Preparation and Its Selective Adsorption Property of Asphalt-Based Carbon Materials for Effictive Separation of Light Hydrocarbons Methane/Ethane/Propane

Preparation and its Selective Adsorption property of Asphalt-based Carbon Materials for Effictive Separation of Light hydrocarbons Methane/Ethane/Propane

Wanwen Liang¹, Huiyu Xiao¹, Daofei Lv¹, Jing Xiao^2**, Qibin Xia¹, Zhong Li^1*

1 School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou 510640, PR China

2 The Key Laboratory of Enhanced Heat Transfer and Energy Conversation Ministry of Education, South China University of Technology, Guangzhou 510640, PR China

ABSTRACT

We used asphalt as carbon source to prepare a series of novel asphalt¨Cbased activated carbons (A-ACs) for efficient separation of light hydrocarbons in pectrochemistry industries, especially recovery C₂H₆ and C₃H₈ from Natural gas. A-ACs were prepared by an one-step preparation method and then characterized. The adsorption isotherms of C₃H₈, C₂H₆ and CH₄ on A-ACs were measured at different temperatures, and the dynamic separation performance of the samples were investigated by fixed bed experiments. The results showed that (a) the BET surface area of the resulting A-ACs reached as high as 2928-3131 m²/g with pore volumes of 1.60-2.10 cm³/g, and meanwhile the surface O and N contents of A-ACs gradually decreased with the KOH/asphalt ratio increasing at which A-ACs were prepared; (b) the sample prepared at 1073 K and the KOH/asphalt ratio = 4 (A-AC-4) exhibited a superior C₃H₈ and C₂H₆ adsorption capacity of 11.76 and 6.59 mmol/g at 298 K and 100 kPa, respectively; (c) the IAST-predicted C₂H₆/CH₄ selectivity of the samples A-AC-3 and A-AC-4 reached 16.9 and 15.1, respectively, at 298 K and 100 kPa, and meanwhile the IAST-predicted C₃H₈/CH₄ selectivity of the samples A-AC-3 and A-AC-4 reached as high as 76.6 and 88.8, respectively at 298 K and 100 kPa; (d) C₃H₈/C₂H₆/CH₄  (0.05/0.1/0.85) mixture can be well separated in the fixed bed packed with the sample A-AC-3 or the sample A-AC-4.

Keywords: Asphalt, Porous carbons, light hydrocarons, Adsorption separations, Isotherms, Selectivity

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* Corresponding author. Tel: +86 20 87110608 Fax: +86 20 87110608 E-mail: cezhli@scut.edu.cn (Z. Li).

** Corresponding author Tel: +86 20 87113513 Fax: +86 20 87113513 E-mail: cejxiao@scut.edu.cn(J. Xiao);