Fluidized Bed Studies of Carbon Particle Oxidation: Gas Phase Surface Products and Surface Area Evolution
作者:
N. R. PURZER,
R. A. YETTER,
F. L. DRYER,
R. J. LAWSON,
期刊:
Combustion Science and Technology
(Taylor Available online 1995)
卷期:
Volume 110-111,
issue 1
页码: 147-167
ISSN:0010-2202
年代: 1995
DOI:10.1080/00102209508951920
出版商: Taylor & Francis Group
关键词: Carbon oxidation;fluidized beds;activation energies;surface evolution
数据来源: Taylor
摘要:
The oxidation of Spherocarb carbon particles is studied in a research-scale fluidized bed reactor (FBR) over the temperature range of 630K-130OK at atmospheric pressure. The reactor uses nitrogen carrier gas to which various amounts of oxidizer (from 6%-30% by volume) are added. Carbon loading (spherical 60/80 mesh spherocarb particles) is kept low so that the reactor remains nearly isothermal overall. A procedure for a non-intrusive approximation of average particle temperature rise was developed and indicated that particle temperatures do not rise more than 20 K above the bed temperature. Oxidation rates are determined by measuring the bed temperature and the time dependent formation of gas-phase carbon oxides. Assuming a first order dependence on oxidizer concentration, overall rates of oxidation for various pure oxidizers in nitrogen are determined. The overall activation energy for O2(37 ± 2 kcal/mole) corresponds well with previously published values. Overall activation energies for CO2(61±9 kcal/mole), and H2O (82 ± 8 kcal/mole) are considerably larger than those for oxygen, and overall rates were found to be the same order of magnitude as those for oxygen at 1500 K and 1380 K, respectively. The overall activation energy for N2O (33 ± 3 kcal/mole) is similar to that for oxygen with a rate about 75% slower.
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