Power Plant Engineering Questions and Answers Part-14

1. What do you mean by vent condenser?
a) a condensing unit
b) a temperature measuring instrument
c) a heat exchanger
d) dissolves oxygen

Answer: c
Explanation: Feedwater is passed through a heat exchanger commonly called as vent condenser.

2. How dissolved oxygen and carbon dioxides are removed?
a) by allowing it to fall from height
b) by series of chemical reactions
c) by condensing feedwater
d) by heating feedwater to saturation temperature

Answer: d
Explanation: The solubility of these gases decreases with an increase in temperature.

3. What chemicals are added for residual dissolved oxygen and carbon dioxide?
a) sodium sulphite
b) hydrazine
c) alum
d) all of the mentioned

Answer: d
Explanation: Na2SO3 and N2H4 are used to remove residual gasses.

4. Why deaerator is installed at a certain height from the pump?
a) to provide a net positive suction head
b) to maintain less pressure
c) to avoid leakage
d) to maintain pressure

Answer: a
Explanation: Deaerator is installed at a certain height from the pump so as to maintain a optimum pressure before suction.

5. Why deaerator is not used in water cooled and moderated nuclear power plant?
a) radioactivity
b) not economical
c) not safe
d) not mechanically possible

Answer: a
Explanation: deaerator is not used in water cooled and moderated nuclear power plant because of the concern regarding radioactivity release with deaeration.

6. What is the location of high pressure heaters?
a) after the deaerator
b) before the deaerator
c) middle of deaerator
d) depends on pressure conditions

Answer: b
Explanation: The feedwater heaters before the deaerator are often called high pressure heaters(h.p.).

7. What is the location of low pressure heaters?
a) after the deaerator
b) before the deaerator
c) middle of deaerator
d) depends on pressure conditions

Answer: a
Explanation: The feedwater heaters after the deaerator are often called low pressure heaters(l.p.).

8. Steam used to heat water comes from?
a) boiler
b) turbine
c) condenser
d) external power source

Answer: b
Explanation: Steam from turbine is at high pressure and temperature.

9. What percentage of fuel energy is actually converted to electrical energy?
a) 50%
b) 40%
c) 34%
d) 25%

Answer: c
Explanation: In overall process due to losses the 66% of energy is lost.

10. Maximum energy of a power plant is lost in __________
a) condensor
b) pump
c) boiler
d) environment

Answer: a
Explanation: In a condensor heat is rejected to cooling water. This is the loss due to heat to work energy conversion in the cycle.