Which of the following statements is not correct for...

Name: Problem 16, Chapter 4: Thermal Engineering
Uploaded: 2021-11-24T19:56:26-08:00
Duration: 1 min 7 s
Channel: Hunza Gilgit
Description: Which of the following statements is not correct for regenerative steam cycle? (a) It increase thermodynamic efficiency. (b) It reduces boiler capacity for a given output. (c) It reduces temperature stresses in the boiler due to hotter feed. (d) The efficiency increases with increased number of feed heaters.

Which of the following statements is not correct for regenerative steam cycle? (a) It increase thermodynamic efficiency. (b) It reduces boiler capacity for a given output. (c) It reduces temperature stresses in the boiler due to hotter feed. (d) The efficiency increases with increased number of feed heaters.

Which of the following statements is not correct for regenerative steam cycle?
(a) It increase thermodynamic efficiency.
(b) It reduces boiler capacity for a given output.
(c) It reduces temperature stresses in the boiler due to hotter feed.
(d) The efficiency increases with increased number of feed heaters.

Key Concepts

Temperature Stresses in Boilers

Temperature stresses in boilers are caused by high thermal gradients between the feedwater and the heated surfaces. Preheating the feedwater in a regenerative cycle generally minimizes these gradients, helping to reduce thermal shock and stress on boiler components. However, the balance between reduced gradients and the effects of higher inlet water temperatures is an important design consideration.

Boiler Capacity

Boiler capacity pertains to the amount of heat transfer surface or energy input required to produce steam at the desired rate. In regenerative cycles, preheating the feedwater lowers the heat duty required in the boiler, which can effectively reduce the necessary boiler capacity for a given output, leading to more optimized and compact system designs.

Feedwater Heating

Feedwater heating involves raising the temperature of the water before it is fed into the boiler. By using extracted steam to preheat the water, the energy required in the boiler to reach vaporization temperatures is reduced. This process not only increases efficiency but can also impact boiler design by potentially reducing the required capacity.

Regenerative Steam Cycle

A regenerative steam cycle is a modification of the conventional steam cycle where part of the steam, extracted from the turbine at intermediate stages, is used to preheat the boiler feedwater. This process enhances efficiency by recovering energy that would otherwise be wasted, leading to improved fuel utilization and overall performance of the thermal power plant.

Thermodynamic Efficiency

Thermodynamic efficiency in steam cycles is the measure of how effectively the thermal energy input is converted into mechanical work. The regenerative cycle, through feedwater heating, minimizes energy losses and increases the average temperature at which heat is added to the cycle, thereby contributing to a higher efficiency.

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