Chapter 8, Problem 8.42CU

On the diagram below sketch a basic Rankine cycle with superheating. Assume that there are irrevesibilities in the turbine and pump. Identify the device associate with each process. Make sure to label: the states and include important features, e.g. lines of constant temperature, volume, pressure, entropy, vapor dome, etc.

Describe the components of a steam power plant and demonstrate the process of it undergoes.

Superheated steam at a pressure of 300 bar and a temperature of 550 ℃ enters a turbine made up of two stages. Steam exits the first stage of the turbine at 35 bar and gets reheated at a constant pressure at 550 ℃. Each stage of the turbine has an isentropic efficiency of 80%. The isentropic efficiency of the pump is 85%. The pressure of the condenser is 10 kPa. (a) Sketch the cycle in a T-s diagram and calculate the enthalpy at each point of the cycle. (b) Calculate the flow rate of the working fluid if the power output of the turbine is 100 MW. (c) Calculate the thermal efficiency of the cycle. (d) Double check the result for the heat rejected in the condenser.

A power plant using a Rankine power generation cycle and steam operates at a temperature of 81.25°C in the condenser, a pressure of 5 MPa in the boiler and a maximum boiler temp of 775°C. The cycle operates at steady state with a mass flow rate of 2.5kg/s. Use the steam tables in the appendix of Sandler (p. 917 to 925). a.) Draw out the cycle, calculate the work required for the pump, the work output by the turbine, the heat into the boiler, and the heat out of the condenser. b.) What is the efficiency of this power plant? c.) If the turbine was only 89% efficient but still adiabatic (only generates 89% of the calculated work from part b), what is the overall efficiency of the cycle?

A steam power plant operates on a theoretical reheat cycle. Steam at boiler at 150 bar, 550°C expands through the high pressure turbine. It is reheated at a constant pressure of 40 bar to 550°C and expands through the low pressure turbine to a condenser at 0.1 bar. Draw T-s and h-s diagrams. Find : (i) Quality of steam at turbine exhaust ; (ii) Cycle efficiency

Q2. A gas turbine operates between pressures of 3 and 9 bar with a minimum and maximum cycle temperatures of 40 "C and 1500 °C. Both the compressor and turbine have isentropic efficiencies of 92%. The mass flow rate through the turbine is 0.4 kg/s. (a) 1. Sketch the ideal cycle on a T-s diagram including labels for: the different states (using the numbering in Figure Q2), heat and work transfers, as well as the pressure and temperature values given above. And add the curves and appropriate labels that show the effect of irreversible processes. ii. Starting from the relationship between pressure and volume for an ideal gas undergoing an isentropic process, and the ideal gas equation (both in Table 2), demonstrate the relationship between temperatures and pressures (Eq. Q2). T2 (Eq. Q2) Where: y is the ratio for specific heat, and 1 and 2 are the initial and final states. iii. Write down the equations for the isentropic efficiencies of the compressor and turbine as a function of the…

Please do parts A and B

4. In a Rankine Cycle, saturated liquid water at 0.1 bar is compressed isentropically to 55 bar. First by heating in a boiler, and then superheating at constant pressure at 55 bar, the water substance is brought to 644 degrees Fahrenheit. After adiabatic reversible expansion in a turbine to 1 bar, it is then cooled in a condenser to a saturated liquid. Draw the flow diagram and T-s diagram. a) What is the moisture content at the exit of the turbine %? b) How much pump work is required, in kJ/kg? c) How much work is generated in the turbine, in kJ/kg? d) What is the thermal efficiency of the cycle %?

1. An industrial company operates a steam power plant with reheat and regeneration. The steam enters a turbine at 115 bar and 550 °C and expands to the condenser at 0.10 bar. Steam leaves the first stage at 30 bar and then reheat at 470 °C before entering the second stage turbine. At the second stage turbine a mass is extracted to the open feed water heater at 6 bar. Both section of the turbine (first stage and second stage) has adiabatic efficiency of 93 %. A condensate pump exists between the main condenser and the heater. Another pump lies between the heater and condensate outlet line from the heater (condensed extracted steam) a. Compute the enthalpies at each point b. Compute for the mass extracted from the second stage turbine to the open feed water heater c. Efficiency of the cycle.