Raw material of biodiesel is becoming increasingly diverse in order to ensure quantitative. Especially microalgae is expected that produce much oils and fats per unit area more than several tens times compared to the ground plants. Therefore it is necessary to develop the technology of direct production of liquid fuel from microalgae. This paper described the feasibility of the direct production of liquid fuel from rice bran powder substituted for microalgae by using super-heated methanol vapor method. From the experimental result it was shown that FAME peaks were identified in the extracted liquid by gas chromatography. This suggests that it is possible to reduce the energy consumed in production of biodiesel fuel and to utilize the unused biomass by present process.
Nine types of metal including bonderized iron, iron, black scale, mild steel, copper, brass, aluminum, SUS 304 and SUS 316 were immersed in rubber seed oil (RSO) at 303, 318 and 328 K to investigate the corrosion behavior of the metals in this oil. Cooking palm oil (CPO) was used as a reference, which contains a lower concentration of free fatty acids (FFA) than RSO. The acid values (AV) of the RSO and CPO were 91.4 and 0.23 mg-KOH/g, respectively. The metals used in this study showed constant corrosion rates in RSO throughout the time period of the corrosion test (28 d). The following order for the corrosion rate was observed: mild steel > iron=bonderized iron = black scale > brass = copper > SUS304 = SUS316 = aluminum. SUS304, SUS316 and aluminum exhibited no substantial corrosion in RSO. The activation energy for the corrosion rate was calculated for iron, mild steel, copper and brass to be 61.4, 46.9, 29.0 and 23.2 kJ/mol, respectively. The corrosion rate of all the metals in CPO was substantially zero at 318 and 328 K.
Enzymatic saccharification of cellulosic biomass is an essential technology for the production of bioethanol and other industrial chemicals. The development of an immobilized cellulase enables to save the cost of cellulase by reuse. Furthermore, it would be ideal if the enzyme support could be recycled after the deactivation. A functional lignin-based material, lignocresol was synthesized from hinoki wood meal by the phase separation treatment with p-cresol and 72% sulfuric acid. Lignocresol physically adsorbs Trichoderma reesei cellulase and functions as an immobilized cellulase. The changes of pH and salt concentration hardly detached the cellulase from lignocresol-immobilized cellulase. Treating with acetone or ethanol was effective. Most of lignocresol was dissolved in organic solvents and then regenerated in diethyl ether. The recovery yields of the lignocresols were 90% by acetone and 72% by ethanol with very tiny or nearly zero residual cellulase. Lignocresol derived from softwood like hinoki has a larger protein adsorption capacity than that from hardwood, and can be easily separated only with organic solvents. Hinoki lignocresol is a new type of recyclable enzyme support.
High temperature air gasification of sludge was carried out in the entrained down flow gasifier. Sludge gasification performance, such as carbon conversion, gasification rate and cold gas efficiency, was evaluated compared with the performance of the woody biomass gasification. Dried sludge, sieved 60 mesh, was injected from the top of the gasifier with air, and the gasification experiment was conducted over 1300 K. Feeding rate of the sludge was controlled around 25 kg/h during the experiment, but the air ratio was changed as an operation parameter. Temperature profile in the gasifier was significantly different between the sludge and the wood. While the temperature at the bottom section of the gasifier was stable in the sludge gasification, the temperature gradually decreased at the bottom section in the woody biomass gasification due to the endothermic CO2 gasification reaction. Since the gasification rate of the sludge was slower than that of the woody biomass, the carbon conversion of the sludge was less than that of the wood, which was around 70 %, while 100 % of the carbon conversion was achieved in the woody biomass gasification. Tar components produced from the sludge were not able to decompose completely even in the high temperature gasification operation due to the slow sludge decomposition. Significant difference was also found in the collected ash and the high ash content sludge built huge slags on the gasifier wall during the high temperature gasification.
