What are the reasons for modification of Rankine cycle?

Use of Modified Rankine cycle causes the

• Reduction of the bore of cylinder.
• Reduction of the stroke of cylinder.
• Increase the work output of an engine.
• Increase the efficiency of an engine.

What are the modification of Rankine cycle?

Modification of the Rankine cycle involves increasing the final feedwater temperature through use of a Reboiler and an Exergetic Heater. It eliminates cycle efficiency from dependency on turbine steam path pressure.

Why is Rankine cycle used over Carnot?

Heat addition in power plants is at constant pressure whereas it is constant temperature process in Carnot Cycle which is not easily achievable. That is why we don’t go for Carnot cycle in power plants but use a more practical Rankine Cycle.

What is the difference between Rankine and Carnot cycle?

Carnot cycle is a theoretical cycle whereas the Rankine cycle is a practical one. Carnot cycle ensures the maximum efficiency under ideal conditions, but the Rankine cycle ensures the operation in real conditions. The efficiency obtained by the Rankine cycle is always lower than that of the Carnot cycle.

What is modified Rankine cycle give its PV & Ts diagram?

The modified Rankine cycle is represented by 1-2′-3′-3-4-1 cycle on p-v and T-s diagram in Fig. 35.1. In this cycle the expansion is stopped at a pressure called release pressure which is above the condenser (back) pressure and then it falls to the condenser (back) pressure at constant volume.

What is the reason behind the fact that the ideal regenerative cycle is practically not possible?

The ideal regenerative cycle is not practically possible because a heat exchanger cannot be installed inside the turbine as there are more chances for the erosion of the turbine blade (last stage). The thermal efficiency of the ideal regenerative cycle is equal to that of the Carnot cycle.

Why is Rankine cycle less efficient than Carnot?

The thermal efficiency of a Rankine cycle is lower then that of a Carnot cycle operating between the same temperature levels. This is primarily because of the fact that the energy transfer as heat in the boiler does not take place at constant temperature in the Rankine cycle.

Why can’t we use Carnot cycle to Analyse steam power plant instead of Rankine cycle?

However; the Carnot cycle is not a suitable model for steam power cycle since: The turbine has to handle steam with low quality which will cause erosion and wear in turbine blades. Thus, the Carnot cycle cannot be approximated in actual devices and is not a realistic model for vapor power cycles.

Why is Carnot cycle not used in steam power plant?

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.

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 is the difference between a Rankine cycle and a Carnot cycle?

Carnot cycle is an ideal cycle for heat engine which gives highest efficiency between given temperature difference but it is a theoretical cycle and actually no engine works on it. Rankine cycle is an ideal cycle of vapor or steam power generation.

Why Carnot cycle is not suitable for gas power plant?

Carnot Cycle 2. Rankine Cycle 3. Modified Rankine Cycle. For some type of heat engines (gases) heat exchange at constant temperature is impracticable and hence, Carnot cycle cannot be practicable for gas power plants.

What happens to the surroundings during the Carnot cycle?

The surrounding continues to do work on the system. In the Carnot cycle, the total work done is given by difference between the work done on the surroundings (step 1 and 2) and the work done by the surroundings (step 3 and 4). Carnot cycle is the most efficient heat engine in theory.

What is Rankine cycle in power system?

Rankine cycle was described in 1859 by the Scottish enigineer William J.M Rankine. The cycle closely describes the process by which steam-operated heat engines commonly found in thermal power generation plants generate power. Power depends on the temperature difference between a heat source and a cold source.