Abstract: The wet steam exiting a low pressure steam turbine does not rapidly attain thermodynamic equilibrium because insufficient condensation nuclei are present in the phase transition zone inside the turbine. Therefore, the steam is subcooled, decreasing the power generated by the turbine, and the liquid water carried by the steam consists of relatively coarse droplets which strike the surface of the turbine blades causing erosion. Corona electrodes installed inside the turbine before the saturation line create electrically charged particles which serve as condensation nuclei, decreasing subcooling, and producing a large number of fine droplets. Thereby, thermodynamic equilibrium is more closely approached, more power is generated, and smaller water droplets cause less erosion inside the turbine.

Abstract: Small, rigid electrodes in the form of sharp-pointed rods (“pins”) installed around the periphery of the diffuser at the exhaust of a steam turbine extend into the path of the wet steam flowing out of the turbine and remove electric charge from the steam, whereby turbine back-pressure and turbulence within the exhaust hood are decreased, and the energy conversion efficiency of the power generating unit is increased. In the preferred embodiment these pins are grounded, but pin electrodes isolated from electrical ground with a suitable voltage applied may give better performance in some situations. Similar pins may be installed around the bearing cone facing the turbine exhaust, along the L-stage guide blades, or along the trailing edges of flow guides or baffle plates within the exhaust hood and condenser to remove from the steam charge that may be present in the steam in those places, whereby energy conversion efficiency is likewise increased.

Abstract: Small, rigid electrodes in the form of sharp-pointed rods (“pins”) installed around the periphery of the diffuser at the exhaust of a steam turbine extend into the path of the wet steam flowing out of the turbine and remove electric charge from the steam, whereby turbine back-pressure and turbulence within the exhaust hood are decreased, and the energy conversion efficiency of the power generating unit is increased. In the preferred embodiment these pins are grounded, but pin electrodes isolated from electrical ground with a suitable voltage applied may give better performance in some situations. Similar pins may be installed around the bearing cone facing the turbine exhaust, along the L-stage guide blades, or along the trailing edges of flow guides or baffle plates within the exhaust hood and condenser to remove from the steam charge that may be present in the steam in those places, whereby energy conversion efficiency is likewise increased.

Abstract: Sufficient negative charge density may be present in the wet steam flowing through the exhaust hood of a steam power generating unit to cause intense electrical discharges which cause severe corrosion of exposed carbon steel members and generate turbulence, decreasing power output. The electric charge density is proportional to current from a charge probe exposed to the flowing steam to ground. Electric charge density can be controlled by adjusting the concentration of ammonia in the steam supply. A small positive charge density will eliminate corrosion and minimize turbulence related to electrical discharges, thereby increasing power generated. The amount of negative charge released can also be decreased by cladding the portions of the flow guides and other carbon steel members located near to the turbine exhaust with stainless steel, or with an appropriately chosen insulating composition.