Comparing reaction orders of anthracite chars with bituminous coal chars at high temperature oxidation conditions

A1 Journal article (refereed)


Internal Authors/Editors


Publication Details

List of Authors: Karlstrom O, Brink A, Biagini E, Hupa M, Tognotti L
Publisher: ELSEVIER SCIENCE INC
Publication year: 2013
Journal: Proceedings of the Combustion Institute
Journal acronym: P COMBUST INST
Volume number: 34
Issue number: 2
Start page: 2427
End page: 2434
Number of pages: 8
ISSN: 1540-7489


Abstract

The influence of concentration of oxygen on the oxidation rates of 5 anthracite chars is investigated at gas temperatures ranging from 1223 K to 1673 K. Reaction orders and kinetic parameters are determined with a multivariable optimization method in which modeled burnout profiles are fitted to experimental burnout profiles from a 4 m isothermal plug flow reactor operating at industrially realistic heating rates, i.e., 10(4) - 10(5) K/s. The determined reaction orders are compared to reaction orders of 10 bituminous coal chars investigated at similar conditions in a previous study. The results show that the optimized reaction order of the anthracite chars is zero, while the reaction order of the bituminous coal char is one. The difference in the reaction orders cannot be explained by using the two semi-global oxidation reactions: C(O) + O-2 > CO/CO2 and C(O) > CO. However, by also considering 2C(O) > CO2 + C as a possible reaction step, the reaction order difference between the anthracite chars and the bituminous coal chars can be explained. In addition, a first attempt to apply the same multivariable optimization method to determine the reaction order for a biomass char is presented.


Keywords

Coal chars, Kinetics, Reaction order

Last updated on 2019-17-11 at 02:53