2300K is the lower limit working temperature below which the electrical conductivity becomes effectively zero. Though there is no physical upper limit working temperature, 3000 to 3500K approximate range fits for practical sustainability. So for this physically attainable temperature the channel enthalpy (thermal efficiency) extraction ration for an open-cycle Mhd generator may range form 30-35%. While experimentally it is 15% for disk channel and 11% for linear Faraday channel under 3.2 Tesla of magnetic field. So far the maximum enthalpy extraction ratio for commercial size MHD generator is 24.5% by U-500 a natural gas fired plant in former USSR. This plant's total electrical power is 582MW that is 270MW from MHD and exhaust steam turbine unit gives 312MW and 1100MW from initial heat steam turbine. Thus the gloss thermal efficiency was 53% with the combustion gas temperature was 2900K.
| Figure shows efficiency of open MHD |
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