The NH₃(l) treated sample had been easily hydrolyzed using enzyme cocktails. These results indicate that NH₃(l) treatment is a promising method for the removing water and recovering chemical components from biomass.

Currently, lots of biomass fuel used in thermal power generation is increasing, biomass fuel has advantages of recycle, carbon neutral and large reserves, etc. But the biomass combustion ash may contain harmful metals such as hexavalent chromium. Therefore, in this study, we used ICP-AES (Inductively coupled plasma atomic emission spectroscopy) to measure the content of chromium in combustion ash collected from an electrically heated drop-tube furnace, and then we used thermodynamic software Factsage to simulate the equilibrium state of the combustion ash. Through the comparison of experimental and simulation results, we can observe changes of hexavalent chromium under different conditions, this can help to find out the method to inhibit the formation of hexavalent chromium.

To improve energy conversion efficiency, it is effective to convert solid biomass into gaseous fuel by gasification. However, tar emission during gasification process is crucial problem as it causes mechanical troubles in gas engines downstream. Therefore, it’s important to elucidate tar emission behavior and lower emission mass. To lower tar emission, we considered that steam reforming of tar might be effective, so we conducted steam gasification experiment and compared with pyrolysis. In the experiment, we analyzed syngas yields and sampled tar using vertical batch furnace. To analyze physical properties of tar, we conducted GC/MS and FD-MS. About steam gasification compared to pyrolysis, it was found that CO₂ and H₂ yields increased and tar emission increased to double. From molecular weight distributions of tar, the increase of tar emission were observed all over the range in the measured molecular weight.

This study focuses on the operation of Ni-YSZ-based SOFC fueled with artificial fuel gas simulating syngas from biomass gasification. H₂, CO, CO₂ and H₂O were mixed to make up artificial fuel gas with various compositions. Electrochemical behaviors were investigated under constant current conditions at 1073K during 8h using Galvano-stat. Cyclic voltammetry was also conducted to assess the stability of SOFC. Measurement results showed that CO₂ and H₂O have significant impacts on power generation performance. In particular, the performance degradation was significant in the absence of CO₂.

Biomass resources are attracting attention as an alternative to fossil fuels such as coal. This is because biomass resources are carbon neutral. However, biomass resources have the disadvantage of low energy density compared to coal. By applying pyrolysis treatment to biomass, the energy density can be expected to increase. As a result of pyrolysis treatment, the degree of carbonization of the samples increased, the calorific value increased 1.2 to 1.3 times, the activation energy decreased, and the combustion state was improved. On the other hand, toxic particulate matter emissions during combustion tended to increase with pyrolysis treatment which have to be controlled in our future research.

In the case of potassium-rich cedar wood, the formation of melts due to eutectic points in the CaCO₃-K₂CO₃ system has been observed in the temperature range of 750-950°C in a gasification atmosphere. Magnesium silicate compounds such as talc were found as a new additive to suppress this solid solution composition. Talc (magnesium hydrous silicate (Mg₃Si₄O₁₀(OH)₂) is widely used in industrial materials as a stable and safe base material. In this study, we report on their effectiveness.

Surplus electricity from variable renewable energy sources was converted to steam with electric heaters and stored as saturated steam in a steam accumulator (SA), which was incorporated into the steam Rankine cycle (2000 kWe, inlet steam temperature 480°C, pressure 6.3 MPa) of an existing biomass power plant. The dynamic profiles of steam emissions from the SA was modeled in Excel Visual Basic for Applications, and the energy performance was calculated in Aspen Plus V12. The steam emission profile and levelized storage cost of storage (LCOS) was estimated for the case of 500 kW_e (25%) power increment and 4 hours per day discharge when the initial steam pressure in the SA (7.0-10.0 MPa). Results show that LCOS ranged from 0.317±0.035 to 0.347±0.043 USD/kWh_e at initial steam pressures of 10.0 to 7.0 MPa for a plant life of 20 years. In addition, the total capital and maintenance costs at LCOS, excluding charging power and labor costs, were found to be approximately less than 0.10 USD/kWh_e.

