The essential parts of all steam turbines are similar, consisting of nozzles through which steam flows and expands (dropping in temperature and gaining kinetic energy) and the blades against which the swiftly moving steam exerts pressure. The blades are mounted on rotor drum, and an outer casing confines the steam to the turbine. Both temperature and pressure fall as the steam passes through the turbine. The greater the pressure drop, the more energy can be captured from the steam. The more efficient power plants condense the steam back to water at the end of the turbine.
The theoretical maximum efficiency of a steam turbine- based power plant is determined by the difference between the temperature at which steam enters the high pressure turbine and the temperature at which it exits the low pressure turbine. The greater the temperature difference, the more energy can be extracted. Steam turbines are finding greater use in process industries (like steel and chemicals) producing large quantities of waste heat. The waste heat produced can be used to generate steam as well as power.
The capital cost of such plants can be slightly higher but the generation of power represents a useful by-product when the waste must be burnt in any case. Steam turbines can also be deployed advantageously in industries with greater requirements of both steam and power. They are used in cogeneration or combined heat and power applications where process steam is also used in the turbine to generate electricity. This also results in substantial improvements in overall process efficiency.
The Term Paper on Steam Engine High Pressure
... advances in the design of steam turbines and boilers allowed for higher pressures and temperatures. These advances led to the ... electricity also called for larger steam units in electric power plants. Here too steam turbines replaced steam engines during the early ... cylinders of increasing size for greater expansion of the steam and higher efficiency. Steam flows sequentially through these cylinders. ...
