Potential Industrial Applications of Magnetohydrodynamics

Magnetohydrodynamic power generation has been presented as limited in application to large generating stations but offering the promise of reduced power cost to be achieved through heat rate improvement. The potential for industrial application will be broadened if generators can be made attractive in smaller ratings, if generating cost can be reduced, and if the generator can be made lighter and more compact. The scaling considerations which make large output more favorable will be reviewed and the possibility of devising attractive MHD generators in smaller ratings will be explored. Improved heat rate is achieved by the combination of an open-cycle regenerative MHD generator with a waste heat steam cycle; however, cost studies of such combined cycles have shown that high capital costs may prevent the expected improvement in the cost of power generated. This cost is decreased by extracting a larger portion of available heat in the MHD converter relative to that extracted in the steam cycle. The effect on power cost of increasing generator inlet temperature without a corresponding increase in exit temperature will be examined. MHD generator size affects power cost both through wall heat loss and as a consequence of magnet capital cost. The effect of magnetic field strength upon generator power density and cost will be discussed and the potential benefit of the superconducting electromagnet will be established.