Direct carbon fuel cells (DCFCs) are expected to be useful devices that effectively utilize carbon resources such as biomass. We are working on the development of a several kW DCFC system for effective use of unutilized biomass. In this report, the possibility of DCFC is discussed through power generation tests using fuel assumed plant biomass. Three types of activated carbon with different particle sizes were used as fuel, and purge gas containing several percent of H₂ and H₂O was supplied into the vessel to simulate the volatile components of biomass. The smaller the activated carbon particle size was, the higher the output voltage of the DCFC was. In addition, it was found that continuous power generation is possible when several percent of H₂ is contained in the vessel.

Biomass is an organic resourceproduced by living organisms from the energy of the sun, etc., which can beused for energy and industrial products. It is attracting attention as a cleanresource that does not accelerate environmental problems such as global warmingbecause of its "carbon neutral" nature, which does not increasecarbon dioxide in the atmosphere．In this study, toproduce syngas biomass pyrolysis / tar coking process was studied. Influence ofbiomass pyrolysis and tar coking temperatures were investigated to reduce taremission and H/C control for synthesis of various hydrocarbons.

Carbonization is one of the means to effectively utilize woody biomass. We are focusing on co-processing of woody biomass and waste plastics. We are expecting to adsorb heavy hydrocarbons derived from waste plastics by carbonized woody biomass and efficiently recover valuable gaseous and liquid products. In this study, PP (polypropylene) and RPF (Refuse derived paper and plastics densified fuel) were pyrolyzed at 500°C, and the adsorption behavior of pyrolysates to carbonized cedar pellets was investigated. The char successfully adsorbed larger molecule-size plastic-derived pyrolysates. Various pyrolysates are generated from RPF, and their adsorption behavior was different from PP.

Biomass fuels are one of the renewable energy resources that will be the energy mainstay of the future.

It has a potential to contribute to the diversification of fuels at coal gasification plant since it can be stably supplied and treated the as solid fuels.

Especially it is expected to play an important role in future CO₂ free power generation and hydrogen production.

Trials of gasification of coal and biomass mixture has been carried out in EAGLE gasifier to investigate impact of mixing of biomass and potential of application to future CO₂ free commercial plant.

The development of catalysts for the decomposition of biomass tar is one of the major challenges for the low-temperature gasification of biomass. Previous studies revealed that the Ni-loaded HAP with higher Ca/P showed higher catalytic activity to decompose biomass tar. In this study, we investigated the effects of Ca/P in HAP on the catalytic activity and Ni dispersibility of Ni/HAP catalysts. The results indicate that the HAP with higher Ca/P leads to higher Ni dispersibility and higher catalytic activity of Ni/HAP catalyst.

For next-generation gasoline engines, elucidation of highly efficient and clean combustion characteristics in various fuel systems is required for decarburization. Therefore, in this research, we focused on butanol as a biomass fuel, and investigated what kind of changes would occur in the process of knocking, the combustion that leads to it, and the self-ignition process when it is included in existing fuels as an alternative fuel.

To decarbonize the steel industry, several studies have been conducted for developing the Hydrogen Direct Reduction of Iron ore (HDRI) route. The current study evaluates the energy and mass balance of HDRI for evaluating the more detailed energy consumption of the system and investigating the possibility of achieving a theoretical amount of hydrogen consumption per ton of liquid steel production. The target amount of liquid steel was set as 1 ton for defining the mass and energy values of HDRI. The calculations did not include hydrogen storage. As a result of energy and mass balance, HDRI needs 54.00 kg of H₂ for reducing 1,428.00 kg of Fe₂O₃ and production of 1 ton of liquid steel (tls). The condition of the experiment was decided as T=800°C, M_Fe2O3= 5g, M_H2=0.19g, P=0.015MPa, 15min of residence time. H₂ was used as a reducing agent and N₂ for evacuating air from the quartz tube. Condition of initial experiments without mass flow controller, viz., T=800°C, MFe₂O₃= 1g, M_H2=continuously during the residence time, P=0.015MPa, 15 min of residence time, M_N2= continuously during the experiment revealed the possibility of reduction of iron ore by hydrogen with 65% of the yield of reduction. Energy consumption of the system accounted for 2.68MWh without considering H₂ storage energy requirements.

