To characterize the chemical structure of oxidized coal, solid state 13C NMR spectra were acquired for two kinds of coal X and Y before and after estimation of their self-heating property by using R70 apparatus. It was found that coal X with higher oxgen concentration reached 80ºC in shorter time than coal Y. Futhermore, the amounts of aldehyde or ketone estimated to be 0.77mmol/coal-g in coal Y during oxidization, while that of calbonyl was estimated to be 0.61mmol/g-coal in coal X. It is suggested that generation of aldehyde or ketone, and carbony might occure at less than 80ºC. In addition, it is indicated that the kinds of oxidized reactions were diffrent between coal X and Y.
The average formula of coal was described by CHm On, and, based on the formula, a skeleton model method for structure analysis of heavy oil was applied to examine coal structure. The carbon skeleton model of coal was determined by the contents of OH, C=O, COOH groups and H/C. The skeleton model of coal was obtained by estimating the number of an aromatic ring and the length of a side chain. The high fluidity larger than 104 DDPM was observed in the coal rank containing 0-1% carbonyl group and two to four fused aromatic rings.
A three-point bending test was performed on a coke sample, which was cut into a flat plate, under the simulated blast furnace conditions with CO2 or H2O gasification reaction using a thermomechanical analyzer. In addition, the X-ray CT images of the coke samples were taken before and after the gasification reactions, and the changes in their internal structure were evaluated. As a result, it is shown that the difference in the changes in the pore structure caused by the rate-controlling step of the reaction affects the coke strength under the blast furnace condition.
Massive introduction of variable renewable energy sources such as wind and solar power could cause instability in power system. For grid stabilization, operational flexibility improvement of thermal power plants is a valid method besides grid reinforcement, and dynamic simulation is an attractive way to understand the effect of operation change and equipment modification. Authors have developed a dynamic analysis tool using Modelica for the purpose of evaluating and improving operational flexibility of thermal power plant. In this manuscript, the results of dynamic modeling and simulation of an actual existing coal-fired power plant were reported. The developed model covers the entire range of a power plant, and simulation are performed based on the output commands. By simulation of increasing the load change rate, it is clarified that the risk of steaming in the economizer is increased.
Ash deposition in pulverized coal boiler is evaluated with various indexes using hemi-sphere temperature and elements of coal, but it is often impossible to evaluate appropriately. In this study, the new predictive model of ash deposition was examined. The model was made to predict heat absorption from elements of coal directly. It was made by the multiple regression analysis of the heat absorption data and elements of coal data at that time.
In this study, the effects of the combination of mesoporous materials and Zn-exchanged ZSM-5 on the activity and selectivity of aromatic compounds in dehydrocyclization of n-pentane were investigated. 65-85wt% of ZnZSM-5 was mixed with 0-20wt% of oxide and 15wt% of alumina-sol binder by a conventional kneading method. Dehydrocyclization of n-pentane was performed using a fixed-bed reactor under the conditions, H2 atmosphere and temperature range 450-550°C. When alumina, titania, zirconia, and kaolin as oxide matrices were compared at the same 10wt%, the activity increased in the order, kaolin < zirconia < titania < alumina and the selectivity for aromatics increased in the order, titania < zirconia < kaolin < alumina. Although the catalyst without an oxide matrix exhibited the high activity, its selectivity for aromatics decreased. When the reaction route was estimated from the amounts of methane and C2 and C3 fractions formed, it was proposed that active Zn species would catalyze the aromatization of olefins where benzene is formed from C2 and C4, toluene from C3 and C4, and xylene from 2 molecules of C4.
Precipitated iron catalyst was synthesized in the interface of gas and liquid phase. Although surface areas of catalysts with a new preparation method and with a conventional method were not different clearly, catalytic activities showed much difference. In the case of ammonia decomposition reaction, ammonia conversion with a new method catalyst was much higher than one with a conventional catalyst. In case of methanation reaction from CO2, yield to methane was increased until 48h.
