A typical coal-fired power plant generates 1000 MW of usable power at an overall

Question

A typical coal-fired power plant generates 1000 MW of usable power at an overall thermal efficiency of 43%.

The plant burns anthracite coal, which has a heat of combustion of 2.65×107J/kg. How much coal does the plant use per day, if it operates continuously?

The river's temperature is 18.0 C before it reaches the power plant and 18.6 C after it has received the plant's waste heat. Calculate the river's flow rate, in cubic meters per second.

By how much does the river's entropy increase each second?

The rate is heat ejected into the cool reservoir, which is the nearby river is 1330 MW

the rate of heat input to the plant is 2330 MW

Explanation / Answer

Let the mass of coal used every day be m

So, heat that can be used for heat , H = m*L

where L = heat of combustion = 2.65*10^7 J/kg

With efficiency, n = 0.43 ,

Heat converted to electrical energy per day, P = n*H/t = 1000*10^6

So, 0.43*2.65*10^7*m/(24*3600) = 1000*10^6

So, m = 7.58*10^6 kg

b)

heat lost to water = m*C*dT

So, power = m*C*dT/t = 0.57*1000/0.43

where

C = specific heat of water = 4186 J/kgC

dT = change in temerature = 0.6 deg

So, mass flow rate, m/t = (0.57*1000/0.43)/(4186*0.6) = 0.528 kg/s

So, flow rate = 528 c3/s

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