High-pressure superheated steam oxidation, which uses hot and high-pressure steam above the critical temperature (374°C) and below the critical pressure (22.1 MPa) of water, is an environmentally friendly treatment of waste biomass. This technique was applied to the treatment of sewage sludge and the recovery of the thermal energy from it. Sewage sludge has high moisture content of around 75 wt% and relatively large nitrogen content of about 7 wt%. It is one of refractory waste biomass. In this study, sewage sludge was decomposed by a flow-type two-stage high-pressure superheated steam oxidation bench plant, in which the first reaction was high-pressure superheated steam oxidation without catalyst and the second was that with solid catalyst. This method was proposed to decrease the reaction temperature and pressure of conventional supercritical water oxidation process largely, keeping high decomposition efficiency. The optimal condition of the first reactor was 400 °C, 8-10 MPa, 15-20 min of reaction time, 1.2 of oxygen supply ratio and that of the second reactor was 385 °C, 8-10 MPa and 0.5-1.0 min of space time. The sewage sludge was mainly decomposed to safe CO2, water and nitrogen. The product yields of TOC, solid carbon, toxic ammonia and nitrogen oxides were negligible. The discharged water from the second rector was clean and satisfied the emission standard established by environment agency in Japan. The thermal energy of the effluent from the second reactor was recovered by a double-piped high pressure heat exchanger. The recovery ratio was 86 % on average. The energy profit ratio of the proposed process as energy production from the sewage sludge was 1.47.
The composition of the biomass producer gas varies for the resource of biomass and the gasification method. In order to establish the operation guideline for dual fuel engines with a traditional injection system to use such gas fuels, the effects of the gas composition, pilot injection quantity and EGR on engine performance and emissions were investigated in experiments. The various mock biomass producer gases consisting of H2, CH4, CO, N2 and CO2 were supplied by mass flow controllers to a direct-injection diesel engine with a jerk type fuel injection pump. JIS 2 type diesel was also used for pilot fuel. It is clarified that the laminar burning velocity is useful index to estimate the operating range regardless of the gas composition, although the suitable equivalence ratio to ensure the stable operation varies according to the gas composition. The laminar burning velocity of over 40 cm/s at the TDC condition is a qualification to keep stable engine operation. At lower loads, EGR improves combustion and leads to the higher thermal efficiency, although it decreases the thermal efficiency because of its lower degree of constant volume at medium loads. In addition, the effect of EGR is small for the fuel with lower hydrogen content.
Plant growth is significantly affected by environmental parameters, such as light, water, atmospheric composition and pressure, temperature, humidity and nutrients. High growth rate of plants should be attained by means of modulating such environmental parameters. These parameters also affect plant physiological responses and quality and quantity of metabolites. In this study, an environment-controlled chamber (Plant Growing Chamber; PGC) was designed and fabricated to offer a variety of growth conditions to plants. The newly developed PGC enabled to modulate temperature, humidity, light intensity, light wavelength, air pressure, etc. Using the PGC, we focused on pressure to examine its effects on plant growth. An aquatic plant, Spirodela polyrrhiza, was used as a test plant to evaluate its growth rate under the elevated pressure varying from 0.1 to 0.4 MPa. Effects of the elevated pressure on the growth rate were analyzed by an imaging processor. The results showed that the growth rate increased up to 1.3 times under 0.2 MPa. These results open possibility that photosynthesis could be improved under the conditions of elevated pressure.
Bamboo is an attractive biomass resource which grows rapidly, reaching their maximum size within a few months. Bamboo pulp, prepared by soda-anthraquinone cooking, was fermented to ethanol with a cocktail enzyme of Aspergillus tubingensis KRCF700-33Y and Trichoderma reesei ATCC66587, and thermotolerant yeast (Saccharomyces cerevisiae BA-11) under simultaneous saccharification and fermentation (SSF) at 40°C. The strain A. tubingensis KRCF700-33Y, having sporeless, high β-glucosidase productive capacity was generated by UV irradiation. The highest activity of 5 FPU/ml was obtained with a cocktail enzyme having a 10% content of A. tubingensis, and the cocktail effect was also shown under the SSF process. An ethanol concentration of 47.1 g/L was achieved using a cocktail enzyme (15% content of A. tubingensis) with a substrate loading level of 15% under small scale SSF, which resulted in an ethanol yield of 76.8% after 96 h. An ethanol concentration of bamboo pulp reached 44.0 g/L under SSF process using a reactor (1-L kneader) with a cocktail enzyme (10% content of A. tubingensis, 4 FPU/g-DM), which resulted in an ethanol yield of 71.8% after 144 h. The results indicated the feasibility of bioethanol production from bamboo pulp under SSF using on-site produced enzyme by solid-state fermentation.
Dimethyl ether (DME) is a clean and economical alternative fuel which can be produced from various resources such as natural gas, coal, biomass through synthesis gas. Storage and transportation of DME is easy because DME has similar properties with liquefied petroleum gas (LPG). DME is already produced and utilized as LPG alternate for domestic and industrial use in China. In this study, to operate a micro gas engine by supplying a mixture fuel of butane and DME, fuel consumption and exhaust gases (NO, CO) were measured. From the experimental results, with an increase in the mixing ratio of DME, the percentage of CO was reduced, but the percentage of NO increased. Particulate matter (PM) generation was not observed either.
