Cellulose has a recalcitrant structure due to its complex and strong inter/intra molecular interactions, which results in the poor chemical reactivity. Pretreatment of cellulose with ionic liquids (ILs) is advantageous because of not only giving high reactivity on cellulose but environmental-friendly and recyclable natures of ILs. However, high cost of ILs themselves is problematic. We discover that smaller amounts of IL on pretreatment step provide regenerated cellulose with lower crystallinity and higher acid hydrolysis rate.

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Microwave is capable of selectively heating solid catalysts which retain high dielectric loss, therefore, accelerating heterogeneous reactions at more benign bulk reaction condition than those operated by conventional heat conductive devices. Due to their high recalcitrance of biomass, the pretreatment or thermochemical treatment of lignocellulose is generally conducted under severe reaction. Microwave reaction is expected to reduce the apparent severity of these treatments. This paper presents hydrolysis of carbohydrates by using polyoxometalate cluster supported carbon POM-supported catalysts which were designed to exhibit high microwave absorption and hydrolytic activity for generation of mono and oligo saccharides from biomass. Polyoxometalate clusters were supported on activated carbons which exhibited significantly high dielectric loss tangent under hydrothermal condition by wet impregnation. These catalysts exhibited higher saccharification rate on hydrolysis of cellobiose and green macroalgae than conventional heating. By using the coaxial line method, the dielectric properties of the POM-supported catalysts were found important to obtain higher saccharification rate.

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This study focuses energy efficiency evaluation in microalgae oil extraction process by middle temperature and low pressure hydrothermal treatment, and proposes optimization method for oil productivity by controlling temperature, pressure, moisture content, and processing time as physical parameters. Native microalgae (Desmodesmus sp.) in Minamisoma City, Fukushima Pref. were used in this research. 50 g microalgae was used for hydrothermal treatment after primary dewatering as pretreatment. Lipid quality and quantity were measured in before and after treatment by the methanol extraction. 0.22 of energy profit ratio (EPR) was calculated by 2,203 kJ of input energy in this experiment from the viewpoint of oil production, and 1.27 of EPR was calculated by 385 kJ of theoretical energy consumption.

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Biodiesel fuel (Fatty acid methyl ester: FAME) shows high boiling temperature, so that it allows to accumulate in the engine oil, causing the premature engine wear. Recently, it was reported that the boiling behavior of biodiesel is adjusted to that of petro-diesel fuel by the cross-metathesis reaction with Grubbs-II catalyst. In this study, the changes of molecule and fuel properties of PME, JME, RME, SME, and WME by cross-metathesis reaction was experimentally investigated. The cross-metathesis reaction of FAME and l-hexene with Umicore M5_l catalyst was carried out at 40 degree-C. From the experimental result, it is found that the long-chain length unsaturated fatty acid methyl esters components; C18:1, C18:2, C18:3, were converted to low & middle chain length fatty acid methyl esters, and the cold flow property of fuel is improved, however the oxidation stability is decreased.

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The supercritical water gasification (SCWG) of wet-biomass holds promise as a technology to convert biological waste wet biomass into valuable, environmentally, and friendly energy. The 24 h continuous operation with the pilot plant (1 t-wet/d) has been conducted and it was successful achieved by appropriate content suspended activated carbon (a. c.) as gasification catalyst. The a. c. content increase makes the decrease of TOC in gasification effluent. The adsorbed TOC quantity onto a. c. from gasification effluent was determined by the adsorption test with SCWG effluent by a. c.. and the constants of Freundlich equation at 25 ℃ was determined as K=2.09, 1/N=0.7588, respectively. The estimated TOC value by this equation suggests the catalytic decomposition ability of a. c. in SCW.

