In order to supply the syngas (CO + H2) to the liquid fuel synthesis reaction in the biomass-to-liquid (BTL) system, woody biomass gasification was carried out using a mixture of CO2 and O2 as a main gasifying agent. Gasification of biomass using a CO2/O2 mixture (79/21(v/v)) exhibited a maximum value of the conversion to gas (88 C-mol%), compared to those (78 C-mol%, 80 C-mol%) using pure CO2 and air, respectively The effects of [H2O]/[C] ratio and O2 content on the gasification behavior with CO2/O2 were investigated. The H2/CO ratio in the product gas increased from 0.3 to 1.0 due to the promotion of water-gas shift reaction when the [H2O]/[C] ratio was increased in the range of 0 - 5. The conversions to gas and tar increased from 88 to 94 C-mol% and from 0.1 to 0.6 C-mol%, respectively; on the other hand, conversion to char decreased from 8.7 to 0.7 C-mol%. The CO2 and H2 contents increased from 53 to approximately 58 mol% and from 11 to 19 mol%, respectively; however, the CO content decreased from 32.3 to 18.1 mol%. The conversion to gas increased with the O2 content (0 - 50 vol%) in the gasifying agent, while the conversions to tar and char decreased from 0.8 to 0.0 C-mol% and from 16 to 4.1 C-mol%, respectively. The CO and H2 contents increased from 36 to 42 mol% and from 9.5 to 20 mol%, respectively, while the CO2 content decreased from 49 to 32 mol%. In all the cases, H2S and COS were detected in the product gas. The conversions to gas on a sulfur basis were approximately 60 S-mol% at all [H2O]/[C] ratios. However, with an increase in the [H2O]/[C] ratio, the conversion to H2S increased from 38 to 46 S-mol%, while that to COS decreased from 25 to 16 S-mol%; this was attributed to the occurrence of the following reaction: COS + H2O → H2S + CO2. With an increase in the O2 content, the conversion to H2S increased from 38 to 44 S-mol%, while that to COS decreased from 25 to 18 S-mol%. The addition of O2 to the gasification with CO2 promoted the gasification of tar and char to produce H2S than COS regardless of the oxidation atmosphere. From the results obtained, the BTL process including the woody biomass gasification with a CO2/O2 mixture, dry gas cleaning, water-gas shift reaction, removal of CO2 and liquid fuel synthesis reaction was proposed.
The economic impacts, CO2 emission, and change in industrial structures using rice husk power plant in Japan were investigated using input-output table of Japan. The direct and second economic impacts by investment to the rice husk power plant sector were 1.5 times higher than that to the power sector. The flow of money shifted to the agriculture, forestry and fisheries sector during introduction rice husk power plant. Increasing rate of using rice husk power plant induce the high-value added and the low CO2 emission society with a very little change in industrial structure.
Wood biomass supply was estimated using spatial distribution of managed forest areas and timber and chip industries with a road network system. The estimation was based on the town level in the Aomori, Iwate and Akita prefectures. Wood biomass from timber and woodchip remains is commonly used in Japan for bio-fuel purpose, while that from remains of silvicultural activity such as harvesting and thinning is not often used due to high logging cost. We primarily specified the area and distance of harvesting and transportation to collect wood biomass. The area was set at 500m from roads, and the transportation distances were 25km, 50km, 75km, and 100km from the starting point, which was city hall. The wood biomass supply was then calculated based upon management activities and tree species. Our results indicate that the wood biomass was more likely to be collected from chip industries in the Iwate and Aomori prefectures and from plywood industries in the Akita prefecture. High potential of wood biomass supply was found in Sannohe, Nanbu, Ichinohe, Kunohe, Kamikoani, and Kitaakita towns at 50km of transportation distance. Conflict for collecting wood biomass was also revealed among Sannohe, Nanbu, Ichinohe, and Kunohe towns.
For the propulsion of the biomass utilization business, there is already the system examining analysis of the economy and environmental load from quantity of local biomass. The purpose of this study was to build a system to advise users how to carry out biomass business better. We analyzed advanced examples to get the ideas that was useful to improve the business, and classified them in terms of problems for the businesses. We arranged the solution for these problems as an idea for business success. Furthermore, we showed these ideas as advice to the business based on economical analysis. Using the developed system, suggestion can be obtained to improve management of utilization of biomass. Thus, this system enables easy development of the successful biomass utilization business by providing proper suggestions.
In-situ catalytic partial oxidation of volatiles derived from rapid pyrolysis of Japanese cedar sawdust was studied with a two stage fixed bed reactor (TS-FBR) with the primary purpose to find a reactor configuration that enables to convert tarry components into non-condensable fuel gas efficiently. The TS-FBR consisted of two sections; the upstream one for the rapid pyrolysis of the sawdust to generate nascent volatiles and the downstream one for the In-situ reforming of the volatiles. A platinum or rhodium supported alumina foam was used as the catalyst and placed at the downstream section. It was found that the selectivity of oxygen consumption to tar conversion was greatly influenced by the catalyst location. A simultaneous contact of the volatiles with the catalyst surface and mixing of the volatiles and oxygen within the foam enabled to get a better conversion of tar as well as a selectivity of synthesis gas. It was found that more than 70 % of hydrogen and 64 % of carbon in the feedstock could be converted into hydrogen and carbon monoxide, respectively, at an optimized condition of T = 800 °C, oxygen/carbon molar ratio = 0.25, and contact time = 100 ms.