This study aims to establish the hybrid methods using the closed and open microalgal cultivation systems for stable mass production of the biomass of marine diatoms Fistulifera solaris JPCC DA580 and Mayamaea sp. JPCC CTDA0820. We will improve the productivity of the diatom biomass by employing a wide range of techniques including more efficient utilization of solar energy, elucidation of the bottleneck of photosynthesis and oil production metabolism, and also genome editing to modify such metabolism.

Efficient heating of solid catalysts in water by microwaves is difficult because of the low microwave penetration into water. Here, we demonstrate selective heating of nickel phosphide nanoparticle catalysts in water by using 915 MHz microwaves, which has excellent penetration into water solvents. 915 MHz microwaves effectively accelerated the D-sorbitol synthesis by hydrogenation of D-glucose over the nickel phosphide nanoparticle on hydrotalcite (nano-Ni₂P/HT) catalyst at 20 bar hydrogen pressure; typically, D-Glucose conversion reached over 90% within 5 minutes. We demonstrated the formation of local high temperature at nano-Ni₂P/HT by microwaves using in situ XAFS and XRD.

In order to improve the economics of biofuel production and to lower the carbon footprint of protein production, It has been proposed to utilize filamentous fungal residues, a process by-product after enzyme production, as mycoprotein. In this study, we employed A. luchuensis, a black yeast fungus with food experience and reported potential for cellulase production. The enzymes produced were analyzed using starch-based, cellulose-based, and mixtures of these as substrates, and their potential utilization as mycoproteins was investigated.

In recent years, livestock excreta has begun to be utilised by technologies such as methane fermentation, but the nitrogen content in livestock excreta inhibits the reaction of methane fermentation. Therefore, it was decided to convert the nitrogen into ammonia by hydrothermal pre-treatment to recover it. When the feedstock was chicken manure, the ammonia production behaviour by hydrothermal treatment could not be identified. Therefore, uric acid and protein, which are abundant as nitrogen sources in chicken manure, were treated and analysed by themselves. By confirming these behaviours, the reaction pathway of chicken manure was made clearer.

Deoxygenation of xylose was carried out using metallic Fe to elucidate the reaction pathway of the deoxygenation of xylose. In the absence of Fe, the deoxygenation of xylose hardly proceeded. In the presence of Fe, the deoxygenation of xylose proceeded. These results suggest that the deoxygenation of xylose was promoted by the addition of Fe. After isomerization of xylose to xylulose, compounds with 2 (C₂) and 3 (C₃) carbons were generated by cleavage of the C-C bond of xylulose. Acetic acid was only detected as a C₂ compound. Acetic acid was might be formed by a successive reaction after the formation of glycolaldehyde. Dihydroxyacetone and hydroxyacetone were deducted as C₃ compounds. Hydroxyacetone was might be formed by dehydroxylation of dihydroxyacetone. Acetoin and 1-hydroxy-2-butanone were detected as compounds with 4 carbons (C₄). These compounds were considered to be formed by dimerization of C₂ compounds. Furfural and furfuryl alcohol were detected as compounds with 5 carbons (C₅). These are might be formed by dehydration and successive hydrogenation of xylose, respectively.

Cellulose nanofibers (CNFs), which is crystalline cellulosic fibers of 3-100 nm in width, is a hopeful advanced material. However, increasing thermal stability is an issue for application of CNFs. The author has reported that thermal-degrading temperature of CNF was increased by biomass-degrading enzymatic treatment, such as a hemicellulase. The properties of their sheets were unknown. The basic sheet properties of enzyme treated CNF were investigated in this study. The tensile strength of CNF sheets was decreased by enzymatic treatment. On the other hand, the contact angle of their sheets was increased. These results indicate that surfaces of CNFs slightly increased hydrophobicity by biomass-degrading enzymatic treatment.