In this work, an exergy-recuperative system for highly efficient CO2 conversion by combining CH4 dry reforming and partial oxidation of methane was proposed and investigated by Aspen Plus commercial software. The system is mainly composed of a dry reformer, a partial oxidation reactor, a CO2 separation unit, heat exchangers and compressors. CH4 gas flow is assigned to two parts: one is reformed by CO2 in the dry reformer and the other is introduced into the partial oxidation reactor to provide heat for the dry reforming process. High-density olivine particles are circulated in the system as the heat carrier to transfer the heat from the partial oxidation reactor to the dry reformer, and simultaneously as the catalysts for the dry reforming of CH4. Meanhile, the most of exergy released in the cooling of syngas is considered to be recuperated for the gas pre-heating to improve the energy efficiency of system. The results demonstrate that the CO2 conversion efficiency could reach to 76.6% with a high exergy recuperation efficiency.
The study program of the MH21 research consortium for methane hydrate resources in Japan was concluded in 2019 with many outcomes such as the world’s first offshore production test (2013). However, the achieved production rates still fell short of the economical criteria. The analyses and evaluations of the obtained data and experiences revealed some important factors such as excess water production and formation damages around wellbores. The newly started phase 4 study focuses on the development and verification of technologies that solve the technical challenges.
In this study, we developed an in situ chamber to measure water permeability as a function of the methane hydrate (MH) habit in pore space using a two-dimensional glass micromodel. We simultaneously observed MH crystallization behavior and measured the water permeability of the porous media. We compared our results with various water permeability models of MH sediments and found that the nonempirical relative permeability (NRP) models showed relatively good agreement.
The CO2-in-Water (C/W) emulsion injection method is expected to be effective for gas recovery from low temperature hydrate reservoirs. We developed a two-dimensional numerical program to predict the flow behavior of C/W emulsion with hydrate formation in porous media and conducted numerical case studies of C/W injection in a two-dimensional system. Sensitivity analysis showed that there would be an optimal injection scheme for CO2 concentration and slug size to maximize the effect of gas recovery from the MH layer.
In this study, the applicability of Microbial Induced Carbonate Precipitation (MICP) to sand control in high-pressure environment assuming methane hydrate reservoir is investigated. The cell culture solution(S.aquimarina, S.newyorkensis) and cementation solution passed through the specimen until the hydraulic conductivity decreased by two order of magnitude. As a result, it was revealed that S.newyorkensis decreases the hydraulic conductivity lower than S.aquimarina in an early stage of injection. In late stage, both S.newyorkensis and S.aquimarina decrease hydraulic conductivity and increase mechanical strength. Our results suggested the applicability of MICP under high confining pressure condition.
Since 2016, Kitami Institute of Technology has been conducting a joint research with the Hokkaido Research Organization on the discovery and recovery of natural gas hydrates off Hokkaido. Samples of near-surface gas hydrate were recovered off Abashiri in 2018, using Hokushin-Maru equipped with a hydrostatic corer. Crystallographic analysis revealed that the crystals belong to the structure I, composed mainly of methane of microbial origin, and contained hydrogen sulfide in the crystal. The SMI depths are less than 0.3m, suggesting large amount of methane supply from deep layer and active anaerobic oxidation of methane in the near-surface sediment layer.
In this study, nondestructive observations of naturally occurring methane hydrates were performed by means of absorption-contrast X-ray computed tomography (CT) with monochromated synchrotron X-rays at a temperature below 120K. The X-ray CT technique using X-ray of 15keV enabled measurments of the methane hydrate coexisting with sediments. However, segmentation between the hydrate and ice can not be achieved.
In the framework of MHP project between Russia, Belgium, and Japan, natural gas hydrates have been discovered and retrieved at Lake Baikal. In the present study, we focus the isotopic difference in methane between hydrate-bound and sediment gases, indicating the condition of natural gas hydrates. Based on the results of hydrogen and carbon isotope difference at the formation of synthetic methane hydrate, we expected the places where the supply of natural gas from deeper sediment layer stops and the crystals start to dissociate.
During the formation of gas hydrate that enclathrated light hydrocarbons, hydrogen isotope fractionation for guest molecules occurs between gas and hydrate phases. We suppose that the relation between the sizes of guest molecules and cage size of crystallographic structure affects the isotopic fractionation. The effect of cage size on the isotopic fractionation can be checked using methane and propane mixed-gas hydrate. In this study, we checked hydrogen isotopic differences for methane and propane between gas and hydrate phases at the formation of their mixed-gas hydrate, and found that the hydrogen isotopic differences between hydrate-bound and residual methane was smaller than that of pure methane hydrate.
