Evaluation of Carbon Monoliths for CO2 Separation

In order to efficiently capture CO2 from gas streams, rapid processes have to be developed. In this work, we have studied carbon monoliths for the separation of CO2 from flue gas. The effect of wall thickness on separation efficiency was studied. Breakthrough experiments were performed at gas velocities between 0.1 and 10 m/s (resulting in contact times as low as 0.01 s) in order to assess mass transfer limitations. Thermocouples inside the monolith channels allowed to follow the thermal wave in the channels during adsorption and desorption. Significant thermal effects were observed during both adsorption and desorption, with a strong impact on the separation efficiency and cycle time. Experiments were performed at different levels of relative humidity, demonstrating that the carbon monoliths are suitable for gas streams containing relative large amounts of water vapour as a result of the hydrophobic nature of the material.

Various regeneration methods were tested in order to optimise the balance between cycle time and dynamic adsorption capacity.