Direct hydrogenation of succinic acid (SA) requires high-pressure hydrogen and widely uses carcinogenic substances as solvents. Therefore, we focused on catalytic transfer hydrogenation (CTH) with a bio-based solvent as a hydrogen donor. By using isopropyl alcohol, which is commonly used in CTH as a solvent, the yield of γ–butyrolactone (GBL) was less than 8mol%, and more than 58mol% of SA esters were obtained as by-products. When water was added to the solvent to reduce the esterification of SA, the GBL yield increased to 9.2mol% when 5vol% water, but the yield decreased when more than 5vol% of water was added. Results indicate that GBL formation from SA in CTH with isopropanol as solvent is inhibited by esterification of SA.

In recent years, there have been many problems with plastics made from fossil resources, which cause global warming, and there has been much research on how to achieve carbon neutrality by using biomass as an alternative. In this study, bamboo wood was liquefied by acid catalyst and polyhydric alcohol. The composition of polyhydric alcohol, particle size of bamboo, addition ratio of bamboo, reaction temperature, and acid catalyst addition ratio were varied to optimize the liquefaction reaction conditions. Biomass-derived PUF was synthesized from the liquefied product obtained.

The utilization of woody biomass is extremely important for the prevention of global warming and the establishment of a recycling-oriented society. Utilization of condensed tannins contained in bark as useful chemicals is expected to promote the utilization of bark that is not effectively utilized. This study aims to develop a method to convert condensed tannins into high value-added chemicals by pyrolysis. Commercially available mimosa tannin derived from Acacia mollissima bark was purified using Sephadex LH-20. Pyrolysis of tannins was performed by heating in nitrogen or solvent (sulforane or water). Catalytic pyrolysis over Pd/C were also conducted at 280°C in hydrogen or nitrogen using an autoclave with agitator. Pyrolysis in nitrogen at 350°C produced mainly char, with small amounts of resorcinol (4.4 mol%, based on mole of flavanol unit) and catechol (2.5 mol%). Under the catalytic hydrogenolysis conditions, the yield of low molecular weight products increased, although the results varied depending on the solvent used. Resorcinol and an unidentified 4-substituted catechol derivative were obtained in sulfolane, while resorcinol, catechol, and their 4- methylated derivatives were formed in water, indicating that the A and B rings of the tannin flavanol units were released in good yields (up to 30 mol%). Since resorcinol and catechol degraded further in the trial of model experiments, it is necessary to suppress the over-decomposition of the products to further improve the yields. Resorcinol and catechol are expected to replace petroleum-based chemicals for the production of adhesives and pharmaceuticals.

The chemical structure and physical properties of the lignin fraction obtained by the pretreatment of palm empty fruit bunches (EFB), an agricultural waste of the palm oil industry, were evaluated in this study. The pretreatment was performed in a two-phase system with aqueous maleic acid and butanol at 180°C. The extracted lignin was quantitatively soluble in organic solvents such as acetone due to the butylation during pretreatment. The weight average molecular weight decreased from 6,400 to 1,200 with increasing pretreatment time up to 45 min. The concentration of aliphatic hydroxyl groups was low (0.99 mmol/g), comparing with the relatively high concentration of aromatic hydroxyl groups (2.24 mmol/g). Selective esterification of aliphatic hydroxyl groups in the lignin molecule was performed by a catalysis of ionic liquid: 1-ethyl-3-methylimidazolium acetate (EmimOAc). We found that the solubility in organic solvents could be adjusted while remaining a large amount of aromatic hydroxyl groups.

In recent years, the attention has been focused on problems related to fossil fuels. Biomass-derived plastics are expected to replace petroleum-derived plastics in the future. Therefore, in this study, driftwood was subjected to liquefaction treatment to prepare biomass-derived polyol material, and liquefied driftwood-based polyurethane foam was also prepared using it. In addition, biodegradability evaluation was also performed.

