Magnetohydrodynamics (MHD) is a promising technology for electric bulk power generation. MHD is accomplished by forcing an electrically conducting fluid or a plasma through a channel with a magnetic field applied across it and electrodes placed at right angles to flow and field (Figure 1). An MHD plant can be directly fired with coal and there are no moving parts. To achieve extra high efficiencies, MHD is combined in a binary thermodynamic cycle with a conventional steam plant to add an extra 40 percent to the total power output and to boost the overall combined efficiency into the 60 percent range. The high temperature MHD process extracts part of the heat energy in the plasma at the high temperature end. The gas leaving the MHD generator, still at relatively high temperatures, is then used in a conventional bottoming steam plant.

A schematic coalfired MHD generator in Figure 2 is shown using a...