Gasification and Chemical-Looping Combustion of a Lignite Char in a Fluidized Bed of Iron Oxide
Gasification and Chemical-Looping Combustion of a Lignite Char in a Fluidized Bed of Iron Oxide
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DOI：
10.1021/ef100068m
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发表时间：
2010-05
期刊：
影响因子：
5.3
通讯作者：
T. Brown;J. S. Dennis;S. Scott;J. Davidson;A. Hayhurst
中科院分区：
文献类型：
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作者：
T. Brown;J. S. Dennis;S. Scott;J. Davidson;A. Hayhurst
报道了一种褐煤(Hambach)焦的气化和化学链燃烧实验，在1073K左右，在直径为25 mm的管内使用电加热的流态化床，流态化气体是氮气中的二氧化碳，将焦批量或连续地加入沙床或Fe2O3颗粒。实验还用流态化的两相理论进行了模拟；假设颗粒相混合良好，气化产物增强了气泡流动。这与Langmuir−HinShelwood(L−H)的气化动力学相结合，该动力学是从这种焦在沙子中与二氧化碳气化的实验中推导出来的。这些L的−H动力学是复杂的，在二氧化碳分压的两个范围内，速率常数是不同的：(I)0-0.05bar和(Ii)0.05-0.9bar。该理论很好地预测了(I)尾气中CO和CO2的浓度以及(Ii)碳在床中的积累。当焦炭被送入由Fe_2O_3颗粒流态化的床中时，也发生了燃烧.
Gasification and chemical-looping combustion experiments with a lignite (Hambach) char are reported, using an electrically heated fluidized bed in a 25 mm diameter tube at about 1073 K. The fluidizing gas was CO2 in nitrogen, with either batch or continuous feed of char into a bed of sand or particles of Fe2O3. The experiments were also modeled using the two-phase theory of fluidization; a well-mixed particulate phase is assumed, and the bubble flow is augmented by gasification products. This was combined with Langmuir−Hinshelwood (L−H) kinetics of gasification deduced from the experiments on gasification, with CO2, of this char in sand. These L−H kinetics are complex; the rate constants are different for two ranges of partial pressure of CO2: (i) from 0 to 0.05 bar and (ii) from 0.05 to 0.9 bar. The theory gives good predictions of (i) off-gas concentrations of CO and CO2 and (ii) accumulation of carbon in the bed. Combustion also occurred when the char was fed into a bed of Fe2O3 particles fluidized by ...