Estimation of Effective Diffusion Coefficient of O 2 in Ash Layer in Underground Coal Gasification by Thermogravimetric Apparatus

Xi Lin, Qingya Liu and Zhenyu Liu
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Xi Lin: Beijing Advanced Innovation Center for Soft Matter Science and Engineering, and State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing 100029, China
Qingya Liu: Beijing Advanced Innovation Center for Soft Matter Science and Engineering, and State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing 100029, China
Zhenyu Liu: Beijing Advanced Innovation Center for Soft Matter Science and Engineering, and State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing 100029, China

Energies, 2018, vol. 11, issue 2, 1-14

Abstract: Underground coal gasification (UCG) proceeds generally in the presence of an ash layer on coal (or char) surface. The ash layer increases the mass transfer resistance of O 2 to the gasification surface, which may become the limiting step of whole process. This paper studies O 2 diffusion in ash layer formed on cylindrical char samples using a specially designed one-dimension setup in a thermogravimetric apparatus (TGA). The effective internal diffusion coefficient ( D e ) is found to increase with an increase in ash layer thickness, due to an increase in median pore diameter. Methods are established to correlate D e with operating conditions and to estimate the role of internal diffusion resistance in overall mass transfer resistance.

Keywords: underground coal gasification; ash layer; effective diffusion coefficient; internal diffusion resistance (search for similar items in EconPapers)
JEL-codes: Q Q0 Q4 Q40 Q41 Q42 Q43 Q47 Q48 Q49 (search for similar items in EconPapers)
Date: 2018
References: View references in EconPapers View complete reference list from CitEc
Citations: View citations in EconPapers (3)

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