Page 107 - Handbook of Energy Engineering Calculations

FIGURE 29 Available energy in turbine depends on the initial
steam state and the exhaust pressure.

With the available energy, flow rate, and engine efficiency known, the

work output = (available energy, Btu/lb)(flow rate, lb/s)(engine
efficiency/100)/[550 ft · lb/(s · hp)]. [Note: 550 ft · lb/(s · hp) = 1 N · m/(W ·
s).] For this turbine, work output = (205 Btu/lb) (1000 lb/s) (40/100)/550 =
149 hp (111.1 kW).

Related Calculations. Use the steps given here to analyze single-stage
noncondensing mechanical-drive turbines for stationary, portable, or marine
applications. Performance curves such as Fig. 29 are available from turbine
manufacturers. Single-stage noncondensing turbines are for feed-pump, draft-
fan, and auxiliary-generator drive.

ENERGY OUTPUT ANALYSIS OF CONDENSING STEAM

TURBINE

What is the available energy in steam supplied to a 5000-kW turbine if the
2
inlet steam conditions are 1000 lb/in (abs) (6895 kPa) and 800°F (426.7°C)
and the turbine exhausts at 1 inHg absolute (3.4 kPa)? Determine the
theoretical and actual heat rate of this turbine if its engine efficiency is 74