All power plants use superheated steam due to which of the following a

1.	All power plants use superheated steam due to which of the following advantages?1. Superheating is mostly done from waste heat of boiler without additional cost of fuel.2. The plant efficiency increases due to higher temperature of steam.3. There is less corrosion and erosion of equipment due to absence of moisture in the steam.Select the correct answer using the code given below:1. 1 and 2 only2. 2 and 3 only3. 1 and 3 only4. 1, 2 and 35.
Answer» Correct Answer - Option 2 : 2 and 3 only Explanation: Superheating of steam: The primary object of superheating steam is to avoid too much wetness at the end of the expansion. The use of an inadequate degree of superheat in steam engines would cause greater condensation in the engine cylinder, while in the case of turbines the moisture content of steam would result in undue blade erosion. Advantages of superheated steam: Superheating reduces the initial condensation losses in steam engines. Improves efficiency as power plant efficiency is a function of inlet temperatures. This saving results due to the fact that the heat content and consequently the capacity to do work in superheated steam is increased and the quantity of steam required for a given output of power is reduced. Although additional heat has to be added in the boiler there is the reduction in the work to be done by the feed pump, the condenser pump and other accessories due to a reduction in the quantity of steam used. Prevents blade erosion as moisture content is minimized. When a superheater is used in a boiler it helps in reducing the stack temperatures by extracting heat from the flue gases before these are passed out of chimney. Regeneration: Regeneration means to take some part of the heat from the expanding steam in the turbine to decrease the overall heat supplied in the process, therefore statement 1 is wrong.

All power plants use superheated steam due to which of the following advantages?1. Superheating is mostly done from waste heat of boiler without additional cost of fuel.2. The plant efficiency increases due to higher temperature of steam.3. There is less corrosion and erosion of equipment due to absence of moisture in the steam.Select the correct answer using the code given below:1. 1 and 2 only2. 2 and 3 only3. 1 and 3 only4. 1, 2 and 35.

Answer» Correct Answer - Option 2 : 2 and 3 only

Explanation:

Superheating of steam: The primary object of superheating steam is to avoid too much wetness at the end of the expansion. The use of an inadequate degree of superheat in steam engines would cause greater condensation in the engine cylinder, while in the case of turbines the moisture content of steam would result in undue blade erosion.

Advantages of superheated steam:

Superheating reduces the initial condensation losses in steam engines.
Improves efficiency as power plant efficiency is a function of inlet temperatures.
This saving results due to the fact that the heat content and consequently the capacity to do work in superheated steam is increased and the quantity of steam required for a given output of power is reduced. Although additional heat has to be added in the boiler there is the reduction in the work to be done by the feed pump, the condenser pump and other accessories due to a reduction in the quantity of steam used.
Prevents blade erosion as moisture content is minimized.
When a superheater is used in a boiler it helps in reducing the stack temperatures by extracting heat from the flue gases before these are passed out of chimney.

Regeneration:

Regeneration means to take some part of the heat from the expanding steam in the turbine to decrease the overall heat supplied in the process, therefore statement 1 is wrong.

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