Novel asphalt-based carbon adsorbents with super-high adsorption capacity and excellent selectivity for separation for light hydrocarbons

Abstract

Abstract Separation and recovery of light hydrocarbons (C2-C3) from gaseous mixtures (C1-C3) such as natural gas is of importance for the petroleum industry, and is profitable for natural gas producers if it can be done at normal temperature. In this work, novel asphalt-based activated carbons (A-ACs) were prepared by using asphalt as carbon source for separation of light hydrocarbons. The resultant A-ACs were characterized, and C3H8, C2H6 and CH4 adsorption isotherms of A-ACs were measured. Besides, their dynamic separation performance were investigated by fixed bed experiments. The resulting A-ACs exhibited a superior C3H8 and C2H6 adsorption capacity of 11.76 and 6.59 mmol/g at 298 K and 100 kPa, respectively and their BET surface area reached as high as 3131 m2/g; The IAST-predicted C2H6/CH4 and C3H8/CH4 selectivity of the sample A-AC-4 reached as high as 15.1 and 88.8 at 298 K and 100 kPa, respectively, which is superior to many MOFs; C3H8/C2H6/CH4 mixtures can be well separated in the fixed bed of A-ACs at room temperature due to the significant differences between affinities of light hydrocarbons with A-ACs. A-ACs are very promising for separation of the light hydrocarbons.