Estimation of Mass Transfer Rate of Oxidant to Coal Char Particle Surface with Partial Oxidation Reaction in O&lt;sub&gt;2&lt;/sub&gt;/CO&lt;sub&gt;2&lt;/sub&gt; System

Matsushita, Yohsuke; Nozawa, Sohey; Miyawaki, Jin; Yoon, Seong Ho; Mochida, Isao

doi:10.1252/kakoronbunshu.38.384

Cited by 1 publication

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“…Furthermore, it was suggested that this trend was significant in the O 2 /CO 2 system and that the CO 2 gasification reaction affected the char consumption rate. In addition, Kim et al (2012) analytically evaluated the mass transfer rate of O 2 to the particle surface of a coal char with partial oxidation in O 2 /N 2 and O 2 /CO 2 systems. In that study, it was found that the mass transfer of O 2 was inhibited by the convection due to the product of the char reaction in both systems, and the effect in the O 2 /CO 2 system was smaller than that in the O 2 /N 2 system.…”

Section: Introductionmentioning

confidence: 99%

Numerical Simulation of Single Coal Char Particle Combustion with the Overall Gas-Phase Reaction

Ishimoda

Akaotsu

Saito

et al. 2019

J. Chem. Eng. Japan / JCEJ

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The quasi-steady state heat and mass transfer around a single coal char particle with and without CO oxidation was numerically analyzed to investigate the e ect of CO oxidation on the reaction process of char. With CO oxidation, the gas temperature around the particle is increased by the exothermic heat of CO oxidation, and the particle itself also experiences a temperature increase due to the heat transfer between high-temperature gas and the particle. In addition, the generation of additional CO 2 by CO oxidation promotes the CO 2 gasi cation of char, whereas the consumption of O 2 suppresses the char oxidation. As a result of balancing among these factors, the net reaction rate of char, which is the sum of the partial oxidation rate and CO 2 gasi cation rate, with CO oxidation became larger than that without CO oxidation. Under conditions of a higher temperature and larger particle size, the net reaction rate with CO oxidation was larger than that without CO oxidation, though the partial oxidation rate with CO oxidation was smaller than that without CO oxidation because of the promoted consumption of O 2 by CO oxidation. This result indicates that CO 2 gasi cation compensates for the decrease in the net reaction rate due to the suppression of char oxidation. Therefore, CO oxidation should greatly a ect the heterogeneous reaction rates of char, especially CO 2 gasi cation, through changes in the temperature and compositions of the gas-phase near a coal char particle.

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Section: Introductionmentioning

confidence: 99%