Question

In: Mechanical Engineering

Consider a combined gas-steam power cycle. The topping cycle is a simple Brayton cycle that has...

Consider a combined gas-steam power cycle. The topping cycle is a simple Brayton cycle that has a pressure ratio of 7. Air enters the compressor at 15 ºC at a rate of 10 kg/s and the gas turbine at 950 ºC. The bottoming cycle is a reheat Rankine cycle between the pressure limits of 6 MPa and 10 kPa. Steam is heated in a heat exchanger at a rate of 1.15 kg/s by the exhaust gases leaving the gas turbine, and the exhaust gases leave the same exchanger at 200 ºC. Steam leaves the high-pressure turbine at 1 MPa and is reheated to 400 ºC in the heat exchanger before it expands in the low-pressure turbine. Assuming 80 percent isentropic efficiency for all pumps and turbines,

1)  determine the steam temperature at the inlet of the high-pressure. (hint: trial and error)

2) determine the net power output of the combined plant.

3)  determine the thermal efficiency of the combined plant

Solutions

Expert Solution


Related Solutions

Consider a combined gas-steam power cycle. The topping cycle is a simple Brayton cycle that has...
Consider a combined gas-steam power cycle. The topping cycle is a simple Brayton cycle that has a pressure ratio of 7. Air enters the compressor at 15 ºC at a rate of 10 kg/s and the gas turbine at 950 ºC. The bottoming cycle is a reheat Rankine cycle between the pressure limits of 6 MPa and 10 kPa. Steam is heated in a heat exchanger at a rate of 1.15 kg/s by the exhaust gases leaving the gas turbine,...
A combined cycle power system uses a simple gas-turbine Brayton cycle in conjunction with a simple...
A combined cycle power system uses a simple gas-turbine Brayton cycle in conjunction with a simple Rankine cycle to produce a total power of 100 MW. In such configuration, the exhaust stream from the gas turbine is used as the heat source for the steam power cycle in a heat exchanger as shown in the figure. The following data are known for the gas-turbine cycle. Atmospheric air enters the compressor at 100 kPa and 20oC, the compressor pressure ratio is...
Prob.1) Consider a combined gas and steam power plant that has a net power output of...
Prob.1) Consider a combined gas and steam power plant that has a net power output of 450 MW. The pressure ratio of the gas turbine cycle is 14. Air enters the compressor at 300 K and the turbine at 1 400 K. The combustion gases leaving the gas turbine are used to heat the steam to 8 MPa. up to 400 ° C in a heat exchanger. The combustion gases exit the heat exchanger at 460 K. An open feedwater...
Consider a steam power plant operating on a simple ideal Rankine cycle in which the steam...
Consider a steam power plant operating on a simple ideal Rankine cycle in which the steam enters the turbine at 3 MPa and 350C and is condensed in the condenser at 75 kPa. Determine the thermal efficiency of this cycle and sketch an appropriately labeled T-s diagram. Also compare this thermal efficiency to that a Carnot heat engine operating between these same two limits. The change in enthalpy across the pump = work done by the pump: h2-h1= v1(P2– P1)
Consider a steam power plant operating on the simple ideal Rankine cycle. Steam enters the turbine...
Consider a steam power plant operating on the simple ideal Rankine cycle. Steam enters the turbine at 15 MPa and 600°C. The steam condenses in the condenser at 10 kPa. Use the EES software to study the effects of the following cases on the cycle performance and to sketch the T-s diagram for each case: Plot the variation of the cycle thermal efficiency with the turbine isentropic efficiency. Take the isentropic efficiency of the turbine in the range 70% to...
Consider a steam power plant operating on the simple ideal Rankine cycle. Steam enters the turbine...
Consider a steam power plant operating on the simple ideal Rankine cycle. Steam enters the turbine at 15 MPa and 600°C. The steam condenses in the condenser at 10 kPa. Use the EES software to study the effects of the following cases on the cycle performance and to sketch the T-s diagram for each case: #Plot the variation of the cycle thermal efficiency with the turbine isentropic efficiency. Take the isentropic efficiency of the turbine in the range 70% to...
A gas-turbine power plant operates on the simple Brayton cycle between the pressure limits of 100 and 1200 kPa.
A gas-turbine power plant operates on the simple Brayton cycle between the pressure limits of 100 and 1200 kPa. The working fluid is air, which enters the compressor at 300K at a rate of 150 m3/min and leaves the turbine at 773K. Using variable specific heats for air and assuming a compressor isentropic efficiency of 82 percent and a turbine isentropic efficiency of 88 percent, determine: (a) the net power output (b) the back work ratio (c) the thermal efficiency
Consider a steam power plant operating on a simple ideal Rankine cycle and having a net...
Consider a steam power plant operating on a simple ideal Rankine cycle and having a net power output of 57 MW. The steam enters the turbine at 9 MPa and 575 ° C and exits at 150 ° C, then it is cooled in the condenser to a pressure of 100 kPa by means of the cooling water from a lake and that circulates through the condenser tubes to a rate of 1370 kg / s. Consider leaving the pump...
The net power of a combined gas-steam power plant is 450 MW. The pressure ratio of...
The net power of a combined gas-steam power plant is 450 MW. The pressure ratio of the gas turbine cycle is 14, the air enters the compressor at a temperature of 300 K and the turbine at a temperature of 1400 K. Combustion end gases coming out of the gas turbine produce steam at a waste heat boiler at 8 MPa pressure and 400 degrees Celsius temperature and exit the boiler at 460 K temperature. The steam cycle has an...
. Air enters the compressor of a gas turbine power plant operating on Brayton cycle at...
. Air enters the compressor of a gas turbine power plant operating on Brayton cycle at 14.5 psia and 540° R. The pressure ratio across the turbine and compressor is same, which is equal to 6. Assume that the compressor work as 0.4 times the turbine work. Take K=1.4 a) Draw the T-S diagram of the cycle. [2] b) Calculate the maximum temperature in the cycle. [3] c) Calculate the cycle efficiency
ADVERTISEMENT
ADVERTISEMENT
ADVERTISEMENT