Turbine Operation In Thermal Power Plant Pdf

Mitsubishi Heavy Industries. Tandem compound are used where two or more casings are directly coupled together to drive a single generator. This is also known as a Rateau turbine, after its inventor.

Steam turbine

Turbine operation in thermal power plant pdfSteam turbine

The exhausted steam is condensed in the condenser by means of cold water circulation. To measure how well a turbine is performing we can look at its isentropic efficiency. Less initial cost as compared to other generating stations.

Steam turbine

Turbine operation in thermal power plant pdf

Basic Layout and Working of a Thermal Power Plant

Condensing turbines are most commonly found in electrical power plants. Induction turbines introduce low pressure steam at an intermediate stage to produce additional power.

However, once fully geared turbines proved economical in initial cost and fuel they were rapidly adopted, with cruising turbines also included on most ships. This reduces the creep mechanisms experienced in the blade. The Ecuadorian Navy currently operates two steam-powered Condell -class frigates modified Leander -class frigates.

That is why the efficiency of thermal plants is quite low. Because of the high pressures used in the steam circuits and the materials used, steam turbines and their casings have high thermal inertia. Thus, conventional steam power is used in very few new ships. The cost of generation is lesser than that of diesel power plants. Nozzles appear similar to blades, but their profiles converge near the exit.

This would be a speed used on long voyages when fuel economy is desired. Extracting type turbines are common in all applications. This was more efficient with high-pressure steam due to reduced leakage between the turbine rotor and the casing. The condenser provides a vacuum that maximizes the energy extracted from the steam, and condenses the steam into feedwater to be returned to the boilers.

The advent of large steam turbines made central-station electricity generation practical, since reciprocating steam engines of large rating became very bulky, and operated at slow speeds. Reheat turbines are also used almost exclusively in electrical power plants. Although this brought the propeller speeds down to an efficient range, turbine efficiency was greatly reduced, and early turbine ships had poor cruising ranges. Also, there were three propellers on each shaft for operation at high speeds. Because of the high temperatures and high stresses of operation, thinking of java pdf steam turbine materials become damaged through these mechanisms.

Nozzles move due to both the impact of steam on them and the reaction due to the high-velocity steam at the exit. The main advantages of a steam turbine locomotive are better rotational balance and reduced hammer blow on the track.

Basic Layout and Working of a Thermal Power PlantAdvertisement

During normal operation, rotor imbalance can lead to vibration, which, because of the high rotation velocities, could lead to a blade breaking away from the rotor and through the casing. Protective coatings are used to reduce the thermal damage and to limit oxidation.

This further increased the turbine speed above the shaft speed, allowing smaller turbines than single-reduction gearing. Blades move entirely due to the impact of steam on them and their profiles do not converge.

Normally the changes in speed are minor. The nickel-based blades are alloyed with aluminum and titanium to improve strength and creep resistance. The Parsons turbine also turned out to be easy to scale up.

The stage efficiency defines a relationship between enthalpy drop in the nozzle and work done in the stage. Due to this high ratio of expansion of steam, the steam leaves the nozzle with a very high velocity. The steam then changes direction and increases its speed relative to the speed of the blades. Practical thermal efficiency of a steam turbine varies with turbine size, load condition, gap losses and friction losses. The mixture of pulverized coal and air usually preheated air is taken into boiler and then burnt in the combustion zone.

This results in a steam velocity drop and essentially no pressure drop as steam moves through the blades. Reduction gears allowed turbines to operate in their efficient range at a much higher speed than the shaft, but were expensive to manufacture. One set of stationary blades is connected to the casing and one set of rotating blades is connected to the shaft. These coatings are often stabilized zirconium dioxide -based ceramics. Newer Post Older Post Home.

The effect of expansion of steam over the moving blades is to increase the relative velocity at the exit. The MacTutor History of Mathematics. The steam then goes back into an intermediate pressure section of the turbine and continues its expansion. His patent was licensed and the turbine scaled-up shortly after by an American, George Westinghouse.

Typical layout and working of a Thermal Power Plant

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British, German, other national and international test codes are used to standardize the procedures and definitions used to test steam turbines. It passes through five Curtis wheels and numerous reaction stages the small blades at the edges of the two large rotors in the middle before exiting at low pressure, almost certainly to a condenser. Non-condensing or back pressure turbines are most widely used for process steam applications, in which the steam will be used for additional purposes after being exhausted from the turbine. After the steam passes through the steam turbine, it is condensed in a condenser and again fed back into the boiler to become steam. Efficiency of a Thermal Power Station.