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Biomass is one of essential renewable energies to reduce the use of fossil fuels resources. Bioenergy production including high yield is required for sustainable cropping system. Therefore, bioenergy crop must be associated with sustainability, local specificity and policy. This study aimed to quantify biomass productivity (BP) and expect fertilizer impact using 5 selected lines of Miscanthus sinensis with different origin for six years long-term field trial in cool region. Experiment plots were established in 2008 on agricultural land with and without fertilizer to assess nitrogen requirement. Nitrogen content in harvested biomass was determined and fertilizer requirement estimated. BP in fertilized field was 12.1 t ha^<-1>, 28 t ha^<-1>, 45 t ha^<-1>, 33 t ha^<-1>, 37 t ha^<-1> in subsequent years after establishment, respectively. Nitrogen uptakes were 56 kg N ha^<-1>, 130 kg N ha^<-1>1, 207 kg N ha^<-1>, 153 kg N ha^<-1>. BP in non fertilizer field decreased only 0〜19%. That performance was associated to nitrogen uptake capacity (98% of fertilized field) as land impact. We conclude that without fertilizer, selected M. sinensis could yield about 90.3% of its potential. Thus M. sinensis could be used in a sustainable bioenergy cropping system.

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The purpose of this study is to estimate the woody biomass potential based on the wood material flow. The wood flow is drawn based on the statistic data from Japan's Forest Agency and METI. Woody biomass potential is estimated using the timber volume in 2007 and 2012, and the wood material production. The timber volume in Japan is 2,658 million m^3 in 2007, and 3,048 million m^3 in 2012. And annual wood production is 14-15 million m^3/year. Thus, the forest growth amount is 93 million m^3/year, and the sustainable availability is 52.9 million m^3/year. Based on the wood material flow, the woody biomass availability for energy is 10 million m^3, higher heating value 72 TJ/year.

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To analyze the economic impact of power generation and CHP (Combined Heat and Power) generation business by wooden biomass, we created a "business cost simulator" focused on various business performance indicators using Microsoft Excel. Comparison of profitability in small-scale their businesses of less than 2,000 kW power output was performed, and evaluation of potential and risks of their business was carried out. In set conditions, the simulation results show that IRR (Internal Rate of Return) of CHP generation business are 5.0% upper than that of power generation business, and payback period of CHP generation business are 5 years earlier than that of power generation business. When heat is available, even if the power generation output and efficiency are small, the profitability of the CHP generation business is higher than the power generation business.

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IRR(Internal Rate of Return) is one of the effective evaluation index of the profitability of the biomass generation business. However, the setting of the hurdle rate to enable business is affected by multiple factor. On the profit and loss model of the 5,700kW biomass generation business with that in mind, I performed the sensitivity analysis by equity ratio was provide to confirmed the influence that the balance of equity and debt gave in capital cost. Evaluation of the profitability allows the assumptions such as procurement cost, the price of fuel..

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In the days of rapid economic growth in Japan, mass consumption was a major contributor to the country's development and was the right thing to do at the time. But times have changed. And with the decline of primary industry in Japan, the problem of global warming, and the occurrence of the Tohoku disaster, a new outlook on energy has emerged. Japan is heading into an era of rapid transition. With this transition, we need business models that develop primary industry, contribute to the global environment, and generate energy in a new way. The production of biogas through methane fermentation, an endeavor that reuses the products of the agriculture industry, is one such business. While proposals like this can already be found here and there in Japan, these plans have failed to make significant progress, as they are being held back by a wall of regulations and inside-the-box thinking. We confront these challenges and provide a model that puts into practice the notion of a recycling-based society. And with this model serving as a pilot venture, we hope to bring about the rise of such small and mid-sized businesses throughout Japan.

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In Japan, the wood biomass combustion apparatuses have not yet spread and remain in "points". By investigating and analyzing the experience and problems of Iwate prefecture, that precedes in wood biomass heat utilization, I consider a policy to make from points to aspects in other areas.

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We quantified how a whole of community heating system from regional forest to nearby buildings, where heating demand emerges works, with the concept of exergy in the case of Shimokawa town. We confirmed the validity of the calculated total heat loss from the residential buildings by comparing it with the measured volume of biomass consumed. We compared the annual exergy consumption pattern, from the forest, via to boiler, pipeline, room-space heaters and to the exergy flow through buildings in two one-year periods: from August, 2013 to June, 2014, and from October, 2014 to November, 2015. It was clarified that a rational planning and method for on community heating system using biomass are necessary.