Natural CO2 hydrates are found in nature. Stable isotope ratio of guest gas provides useful information to know gas origin and formation processes. Recently, the difference in the equilibrium pressures of the hydrates containing CH4 and CH3D, respectively, has been detected and shown to be consistent with the results of hydrogen isotope fractionation of methane during formation of methane hydrate. In this study, carbon isotope fractionation during formation of CO2 hydrate and the difference in the equilibrium pressure of hydrate between CO2 isotopologues were investigated. The results show that 13CO2 molecules are less likely to be encaged in the hydrate lattice than 12CO2 molecules, because the equilibrium pressure of the 13CO2 hydrate is slightly higher than that of 12CO2.
Alcohol molecules contains both of hydrophilic part and hydrophobic part in the structures. Usually these alcohol molecules are used as a thermodynamic inhibitor for the formation of clathrate hydrates. However, the ethanol molecules are also known as the guest substance and the mechanism of the cage formation with such hydrophilic guest substances are not clear. To reveal the mechanism of crystal growth and effect of hydrophilic and hydrophobic part in alcohol molecules, we performed molecular dynamics simulation of ethanol-CO2 clathrate hydrates. As results, the initial enclathration process of the ethanol molecules are started with the hydrophobic part.
In this study, CO2 absorption behavior of TBAB semi-clathrate hydrate slurries were investigated with a bubble columm reactor. CO2 absorption amounts were compared with estimated theoretical values from thermodynamic models. Under constant temperature (278K), CO2 amount in the hydrate phase was half that of its theoretical value. Considering the formation mechanism of CO2 enclathration in the slurry solid fraction, it is likely that CO2 was unable to be enclathrated in the initial hydrate solids, because it could not diffuse into the slurry solids, however CO2 could be enclathrated as the hydrates grew due to changing conditions. Under temperature swing conditions, the amount of CO2 enclathrated by the hydrate phase became higher than that at 278K. The CO2 absorbed slightly decreased when the temperature was increased over 278K, that indicated that CO2 occupancy in the hydrate cages was maintained. Therefore, the rate-determining step for CO2 enclathratation under temperature swing conditions is the hydrate formation rate.
Tetra-n-butylammonium bromide (TBAB) hydrate and tetra-n-butylammonium chloride (TBAC) hydrate are used as a thermal energy storage media for air-conditioning system. However, these hydrates often tend to be in supercooling state when the hydrates form from the aqueous solutions. This is a prime problem to use them as thermal storage media because the COP is decreased by supercooling. In a previous study, it was revealed that applying voltage to the solution can promote the nucleation of TBAB hydrate. The key factor of the nucleation-promoting effect was a material generated from electrodes and it was revealed that the material was composed of some metals by X-ray diffraction analysis. In this study, the nucleation-promoting effects of these metallic particles on tetra-n-butylammonium salt hydrate were investigated experimentally. It was found that significant nucleation-promoting effect on TBAB hydrate was confirmed when 2 kinds of metallic particles were ground by a mortar and added to the solutions.
Utilization of unused thermal energy is important for the development of sustainable society. Semiclathrate hydrate (SCH), consisting of hydrogen bonded water molecules and guest substances like quaternary ammonium/phosphonium salts, is a suitable material for using unused thermal energy. In the present study, the SCHs with tetra-n-butylphosphonium dicarboxylates were prepared to investigate the potential as heat storage materials. Their equilibrium temperatures not only decreased with the increasing methylene length from oxalate to succinate, but also increased at glutarate. Although this trend has been seen in the case of ammonium SCHs, the differences were smaller than the ammonium ones. The dissociation enthalpies were determined to 193, 193, and 194 J·g-1 in oxalate, malate, and succinate anions, respectively. The glutarate-based SCH showed the dissociation enthalpy for 206 J·g-1
Semiclathrate hydrate (SCH), a kind of clathrate hydrates, consists of hydrogen bonded water molecules and guest substances like quaternary ammonium/phosphonium salts. In the present study, ionic conductivity/resistivity of tetra-n-butylammonium bromide (TBAB) SCH was evaluated by AC impedance spectroscopy at 263–280K. In the annealing process, the resistivities were gradually changed: the resistivities decreased at the lower temperature, whereas the resistivities increased at the higher temperature which was close to solid-liquid phase equilibrium temperature of TBAB SCH. The results may be caused by different annealing process. AC impedance spectroscopic method can be applied to monitoring the SCH crystals and their boundaries.
