Sub-atmospheric disk generators for coal-fired MHD/steam combined cycle power plant

A coal fired MHD disk generator in a combined cycle MHD/steam power generation system with a diffuser operating at sub-atmospheric pressure is proposed. The effects of pressure on the performance of a radial outflow MHD disk generator and other systems components are analysed. Using a previous study as a reference case, preliminary calculations show that, in such a sub-atmospheric system, improved power station efficiency can be achieved. In addition, operation at reduced values of magnetic field strength would be feasible. Calculations have also been carried out for a 30 MW_th experimental disk generator operating at reduced pressure with a magnetic field strength of 2 T. Flow conditions at sub-atmospheric pressure would provide an improved simulation of a full-scale generator operating at normal pressures.