Various configurations of a power plant are described. The power plant is configured to supply power to a receiving electrical grid by the combustion of metal powder. The power plant is also configured absorb power by recovering the metal powder from the metal oxide produced by the combustion of the metal powder, with electricity from a source electrical grid.

The present invention relates to a waterless system and method for cooling a metallurgical processing furnace. Supercritical carbon dioxide (sCO.sub.2) is used as a coolant, as opposed to water, which provides several advantages. For example, sCO.sub.2 can be used at higher temperatures, the risk of an explosion (with use of water) is eliminated, there are no problems with regard to reverse solubility of water at higher temperatures that can foul passageways, and smaller cooling passages can be used thus reducing the cost of cooling panels. A system is disclosed which uses a reservoir to store the sCO.sub.2, a compressor or pump to cause the delivery of the sCO.sub.2 to cooling passages in the furnace, a pressure reducing valve or a turbine to decrease the pressure of the sCO.sub.2, and a heat exchanger to cool the sCO.sub.2 to a liquid state as the sCO.sub.2 travels back to the reservoir.

To provide a waste heat recovery power generation plant for sintering facility capable of efficiently recovering a waste heat of a sintering machine in addition to that of a sintered-ore cooler, while restraining that sulfuric anhydride contained in an exhaust gas of the sintering machine forms drops. An SM boiler is configured to heat all of or a part of hot water generated by an SC boiler, by introducing a high temperature part of an exhaust gas of a sintering machine. At this time, a temperature of the hot water to be supplied to the SM boiler is controlled such that a temperature of an exhaust gas at an exhaust-gas temperature of the SM boiler is maintained at a temperature higher than an acid dew point.