Biomass-Academy has been established to enhance business expansion of Biomass Thermal Use along with utilization of Biomass Boilers. In Japan, we have been enjoying basic energies made of fossil fuels for long time. Today, it’s time to change an energy scheme from fossil fuels to Biomass fuels to create the environmentally friendly society for CO2 reduction. Japan is covered 70% of the land with forest and has enough demands of heat utilities. Even though such strong aspects for Biomass Thermal Energy, the utilization is still low level. Here, I would like to show several proposals for Biomass Boiler expansion from the legal points of legal system revision and deregulation.
Woody biomass (WB) as an energy resource has attracted interest because of lowering CO2 emissions. On the other hand, the cost of WB power generation is higher than that of the grid. One of the reasons for higher WB power generation cost is that the WB cost accounts for more than 50% of the total power generation cost, which is necessary to reduce WB cost for its wide-spread use. Numerous previous studies on WB have discussed costs, CO2 emissions, and technological improvement. However, those reports tend to focus on a specific research area, and they have not discussed the impacts of technological improvements on the WB power generation costs and interrelationship between elements of each process. In this study, we clarified the interrelationship of factors that cover a series of process from WB production to energy utilization in terms of technological improvement and cost. We find that improving Rankine cycle efficiency is one of the important factors to reduce fuel cost, suggesting that the WB power generation cost can achieve almost the same level as the grid cost.
In order to secure the supply source as well as promote the further utilization of “Untapped wood” following the completion of the Feed-in Tariff Scheme for Renewable Energy (FIT), small-sized trees such as not only cleanings from young planted forests but also broad-leaved trees from coppice forests can be expected to be prospective in Japan. This study carried out basic discussion on the effective method of harvesting such small-sized trees as unutilized forest biomass by experimenting the harvest of small-sized trees with a truck-mounted multi-tree felling head.
To evaluate the particle size distribution of each coal and biomass mixture, its neutral sugar which is only contained in biomass, was measured. Mixtures of coal and pine chips with three different degrees of carbonization were prepared and ground using Hardgrobe Grindability Index mill. In the pulverized mixture of low carbonized biomass and coal, biomass contents at all particle size ranges were almost the same as that of the input feedstock. While the biomass content in the mixture of large particle sizes decreased, the biomass content in the mixture of small particle sizes increased as carbonization progressed. The current study indicated that particle size distribution of coal as well as biomass in the pulverized mixture depends on the degree of carbonization of biomass.
Wood pellets, which is one of the biomass fuels, have been attracting attention as fuels with low environmental impact.
We have developed and provided residential pellet stoves using wood pellets. In recent years, with the advent of highly insulated and airtight houses, smaller output of heating performance is required for residential pellet stoves. The purpose of this research is to realize a small output of pellet stoves. In this talk, we discuss the current state of pellet stoves and the problems in reducing power output.
This report aimed to investigate the time & temperature-dependent crystallisation of rice husk silica upon combustion. Rice husk was combusted at various temperatures between 600 and 1150°C, kept for various duration of time between 0min to 13day, and cooled at the various ratios between 0.05 and 20°C/min. Cristobalite, a crystal structure of SiO2 in the resultant ash was detected by X-ray diffraction (XRD). The phase diagram of crystallization related to combustion time & temperature was generated by basing on the results.
