Characteristics of an advanced carbon sorbent for CO2 capture

The adsorption and desorption characteristics on an advanced carbon sorbent for gases present in the flue gas stream, including CO2, N-2, O-2, Ar, H2O vapor, and impurities NO and SO2 are discussed. At 5 degrees C and 1 atm CO2 pressure, this carbon sorbent can uptake 20 wt% (or 4.5 mmol/g) of CO2, with high Henry's law selectivity over N-2, O-2, and Ar. The heat of adsorption for CO2 decreases from similar to 28 kJ/mol (290 meV) to similar to 25.7 kJ/mol (260 meV) as the coverage of CO2 increases; whereas the heat of adsorption for N-2, O-2, and Ar is in the range of 16-17 kJ/mol. The carbon sorbent has a high surface area of 1270 m(2)/g, high thermal conductivity (0.8 W/m K), low heat capacity (1 J/g K), high mechanical strength, and high attrition resistance. his an ideal candidate for post-combustion CO2 capture using rapid pressure swing and rapid temperature swing methods. (C) 2013 Elsevier Ltd. All rights reserved.