Help me!! Within the processes of a power plant, combustion product gases are available at 430 ºC. It is required to take advantage of the heat of these gases and it is proposed to size an economizer to heat pressurized water from 70ºC to 180ºC.
It is known that there is 8 kg/s of water with Cp=4260 J/kg. K. The gases have a flow of 30 kg/s and Cp=1100 J/kg. K. Calculate:
a) the heat that can be transferred from the gases to the water, in kW.
b) the outlet temperature of the combustion gases, in ºC.
b) the average logarithmic difference of temperatures of the economizer, in ºC.
c) the required heat transfer area in m2, for a counterflow configuration if the overall heat transfer coefficient is 60 W/m2 K.
d) If you plan to use a coil of tubes 4 m long and 15 cm in diameter, calculate the number of tubes needed for the economizer.