Rice wastes i.e. rice straw and hull increase as more rice is produced to feed the increasing population. This study was conducted in Pangasinan, the Philippines’ third largest rice producing province. Three agricultural systems were looked into: Organic Agriculture (OA), Low External Input Sustainable Agriculture (LEISA), and Conventional Agriculture (CA). Purposive sampling was done in selecting the farms, and systematic sampling in identifying the farmer respondents. Secondary data were gathered from various documents while primary data were taken with the use of questionnaire. Rice wastes generated during the first cropping season were weighed from dumping and milling areas. The equivalent carbon dioxide emitted due to burning or composting rice straw was computed using basic assumptions and formula. It was found out that OA produced the highest amount of rice straw, followed by LEISA. Farmers practicing OA or LEISA fully utilized rice wastes. Organic Agriculture farmers who practiced rice straw composting significantly helped reduce carbon dioxide emission by 54 %. The carbon dioxide emitted from carbonized rice hull was also computed. It is recommended that farmers should be given training on various ways of utilizing rice wastes. Calculations on carbon dioxide emission from burning of rice wastes should also be validated.
Coal is very important resource for producing high quality metallurgical coke. In Japan, improvement of coke quality is strongly demanded to operate large inner volume blast furnaces smoothly. So, effective coal utilization technologies involving new cokemaking process were developed for a long period. Research themes are mainly focused on the expansion of coal resources useable for cokemaking, improving coke productivity and reducing energy consumption. Especially improvement of coke quality is very important, because it generally leads to increase the blending ratio of low grade coals in coal charge without deteriorating coke strength. In this paper, new cokemaking technologies such as DAPS process and SCOPE21 process are introduced. Understanding of these processes is expected to contribute to further innovative development of new cokemaking process.
Efforts to make effective use of biomass resources on a regional basis have been promoted in Japan. Although it is expected that these efforts have positive influences on environment and socio-economic aspects, the sound methodologies to evaluate the impacts in objective manners are yet to be proposed. In addition, in terms of the projects utilizing waste biomass, which is general case in Japan, the characteristics of waste biomass should be taken into consideration of the evaluation methodology. This study aims at providing methodology to evaluate environmental impacts suitable for waste biomass projects. Fossil fuel consumption, GHG emissions and final waste volume are chosen as environmental indices and their estimation methodologies are proposed based on input-output tables. The methodology proposed is applied to the waste biomass project at Miura Prefecture as a case study. The results reveal that the project has positive effects on all the indices. In addition, a scenario analysis is carried out to evaluate GHG emissions associated with the waste treatment of unused amount of fertilizer that is produced from the target project, whose result indicates that emissions by incineration of surplus fertilizer does not affect to the total GHG reduction of the project.
Solar cells are getting familiar to science teachers as teaching materials in a new course of study which started in 2011. Among many types of solar cells, researchers are paying attention to the dye-sensitized solar cells experiment because students can produce by themselves. After the Great East Japan Earthquake, we cannot teach the experiment classes to produce the dye-sensitized solar cells because we cannot obtain the electrically conductive glasses. Therefore, we developed a production method of the electrically conductive glasses which high school students can perform, and practiced the dye-sensitized solar cells experiment with them. We report on the results.
The effects of biomass type, size, and pyrolysis temperature on pyrolytic products distribution have been investigated. Hence, reaction temperatures (400, 450, 500, and 550 °C) and biomass feedstock sizes (0.15-0.5, 0.5-1.0, and 1.0-2.0 mm) were applied. Decomposition of palm kernel shell and mesocarp fiber was performed in a fluidized bed pyrolyzer with nitrogen gas flow rate of 25 L(NTP)/min. The maximum bio-oil yield (39.6 %) was gained from PKS of 0.15-0.5 mm at 500 °C. Many evidence showed that small particle size produced the most noticeable amount of bio-oil production. The fluidized bed pyrolysis reactor used possesses six successive condensers operated at three temperatures. Thus, six fractions of bio-oil samples were obtained from these six condensers. The properties of each bio-oil sample were determined including calorific value, elements, water and ash contents, and major compounds in the bio-oils. The compositions of water and major compounds in the fractional liquids of these six successive condensers were also reported.