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Power generation business utilizing FIT system is widely diffused nowadays. There are, however, some problems in such a business due to the required much materials, low efficiency of its power generation, and no economical contribution surrounded area. This work introduces an example of a solution addressing those problems, for examples, in which we designed more stable balance of power supply and consumption over the seasons, with constrained distribution distance because of thermal loss and so on.

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The business model which utilize the high potential in the cost performance and LCA of the grass resource crop was proposed. The business model was based on the outcome of technical development in breeding, cultivation technique and storage technique of Erianthus (Erianthus arundinaceus) which can maintain the high productivity in a sustainable way. The small-scale heat use for business in the towns and villages is proposed as a universal business model which stands up economically.

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Promotion of the use of energy from renewable sources is expected to solve issues of global climate change, environmental destruction and the problem of energy supply. The use of wood to generate energy is expected in Japan, because 67 percent of the land is forest in Japan. Japanese government started FIT in 2012 for renewable energy promotion. Woody biomass depletion has been happening, because many biomass power plants are standing in disorderly. For the use of woody biomass, amount estimation of the available wood is the essential. The available wood in the Kumano region (the south of Mie prefecture in the middle of Japan) was measured in this study. Furthermore, we were measuring the volume, weight, moisture content and water content of the wood and wood chips. Four moisture meters used to determine water content of logs with electrical resistance method, and also the moisture content of wood chips was measured by balances equipped with heater. As a result, the total amounts of available wood in the Kumano region were estimated 74,000 t/year.

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We performed a comparative analysis of the expression levels of proteins secreted by Phanerochaete chrysosporium cultured with either untreated or ammonia-treated lignocellulosic biomass. The results indicated that P. chrysosporium produced enzymes related to the degradation of de-acetylated xylan and nitrogen-containing biomass. The results also suggested that P. chrysosporium recognized ammonia-treated biomass as a xylan and nitrogen-containing biomass, and that it regulated the production of related enzymes. A better understanding of the mechanisms underlying these processes might facilitate the optimization of enzyme cocktails for the production of bio-fuels.

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The thermal stability of Trichoderma reesei Xyn III was improved by directed evolution. The random mutations were introduced into xyn III gene using error prone PCR and random mutagenesis library was constructed into E. coli cells. The mutated Xyn III that had higher thermal stability was screened. The selected mutant had two amino acids substitutions. Next, the saturation mutagenesis was introduced into this two amino acid positions. The most effective mutations were Gln to Ala and Asn to Tyr. This Xyn III mutant showed high thermal stability at 50℃ for 48 h.

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Sorghum bagasse pretreated with diluted acid, which was predominantly composed of glucan (59%) and xylan (7.2%), was used as a lignocellulosic feedstock to produce D-phenyllactic acid (PhLA) by a recombinant Escherichia coli strain expressing phenylpyruvate reductase from Wickerhamia fluorescens. Compared to filter paper hydrolysate, the PhLA yield was reduced by 35% during fermentation with enzymatic hydrolysate of sorghum bagasse as a carbon source, and metabolomics analysis revealed that intracellular levels of erythrose-4-phosphate and phosphoenolpyruvate and NAD(P)H regeneration for PhLA production from glucose markedly reduced. Compared to the separate hydrolysis and fermentation (SHF) with sorghum bagasse hydrolysate, simultaneous saccharification and fermentation (SSF) of sorghum bagasse under glucose limitation conditions yielded 4.8-fold more PhLA with less accumulation of eluted components of p-coumaric acid and aldehydes, which inhibited PhLA fermentation. These results suggest that gradual hydrolysis of sorghum bagasse during SSF reduces the accumulation of both glucose and fermentation inhibitors, collectively leading to increased PhLA yield.

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Worldwide attention is focused on the biorefinery industry as a means to tackle current global warming and energy security concerns. However, current production using food crops should give way to production from cellulose obtained from non-food biomass. We developed a growth-arrested bioprocess "RITE Bioprocess" to produce biofuels and biochemicals from non-food biomass. The RITE Bioprocess utilizes Corynebacterium glutamicum, which is widely used in industrial production of amino acids. The process is based on a new concept that fundamentally resolves the technological problems of existing bioprocesses. Using genetically modified C. glutamicum cells, various substances can be produced at high volumetric productivity with cells packed in a reactor to high density under growth-arrested conditions generated upon oxygen deprivation. In this presentation, our current research into aromatic compound productions will be discussed.

