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Steam Temp 700" I-800'F 900T

200 4,00 600 SOQ 10001200 1400 Steam Ptess'jrs, psia

Steam Temp 700" I-800'F 900T

200 4,00 600 SOQ 10001200 1400 Steam Ptess'jrs, psia

Figure 8-41 Full-Load Steam Production Capability for Exhaust of

17,000 hp Single-Shaft Gas Turbine at ISO Conditions.

Source: United States Turbine Corp./Mitsubishi Heavy Industries, Ltd.

exhaust flow would be adjusted by multiplying the exhaust flow of385,000 lbm (175,000 kg) per hour at ISO conditions by 0.95, which would yield a corrected exhaust flow rate of about 366,000 lbm (166,000 kg) per hour. In this example, exhaust temperature is not affected by elevation.

2. If actual site ambient temperature was 80°F (27°C), the correction factor for exhaust flow would be about 0.95 and the correction factor for exhaust temperature would be about 1.02. Thus, the rated temperature of 1,017°F (547°C) would be corrected to 1,037°F (558°C) and the exhaust mass flow would be corrected to 347,700 lbm (157,715 kg) per hour.

3. The temperature correction factor for inlet pressure drop is to add 6.7°F (3.7°C) for every 10 in. (25 cm) of water excess loss in inlet above the base condition of 3 in. (8 cm) of water. At 2 in. (5 cm) of excess loss, the temperature correction would be 1.34°F (0.74°C), yielding a corrected exhaust temperature of about 1,038.3°F (559.1°C). Correspondingly, the correction factor for exhaust mass flow at 10 in. (25 cm) of excess loss in inlet is about 0.975, which would yield a corrected exhaust mass flow of 339,008 lbm (153,773 kg) per hour.

4. The temperature correction factor for exhaust pressure drop is to add 1.04°F (0.58°C) for every inch of water excess loss in exhaust, above the base condition of 3 in. (7.6 cm) of water. At 8 in. (20 cm) of excess loss, the temperature correction would be 5.36°F (2.98°C), yielding a corrected exhaust temperature of about 1,044.2°F (562.3°C). No exhaust flow correction is required.

5. If steam injection was applied at a rate of 1 lbm per lbm of fuel, the exhaust mass flow correction factor would be about 1.02, yielding a corrected exhaust mass flow of 345,788 lbm (156,848 kg) per hour. The temperature correction factor would be about 1.01, yielding a corrected exhaust temperature of about 1,054.6°F (568.1°C).

6. Finally, exhaust mass flow and temperature must be corrected for part-load operation at each load point over the operating regime. Exhaust mass flow tends to remain constant under part-load operation of single-shaft gas turbines and decrease with multi-shaft turbines. When inlet guide vanes (IGVs) are used with single-shaft turbines, exhaust mass flow is reduced as load is decreased over the upper part of the operating range. Flow tends to remain constant below 60 to 80% of full load, depending on ambient temperature. In this example, IGVs are used to maintain a constant exhaust temperature down to about 60% of full load. At that operating point, the correction factor for exhaust mass flow is about 0.79. At

90% of full load, for example, the correction factor for exhaust mass flow is about 0.95. Summary equations that would be used to apply the correction factors discussed above are as follows:

Exhaust = EMFjso x EFj x EF2 x EF3 x EF5 x EF$ mass flow (8-7)

Exhaust = (ETiso x ET2 x ET5 x ETg) + ET3 + ET4 temperature (8-8)

Where subscripts:

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