In this study, mass transfer of ash during bamboo powder combustion on a flat flame is investigated experimentally and numerically. The bamboo powder combustion consisted of volatiles emission, volatiles combustion, char formation, char combustion, and finally ash formation. The mass of ash formed was about 3 wt% that of raw bamboo powder. The mass of ash decreased with the equivalence ratio Φ for flat flame combustion. Part of the ash fused and then adhered to the Inconel mesh for wrapping of bamboo powder as bottom ash, flowing through the mesh. The mass adhered to the Inconel mesh depended strongly on the equivalence ratio Φ. The fusion tendency of the atmospheric oxidization ash agreed qualitatively with Liu’s standard bamboo ash fusion test. On the other hand, as ash fusion started locally in this work, it suggests that the concentration of metal oxides of the atmospheric oxidization ash was not uniform. For the atmospheric oxidization ash at 600°C, K2Si2O5, KAlSiO4, Na2CaP2O7, Mg2SiO4, K2SO4, and Fe2O3 were predicted to be the major eutectic materials. At 1120°C, only Fe2O3 remained and the liquid components accounted for about 95%. On the other hand, the major eutectic materials for the combustion ashes of Φ = 0.85 and Φ = 1.0 at 1260°C were MgO and Fe2O3, respectively. Therefore, the predicted eutectic materials of the combustion ash were changed appropriately in comparison with those for the atmospheric oxidization ash because of the fusion and disappearance of some metal oxide components during combustion.
Woody biomass fuel demand for domestic power and heat production has been 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 and stand dead, leading to small drying cost. However, clinker formed by ash or char melting during gasification could decrease in operating time, leading to a worsening of profitability. In this study, the fusion characteristics of Erianthus ash and char were investigated. XRF analysis showed that the main components of Erianthus ash were Si, K, Ca, P, and S. In the XRD pattern, the crystal structures of SiO2 and KHSiO2 were observed. Higher SiO2 peak was observed in air atmosphere than in N2. Through the melting experiment at 1250°C, Erianthus ash melted and had a different crystal structure of SiO2, decreasing the amount of K in molten ash.
To estimate reactivity such as char yield and ash melting for softwood pellets during gasification CHP process, Japanese cedar and German spruce pellets were employed to thermogravimetry, proximate analysis and chemical composition analysis. Then we found that Japanese cedar showed higher fixed carbon content and mass yield from proximate analysis and thermogravimetry, suggesting that higher char yield during gasification. That was supported from the higher cellulose and lignin content of Japanese cedar. Furthermore, Japanese cedar contained a large amount of alkali metals and silica contents, suggesting that the molten alkali metal easily forms larger clinker at lower temperature with involving the surrounding char.
Woody biomasses are converted into combustible gases by pyrolysis. In this study, gasification of woody biomass was conducted under various gas atmosphere at 900°C with/without iron ore. As the result, gas compositions were not affected addition of iron ore except for amount of CO2 generation. On the other hand, it was revealed that iron ore reduces char and tar amount. In case of gasification using CO2, CO2 converted into CO and amount of CO2 of outlet was smaller than one of inlet. The result is important for realizing “Negative Emission”. Finally, lower heat value of recovered component from biomass, it was achieved over 90% with including reduction energy of iron ore.
Peach pruning is a regional woody biomass resource that could be used for gasification. Some previous studies showed that CO2/O2 gasification rate increases with increasing O2 in gasifying agent and reaction temperature. In this study, the effect of O2 concentration and reaction temperature on CO2/O2 gasification rate and kinetic parameters of peach pruning were clarified, as well as comparison with those for timber waste. The results showed that peach pruning char was gasified with larger rate constant, kp, and smaller structure parameter, Ψ, than for timber waste char. On the other hands, with increasing O2 in the gasifying agent, kp decreased during CO2/O2 gasification, while Ψ and reaction rate, dX/dt, increased.
For supercritical water gasification of biomass, it is said that biomass components such as cellulose is first dissolved into hot compressed water, and then decomposition reaction including hydrolysis and gasification takes place. If it is the case, particle size should not affect the gasification characteristics because no solid particle should be remaining in the supercritical water reactor. However, this hypothesis has not been systematically investigated. In this study, biomass of the same kind but with different particle diameter was gasified in supercritical water, and surprisingly, effect of particle size was observed.
Tar is a complex mixture of condensable organic compounds. Tar adheres to the inner surface of equipment and apparatus, and it is difficult to remove easily, causing problems when it is fed into equipment. Therefore, it is necessary to decompose and remove tar.
Conventionally, many studies have been made on tar reduction in a gasification furnace. However, no research has been conducted on tar removal at a later part. Therefore, I investigate by analyzing the tar component after gasification, and consider about an efficient tar component treatment method. In this report, quantitative analysis of tar components was difficult. So, we introduced the concept of standardized area value.
