Gasification of brown coal and char with carbon dioxide in the presence of finely dispersed iron catalysts

被引:67
作者
Asami, K
Sears, P
Furimsky, E
Ohtsuka, Y
机构
[1] CANADA CTR MINERAL & ENERGY TECHNOL, ENERGY RES LABS, NAT RESOURCES CANADA, OTTAWA, ON K1A 0G1, CANADA
[2] TOHOKU UNIV, INST CHEM REACT SCI, RES CTR CARBONACEOUS RESOURCES, SENDAI, MIYAGI 98077, JAPAN
关键词
brown coal; carbon dioxide; char; gasification; iron catalyst; Mossbauer spectra;
D O I
10.1016/0378-3820(96)01000-4
中图分类号
O69 [应用化学];
学科分类号
081704 ;
摘要
Gasification of brown coal and char with CO2 using iron catalysts precipitated from an aqueous solution of FeCl3 has been studied, When the pyrolyzed char is gasified in the temperature-programmed mode, the presence of the iron can lower the temperature giving the maximal rate of CO formation by 130-160 K, a larger lowering being observed at a higher loading in the range of less than or equal to 3 wt.% Fe. The specific rates of the isothermal gasification of iron-bearing chars at 1173 and 1223 K increase with increasing char conversion, resulting in complete gasification within a short reaction time. Comparison of the initial rates of uncatalyzed and catalyzed gasification reveals that iron addition can lower the reaction temperature by 120 K, Mossbauer spectra show that the precipitated iron exists as fine FeOOH particles, which are reduced mainly to Fe3C on charring at 1123 K. Most of the Fe3C is transformed into alpha-Fe and gamma-Fe at the initial stage of gasification, and subsequently these species are oxidized to FeO and Fe3O4. The changes during gasification are discussed in terms of solid-gas and solid-solid reactions.
引用
收藏
页码:139 / 151
页数:13
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