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Increase in the degree of oil self-sufficiency is an important issue in Japan. Due to the decrease in agricultural population and the extent of land area in Japan, we cannot expect an increased yield of oil plant. Therefore, we noted the oleaginous yeast Lipomyces starkeyi, which can convert various saccharides such as glucose and xylose to lipid. L. starkeyi is an excellent lipid producer that is able to accumulate up to 70% of its biomass as triacylglycerols. However, there are issues of lipid productivity (lipid production rate and lipid conversion efficiency) for commercial applications. In this study, we aimed the isolation of L. starkeyi mutants accumulating a high level of lipid. L. starkeyi mutants with high accumulation of lipid were isolated following mutagenesis with Ethyl methanesulfonate. Enrichment procedures for separating high lipid accumulation cells of L. starkeyi from wild type cells were devised employing percoll density gradient centrifugation. The mutants, E15, E47, and E42, were identified in lipid accumulation using Flow cytometry and microscope analysis. Three mutants were characterized with respect to their lipid productivities.

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To clarify the combustion behavior of mixed pellets of waste plastics and waste wood injected into CaCO_3 calcination furnace, a combustion test of mixed pellets has been carried out in the electric furnace and commercial furnace. A burning time of mixed pellets was about 18sec at 1000 degree C. Moreover, it is considered that a property such as the mixed ratio of waste wood can affect combustion behavior. From the result of mixed pellets injection into CaCO_3 calcination commercial process, it was clarified that mixed pellets are available in equivalent to the coke oven gas.

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Palm Kernel Shell is the biomass resource which is generated in large quantities in Indonesia and Malaysia. But PKS is very difficult to pulverize, it is necessary to improve grindability of PKS to use PKS at PC boiler with coal. So, we tried to improve PKS's grindability by low temperature carbonization technology. We produced carbonized PKS of varied VM, and we evaluated these grindability. As results, we have demonstrated 11 cal.% biomass co-firing by using carbonized PKS at the 216 MW commercial power plant.

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Enokitake (Flammulina velutipes) is one of the most popular cultivated mushrooms in Japan. A huge amount of waste culture is disposed thus its utilization as biomass fuel is needed. In addition, the ash can be used as fertilizer because the waste culture contains plant nutrients (P, K, Mg and Si). Due to high moisture content of waste mushroom culture, however, drying is necessary prior to use. As an approach for drying, compositing was conducted. The waste culture after drying was burned in a semi-pilot scale combustor with a combustor volume of 535 L. Reduction of NOx emissions by urea solution injection and SO_2 capture by Ca(OH)_2 powder injection were attempted. The ash was analyzed to determine contents of plant nutrients. Though the content of silica was high, the contents of water-soluble and citric-acid-soluble components were low. The treatment at high temperatures is considered to decrease the solubility of silica. Heavy metal contents were sufficiently lower than the acceptable level for the case of sludge fertilizer.

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Element contents in wood ash from electric power plants were same level as from pellet boilers, but some elements were higher from power plants. The sand was used for the fluidized bed boiler collected in this measurement. Then, it needs to pay attention element concentration in sand when sand was used for the combustion boiler. Japanese cypress seed in the ash bed was germinated when mixing rate of the wood ash to the peat was below 1:3, but germination rate was not statistically different among media such as peat moss, coconut peat and ash with peat moss. This result indicates that production cost of container seedlings will be possible to decrease 25%. Nutrient stock in the soil and aboveground biomass of Japanese cedar and cypress stand were calculated. Calcium stock in the soil was higher than those of biomass at all sites, but potassium (K) were higher in the biomass than soil at some sites. It means that K deficiency will be occur when intensive harvesting such as whole tree harvest was conducted and will affect tree growth after harvesting. As a woody combustion ash contains high amounts of K, ash return to the forest site will supply K when harvested.