Biomass gasification technology has developed aggressively as an alternative to oil since the 1970s. The problem to be solved is the reduction of tar in the product gas from biomass gasification. During biomass gasification, tar will undergo the process of generation, decomposition and reformation. By summarizing the reaction equations in previous literature, decomposition reactions of biomass and agglomeration reactions are selected. Through the analysis of simulation, changes of the molar concentration of each substance in the reactor can be known.
Utirization of SI-ICE is suitable for small-scale power generation systems with bio-syngas. Since exhaust gas is one of the important parameter of SI-ICE, emission performance was evaluated. Bio-syngas mainly contains CO, H2 and CH4 as a flamable gases and N2, CO2 as inert ones. Cralifying the effects of CO2, SI-ICE was operated in a partial load with CO2 additional bio-syngas and elementary reaction analyses was carried out using CHEMKIN pro. As a result, the CO emitted on SI-ICE is influenced by high temperature range reactions and as increasing EAR causes low CO contents of fuel, it results in deacrese of CO emission. It was revealed that CO2 addtion has a potential to restrain increasing of CO emission because it deacreases lower heating value of fuel.
Two type biomass, Rubber tree pellet and Eucalyptus wood chip were gasified 185h and 150h, respectively, with a CaO tar reformer to produce F-T synthesis gas. About 590 Nm3 and 345 Nm3 synthesis gases were produced, respectively with H2/CO ratio about 2.
An efficient woody biomass degradation method for the production of vanillin and vanillic acid with copper oxide-peroxide under alkali condition by microwave heating was developed in our previous study.1) Herein, the thermal distribution in this reaction system was analyzed to clarify the heating behavior of microwave heating. The permittivity and loss factors of reaction mixture (2M sodium hydroxide (NaOH) solution, woody powders, and copper oxide powder), NaOH solution, copper oxide powder were measured, respectively. The thermal distribution was simulated by a designed model based on the permittivity values. The simulation results revealed that microwave frequency affects the vanillin and vanillic acid production yield. The microwave frequency dependence on reaction yields was confirmed by wood degradation experiments.
Microwave heating enables rapid heating of biomass. We have previously reported that cellulose and rice straw can be rapidly pyrolyzed by using a semiconductor microwave oscillator and a cylindrical cavity resonator. On the other hand,the progress in carbonization of the biomass cause plasma and decreases the heating efficiency by the microwave electric field. Therefore, we newly applied conductive heating by microwave magnetic field for heating carbonized biomass with suppression of plasma formation. Furthermore, we found that the larger Q value of the cavity resonator is effective to improve the heating rate and the maximum temperature during pyrolysis of the biomass.
Lignocellulosic nanofibers from prehydrolyzed soda pulp with trace amount of phenolic chemicals were prepared and characterized for high functionality of cellulose and lignin. Our results suggest that the thermal degradation temperature of ligno-CNF containing phenolized lignin was increased due to the coverage of cellulose nanofiber with lignin.
In this study, different types of food wastes (udon, konjac, fish, chicken, apple, radish, cabbage and rice) obtained from Aomori Prefecture were used as the gasification feedstocks to investigate the potential feasibility for fuel gas production. The steam gasification of food wastes was conducted at a gasification temperature of 700°C with a water injection rate of 0.10 g/min. The experimental results indicated that high reaction temperature and high water flow rate were both beneficial to the fuel gas yield, and it was found that the vegetables and fruit had high reactivities with high hydrogen yields during the gasification processes. Meanwhile, for the gasification of wasted meat, the amount of liquid products was larger than that of gaseous products.
For utilization of biomass-derived polyols, such as glycerol, erythritol, and xylose, as raw material for alternative petroleum resources, removal of OH groups in polyols is indispensable. Hydrodeoxygenation reaction (HDO) is generally applied to remove OH groups in polyols, in which the catalyst with high activity at low temperature and high selectivity is required. In this study, we prepared carbon supported Cu catalyst (Cu/C) with high metal loading (67 wt%) and small Cu particle size (14.7 nm) by using an ion-exchange resin as a raw material of carbon support and carried out HDO of erythritol over the Cu/C prepared. The Cu/C catalyst showed high activity and selectivity in HDO of erythritol to C4 diols possessing vicinal OH groups, which could be because that vicinal OH groups were adsorbed on Cu surface and HDO reaction proceeded at the other OH groups.
