Evaluation of improved anion-exchange resin-based seed regeneration concept for coal fired MHD power system

Application of the technology of Magnetohydrodynamics (MHD) to coal fired power plants can result in higher overall efficiencies than those shown by conventional coal fired power plants. Coal-fired MHD power plants require the use of a seed material to make the combustion gases electrically conducting, and this results in an inherent sulfur removal process which makes such plants environmentally atttractive. In order for the MHD technology to be economically feasible, an efficient method of recovery, regeneration, and recycle of the spent seed material must be found. To accomplish this task, Butler (UTSI 1986) investigated an ion-exchange resin-based seed regeneration concept and also identified a fixed-bed sorption model of Selke and Bliss to satisfy the experimental breakthrough behavior of an ion-exchange system. The Selke and Bliss fixed bed model assumes liquid-film diffusion control and a non-linear equilibrium isotherm. This study extended the work done by Butler by using a model developed by Antonson which assumes particle diffusion control with non-linear equilibrium . In addition, the ion-exchange experiments were done under CO₂ pressure in an effort to combine the resin exhaustion and carbonation steps, and also to see if an an increase in resin capacity would occur. Results from a series of fixed bed experiments verified that the equilibrium of the sulfate- bicarbonate exchange system was non-linear. The results also showed that at higher CO₂ pressures, the equilibrium capacity of the system was increased. Finally, results obtained from the mathematical model used to describe the sulfate-bicarbonate system compare favorably with the experimental results.