What is ideal regenerative cycle?
What is ideal regenerative cycle?
In an ideal regenerative Rankine cycle, steam enters the turbine at the boiler pressure and expands isentropically to an intermediate pressure. Some steam is extracted at this state and routed to the feedwater heater, while the remaining steam continues to expand isentropically to the condenser pressure.
Why ideal regenerative cycle is not practicable?
Although it is more efficient when compared to rankine cycle, this cycle is not practicable for the following reasons. 1) Reversible heat transfer cannot be obtained in finite time. 2) Heat exchanger in the turbine is mechanically impracticable. 3) The moisture content of the steam in the turbine is high.
What is the ideal regenerative reheat cycle?
The ideal regenerative Rankine cycle Heat is transferred to the working fluid during process 2-2 at a relatively low temperature. This lowers the average heat- addition temperature and thus the cycle efficiency. In steam power plants, steam is extracted from the turbine at various points.
What type of process is the ideal Rankine cycle?
Explanation: Ideal Rankine Cycle is a reversible process. Explanation: For analytical purposes, always steady flow operation is considered, as in unsteady flow, the various fluid properties vary considerably which remain same when the steady flow operation is assumed.
What kind of improvement was done in an ideal regenerative Rankine cycle?
Fig. 8: The ideal regenerative Rankine cycle with an open FWH. Thermal efficiency of the Rankine cycle increases as a result of regeneration since FWH raises the average temperature of the water before it enters the boiler. Many large power plants have as many as 8 FWH’s.
What are the four process of Rankine cycle?
The four processes of an ideal Rankine cycle are as follows; Process 1-2: Isentropic compression in a pump. Here the working fluid is pumped from low to high pressure. 2-3: Constant pressure heat addition in the boiler….Thank you.
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What is the efficiency of an ideal regenerative Rankine cycle?
The Effect on Cycle Efficiency
| Cycle Efficiencies | Unmodified Rankine Cycle | Rankine Cycle with Regeneration |
|---|---|---|
| Carnot efficiency | 52.6% | 52.6% |
| Thermal efficiency | 36.2% | 38.4% |
| % Increase in Power Generation | 0% | 6.1% |
| mean temperature of heat addition | 226.7 C | 251.5 C |
What are the main process in the regenerative Rankine cycle?
The Ideal Regenerative Rankine Cycle The regeneration process in steam power plants is accomplished by extracting (or bleeding) steam from turbine at various stages and feed that steam in heat exchanger where the feedwater is heated. These heat exchangers are called regenerator or feedwater heater (FWH).
Which is more efficient reheat cycle or the regenerative cycle?
Small increment in thermal efficiency leads to large investment return and more power production for a given set of operating parameters. Analysis shows that regenerative cycle is more efficient compare to reheat cycle for a given set of operating conditions.
What are the four process in Rankine cycle?
1-2: Isentropic compression in a pump. 2-3: Constant pressure heat addition in a boiler. 3-4: Isentropic expansion in a turbine. 4-1: Constant pressure heat rejection in a condenser.
What is the basic principle of regeneration?
What is the basic principle of regeneration? Explanation: In regeneration steam from condenser is circulated through turbine to increase steam temperature before it enters boiler. Explanation: Feedwater is preheated so as to decrease the fuel consumption which increases efficiency.
What are the disadvantages of a regenerative Rankine cycle?
Disadvantages of regenerative power cycle: The plant becomes more complicated and cost. The added heater in the circuit increases the maintenance is required. For a given power a large capacity of boiler is required.
How does the ideal regenerative Rankine cycle work?
In an ideal regenerative Rankine cycle with a closed feedwater, steam from the boiler (state 4) expands in the turbine to an intermediate pressure (state 5). Then some of the steam is extracted at this state and sent to the feedwater heater, while the remaining steam in the turbine continues to expand to…
How are regenerative cycles used in steam power plants?
This is done either by direct mixing of the fluids (Open Feedwater Heater) or through a heat exchanger (Closed Feedwater Heater), In many practical steam power plants various combinations of open and closed feedwater heaters are used, and systems using them are generally referred to as Regenerative Cycles.
How is work output reduced in a regenerative cycle?
Notice that the work output is reduced by having bled off a fraction y of the steam, and the boiler heat input is reduced by the increased temperature of the compressed liquid entering the boiler T 9. Thus: We always confirm our results by the alternate evaluation of efficiency using the heat flow out from the condenser to the cooling water:
Which is the ideal reheat cycle for a power plant?
The Ideal Regenerative Reheat Cycle using both an Open and a Closed Feedwater Heater. In a practical power plant one may find various combinations of closed and open feedwater heaters. For example the Gavin Power Plant has one open- and 7 closed-feedwater heaters in each of the two sections of the plant