This study aims to estimates the amount of sustainable woody biomass available using a forest inventory and geographic information system. It is investigated that the impact of different transportation routes and power generation methods on the amount of electricity generated through scenario analysis. As a result, the amount available was much smaller, about one-tenth of Akita Prefecture's material production. This may be due to the fact that subsidies for forestry projects such as afforestation and thinning were not taken into account, and that cedar planted forests in Akita Prefecture have reached the optimum age for harvesting. Comparing the scenario with the shortest transportation distance and the scenario with the smallest carbon dioxide emissions by using high-capacity trucks even if the transportation distance increases, the former results in a larger reduction in carbon dioxide emissions. Comparing the large scale intensive and small scale decentralized scenarios, the large scale intensive scenario using co-firing resulted in larger reductions in carbon dioxide emissions because of the direct substitution of coal.

Since some used woody materials for civil engineering contain various wood preservatives, they have generally been incinerated without further utilization. However, it might be possible to reuse them as materials by taking advantage of their high durability against biodegradation. In this study, possibility of a cascade recycling in which the used wood is once converted such as wood pavement material, and then finally used as a fuel is studied.

This study estimated the availability of unused materials for woody biomass power generation plants under operation with FIT at the end of June 2020 as the supply potential from the profitable aggregated forests. As a result, supply potentials of used and unused materials were estimated at 65,413,601 m³/year and 13,082,720 m³/year, respectively whereas those availabilities were estimated at 54,202,304 m³/year and 10,840,481 m³/year respectively. Therefore, the rate of the availabilities to the supply potentials was 82.9%. Furthermore, the rate of the availabilities to the demands was 124.8%. With woody biomass power generation plants registered in FIT at the end of June 2020, the rate of the availabilities to the demands was 98.5%. Considering the subsidy rate of 100% to secure the reforestations, the availabilities met the current demands in Japan as a whole.

Kenaf is a plant having a high CO₂ absorption and growth rates. Therefore, we focused on kenaf as a CO₂ capture medium for small and medium stationary CO₂ emission sources such as garbage disposal plants. We propose CO₂ fixation at a high rate by cultivating kenaf under elevated CO₂ concentrations in exhaust gas, and utilization of the harvested kenaf as a fiber material. In this study, the cultivation experiment of kenaf was conducted under different CO₂ concentrations of 400 and 1500 ppm. As a result, kenaf grown under 1500 ppm showed higher growth and carbon fixation rates. Furthermore, fibers were extracted from the harvested kenaf stems. The results showed that the fiber yield under 1500 ppm cultivation was greater than that under 400 ppm cultivation even with the same stem length. However, no effect of CO₂ concentration on fiber dimensions was observed.

The effects of different colony sizes of Botryococcus braunii (B. braunii) on transmittance and photosynthetic rate were examined in this study. We found that B. braunii with larger colony size grown in medium with higher salinity increased the number of photons transmitted through the culture medium at a constant light path length. Net photosynthetic rates of B.braunii grown in each culture medium were measured and net photosynthetic rates were estimated assuming a pond. These results suggested that the net photosynthetic rate of B. braunii with larger colony size in a pond could be larger than that of B. braunii with smaller colony size.

In microalgae culturing, contamination is an issue in open-air systems. Miscellaneous algal blooms inhibit the growth of target species and prevent efficient mass production. In this study, we introduced rotifers into B. braunii culture tanks in which the colonies were enlarged in high-salt medium, and investigated a method to remove only the contaminating algae by grazing. The results showed that the concentration of enlarged B. braunii was not reduced by B. calyciflorus, which is a type of rotifer, while that of Westella sp., which is a contamination model alga, decreased with the growth of B. calyciflorus. This indicated that selective removal of contaminant algae using rotifers could be established as a culture method.

