Adsorption Performance Of CO₂ On Different Carbonaceous Porous Materials

Energy saving and mitigation of CO2 has attracted much attention because of the global warming, especially CO2 capture. It is well known that 60% CO2 results in the combustion of fossil fuels, and then it is an efficient way to capture CO2 from flue gases.In our works, the adsorption/desorption performance of CO2 on different carbonaceous porous materials are investigated, including pitch-based spherical activated carbon (PSAC), carbon molecular sieves, coconut activated carbon, activated carbon fiber, super activated carbon and honeycomb carbon. Further more, the comprehensive properties of above adsorbents are analyzed, and the results are given as follows.1) Under atmospheric pressure, the adsorption capacity of 15 vol% CO2 on the adsorbents follows the sequence:PSAC>carbon molecular sieves>activated carbon fiber> coconut activated carbon>honeycomb carbon. The equilibrium adsorption amount of CO2 on PSAC is 1.02mmol/g. The cyclic adsorption/desorption efficiency of the absorbents follows the order:PSAC>activated carbon fiber>honeycomb carbon>coconut activated carbon> carbon molecular sieves, and PSAC has a high adsorption/desorption cycle efficiency,98.5%.2) Super activated carbon implies a good adsorption performance at high adsorption pressure due to its high specific surface area and total pore volume compared with other adsorbents. The saturated adsorption amount of CO2 on super activated carbon is 12.85 mmol/g at 1.2MPa obeying the micropore filling theory.3) PSAC has a good electric swing adsorption (ESA) performance because of its good thermal conductivity and electrical conductivity. A low electrical voltage (3.2V) can cause the temperature of 60g PSAC to 200℃from room temperature within 50s. The energy consumption of the ESA process is only 150 kJ/kg.4) When adopting the combined process of ESA/VSA, the cyclic adsorption/desorption efficiency of CO2 on PASC is about 100%.