Power Plant Engineering In Ee - Study Mode
[#11] Rankine efficiency of a steam power plant
Correct Answer
(B) improves in winter as compared to that in summer
Explanation
Solution: Rankine efficiency is a measure of how well a steam power plant converts heat into electricity. The efficiency is affected by the temperature of the steam and the temperature of the cooling water that condenses the steam back into water. In winter , the cooling water (often from a river or lake) is colder . A colder cooling water temperature leads to a lower condenser pressure . A lower condenser pressure increases the net work output of the cycle. This ultimately increases the Rankine efficiency . In summer , the cooling water is warmer , so the efficiency is lower. Therefore, the Rankine efficiency is better in winter than in summer .
[#12] The artificial draught normally is designed to produce
Correct Answer
(D) all of the above
[#13] In a boiler installation the natural draught is produced
Correct Answer
(B) due to the fact that pressure at the grate due to cold column is higher than the pressure at the chimney base due to hot column
[#14] In a regenerative feed heating cycle, the greatest economy is affected
Correct Answer
(B) when steam is extracted from several places in different stages of steam turbine
[#15] In jet type condensers
Correct Answer
(C) steam and cooling water mix