Biomass has been explored as an effective alternative fossil fuel resource. Therefore, catalytic cracking behavior of cellulose in hydrocarbon solvent was investigated by using a cellulose which is main component of biomass.
The results indicated that residue generation was suppressed because decarboxylation of cellulose was promoted and dehydration was suppressed in catalytic cracking in hydrocarbon solvent. In addition, cellulose degradation products such as furfural and levulinic acid hydrogenated to tetrahydrofurfuryl alcohol and ɤ-valerolactone which are precursor of hydrocarbon, and hydrocarbon derived from cellulose produced.
In this study, Japanese cedar was delignified using 20wt% different fatty acid sodium salt dissolved in glycerol at 250°C for 1h. The fatty acid sodium salt dissolved in glycerol simulated by-product of biodiesel production. In case of 4‒18 carbon chain length of fatty acid sodium salt, lignin content in Japanese cedar was decreased to about 10wt% from initial 36wt%. However, sodium salt whose length is under 3 carbon chain were less effective for delignification.Enzymatic saccharification of delignified Japanese cedar was conducted at 45°C. Behavior of enzymatic saccharification of Japanese cedar treated with sodium octanate, sodium myristrate, and sodium oleate were different, in spite of lignin content of substrates were same around 8wt%. It suggested that effect of residual sodium salt in deliginified Japanese cedar on saccharification was performed. As the result, it was found that enzymatic saccharification was promoted or impeded by type of sodium salt and their residual quantities.
In this study, as a part of the study of SiCl4 production from rice husk char, the volatilization behavior of Si from rice husk char by the chlorination method were first examined with a gas flow-type fixed-bed quartz reactor. Next, changes in Cl content and pore properties with chlorination temperature were investigated. In addition, the basic Hg2+ removal performance of the residue obtained after chlorination was evaluated. The volatilization of Si in the char during chlorination started at 300°C, and volatilization rate reached 80% at 1000°C, 10min. It was also found that most of the Cl taken into the chlorination residue is the H2O-insoluble form. The specific surface area of the chlorination residue tended to increase with increasing of chlorination temperature. The Hg adsorption capacity of the chlorinated residue obtained by holding at 1000°C for 10min was 620mg/g, which indicated that the chlorinated residue could be a relatively high-performance mercury scavenger.
Palm kernel shell (PKS) can be converted into a high calorific liquid fuel by solvolysis. In the previous study, we observed that the solvolysis of PKS proceeded rapidly even without pulverization pretreatment. In this study, therefore, we investigated the reaction mechanism in the solvolysis of unpulverized PKS (particle size 1-2 cm). Lignin and hemicellulose were dissolved rapidly in the initial reaction, while cellulose was relatively stable. During the initial reaction, the PKS feedstock was subdivided to fine particles (< 45 μm), and the surface area of solid residue increased. From these results, we concluded that the solvolysis of unpulverized PKS proceeded rapidly because the large feedstocks can be converted to fine particles naturally in the reactor during the initial reaction.
The steam pretreatment conditions that have been successfully used to enhance the durability of wood derived pellets are typically less severe than those used to enhance the enzymatic hydrolysis of woody substrates. In the work reported here steam pretreated softwoods were used to make pellets and their robustness and ease of enzymatic hydrolysis were assessed. Although pre-steaming enhanced the durability of pellets it decreased the ease of enzymatic hydrolysis when compared to non-pelletised pretreated softwoods. However, subsequent mechanical disintegration of the pellets resulted in comparable hydrolysis yields. Transmission Electron Microscopy (TEM) observations suggested that steaming resulted in lignin redistribution, consequently enhancing pellet durability. However, as pelletisation had not changed the lignin distribution within the cell wall subsequent, mild, mechanical disintegration resulted in a softwood substrate that could be as readily hydrolyzed as the non-pelletised feedstock. The addition of lignosulfonates prior to pelletisation substantially enhanced pellet durability with concomitant beneficial effects on subsequent cellulose hydrolysis, likely due to the lignosulfonate acting as a surfactant and decreasing the unproductive binding of enzymes to the lignin.