Chapter 8, Problem 8.12P

An industrial process discharges 75.3 kg/s of gaseous combustion products at 204°C, 100 kPa (properties at state 1). As shown in the figure, a proposed system for utilizing the combustion products combines a heat-recovery steam generator with a well-insulated turbine. At steady state, combustion products exit the steam generator at 130°C, 100 kPa, and a separate stream of water enters at 350 kPa, 46°C with a mass flow rate of 150 kg/min. At the exit of the turbine, the pressure is 7.5 kPa and the quality is 88%. Heat is lost from the steam generator at a rate of 93600 kJ/h. The changes in kinetic and potential energies of the flowing streams can be ignored as can the pressure drop for the water flowing through the steam generator. The combustion products can be modeled as air acting as an ideal gas with constant specific heats of Cv= 0.718 kJ/kg-K and Cp=1.005 kJ/kg-K. Use Rair = 0.287 kJ/kg-K. Also, for the compressed liquid, assume the substance is a saturated liquid at the given…

An industrial process discharges 75.3 kg/s of gaseous combustion products at 204°C, 100 kPa (properties at state 1). As shown in the figure, a proposed system for utilizing the combustion products combines a heat-recovery steam generator with a well-insulated turbine. At steady state, combustion products exit the steam generator at 130°C, 100 kPa, and a separate stream of water enters at 350 kPa, 46°C with a mass flow rate of 150 kg/min. At the exit of the turbine, the pressure is 7.5 kPa and the quality is 88%. Heat is lost from the steam generator at a rate of 93600 kJ/h. The changes in kinetic and potential energies of the flowing streams can be ignored as can the pressure drop for the water flowing through the steam generator. The combustion products can be modeled as air acting as an ideal gas with constant specific heats of Cv= 0.718 kJ/kg-K and Cp=1.005 kJ/kg-K. Use Rair = 0.287 kJ/kg-K. Also, for the compressed liquid, assume the substance is a saturated liquid at the given…

is true for first law & second law efficiency (exergetic efficiency), respectively. + x Carnot efficiency and Carnot efficiency To Exergy used Exeryy supplied Desired output and Supplied Input Desired output Exergy lost and Supplied Input Exergy used Entropy generation Energy generation