The objective of this study was to investigate the combustion characteristics of a gas mixture produced by the copyrolysis of thinned wood and plastics. The low-calorie gas produced in a fixed-bed reactor at low temperature was combusted in a combustor with an air atmosphere. The addition of a small amount of PP to a fuel based on thinned wood and PET was advantageous for the formation of light hydrocarbons, however, was not effective for the reforming of light hydrocarbons by Ni catalyst at PP addition rates of 20 wt.% or higher. In addition, an increase in the PP addition rate was effective in improving ignition performance in lean combustion of the gas mixture.

We focused on aerobic fermentation of biomass as a method to supply CO₂ to plant cultivation facilities. In addition, acetoin and 2,3-Butanediol (2,3-BDO) produced by fermentation were reported to have growth-promoting effects on plants. In this study, fermentation experiments of oyster mushroom waste were performed using Acremonium cellulase and Bacillus subtilis in a fed-batch reactor with aeration. Effects of fermentation conditions such as moisture and substrate mass on production of Acetoin and 2,3-BDO were investigated. The results showed that acetoin and 2,3-BDO were produced when the oxygen concentration decreased to the microaerobic level.

Toward a decarbonized society, biomass energy is promising in terms of its weather-independence and adjustable output. In this study, eggshell-added cedar was carbonized using a continuous carbonization furnace and the energy was recovered as product gases (H₂, CO and CH₄). The effect of eg gshell addition to cedar on the yield and composition of the gases produced in the carbonization process was investigated. The addition of eggshells to cedar increased the product gases (H₂, CO, and CH₄) and the activation energy, E_a, of eggshell pyrolysis. The pyrolysis of eggshells was considered to be inhibited by the CO₂ produced from the cedar.

For the realisation of a decarbonised society and the enhancement of disaster resilience, wood gasification combined heat and power (CHP) as a decentralised power source is promising in terms of its high power-generation efficiency and overall efficiency, despite its small scale. The use of cedar as a wood fuel for CHP has been a challenge due to its inorganic components that causes clinker formation. It is also necessary to clarify the fusibility of ash in co-gasification with various biomasses to ensure stable use of wood fuel. In this study, the possibility of inhibition of clinker formation was investigated by evaluating the fusibility of binary blended biomass ashes of cedar and other biomasses using thermogravimetry/differential thermal analysis, ash fusion test, and multi-component equilibrium calculations.

In this study, torrefaction was performed using cedar and fibrous biomass, and the higher heating value was measured. Visualization experiments and TG measurements were also conducted to investigate the behavior of the samples during the torrefaction process. The results showed that the char yield decreased as the torrefaction temperature increased, and that there were differences between the yields of cedar and fibrous biomass due to the components contained in the samples. The HHV of both samples increased as the torrefaction temperature increased, and the HHV of cedar was comparable to that of coal at the set temperature of 573 K. In the visualization experiment, the volume of both samples expanded just before the organic matter generated during torrefaction was released from the inside to the outside, and the mass of both samples decreased at the same time.

In this study, we investigated the combustion temperature, the amount of ash produced, and the amount of ash adhered by changing the distance h between the flame surface and the bottom surface of the biomass packed bed. As a result, for a packed bed of the Japanese cedar the lower the h, the higher the maximum combustion temperature and the more ash adhered on the mesh. In the case of h = 4 mm, the flame temperature increased sharply, and ash adhered and fused rapidly on the mesh surface. On the other hand, when h = 11 mm, some of the generated ash could be dispersed as the fly ash, the less ash adhered to the titanium mesh. It was found that the tendency became clearly when changing from the Japanese cedar packed bed to its bark packed bed.

In this study, seven ash samples of woody biomass combustion were investigated on the fusion. From the thermogravimetry experiments, it was found that the samples were roughly divided into samples that volatilized about 10% and samples that volatilized up to about 50%, and that the results could be explained by mass percentage of lowboiling materials. Ash fusion progressed in the order of shrinkage, part fusion, and full complete fusion. However, even though the shrinkage temperature was low, the complete fusion temperature was high, and there was no clear correlation between these temperatures.

