KINETICS OF SULFUR-DIOXIDE UPTAKE ON SUPPORTED CERIUM OXIDE SORBENTS

A thermogravimetric technique has been used to evaluate the apparent rate of SO2 absorption by ceria supported on alumina. A kinetic model for the sulfation of the CeO2/Al2O3 sorbent has been developed that is first order with respect to the partial pressure of SO2 and first order with respect to the fractional unreacted cerium oxide on the sorbent. The reaction was also found to be zero order with respect to the oxygen and water vapor content of the gas over a range of concentrations that might reasonably be encountered in actual flue gas streams. CeO2/Al2O3 sorbent is being studied at the Pittsburgh Energy Technology Center as a potential new sorbent for simultaneous removal of 90+% of both SO2 and NO(x) from coal combustion flue gas in a dry, regenerable process.