A typical coal-fired power plant burns 250 metric tons of coal every hour to gen
ID: 1475357 • Letter: A
Question
A typical coal-fired power plant burns 250 metric tons of coal every hour to generate 730 MW of electricity. 1 metric ton= 1000 kg. The density of coal is 1500 kg/m3 and its heat of combustion is 28 MJ/kg. Assume that all heat is transferred from the fuel to the boiler and that all the work done in spinning the turbine is transformed into electrical energy. Part A Suppose the coal is piled up in a 12 m × 13 m room. How tall must the pile be to operate the plant for one day? Express your answer using two significant figures. Part B What is the power plant's thermal efficiency?
Explanation / Answer
(a)
density of coal is d = 1500 kg/m^3 and the mass of the coal per day is, = 24*250*1000 kg
volume of coal using per day is calculated as follows:
V = mass/density
= 24*250*1000/1500
= 4000 m^3
but, volume of coal is equal to volume of room.
4000 = 12*13*h
hence, the height of the room is,
h = 4000/12*13 = 25.64 m
(b)
the heat energy is,
Q = mL= 250*1000*28*10^6 J/kg
power is given, P = 730*10^6 W
therefore, the efficiency is,
= out put/input
= 730*10^6/250*1000*28*10^6
= 1.04*10^-4
= 0.0104%
Related Questions
drjack9650@gmail.com
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.