| Project/Area Number |
07555246
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| Research Category |
Grant-in-Aid for Scientific Research (A)
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| Allocation Type | Single-year Grants |
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| Section | 試験 |
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| Research Field |
触媒・化学プロセス
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| Research Institution | Tohoku University |
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Principal Investigator |
OHTSUKA Yasuo Tohoku University, Institute for Chemical Reaction Science ; Associate Professor, 反応化学研究所, 助教授 (20091663)
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| Co-Investigator(Kenkyū-buntansha) |
ZHUANG Qianlin Tohoku University, ICRS,Research Associate, 反応化学研究所, 助手 (70271997)
MURAMATSU Junji Tohoku University, IAMP ; Associate Professor, 素村工学研究所, 助教授 (40210059)
SUGAWARA Katsuyasu Akita University, Department of Mining ; Associate Professor, 鉱山学部, 助教授 (60154457)
SATOH Yoshiki MITI,NIRE ; Chief of Hydrocarbon Technology, 資源環境技術総合研究所, 室長(研究職)
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| Project Period (FY) |
1995 – 1996
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| Project Status |
Completed (Fiscal Year 1996)
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| Budget Amount *help |
¥8,800,000 (Direct Cost: ¥8,800,000)
Fiscal Year 1996: ¥2,700,000 (Direct Cost: ¥2,700,000)
Fiscal Year 1995: ¥6,100,000 (Direct Cost: ¥6,100,000)
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| Keywords | Fine metal particles / Coal / Fuel nitrogen / Inherent minerals / Nitrogen removal catalyst / Pyrolysis / Non-pollution / 脱窒素 / 無公害化 |
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| Research Abstract |
1.Nanoscale FeOOH particles, precipitated onto low rank coals from an aqueous solution of FeCl_3 by using Ca(OH)_2, are reduced into metallic iron with the size of 20-30nm during fluidized bed pyrolysis, and metal nanoparticles promote efficient conversion of fuel nitrogen to N_2. There are two formation routes of N_2, secondary decomposition reactions of volatile nitrogen (tar, HCN,and NH_3) and conversion reactions of char nitrogen, and the latter is the main route with more highly-dispersed iron.
2.When 15 coals with different ranks are pyrolyzed at 1000ﾟC with a fixed bed reactor, some low rank coals show extremely high conversion of fuel nitrogen to N_2,50-60%. Demineralization of these coals with HCl washing, XRD analyzes of low and high temperature ashes, and ICP analysis of HCl leachate lead to the conclusion that the presence of Fe-containing minerals in ion-exchangeable forms is the key factor determining for remarkable N_2 formation.
3.The XPS and TEM-EDX measurements of the cahrs after pyrolysis reveal that such minerals are transformed into iron metal particles with the size of <approximately equal> 10nm, and that the mineral-derived iron show much higher activity for selective conversion of char nitrogen to N_2 than the externally-added iron. It is likely that iron-catalyzed solid phase reactions proceed through formation of interstitial iron nitrides and subsequent decomposition into N_2.
4.Pyrolysis of these low rank coals with a free-fall type reactor is also carried out from a practical point of view, and it is suggested that tarry materials with pyrrolic and pyridinic nitrogen forms are converted to N_2 on the surface of the mineral-derived fine iron. When these compounds are passed over iron metal particles with the size of 20nm supported on pure carbon to verify this possibility, the conversion to N_2 take place exclusively.
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