Give the temperature of the steam at the inlet (T2) and the exit (T3) of the boiler in a steam power plant the rate of heat transfer into the boiler is best estimated by
Question
Give the temperature of the steam at the inlet (T2) and the exit (T3) of the boiler in a steam power plant the rate of heat transfer into the boiler is best estimated by
Solution
To estimate the rate of heat transfer into the boiler, you can use the first law of thermodynamics, which states that the energy entering a system must equal the energy leaving the system plus the change in the system's internal energy.
In the case of a boiler in a steam power plant, the energy entering the system is the heat transfer into the boiler (Q_in), and the energy leaving the system is the work done by the steam (W_out), plus the change in the steam's internal energy (ΔU).
The equation for this is:
Q_in = W_out + ΔU
To find Q_in, you need to know the values of W_out and ΔU.
W_out can be found using the equation:
W_out = m * (h3 - h2)
where m is the mass flow rate of the steam, h3 is the specific enthalpy of the steam at the exit of the boiler (which can be found using the steam tables and the temperature T3), and h2 is the specific enthalpy of the steam at the inlet of the boiler (which can be found using the steam tables and the temperature T2).
ΔU can be found using the equation:
ΔU = m * (u3 - u2)
where u3 is the specific internal energy of the steam at the exit of the boiler (which can be found using the steam tables and the temperature T3), and u2 is the specific internal energy of the steam at the inlet of the boiler (which can be found using the steam tables and the temperature T2).
Once you have found the values of W_out and ΔU, you can substitute them into the first equation to find Q_in.
Similar Questions
A steam turbine operates under steady flow conditions, receiving steamat 1.2MPa and 1880C, and enthalpy 2785kJ/kg, velocity 33.3m/s andelevation 3m. Steam leaves the turbine at 20 kPa, and 2512kJ/kg, velocity100m/s and elevation zero m. Heat is lost to surroundings at the rate of0.29kJ/s. If the rate of steam flow through the turbine is 0.42kg/s, what isthe power output of the turbine?
A steam turbine operating under steady flow, conditions of steam at inletof steam turbine: p=13.8 bar, v=0.143 m3/kg, u=2590 kJ/kg, C= 30m/s. Thestate of the steam at the outlet leaving the turbine: p=0.35bar, v=4.37 m3/kg,u=2360 kJ/kg, C=90m/s. Heat is rejected to surroundings at the rate of 0.25kW and rate of steam flow through turbine is 0.38kg/s. Calculate powerdeveloped by the steam turbine.
A boiler delivers 5400kg of steam per hour at a pressure of 800kN/m2 and with a drynessfraction of 0.98. The feedwater to the boiler is at a temperature of 42oC. The fuel usedfor the boiler has a calorific value of 31000kJ/kg.(i) Determine the heat energy absorbed by the steam per hour in the boiler
Q2. Consider an ideal Rankine cycle where the boiler operates at 12.5 MPa and thecondenser operates at 40 kPa. The steam is superheated after the boiler to 600 oC. Theturbine produces 100 MW of shaft work. Determine:a) The mass flow rate of water through the turbine (in kg/s).b) The work required for the pump.Q3. For the process in Q2. Determine:a) The heat input into the boiler (in MW).b) The heat out for the condenser (in MW)c) The thermal efficiency of the cycle (in %).
For the process in Q2. Determine:a) The heat input into the boiler (in MW).b) The heat out for the condenser (in MW)c) The thermal efficiency of the cycle (in %).
Upgrade your grade with Knowee
Get personalized homework help. Review tough concepts in more detail, or go deeper into your topic by exploring other relevant questions.