Pitch-Polymer CO2 Adsorbents

There is a growing need to find new, improved ways of limiting the emission of carbon dioxide from coal fired power plant in order to decrease the cost of advanced power systems and to mitigate environmental concerns for using coal. Amine-based scrubbers, the current method used for carbon dioxide capture, have inherent limitations and are expensive to build and operate. Alternative methods that offer significant improvements in their environmental impact need to be developed. Porous carbons are commonly used to absorb contaminants from gas and liquid process streams but their application to the removal and recovery of CO2 has not been practicable, as the range of pore size distributions achievable provided only relatively low capture efficiency for CO2. However, the results from a recent CPCPC research program have shown that activated carbons can be produced that offer the potential for successful implementation as CO2 adsorbents. In the previous study polymers were blended with a pitch to provide a source of heteroatoms with the objective of modifying the properties of the pitch to enhance fiber processing. The pitch/polymer composite materials produced were separately assessed as precursors for the synthesis of activated carbons. Preliminary tests have shown that the capacity for CO2 absorption is significantly increased, and compares favorably with current best CO2 adsorbents. Thus, it is proposed to undertake a detailed study of this effect to determine the efficiency of CO2 capture and controlled release from activated carbons derived from modified pitches. A range of pitch/polymer blends will be produced with different functionalities. These will be converted into activated carbon fibers and carbon granules to assess their ability to adsorb CO2 from synthetic coal combustion flue gas.