Steam turbine/generator

A wide variety of turbine types and arrangements are used in modem power plants. For example, some smaH industrial plants may use only a single condensing turbine. Prepackaged steam/turbine generator systems can be economical for small-to-midsize instaHations. 

W. T. Lindsay, Jr., Proceedings of the Westinghouse Steam Turbine-Generator Symposium, Charlotte, N.C., 1978. 

Ejftciency Factors Representative efficiency data for boilers, pyrolytic reacdors, gas turbines, steam-turbine-generator combinations, electric generators, and related plant use and loss factors are... 

OPTIONS WITH STEAM-TURBINE-GENERATOR COMBINATION... 

Boyce, M.P., Performance Characteristics of a Steam Turbine in a Combined Cycle Power Plant, Proceedings of the 6th EPRI Steam Turbine Generator/ Workshop, August 1999. 

In the United States the early decades of the new centuiy were dominated by ever-increasing size steam-turbine generators with capacities that reached over a thousand megawatts, and transmission voltages (the highest ones now often dc) above 700,000 volts. But after mid-centnrv these economies of... 

Parsons adopted this multistage design to reduce turbine operating speeds to a useful level. His initial turbine was developed to produce electricity onboard ships and had an output of about 7 kW. In 1888 he designed the first steam turbine generating unit for public utility sei-vicc. By the time of his death in 1931, his company manufactured turbines generating more than. 30,000 kW. 

The first three boiler types may be variously used for commercial, institutional, or industrial applications. Fire tube boilers also may be used for steam turbine generator duty at lower electrical outputs, whereas only WT and nuclear reactor boilers are employed for utility power generation. 

If a steam turbine generates electricity, then the flow through the turbine can be varied within the minimum and maximum flows allowed by the machine. If a steam turbine is connected directly to a drive (e.g. a back-pressure turbine driving a large pump), then there is likely to be no flexibility to change the flowrate through the steam turbine as this is fixed by the power requirements of the process machine. 

Coal gasification offers a more efficient way to generate electric power than conventional coal-burning power plants. In a conventional plant, heat from the coal furnaces is used to boil water, creating steam for a steam-turbine generator. 

Steam turbines are an even older technology, providing power for over 100 years. Most utility power is produced by steam turbines. The steam turbine generator depends on a separate heat source for steam, often some type of boiler, which may run on a variety of fuels, such as coal, natural gas, petroleum, uranium, wood and waste products including wood chips or agricultural by-products. 

Steam turbine generators range from 50-kW to hundreds of megawatts. By 2000, almost 20,000-MW of boiler and steam turbines were used... 

FCE, of Danbury, CT, teamed with Allison Engine Company to evaluate a carbonate fuel cell combined with a gas turbine and a steam turbine generator. The system was operated at ambient pressure. The net power of the hybrid system was 20.6 MW and the NOx levels were less than 1 ppm. The process showed a 65 % efficiency with off-the-shelf turbomachinery and 72 % efficiency with cycle specific machinery. The COE is predicted to be comparable to present day alternatives. 

The facility consists of two whole-tire boilers that together generate 125,000 pounds per hour of 930 psig steam.6 The output steam of the 80-foot high boilers combines to drive a 15.4 MW General Electric steam turbine generator. Figure 3-1 provides a schematic of the process flow at Oxford. 

In the case of "flash steam" power plants, the steam is either generated directly by the production wells or the wells produce hot water from which steam can be separated to drive conventional steam turbine generators. The size of these plants ranges from 100 kW to 150 mW. Figure 2.104 illustrates the optimizing control system for such a geothermal facility. 

For a modern gas-fired power station in the UK the electrical efficiency is about 45% and for a coal-fired station about 37%. There are combined cycle plants in which the waste heat from the gas turbines is used to produce steam that in turn drives a steam turbine generator. Such combinations, which are... 

Today s biopower capacity is based on mature, direct-combustion boiler/steam turbine technology. The average size of biopower plants is 20 MW (the largest approach 100 MW) and the average efficiency from steam-turbine generators is 17 to 25 percent. The small plant sizes lead to higher capital cost per kilowatt-hour of power produced and the low electrical conversion efficiencies increase sensitivity to fluctuations in feedstock price.658... 

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