Why reheating is used in some power plants?

Reheating increases the efficiency by raising the mean temperature of the heat addition process, by increasing the steam temperature at the turbine inlet and also by increasing the efficiency of the expansion process in the steam turbine.

What is reheating in power plant?

Reheat turbines are also used almost exclusively in thermal power plants. All turbines, that have high-pressure turbine and low-pressure turbines use a steam reheat between these stages. Reheat allows to deliver more of the heat at a temperature close to the peak of the cycle (i.e. thermal efficiency increases).

What is the use of reheat *?

What is the use of reheat cycle in steam turbines? Explanation: Reheat cycle is worked with rankine cycle to remove the moisture from the steam.

What is reheat and non reheat turbine?

description. In turbine: Reheat and nonreheat turbines. If high-pressure, high-temperature steam is partially expanded through a turbine, the efficiency can be increased by returning the steam to the steam generator and reheating it to approximately its original temperature before feeding it back to the turbine.

What is the efficiency of Rankine cycle?

In modern nuclear power plants, which operate the Rankine cycle, the overall thermal efficiency is about one-third (33%), so 3000 MWth of thermal power from the fission reaction is needed to generate 1000 MWe of electrical power.

What is the effect of reheat on heat rate?

Heat rate can be improved through reheating, depending on the respective final feed temperature for either single or double reheat cycles. Increasing reheat temperature reduces leakage and blading losses, and increases cycle available energy.

Which power plant has minimum operating cost?

Which power plant has minimum operating cost? Explanation: Hydroelectric power plant has lowest running cost because it does not needs any fuel and can be operated by few number of persons. Nuclear gas and thermal power plant requires fuels also the handling cost of fuels is added with the total cost. 3.

Is used to heat feed water?

Superheater: A superheater is a device used to convert saturated steam or wet steam into superheated steam or dry steam. While the temperature of the steam in the superheater rises, the pressure remains the same as that of the boiler.

Is one of the advantage of reheat cycle?

Advantages: The advantages of using a reheat cycle are higher thermal efficiency, reduced feed water pump power, smaller condenser, smaller boiler, long life of the turbine and less handling of the fuel and firing requirement.

What is the effect of reheat on stream quality?

Reheat not only effectively reduced the penalty of the latent heat of vaporization in steam discharged from the low-pressure end of the turbine cycle, but it also improved the quality of the steam at the low-pressure end of the turbines by reducing condensation and the formation of water droplets within the turbine.

What is non reheat turbine?

Page 1. Non reheat steam turbines are efficient, flexible and reliable machines based on a broad design platform, capable of satisfying a wide range of steam cycles, site conditions and operating modes for both 50 and 60 Hz applications.

What are the purpose of reheating of steam?

The main purpose of reheating is to avoid excess moisture in steam at the end of expansion to protect the turbine.

How are reheat steam turbines used in power plants?

Reheat steam turbines are also used almost exclusively in thermal power plants. This requires the addition of another type of heat exchanger called a reheater. Thermal Engineering Steam turbines may be classified into different categories depending on their purpose and working pressures.

What does cold reheat mean in a steam cycle?

Mollier chart for a A-USC steam cycle using the design configuration depicted in Fig. 2.1. After expansion in the HP turbine, the HP steam turbine exhaust is called cold reheat and enters the reheater section in the boiler, where its temperature is raised to 760 °C (1400 °F), as shown in point C.

Why do you need drain pots for cold reheat?

Drain pots are provided for draining condensate from cold reheat pipelines and other steam pipelines prone to water accumulation from which there is concern of water/wet steam entering the hot turbine. Entry of water/wet steam would cause serious damage to steam turbines and should be prevented by all means.

Where does the water go after cold reheat?

Drains from this system are transferred to the condenser. Drain pots are provided for draining condensate from cold reheat pipelines and other steam pipelines prone to water accumulation from which there is concern of water/wet steam entering the hot turbine.