Power Plant Questions and Answers – Optimum Degree of Regeneration

This set of Power Plant Engineering Multiple Choice Questions & Answers (MCQs) focuses on “Optimum Degree of Regeneration”.

1. What is the value of “beta” if h represents the local enthalpy on the given expansion line at a given pressure & h_f is the enthalpy of saturated water at that pressure?
a) h + h_f
b) h x h_f
c) h – h_f
d) none of the mentioned
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2. The expression for temperature rise t in feedwater heater when a & b are the temperatures of boiler saturation & condenser respectively, is given by which of the following expression?
a) t = 0.5 (a x b)
b) t = 0.5 (a / b)
c) t = 0.5 (a + b)
d) t = 0.5 (a – b)
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3. What happens to the feedwater that enters the economiser?
a) Feedwater is heated to the saturation temperature at the boiler pressure
b) Feedwater is heated to the boiler temperature at the saturation pressure
c) Feedwater is cooled to the saturation temperature
d) Feedwater is cooled at the boiler pressure
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4. The economiser can also be assumed as?
a) Feedwater cooler
b) Feedwater heater
c) Economiser has nothing to do with Feedwater
d) None of the mentioned
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5. The feedwater in the Economiser _________
a) is heated by bled turbine steam
b) is cooled by bled turbine steam
c) is heated by outgoing flue gases
d) is cooled by outgoing flue gases
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6. The temperature rise from condenser to boiler saturation is divided __________ among the feedwater heaters for maximum gain in efficiency.
a) unequally
b) partially
c) equally
d) remains undivided
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7. What is the expression for enthalpy of each heater h_{per heater} if a represents the enthalpy of heated feedwater from the economiser and b represents the enthalpy at condenser & n represents the number of heaters?
a) h_{per heater} = (a-b)/ (n + 1)
b) h_{per heater} = (a-b) x (n – 1)
c) h_{per heater} = (a-b) + (n – 1)
d) h_{per heater} = (a-b) – (n + 1)
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8. If n denotes the number of heater, t_OA denotes the overall temperature difference & T_fw denotes the total temperature rise of feedwater. The expression for T_fw is?
a) (n/(n+1)) x t_OA
b) (n/(n-1)) x t_OA
c) (n/(n+1)) / t_OA
d) (n/(n+1)) – t_OA
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9. The expression for the overall temperature difference T_OA is given by?
a) t_OA = boiler saturation temperature – condenser temperature
b) t_OA = boiler saturation temperature + condenser temperature
c) t_OA = boiler saturation temperature x condenser temperature
d) t_OA = boiler saturation temperature / condenser temperature
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10. Efficiency gain follow the law of ____________
a) diminishing forward motion
b) increasing return
c) decreasing return
d) none of the mentioned
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11. The number of heaters for a plant is fixed by?
a) Mass Balance
b) Energy balance
c) Heat balance
d) None of the mentioned
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12. The effect on the degree of regeneration due to an increase in feedwater temperature is?
a) degree of regeneration increases
b) degree of regeneration decreases
c) degree of regeneration remain same
d) degree of regeneration is optimised
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13. The expression for efficiency when a & b are two constants corresponding to alpha & beta and c corresponds to gamma, is?
a) Efficiency = 1 – ((b²))/((b + c)(a + b – c)))
b) Efficiency = 1 + ((b²))/((b + c)(a + b – c)))
c) Efficiency = ((b²))/((b + c)(a + b – c)))
d) Efficiency = 1 / ((b²))/((b + c)(a + b – c)))
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14. What is the relation between a & c if a & c correspond to alpha & gamma respectively, for maximum efficiency of a cycle?
a) a = 3c
b) c = 2a
c) c = (a/3)
d) a = 2c
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15. The expression for efficiency gain due to regeneration if a, b, n correspond to alpha, beta, cycle efficiency respectively, is?
a) n = ((a x a x b)/((a + b)(a + 2b)²))
b) n = ((a x a x b)/((a – b)(a + 2b)²))
c) n = ((a x a x b)/((a + b)(a + b)²))
d) n = ((a x a x b)/((a + b)(a + 2b)³))
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Sanfoundry Global Education & Learning Series – Power Plant Engineering.

To practice all areas of Power Plant Engineering, here is complete set of 1000+ Multiple Choice Questions and Answers.

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