Variation of the pore structure of coal chars during gasification

Feng, Bo and Bhatia, Suresh K. (2003) Variation of the pore structure of coal chars during gasification. Carbon, 41 3: 507-523. doi:10.1016/S0008-6223(02)00357-3


Author Feng, Bo
Bhatia, Suresh K.
Title Variation of the pore structure of coal chars during gasification
Journal name Carbon   Check publisher's open access policy
ISSN 0008-6223
Publication date 2003
Sub-type Article (original research)
DOI 10.1016/S0008-6223(02)00357-3
Volume 41
Issue 3
Start page 507
End page 523
Total pages 17
Place of publication Oxford, England
Publisher Pergamon-Elsevier Science Ltd
Collection year 2003
Language eng
Subject C1
290699 Chemical Engineering not elsewhere classified
660103 Coal-other purposes
290501 Mechanical Engineering
Abstract The variation of the pore structure of several coal chars during gasification in air and carbon dioxide was studied by argon adsorption at 87 K and CO2 adsorption at 273 K. It is found that the surface area and volume of the small pores (<10 Å) do not change with carbon conversion when the coal char is gasified in air, while those of the larger pores (10–20 Å, 20–50 Å, 50–2500 Å) increase with increase of carbon conversion. However in CO2 gasification, all the pores in different size ranges increase in surface area and volume with increase of carbon conversion. Simultaneously, the reaction rate normalized by the surface area of the pores >10 Å for air gasification is constant over a wide range of conversion (>20%), while for CO2 gasification similar results are obtained using the total surface area. However, in the early stages of gasification (<20%) the normalized reaction rate is much higher than that in the later stage of gasification, due to existence of more inaccessible pores in the beginning of gasification. The inaccessibility of the micropores to adsorption at low and ambient temperatures is confirmed by the measurement of the helium density of the coal chars. The random pore model can fit the experimental data well and the fitted structural parameters match those obtained by physical gas adsorption for coal chars without closed pores.
Keyword Gasification
Modeling
Porosity, Surface areas
Carbon Dioxide Reaction
Fluid-solid Reactions
Active surface areas
Heat treatment
Kinetics
Oxygen
Temperature
Q-Index Code C1

 
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Created: Wed, 15 Aug 2007, 01:55:18 EST