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Effects of pyrolysis temperature and addition of inorganic salts on fast pyrolysis of kraft pulp prepared from mosobamboo were evaluated. Increasing pyrolysis temperature for the kraft pulp led to increasing pyrolysate yield, which was similar to those of holocellulose and a-cellulose prepared from moso-bamboo. Compared with the holocellulose pyrolysis, the kraft pulp pyrolysis produced acetic acid in lower yield. Fast pyrolysis of kraft pulp impregnated with calcium salts produced levoglucosan in higher yield at pyrolysis temperature below 500 ℃ than that of untreated kraft pulp. Therefore, it was indicated that pyrolysis temperature and calcium salts could influence levoglucosan production from fast pyrolysis of kraft pulp.

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In this study, the pyrolysis of biomass and brown-coal have been studied in artificial sunlight heat fluidized bed. The property of the heated treated biomass and brown-coal were investigated. As a result, in the case of biomass, C ratio was increased with treating temperature increasing. The HHV has been taken the maximum value,5500kcal/kg, at 500℃.In the case of brown-coal, C ratio was increased with treating temperature increasing. The HHV has been taken about 7000 kcal/kg between 500℃ to 700℃. However, the C ratio and HHV are decreased between 700℃ to 800℃.

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Co-pyrolysis of waste copier paper with phenols was performed to estimate the effect on the yields of major products. Levoglucosan and hydroxymethylfurfural are known as major pyrolysis products from cellulosic materials, and valuable chemicals as biologically active substance. Yields of these products are sensitive to contaminants, such as inorganic substance, additives, other carbohydrates and phenols. The result of this study was indicated that formation of levoglucosan from waste copier paper pyrolysis was inhibited by presence of sinapylalcohol and coniferylalcohol. On the other hand, ferulic acid had no effect on the yield of levoglucosan. Presence of all phenols used in this study were inhibited the formation of hydroxymethylfurfural. The formation of 4-vinylguaiacol from ferulic acid with waste copier paper was accelerated and increased the yield proximately 200%.

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Buck wheat is known to include valuable flavonoids, such as rutin, however, the husk have been discarded so far. The object of this study is to estimate the possibility of buck wheat as a new resource for production of valuable chemicals by extraction and fast pyrolysis. In this study, Influence of extraction of buckwheat husk on distribution of pyrolysis products was evaluated. Extraction with water and 70% methanol was significantly increased the yield of levoglucosan in the pyrolysate from extracted husk residue. Furthermore the levoglucosan yield was increased by the washing with 1% hydrochloric acid. It is thought to be because the alkali metal for promoting the decomposition of the record book is extracted. The formation of the phenol products from the pyrolysis of the buck wheat are inhibited by extraction with methanol and water.

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The kinetic mechanism of the initial step in the thermal decomposition of biomass derived compounds was studied using quantum chemical calculations. Energies along the dissociation reaction coordinates were evaluated based on density functional theory (DFT), and variational transition state theory (VTST) was performed by processing the calculated microscopic rate constants.

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Temperature and heat of reactions have been measured during fast pyrolysis of biomass powder packed bed. For cellulose powder, temperature at the center of the bed, T_c, increased monotonously with time due to thermal conduction for T_c < 500K. The temperature increased slowly with time due to endothermic decomposition of cellulose for 500 K < T_c < 600 K. On other hand, exothermic behaviors for xylan powder and lignin one were significantly observed at T_c > 500 K and at T_c > 600 K, respectively. The heats of reactions were measured by differential scanning calorimetry (DSC). For Cellulose powder, endothermic and exothermic signals were observed at 560 K < T < 607 K and at 607 K < T < 638 K, respectively. For Lignin powder has two endothermic peaks at 491 K < T < 495 K and 503 K < T < 549 K while the exothermic signal was observed at 549 K < T < 682 K. For Xylan powder, endothermic and exothermic signals were observed at 371 K < T < 477 K and at 477 K < T < 602 K, respectively. Furthermore, numerical simulation of fast pyrolysis of cellulose powder packed has been conducted.

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Price of high grade coal is rising with increasing the consumption of low grade coal. Furthermore, biomass use has become important because of depletion of fossil fuel and global warming issues. Biomass have problems such as low melting points of ash. In boiler, performance of heat transfer tube is decreased and surface of metal tube is corroded. In this study, we examined the melting characteristics of the peat ash and mushroom agriculture waste ash. As a results, weight of ash was decreased with increasing temperature. The melting points of peat ash is 1200℃ and biomass ash is 1300 ℃.

