著者

赤塚 真依子 玉村 修司 五十嵐 敏文 金子 勝比古

出版者

一般社団法人 資源・素材学会

雑誌

Journal of MMIJ (ISSN:18816118)

巻号頁・発行日

vol.131, no.7, pp.459-464, 2015-07-01 (Released:2015-07-01)

参考文献数

30

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As one of the application of coal resources, domestic and overseas industries have been focusing on the recovery of methane from coal resources by methanogens using low-molecular weight acids or hydrogen that are converted from the organic matter in coal. For this application, it is essential to enhance the extraction of organic matter from low-rank coal (lignite) and maximize the conversion rate to consumable substrates for methanogen. In this study, we focused on the effects of chelating and reducing agents on the extraction of organics and metals from low-rank coal. Citric acid (chelating and reducing agent) and EDTA (chelating agent) were chosen as typical solvents. In the presence of citric acid, the Fe (II) concentration was correlated with the concentration of extracted organics as well as the total Fe. By contrast, the Fe (II) concentration was constantly at a low level for each EDTA concentration and pH. The absorbance (280 nm) of both solutions was almost the same when the total Fe concentrations were similar, regardless of the concentrations of Fe (II) , Al, Mg and Ca. These results indicated that organics from lignite were extracted with the leaching of Fe (III) and that the effects of reduction on the extraction of organics were insignificant. Excitation emission matrix spectra analysis suggested that humic acid was the main component of the extracted organics from lignite. The amount of acetic acid and formic acid released from 1g of lignite was calculated to be in the range 0.14 to 0.25 mg, and it was observed no correlation of the released amount with the citric acid /EDTA concentrations. Further research to obtain substrates such as low-molecularweight acids from the extracted organic materials is necessary for methane production using methanogens.

著者

荒牧 憲隆 A.K.M. Badrul Alam 玉村 修司 上野 晃生 村上 拓馬 金子 勝比古

出版者

一般社団法人 資源・素材学会

雑誌

Journal of MMIJ (ISSN:18816118)

巻号頁・発行日

vol.133, no.7, pp.173-181, 2017-07-01 (Released:2017-07-28)

参考文献数

33

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Peat from highly organic soil is abundant in Northern Hokkaido, Japan. In the past, peat was used in various applications in Japan, such as an artificial culture of soil, as a fertilizer for gardening, and as an energy resource. However, peat is not used by the modern energy and manufacturing sectors in Japan because it has a high moisture content and low calorific value, which lowers its value as a resource considering its material characteristics and handling difficulties. Furthermore, large amounts of peat are generated at the construction sites in this area, and they are difficult to be reused at their generation sites because peat is a very soft soil and not suitable for construction work. Recently, many Japanese research institutions have been carrying out research and development on renewable energy resources including biomass energy. In Hokkaido, there are many biogas plants for methanizing biomass derived from livestock excrement or food waste. Thus, peat which is high in organic matter could potentially be used as an energy resource. In this study, we investigated the potential of utilizing peat as an energy resource for biogenic methane production in regional cities of Northern Hokkaido, while considering both its material characteristics and resource circulation. Batch tests using a hydrogen peroxide solution were performed on peat and silty soil to estimate the quantity of low-molecular-weight organic acids and the producing potential for biogenic methane gas. The oxidative decomposition of the peat produced a high yield of low-molecular-weight organic acids that were used as substrates for methanogenic microorganisms. In addition, a novel resource circulation method was proposed for peat in order to use it as an energy resource. Moreover, the energy resources problem in Northern Hokkaido was discussed in association with geographical parameters and the construction recycling system in Japan.

著者

荒牧 憲隆 A.K.M. Badrul Alam 玉村 修司 上野 晃生 村上 拓馬 金子 勝比古

出版者

一般社団法人 資源・素材学会

雑誌

Journal of MMIJ (ISSN:18816118)

巻号頁・発行日

vol.132, no.12, pp.190-198, 2016-12-01 (Released:2016-12-16)

参考文献数

23

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Recently, the possibility of realizing a subsurface bio-reactor has been realized since microbial methanogenesis has been confirmed in diverse subsurface environments such as coalbeds or petroleum reservoirs. We propose a new gasification method for use in subsurface environments, known as the Subsurface Cultivation and Gasification (SCG). SCG was devised based on the production of biogenic methane gas in subsurface environments. This approach employed hydrogen peroxide to decompose organic matter rapidly. Conversion of organic matter from source rocks into biomethane with the help of microorganisms is expected to be highly profitable. In this study, a series of batch tests using a hydrogen peroxide (H2O2) solution were performed on lignite to estimate the potential of low-molecular-weight organic acid production. The effects of several factors on the production of low-molecular-weight organic acids have been considered, such as, concentration of H2O2, temperature, liquid-solid ratio, and specific subsurface area of lignite. It was found that the quantity of low-molecular-weight organic acids depended on temperature, liquid-solid ratio, and specific subsurface area of lignite; however, there isn't a unique relationship between them and the H2O2 concentration. Moreover, the mass of lignite reduced remarkably when batch tests were performed with a high concentration of H2O2. If H2O2 is to be injected into a target seam with the SCG method, we should estimate the optimum H2O2 concentration to produce low-molecular-weight organic acids with taking into consideration the mechanical stability of the target seam as well as the subsurface environmental chemical reaction with a geological improvement.