Hemp has been recently rediscovered as a novel resource crop in various regions of Japan. In this study, hemp pellets were manufactured from a raw material that was derived by removing the fiber from hemp stem. The manufactured hemp pellets, intended to be used as fuel, were measured for size, bulk density, fineness, moisture content, ash content, heating value, and presence of toxic substance. We also conducted tests by continuously feeding the pellets to a stove and a grill. The hemp pellets fulfilled the standard quality criteria and were considered to be of practical use.
We performed a serious demonstration test on woody biomass gasification and power generation system with a tar-free gas refinement process using oxygen. Our gas refinement process is composed of main two components, a gas reformer and a dust capture filter. In the gas reformer raising gas temperature over 1100 °C with the partial oxidization, most tar is decomposed but some soot is generated. First, we investigated gas reforming performance, changing the operating temperature and residence time As a result, the tar amount in the produced gas decreases on the higher operating temperature, longer residence time. In addition, the tar as carbon percentage in the reformed gas decreases obviously. Second, we investigated the lowest possible operating temperature of the dust filter, in order to cost saving and decrease tar amount in gas. As the result, it is possible to operate on 270 °C with no sticking. But it is difficult to capture the tar in the reformed gas.
In order to estimate the potential of ethanol production from the macro green algae, we collected 10 species of macro green algae in Thailand, Vietnam and Japan, classified into 3 families; and determined the neutral monosaccharides compositions. The contents of neutral monosaccharides differed in the same family, however those compositions were almost same. Cheatomorpha aereas collected in Vietnam was the most glucose-rich sample of these samples, about 300 mg of glucose per gram of organic matter. The experiments of enzymatic saccharification and the ethanol fermentation were carried out by using Ulva spp. collected in Japan. The glucose yield was about 95% by using Acremonium cellulase after the pretreatment of autoclave (120°.C, 20min.). The efficiency of ethanol fermentation by using S. cerevisiae IR-2 after the enzymatic saccharification was about 90%. Over 4 % (w/v) of NaCl concentration inhibited the ethanol fermentation, while the effect of NaCl concentration for the saccharification was small.
For the synthesis of bio-dimethyl ether (DME) from woody biomass via gasification, we have developed and promoted the biomass-to-liquid (BTL) process. This process consisted of oxygen-enrichment gasification of woody biomass by a bench-scale fixed-bed gasifier, wet gas cleaning, gas compression, desulfurization, removal of CO2, DME synthesis reaction by a fixed-bed reactor. The composition obtained at gasification step was as follows: 25.6 vol% of H2, 31.2 vol% of CO, 2.7 vol% of CH4, 0.4 vol% of CO2, 40.1 vol% of N2, <5 ppb of H2S, and <5 ppb of COS. In the DME synthesis step, DME was synthesized via methanol synthesis and following dehydration reaction in a fixed-bed reactor using the Cu-Zn catalyst for methanol synthesis and γ-Al2O3 catalyst for dehydration. It was found that the Cu-Zn and γ-Al2O3 catalysts exhibited higher activity when used as mixed powder form than used as separated pellet form. DME concentration 5.2 vol% in the product gas was obtained under the following conditions: 0.98 MPa, 230 °C, W/F=37.9 cat.-kg h/m3. It was possible to recover the almost all DME in the gas phase by using the activated carbon trap with dry ice. Finally, we succeeded in the continuous synthesis of DME over 200 h and recovery of approximately 120 g of liquefied bio-DME.
Much attention has been paid to fuel ethanol recently, but the use of food resources for fuel ethanol is problematic and the use of non-food resources is anticipated. We are developing ethanol production technology from lignocellulosic biomass subject to milling pretreatment and enzymatic hydrolysis, and also developed new yeast strains which can ferment xylose into ethanol efficiently. We estimated ethanol production potential from oil palm empty fruit bunches (EFB) in Indonesia, Malaysia, and Thailand with our experimental data. Even estimation based on moderate resource availability and without xylose utilization showed 1-2 % of gasoline consumption can be substituted by ethanol produced from EFB in Indonesia and Malaysia. If xylose can be also used as a substrate for ethanol fermentation, its contribution to production increase was significant. The use of other wastes generated in oil palm industry can increase ethanol production furthermore. The ethanol production potential from wasted oil palm trunk in Malaysia is comparable to that from EFB by our estimation which also based on the experimental data. Palm-oil-producing Southeast Asian countries have large ethanol production potential without utilizing food resources.