2. We wish to consider the work that can be obtained by carrying out the following...

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2. We wish to consider the work that can be obtained by carrying out the following reactions in a steady- flow process: H2(g) + O2(g) HO(1) H2(x)+202(x)HO(g) Hydrogen is burned completely with the theoretical amount of air, both initially at 101.325 kPa and 300 K, in an adiabatic reactor at constant pressure. If the flue gases are cooled to 500 K at a constant pressure of 101.325 kPa by the transfer of heat to a boiler to generate superheated steam at 3.5 MPa and 540 C, what is the work that will be obtained from a simple power-plant cycle operating as follows? A turbine (n=80%) expands the steam from the boiler to 0.014 MPa. A condenser at 0.014 MPa delivers saturated liquid water to a pump (n=80%) that returns the water to the boiler. The total enthalpy and entropy changes for the reversible cooling of flue gases to 500 K are AH=-224.021 kJ and AS-0.1714 kJ/K. Take as a basis 1 mol of H2 burned to form the flue gases and To 300 K. Make a thermodynamic analysis of the process. Represent your results in a table including Wnet, Wideal and Wlost. Calculate all work values as percentage of Wideal. Evaluate the thermodynamic efficiency (nt) of the process. PS: There is no heat transfer between surroundings and the boiler. Flue gases at 2522 K Flue gases at 500 K Boiler Point Condition T 1 P H (C) (MPa) (kJ/kg) (kJ/kgK) Superheated 540 3.5 3540,8 7,2717 S vapour Pump Work to pump We -80% Turbind -80% 2 Wet vapour 52,6 0,014 2587,1 8.0037 (vap.+liq.) 3 3 2 Saturated 52,6 0,014 220,0 Liquid 0,7367 Condenser 4 Liquid 52,9 3.5 224,64 0.7395 Qc Surroundings To=300 K 2. We wish to consider the work that can be obtained by carrying out the following reactions in a steady- flow process: H2(g) + O2(g) HO(1) H2(x)+202(x)HO(g) Hydrogen is burned completely with the theoretical amount of air, both initially at 101.325 kPa and 300 K, in an adiabatic reactor at constant pressure. If the flue gases are cooled to 500 K at a constant pressure of 101.325 kPa by the transfer of heat to a boiler to generate superheated steam at 3.5 MPa and 540 C, what is the work that will be obtained from a simple power-plant cycle operating as follows? A turbine (n=80%) expands the steam from the boiler to 0.014 MPa. A condenser at 0.014 MPa delivers saturated liquid water to a pump (n=80%) that returns the water to the boiler. The total enthalpy and entropy changes for the reversible cooling of flue gases to 500 K are AH=-224.021 kJ and AS-0.1714 kJ/K. Take as a basis 1 mol of H2 burned to form the flue gases and To 300 K. Make a thermodynamic analysis of the process. Represent your results in a table including Wnet, Wideal and Wlost. Calculate all work values as percentage of Wideal. Evaluate the thermodynamic efficiency (nt) of the process. PS: There is no heat transfer between surroundings and the boiler. Flue gases at 2522 K Flue gases at 500 K Boiler Point Condition T 1 P H (C) (MPa) (kJ/kg) (kJ/kgK) Superheated 540 3.5 3540,8 7,2717 S vapour Pump Work to pump We -80% Turbind -80% 2 Wet vapour 52,6 0,014 2587,1 8.0037 (vap.+liq.) 3 3 2 Saturated 52,6 0,014 220,0 Liquid 0,7367 Condenser 4 Liquid 52,9 3.5 224,64 0.7395 Qc Surroundings To=300 K