The socalled feed water is the main tool in the power plant. It is routed thrpough a closed circuit, (steam turbine - condenser - feedwater pump - steam generator - steam turbine). The following describes the circuit process: The feedwater which is located in the pipe system of the steam generator condenses with the heat of the furnace. From there it is routed under high termperatures/pressures (up to 540°C/250 bar, )to the steam turbine blades. The mechanical rotor energy is converted into electrical energy in the generator. The largest demand on the cooling effect is present during the condensation of the steam in the main condenser which is located below the turbine. Because of the condensation of the steam, the water suddenly reduces its volume. This creates a large underpressure in the condenser, far below the air pressure. As a subsequence of the temperature difference between the input and output of the thermoelectric generator (turbine), the thermic effeciciency increases, decisive for the total efficiency of the power plant. Following condensation in the main condenser, condenser pumps transport the condensate through connected low pressure heaters (NDPH) to the gas remover in the feedwater container. From the feedwater container, the feedwater pumps convey the water with the reqiured supply pressure to the high pressure heater (HPH) into the pipe bundle of te steam generator (boiler). The ND/HD - heater (heat exchager) are fed with extraction steam from the turbine.
The heating and gas removal of the main condensate from the turbine main condenser as well as the supplied feed warter is of greatest importance for the effectivitiy of the steam generator plant. Because of the incremental heating of the main condensate and the feedwater with extraction steam which has already been used, the overall efficiency of the power plant is increased as the steam transmits its condensation heat to the feed water and not to the cooling water. In this way the energy remains in the feed water and is not wasted in the cooling water.
The energy is retained and need not be replenished in the form of combustion materials. The feedwater must have a certain quality. It must be free of socalled hardness and may not carry dissolved gases (e.g. carbon dioxed, oxygen). Finally it must be free of mechanical pollutants and must have a defined salt content. |
