Low Pressure Steam Turbine For Electricity Generation

ABSTRACT

In this research work a low pressure steam turbine was designed, constructed and tested for the purpose of studying how electrical power can be generated using low pressure steam from concentrated solar power (CSP) sources. The turbine consist essentially of a two cylindrical casings to which stationary blades are fixed on the inside and a shaft carrying rotating blades (rotors) penetrating between the rows of stators. Steam fed into the turbine passes alternately through the stators and rotors with the stators directing the steam at the right angle for impingement to the rotor blades. A seal was applied to the ends of the casing since the shaft of the rotor passes through the ends of the casings. Leakages were not really eliminated but merely controlled to a minimal level, the shaft of the rotors is attached two bearings, one at each end. The data obtained during the experimental operation of the turbine indicates that temperature is maximum at the beginning, that is at inlet to the first stator blade and is around 88oC and the temperature at the exit of the turbine is 59.50C. We also observed that steam velocity is maximum at the inlet to rotor blade and the velocity increases as the steam passes through the stator blades. The velocity is also maximum at the exit of the stator blade and decreases as the steam impinges over the moving blade (rotor blade), and thus satisfies condition of Impulsereaction turbine. The maximum steam velocity at the inlet of the moving blade is 256 m/s and the velocity of steam at the exit of stage is 42 m/s. Again it was also observed that the power output and the thermal efficiency are highest when turbine inlet temperature is increased and the specific steam consumption is least with the increase in turbine inlet temperature. The satisfactory performance at low steam pressure demonstrates that this turbine may be applied in solar-thermal based power generation application where steam pressures are usually low.