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For Studying Gasification characteristic of the mushroom culture waste and Brown coal, We investigated pyrolysis behavior of the mushroom culture waste and Brown coal. As a result, in all samples CO_2 ratio of gas generation decreased with increasing temperature. H_2 generation of Brown coal is little (less than 1%) from 400℃ to 500℃. And then, it increased rapidly from 600℃ to 800℃. However, H_2 generation of mushroom culture waste is increased from 400℃ to 800℃. About the mixture of the mushroom culture waste (5%) and Brown coal, H_2 generation is increased with temperature. The ratio is 41% at 800℃.

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The Fischer-Tropsch synthesis (FTS) of syngas, whose composition was H_2:CO:N_2 = 2:1:3 (volumetric ratio), was carried out using Co-based catalysts in order to produce hydrocarbons (HCs) equivalent to kerosene, which is used as an alternative aviation fuel. Co-based FTS catalysts modified using a metal were prepared and characterized. The FTS had been conducted in a downdraft continuous-flow-type fixed-bed reactor under a temperature of 225℃ and a pressure of 3.0 MPa for 4.5 h. The effect of metals included in the Co-based catalyst on the FTS was studied by focusing on CO conversion, primary kerosene yield, and the carbon mass balance.

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A natural limonite ore is used as catalyst for tar reforming at 650 ℃. Researches on the catalytic role of the limonite ore, deactivation mechanism, influence of steam addition were conducted. The characteristics of the catalyst were analysed by X-ray diffraction (XRD) and scanning electron microscope (SEM). Effects of steam addition and the steam/carbon ratio on catalyst activity and lifetime were discussed.

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The high-temperature removal of sulphur from biomass-gasification-derived synthesis-gas (bio-syngas) using nickel oxide supported by calcium aluminate (NiO/CaAl_2O_4) was investigated with the objective to desulphurise bio-syngas via utilisation of the sensible heat cascade, which is maintained at the temperature of the gasifier. In this study, the effects of the operating temperature (750-950℃), moisture content of the lignin slurry (73-90 wt%), and catalyst loading (0.00-0.61 g-catalyst/g-feedstock) on the sulphur yield/concentration and distribution of sulphur in the products of gasification of wet-lignin were clarified; subsequent sulphur removal on the catalyst surface was also investigated. The performance efficiency was introduced as a parameter and was maximised to determine the optimal operating conditions for producing bio-syngas with a higher sulphur removal and smaller additional heat for the operation.

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Hydrogen sulfide in fuels for Solid Oxide fuel Cell (SOFC) typically lead to signicant losses in performance due to the sulfur sensitivity of Ni/YSZ anodes for SOFC. This paper investigates the effects of hydrogen sulfide contained in the fuel which is purified by the Blue Tower (BT) gasification. The results of experiment under the constant current condition show that significant voltage drop becausse of hydrogen sulfide. In addition, We observed the sulfur adhered to the NiO/YSZ from BT-syngas by SEM-EDX. As a result, a small quantity sulfur was captured on the anode surface. This experimental datas would be available for design the SOFC integrated the BT gasification.

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This study proposes electrolysis of alkaline water that has dissolved lignin (LG) that is often termed black liquor. It was demonstrated that, H_2 was formed as the ratio of 1:2 to electrons at the cathode, but O_2 wasn't evolved in a continuously electrolysis. It means that lignin oxidation had occurred at the anode instead of O_2 generation in the electrolysis, in other words, electrochemical gasification. Linear-sweep voltammetry of LG showed that the oxidation occurred at voltage of -0.1-0 V, which was lower than the theoretical voltage in the absence of the lignin, i.e., 0.4 V. The oxidation of LG was further enhanced by its hydrothermal treatment (HT) prior to the electrolysis. HT caused depolymerization producing reactive monomers such as guaiacol and syringol. It was thus concluded that use of LG potentially but significantly raised the efficiency of the electrolysis and further, the reactivity is enhanced through depolymerization of lignin by HT.