In this study, we improved the drying efficiency of sludge by adding resin emulsion to the sludge to change its properties to those suitable for drying. In the experiment, various types of resin emulsions were added to the sludge as drying accelerator, and resin emulsions suitable for sludge drying were selected. In addition, drying demonstration test was conducted using a full-scale dryer by mixing the selected resin emulsion. As a result, it was clarified that the drying efficiency can be significantly improved by adding the resin emulsion even in a full-scale dryer.

The estimation of the solubility of biomass-derived organic compounds in high-temperature water is important for designing chemical processes. This study aimed at predicting the solubility of organic compounds in high-temperature water in the range of 100–250 °C using machine learning. The chemical structure of the organic compound was converted into 196 descriptors (parameters) using an open-source toolkit. The experimental solubility data were regressed using the descriptors, temperature, and water density. The regression methods of ordinary least squares (OLS), least absolute shrinkage and selection operator (Lasso), and support vector regression (SVR) were compared. A regression method combining the Lasso and SVR (Lasso + SVR) was developed. The model thus obtained by Lasso + SVR was found to accurately predict the solubility of organic compounds in high-temperature water, with a root-mean-square error of 0.5. The findings in this study would be useful for predicting the solubility of any organic compound in high-temperature water.

In this study, the effect of carbonization temperature on the saccharification performance of cellulase recovered using Japanese cedar char was examined. The higher the carbonization temperature of char was, the higher the saccharification performance of the recovered cellulase became. It was also suggested that not only the specific surface area and pore volume of char but also the surface functional groups on the char and the metal content in char would affect the amount of the recovered protein.

Concentrated sulfuric acid hydrolysis of lignocellulose is widely used to convert polysaccharides to monosaccharides in high yield, but highly condensed lignin with low-chemical reactivity is also obtained as a byproduct. We previously reported that tert-butyl alcohol (TBA) efficiently prevented lignin condensation in the concentrated sulfuric acid hydrolysis. In this study, the TBA/concentrated sulfuric acid hydrolysis system was scaled up to 10-fold, and acquired tert-butyl alcohol lignin (TBL) was characterized by TGA, TMA and FT-IR analysis. The TBL produced in the large scale contaminated polymerized TBA, which induced different thermal response compared to the TBL obtained in a small scale. Hexane was found to be a suitable solvent to remove the polymerized TBA from TBL prepared in large scale.

Paper has an established recycling method, as its raw material, the wood, used to make pulp, takes about 10 years to grow. Its product life, however, is short. The process of removing the plastic coating of water-resistant paper during re-extraction of pulp while recycling is inefficient. Therefore, in this study, a fabrication method was devised to directly pulverize water-resistant paper and utilize it as a filler for plastic. The “crushability of water-resistant paper” and “compatibility of filler and resin” are important factors for using pulp as filler. Hence, we also evaluated the shape of pulp and conducted tensile tests on composite materials using the pulp. Results showed that pulp is less likely to form agglomerates and exhibited optimal tensile properties when subjected to the absolute, dry, blade-impact milling method.

Seaweeds are attracting attention as blue carbon because they absorb and store CO₂. The amount of Ulva sp. is rapidly increasing around the world due to high daily growth rates by the eutrophication of coastal waters. The effective utilization of Ulva sp. is highly expected because the large amount of seaweed is removed as it decomposes and has a negative impact on the surrounding environment and ecosystem. Ulva contain a large amount of sulfated polysaccharide called ulvan, which is a functional polysaccharide, is expected to be used effectively. Conventional extraction process of ulvan requires a long extraction time of 1-3 hours using acids and chelating agents. In this study, efficient extraction of ulvan from Ulva meridionalis was achievd using 2.45 GHz microwaves. The extraction time was reduced to 1/6 of the conventional conduction heating extraction. The highest yield was obtained when the solid/liquid ratio was 1:20.