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Journal Article 2

Year

2021 2

Keywords

CO₂ gasification 1

Zhundong lignite (ZD) 1

ash deposition 1

circulating fluidized bed (CFB) 1

coal char 1

internal diffusion 1

mineral transformation 1

oil shale semi-coke (SC) 1

pore evolution 1

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Effect of oil shale semi-coke on deposit mineralogy and morphology in the flue path of a CFB burning Zhundonglignite

Zhuo LIU, Jianbo LI, Mingming ZHU, Xiaofeng LU, Zhezi ZHANG, Dongke ZHANG

Frontiers in Energy 2021, Volume 15, Issue 1, Pages 26-37 doi: 10.1007/s11708-020-0668-1

Abstract: ash deposited on probes situated in the flue path of a circulating fluidized bed (CFB) which burns Zhundonglignite (ZD) was investigated. 10 wt% or 20 wt% SC was added to ZD, which were then combusted in theWhen ZD was burned alone, the P W deposit was comprised of agglomerates (<30 m) enriched in CaSO andtherefore help alleviate the propensity of ash deposition in the flue path in the CFB combustion of ZD

Keywords： ash deposition circulating fluidized bed (CFB) mineral transformation oil shale semi-coke (SC) Zhundonglignite (ZD)

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Reaction kinetics and internal diffusion of Zhundong char gasification with CO

Yun Liu, Jiangyuan Qu, Xuehui Wu, Kai Zhang, Yuan Zhang

Frontiers of Chemical Science and Engineering 2021, Volume 15, Issue 2, Pages 373-383 doi: 10.1007/s11705-020-1949-2

Abstract: Mass transfer usually affects the rate of chemical reactions in coal. The effect of internal diffusion on char gasification with CO in the temperature range from 1123 K to 1273 K was investigated via thermo-gravimetric analysis and assessment of char morphology features. The results revealed that the effect of internal diffusion on the initial reaction rate was more significant with an increase of particle size, due to the concentration gradient of the gasification agent within the solid particles. In the early stage of gasification, the generation of new micropores and the opening of closed pores led to an increase in specific surface area. As the reaction proceeded, the openings were gradually expanded and the specific surface area continued to increase. However, with further reaction, disappearance of edge pores, melting and collapse of the pore structure led to a decrease in specific surface area. The intrinsic activation energy and reaction order based on the th-order model were 157.67 kJ∙mol and 0.36, respectively. Thus, temperature zones corresponding to chemical reaction and diffusion control were identified. Moreover, the calculated effectiveness factor provided a quantitative estimation of internal diffusion in the initial stage.

Keywords： coal char CO₂ gasification internal diffusion pore evolution