A certain indutrial process requires a steady stream of saturated vapor steam at 200 kPa at the rate of 2 kg/s. There are two alternatives to be considered for supplying this steam from ambient liquid water at 20 degrees celsius, 100 kPa.
Alternative 1: Pump the water to 200 kPa and feed to a steam generator.
Alternative 2: Pump the water to 5MPa, feed to a steam generator, and then expand through a turbine, from which the steam exhausts at the desired state. Assume an isentropic efficiency of 80% for the pump in each case. The turbine is non-isentropic. Justify any assumptions you make in solving the problem.
a) Draw neat and clearly labeled schematics of the two alternatives.
b) Represent the two alternatives on T-s and P-v diagrams
c) For each alternative, determine the state (temperature, pressure, etc.) of the working fluid at each stage of the process, from entry to exit.
d) For each alternative, determine the power in kW required to run the pump.
e) For each alternative, determine the rate of heat (energy) input, in kW, for the boiler.
f) Determine the power output of the turbine in Alternative 2.
g) For each alternative, determine the rate of net entropy increase (generation) in kilo-watt/kelvin.
h) Compare the two alternatives based on engineering and economic reasoning and make a justifiable recommendation for the selection of an alternative.