環境資源工学
Online ISSN : 1349-9262
Print ISSN : 1348-6012
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56 巻 , 1 号
選択された号の論文の6件中1~6を表示しています
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論説報文
  • 芝田 隼次, 村山 憲弘, 立山 正人, 中澤 孝一
    56 巻 (2009) 1 号 p. 3-7
    公開日: 2009/04/24
    ジャーナル フリー
    It is important to decide the height of interface between aqueous and organic phases in a settler and to measure the mass of objects in a closed vessel in order to operate a mixer-settler extractor and a liquid mixing reactor. In this study, we measured the height of interface between aqueous and organic phases and the mass of objects in a closed vessel such as a liquid mixing reactor and a storage tank by using the compact pressure sensor. The position of objects in a closed vessel and the installation position of the compact pressure sensor affect the pressure measurement. It is possible to measure the mass of objects such as stones and sand in the bottom of a closed vessel by using the compact pressure sensor. In the same way, the compact pressure sensor enables the measurement of the height of interface between aqueous and organic phases.
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  • W. WINKLER, P. NEHTER, M. C. WILLIAMS
    56 巻 (2009) 1 号 p. 8-12
    公開日: 2009/04/24
    ジャーナル フリー
    One of the great opportunities for waste utilization and reduction of global warming (carbon footprint) is the utilization of the methane in the gas to produce electric power with a fuel cell. These waste gases are primarily methane which must be reformed to hydrogen before use in a fuel cell. There are three basic types of methane reforming–steam, autothermal and partial oxidation. Temperature, pressure, and steam-to-carbon ratio play an important role in the performance of steam reforming. These variables also influence the reversible work and reaction enthalpy of the reforming products. A fuel cell stack or cell integrated steam reformer allows a recirculation of reversible heat as long as the operational temperature of the fuel cell is appropriate to the temperature of the reformer. The maximum total reversible work (highest exergetic efficiency) of the hydrogen and the carbon monoxide Wrev,H2,CO,ox is achieved at 762kJ per 1 mol methane which is converted in the fuel processor. This corresponds to a maximum intrinsic thermal efficiency ηTh,Max, of 95% at an optimum temperature of 1023K. This optimum temperature is in the operating temperature range of the high-temperature fuel cells like the molten carbonate and solid oxide fuel cells. Higher efficiencies can be expected with these fuel cells with steam reforming when utilizing natural gas, anaerobic digestor gas, or landfill gas.
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  • 中村 貴司, 大川 浩一, 川村 洋平, 高畑 重幸, 中 秀男, 菅原 勝康
    56 巻 (2009) 1 号 p. 13-20
    公開日: 2009/04/24
    ジャーナル フリー
    Hinai green tuff is quarried in Odate-shi, Akita prefecture in Japan and used for architectural materials. Hinai green tuff suspension is generated from the cutting and the grinding process and it is necessary to treat the solution with precipitants. A chemical flocculant has been used as a precipitation agent for fine particles in the suspension. However, using a chemical flocculant agent produces a wasteful mixture of particles and flocculants, which are impossible to be used as a resource. Therefore, it is necessary to develop a new precipitation method without using precipitants for green tuff particles. In this study, the zeta potential of Hinai green tuff particles in suspension was measured to gain the basic electrochemical properties of the colloidal suspension. We then developed a new precipitation method using sonochemical reaction at 200 kHz, 200 W. From results of the zeta potential measurement using an electrophoresis method, the particles exhibited −50 mV at pH 7.0 and 0 mV at below pH 4.0. Sonochemical reaction was applied to control the pH of the suspension to precipitate the Hinai green tuff particulate. When ultrasonic irradiation was applied to the Hinai green tuff suspension, the pH decreased to 4.0 in 80 min and finally reached 3.3 in 180 min. We successfully extracted pure Hinai green tuff particles as precipitates from the suspension using ultrasonic irradiation.
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  • Takashi FURUYAMA, Hitoshi OHYA, Gjergj DODBIBA
    56 巻 (2009) 1 号 p. 21-25
    公開日: 2009/04/24
    ジャーナル フリー
    A new manufacturing process of biomass solid fuel derived from wasted coffee beans and wasted plastics was proposed in this study. A biomass sample and wasted plastics were used discharged from the certain coffee beans processing factory. At the biomass proportion of 60wt% the calorific value was 29,750 kJ/kg and corresponded to sub bituminous coal. The contents of water, ash and chlorine were 5.08wt%, 4.00wt% and 0.14wt%, respectively and these values satisfied the acceptable standard of RPF in a papermaking company. In the CO2 assessment, the amount of discharged CO2 of biomass solid fuel was calculated by fixing the functional unit and the calculated data were compared with the amount of discharged CO2 of coal for fuel. When biomass and wasted plastics are mixed at the mixture ratio of 60 to 40 and is manufactured by 1 ton/hour, CO2 is generated at the amount of 0.108 tons/hour. Concerning transportation, the distance between the place where wastes are generated and the manufacturing place of biomass solid fuel was fixed to be 200 km. Consequently CO2 of 0.0523 tons is generated in the raw material transportation. The combustion of this material must emit CO2 of 0.412 tons. As the final results, it was found that CO2 of about 0.999 tons can be reduced comparing combustion of coal for power generation when 1 ton of biomass solid fuel is manufactured and combusted.
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  • 王 立邦, 佐藤 大輔, DODBIBA Gjergj, 岡屋 克則, 定木 淳, 藤田 豊久, 柴山 敦, 菱田 元
    56 巻 (2009) 1 号 p. 26-32
    公開日: 2009/04/24
    ジャーナル フリー
    In order to recover trace of platinum (Pt) from Cobalt-Rich-Crust (CRC), electrical disintegration was carried out to liberate the CRC. Electrical disintegration was performed by introducing high voltage impulse to the CRC, which broke down the CRC along the grain boundaries of minerals with different electrical parameters in it. In this study, the feasibility of liberating CRC by electrical disintegration was investigated, and the Pt grade in the CRC fragments after electrical disintegration was compared with the one after mechanical comminution.
    The results showed with the increase of the thickness of CRC, the applied voltage for the electric breakdown was also increased. Higher applied voltage made the particle size of CRC fragments smaller. When electrical disintegration was performed in conductive solution, the applied breakdown voltage and electric energy consumption needed was greatly increased since the majority of the current flowed through the solution instead of CRC. However, it could be prevented by using coated discharge electrode, which makes electrical disintegration of CRC perform in seawater possible. The Pt grade in smaller CRC fragments from electrical disintegration and mechanical comminution were almost the same; however, larger CRC fragments possessed higher Pt grade from electrical disintegration than the one from mechanical comminution.
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