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The behavior of shochu residue during supercritical water gasification was investigated experimentally. The reaction rates of gasification and char and tar formation were determined. Shochu residue (1.0 wt%) was gasified in supercritical water (SCW) at 600 ℃ and 25 MPa using a tubular reactor. In addition, liquid and solid phase of shochu residue was gasified separately in order to confirm detailed reaction mechanism. The reaction pathway of decomposition of shochu residue was proposed and the reaction rate constants were calculated.

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The main objective of this research is to study the effect of feedstock concentration on supercritical water gasification of shochu residue with addition of acetic acid. It was reported in previous study that yield of char or tar decreased in the presence of acetic acid. However, the effect of feedstock concentration is still unclear. In this study. the experiment was conducted at 600 ℃, 25 MPa, changing concentrations of shochu residue between 0.1 and 0.5 wt%. The liquid product was analyzed using total organic carbon (TOC) analyzer, while gas product was analyzed using gas chromatography (GC). In the result, the tendency with changing concentrations of shochu residue.

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Char formation reduces carbon gasification efficiency and plugs the reactor in supercritical water gasification of biomass. Char can be suppressed by radical scavenger if the char is produced by radical reaction. Shochu residue as the commercial food waste was gasified in supercritical water together with acetic acid as radical scavenger in the continuous flow reactor at 600 ℃, 25 MPa. The residence time was set to be 94 s. The amount of solid decreased with the concentration acetic acid. Addition of acetic acid was effective for suppression of char.

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Lactic acid was gasified in supercritical water at 430 ℃, 25 MPa, and its decomposition characteristics were investigated. Concentration was 0.1 mol/dm3, and residence time was changed in the range of 1-60 s. Gas yield of 0.4 was obtained, other part remaining in liquid phase.

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A 1.0 wt% solution of histidine was gasified in supercritical water using a tubular reactor at temperature of 500-650 ℃ and pressure of 25 MPa. The gaseous product was identified and quantified by gas chromatography (GC) and the amount of organic carbon in the aqueous phase product was also determined by total organic carbon analyzer (TOC). Based on the experimental results, increasing reaction temperature led to increasing of carbon gasification efficiency, indicating the reaction rate constant following the Arrhenius equation. The carbon gasification efficiency was calculated, and reaction rate parameters were determined assuming the first-order reaction. The Arrhenius rate parameters were determined, and pre-exponential factor of 3.0×10^2 s^<-1> and activation energy of 77 kJ mol^<-1> were obtained for histidine gasification.

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Phosphorus is known as one of three major elements of fertilizer, essential substance on conducting agriculture, and resource which is concerned about the depletion in the future. Thus, it is important to establish the phosphorus recycling system. Sewage sludge is considered as one of the main resource for realization of this system. Now, there are many ways to collect phosphorus from sewage sludge such as HAP method, MAP method, and partial reducing melting method. Hydrothermal treatment of sewage sludge to collect inorganic phosphorus was also studied in previous study. However, research which focuses on gasification characteristic of organophosphorus compounds under hydrothermal condition has not been reported yet, which is the purpose of this study. To confirm gasification characteristics, we used adenosine triphosphate (ATP) disodium salt hydrate as a first feedstock. It was treated under hydrothermal condition of 25 MPa. As a result, about 50 % of carbon gasification efficiency could be confirmed after 40 s of hydrothermal treatment at 400 ℃. Main component of the product gas was carbon monoxide.

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Supercritical water is water at fluid phase whose temperature and pressure are above its critical values (374 ℃, 22.1 MPa). At this state, water has high potential as a solvent for organic components and gases. As a result, biomass could be homogeneously dissolved in supercritical water and consequently converted into gas with high efficiency. In this study, tomato residue, which is an agricultural waste, was used as feedstock model for process design and evaluation of supercritical water gasification (SCWG) process. Liquefaction process was introduced as pretreatment step prior to SCWG. The feedstock was heated up to 600 ℃ and pressurized to 25 MPa. Process equilibrium was calculated based on Gibb's free energy minimization. Carbon dioxide was absorbed by additional water from final gas product. Heat recovery and energy production were estimated.

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