Turbines, steam single stage

FIG. 29-15 Approximate steam rate for single-stage turbines. To convert pounds per Idlowatthour to kilograms per Idlo-watthour, multiply by 0.4537 to convert inches to meters, multiply by 0.02 and to convert pounds per borsepower-bour to kilograms per Idlowattbour, multiply by 0.6084. 

As steam temperatures increase, more expensive materials must be used to manufacture the turbine. Above 750" F, the price increase will be about 5% to about 850°F. Another 5% will be added for temperatures between 850°F and 900°F, and another 5% for temperatures above 900°F Steam turbine designers have selected as a standard for single-stage turbines a limit of 600 psia and 750°F maximum inlet steam conditions. 

Steam cost, and the value of turbine efficiency. Should it be single-stage or multistage Should it be single-valve or multivalve Is the steam an inexpensive process by-product, or is the entire cost of generating the steam chargeable to the driver ... 

TTiere are two main types of expansion turbines axial flow and radial flow. Axial flow expansion turbines are like conventional steam turbines. They may be single-stage or multistage with impulse or reaction blading, or some combination of the two. Turbines of this type are used as power recovery turbines. They are used where flow rates, inlet temperatures, or total energy drops are very high. 

Turbine designers had been experimenting with machines in which the blades were driven by a high-velocity steam jet that expanded through them in a single stage. It had been shown that steam-jet velocities of the order of 1000 m/s were required. 

Figure 14-16B. View of Elliott YR Single Stage Steam Turbine, with top cover removed. (Used by permission Elliott Co.)...

Figure 14-16G. Impulse type single stage steam turbine with shaft type governor. (Used by permission Westinghouse Electric Corp., Steam Div.)...

The TSR can be obtained from published manufacturers tables. For estimating condensing steam rates for single-stage turbines, refer to Figures 14-21 and 14-22. 

Figure 14-22. Steam rate estimating curves for single-stage turbines. (Used by permission Althearn, F. H. Hydrocarbon Processing, p. 87, Aug. 1979. Gulf Publishing Co. All rights reserved.)...

Figure 14-30. No-load flow factors for single-stage general-purpose turbine. (Used by permission Westinghouse Eiectric Corp., Steam Division.)...

General Purpose Steam Turbines, Single Stage, Bulletin 1110, Performance, Westinghouse Electric Corp., Philadelphia, PA, August (1954). 

The single-stage, single-valve turbine is the simplest option. Such a machine is suitable for applications requiring powers up to 300 kW, steam conditions up to a nominal 115 bar, 530°C and rotational speeds... 

Figure 15.37 A single-stage steam turbine driving an alternator...

No matter the duty (utilities excepted), most boiler plant systems employ electric motor-driven, single-stage or multistage centrifugal pumps to supply FW. These may be of conventional design or derivations such as a turbine pump. However, steam-driven reciprocating FW pumps (steam pumps) are still employed in some countries and for certain smaller applications. 

These larger turbines often let down the steam in two or more stages. They are called multistage turbines. Their principle of operation is not significantly different from a simple single-stage machine. 

Average efficiency of single-stage turbines (noncondensing, dry, and saturated steam). 

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