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Effect of CO$_{2}$ and H$_{2}$O on Char Properties. Part 2: In Situ and Ex Situ Char in Oxy-Steam Combustion

Li, Zehua; Zou, Renjie; Hong, Dikun; Ouyang, Juncheng; Jiang, Liangkui; Liu, Huan; Luo, Guangqian; Yao, Hong

Abstract (englisch):
The physical and chemical properties of H2O (oxy-steam combustion) and N2 (air combustion) are different, which has influence on the char properties in oxy-steam combustion. Measuring in situ char (without any cooling) kinetic parameters is very important, especially at oxy-steam atmosphere. Both in situ and ex situ char properties were investigated in this paper. Ex situ char was obtained at different cooling rates. Char properties were measured by X-ray diffraction, H/C ratio, Raman spectrum, and specific surface area. The effect of steam on in situ and ex situ char combustion kinetics were determined. We found that the combustion reaction rates of different chars are in order of in situ > rapid cooling (103–104 K/s) > medium cooling (10–100 K/s) > slow cooling char (0.1 K/s). The rapid cooling char structure is disordered and has a high active surface area, which results in the high reactivity. In situ char has a shorter burn-out time, a faster combustion rate, and a higher reaction constant. For example, at 903 K, it appears the reaction rate of 0.048 s–1 for ex situ char (Vientiane coal char) in oxy-steam atmosphere (30% O2 + 15% H2O), while that of in situ char is 0.07 s–1. ... mehr

DOI: 10.1021/acs.energyfuels.0c00845
Zitationen: 1
Web of Science
Zitationen: 1
Zugehörige Institution(en) am KIT Institut für Quantenmaterialien und -technologien (IQMT)
Publikationstyp Zeitschriftenaufsatz
Publikationsmonat/-jahr 06.2020
Sprache Englisch
Identifikator ISSN: 0887-0624, 1520-5029
KITopen-ID: 1000124669
HGF-Programm 43.21.01 (POF III, LK 01)
Quantum Correlations in Condensed Matter
Erschienen in Energy & fuels
Band 34
Heft 6
Seiten 7554–7563
Vorab online veröffentlicht am 04.05.2020
Nachgewiesen in Scopus
Web of Science
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