Investigation of combined SO{sub 2}/NO{sub x} removal by ceria sorbents. Quarterly technical progress report, October--December, 1994

Simultaneous removal of SO{sub 2} and NO{sub x} using a regenerable solid sorbent will constitute an important improvement over the use of separate processes for the removal of these two pollutants from stack gases and possibly eliminate several shortcomings of the individual SO{sub 2} and NO{sub x} removal operations. Recent studies at PETC considered cerium oxide as an alternate sorbent to CuO. The present study aims to determine the effects of ammonia on the sulfation of the sorbent and to obtain a rate expression for the regeneration of alumina-supported CeO{sub 2} sorbents. The sulfation experiments indicated that 100% conversion of ceria could be attained. Activation energy for the sulfation reaction was found to be 19 kJ/mol. The rate of sulfation reaction is first order with respect to SO{sub 2} and solid reactant concentrations. For regeneration with hydrogen, the activation energy and the reaction order with respect to hydrogen was found to be 114 kJ/mol and 0.56, respectively. The ceria sorbent preserved its activity and structural stability after 6 cycles. The information obtained from these studies will be used to develop models for reactor-regenerator configurations. Subsequently, the SO{sub 2}/NO{sub x} removal facility will be integrated into the power production process using a commercial process simulation software. In this quarter of the project, the main focus was on the performance of the experimental program for the regeneration of the ceria sorbent by hydrogen and evaluation of experimental results