What are the disadvantages of reheat cycle?
Disadvantages of Reheating: 1- Reheating requires more maintenance. 2- The increase in thermal efficiency is not appreciable in comparison to the expenditure incurred in reheating.
What are the effects of reheat cycle?
The reheat cycle increases the turbine work and consequently the net work of the cycle. This is accomplished not by changing the compressor work or the turbine inlet temperature but instead by dividing the turbine expansion into two or more parts with constant pressure heating before each expansion.
Which of the following is true about reheat cycle?
Which of the following is true about a reheat cycle? Explanation: This is the functioning of a reheat cycle. Explanation: Here HP is the high pressure turbine and LP is the low pressure turbine. 10.
What is the effect of reheat on system quality?
Explanation: Reheat increases work output.
Does reheat increase efficiency?
A high reheat pressure increases the the moisture content at turbine exhaust which results in scaling and it should be optimised. Thus the work produced is increased ,thereby efficiency increases.
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.
Why reheating of system is used?
The main purpose of reheating is to avoid excess moisture in steam at the end of expansion to protect the turbine. But it need not improve the cycle efficiency.
Why both reheating and regeneration is used together?
Explanation: When vaporization pressure is high, the reheating of steam is adopted. 2. Why both reheating and regeneration is used together? Explanation: Thus a modern steam power plant has both reheating and regeneration.
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 purpose of reheating?
The main purpose of reheating is to avoid excess moisture in steam at the end of expansion to protect the turbine. But it need not improve the cycle efficiency. That will depend (as Dmitri said) upon whether the mean temperature of reheat addition is > or < the mean temperature of heat addition before reheat.
What is the effect of reheat in steam quality?
In case of two reheats, steam is super-heated twice at different constant temperatures. A high reheat pressure increases the the moisture content at turbine exhaust which results in scaling and it should be optimised. Thus the work produced is increased ,thereby efficiency increases.
How can I improve my Rankine efficiency?
There are three ways to increase the efficiency of the simple ideal Rankine cycle.
- Decreasing the condenser pressure. The effect of lowering the condenser pressure on the Rankine cycle efficiency is illustrated on a T-s diagram on the left.
- Superheating the steam to a high temperature.
- Increasing the boiler pressure.
What is the efficiency of a reheat cycle?
Setting 90% quality at the low-pressure turbine outlet, CyclePad tells us that we can set the pressure at the outlet of the first turbine to over 2 MPa. With this modification, we raise the mean temperature of heat addition to nearly 274 C, improving our overall cycle efficiency to 41.7%.
Where does the steam go in the reheat cycle?
The steam expands in the high-pressure turbine to some intermediate pressure, then passes back to the boiler, where it is reheated at constant pressure to a temperature that is usually equal to the original superheat temperature. This reheated steam is directed to the low-pressure turbine, where is expanded until the condenser pressure is reached.
How is a reheat cycle related to intercooling?
This cycle modification, as shown in Fig. 1.8, is known as reheating. By reasoning similar to that used in connection with intercooling, it can be seen that the thermal efficiency of a simple cycle is lowered by the addition of reheating, whereas the work output is increased.
How does the reheat cycle increase turbine work?
The reheat cycle increases the turbine work and consequently the net work of the cycle. This is accomplished not by changing the compressor work or the turbine inlet temperature but instead by dividing the turbine expansion into two or more parts with constant pressure heating before each expansion.
