著者
奥村 幸彦 岡崎 健
出版者
一般社団法人日本機械学会
雑誌
日本機械学會論文集. B編 (ISSN:03875016)
巻号頁・発行日
vol.73, no.731, pp.1434-1441, 2007-07-25
被引用文献数
3

This paper reports on the pyrolysis and CO_2-gasification of various biomass materials in a pressurized thermobalance. In particular, the primary yields of total volatiles, tar and non-condensable gases, together with the composition of non-condensable gases, are measured as a function of temperature at 1 atm and 10.8 ata. The use of a high-intensity infrared heating source, in conjunction with a non-absorbing carrier gas (viz. argon), is reported to reduce the significance of secondary gas-phase pyrolysis reactions. Linear trends with atomic H/C ratio are observed in the tar yield, total volatile yield and CH_4 yield during pyrolysis. The gasification kinetics of biomass chars (pyrolysed to 700℃ at a medium heating rate) have also been measured by measuring the rate of weight loss during reaction with CO_2 as a function of temperature. First-order kinetic rate constants are then determined by fitting the weight loss data using a random pore model. The results indicate that the reactivity of the biomass materials is intermediate between lignin and cellulose and that they are much more reactive than a black coal char.
著者
奥村 幸彦 金内 健 岡崎 健
出版者
一般社団法人日本機械学会
雑誌
日本機械学會論文集. B編 (ISSN:03875016)
巻号頁・発行日
vol.71, no.702, pp.702-710, 2005-02-25
被引用文献数
1

The coal-pyrolysis experiment under elevated pressure conditions using a pressurized ther-mobalance has been carried out to clarify the mechanisms and the processes at conditions changing from normal pressure to higher pressure (10.6 ata) and from slow (0.1 K/s) to rapid heating rate (20 K/s). Simultaneously, a new pyrolysis model which can describe a pressure effect on the evolution behavior has been developed based on the FLASHCHAIN^[○!R] model including a quantitative estimation of the volatilized gases and released tar vapor. From the experiment, the tar vapor formation is suppressed and the yields of CH_4 gas shows increasing behavior at higher pressure conditions. Because the mole fraction of tar vapor decreased with the increase of the pressure by Raoult's law, and the recombination reactions of remaining metaplast (precursor of tar) within the coal are activated, resulting in more chars and more gas yields (CH_4, CO_2). At rapid heating rate conditions, the conversion from the metaplast to the volatile matter would be more active, because the reaction temperature range for thermal pyrolysis shifts to higher range with increase of heating rate. It was found that the rapid heating rate affects the molecular structure of the coal substantially.
著者
土肥 智弘 奥村 幸彦 安達 文幸
出版者
一般社団法人電子情報通信学会
雑誌
電子情報通信学会技術研究報告. RCS, 無線通信システム
巻号頁・発行日
vol.97, no.31, pp.17-24, 1997-04-25
被引用文献数
31

広帯域コヒーレントDS-CDMA(W-CDMAの野外伝送実験を行い、チップレート(拡散帯域幅)と送信電力の関係、チップレートと誤り率特性の関係を明らかにした。チップレートの高速化によりマルチパスの分解能力が向上し、RAKE受信後の受信電力の変動幅が小さくなり、低レベルへの落ち込み確率が減少するため、チップレートが高速になるほど送信電力は低減されることを実証した。また、アンテナダイバーシチ受信により誤り率特性が約3dB改善されることも明らかにした。