Boilers and Steam

Question 1

Describe the main processes that occur in an electrical power station that
uses steam to generate power.

Answer 1

1. Boiler/superheater; combustion of fuel to generate steam at high pressure & temperature
2. Steam turbine; expansion of steam via turbine, mechanical work produced
3. Condenser; cooling of vapour/water to water
4. Pump: Circulation of water back to boiler

Question 2

Turbine Work Output equation

Answer 2

h2 - h1

Question 3

enthalpy of the wet steam exiting the turbine (h3) equation

Answer 3

h3 = hf + x ⋅ hfg
h3 = Enthalpy of saturated liquid + dryness x Latent heat of vaporization

Question 4

System efficiency equation

Answer 4

= work output / heat input

Question 5

Turbine power output equation

Answer 5

W = m(dot) x w
W = mass flow rate of steam x work output (h2 - h3)

Question 6

Specific Volume of Wet Steam equation

Answer 6

v = x⋅vg