A process for generating power from the oxidation of coal in supercritical water

dA theoretical study of power generation from oxidation of coal by supercritical water oxidation (SCWO) is presented. Two versions of SCWO power plant are compared to two of the most efficient conventional power plant processes: pulverised coal power plants and pressurised fluidised bed power plant. The effects of steam pressure and temperature on produced (W-p), consumed (W-c) and net work (W-N) are calculated in order to compare the efficiency of these power plants for the same steam conditions. Enthalpies have been calculated using residual enthalpies by Peng-Robinson equation of state. Calculated results show that net work in SCWO power plant is 5% higher than in other power plants, due to the fact that no air surplus is necessary for complete combustion and because steam is produced by direct heating. Energetic efficiency of SCWO increases more quickly with temperature than for the other power plants. The effect of steam pressure is different: until 30 MPa power plant efficiencies increase more quickly in SCWO power plants than in conventional plants, but when steam pressures increases beyond 30 MPa, efficiencies decrease in SCWO power plants. (C) 2004 Elsevier Ltd. All rights reserved.