As an alternative to the conventional steam Rankine Cycle,Kalina Cycle has witnessed a growing interest over the past years for high-temperature applications(A working fluid temperature of 500◦C at the turbine inlet)....As an alternative to the conventional steam Rankine Cycle,Kalina Cycle has witnessed a growing interest over the past years for high-temperature applications(A working fluid temperature of 500◦C at the turbine inlet).However,the possibility of implementing an additional multi-phase expander on the weak ammonia-water solution loop of the Kalina cycle was hardly analyzed in the available literatures.In this research,two novel Kalina cycles(Kalina cycle-12A and Kalina cycle-12B)have been presented by integrating a multi-phase expander in addition to the turbine installed downstream of the Kalina evaporator.For Kalina cycle-12A,this additional multi-phase expander is positioned downstream of the Kalina separator and on the weak ammonia-water solution loop for Kalina Cycle-12B.A detailed mathematical model based on the thermodynamic laws has been developed to solve and optimize the Kalina Cycles.The influence of critical decision parameters,specifically the ammonia concentration on working fluid and evaporation pressure,were investigated.The optimization was performed based on the objective to maximize the net power output from the multi-phase expander under steady-state operating conditions.When the performance of the proposed Kalina cycles was compared with the conventional Kalina Cycle-12,both of them demonstrated superior performance,i.e.,net power output and peak thermal efficiency increased by a maximum value of 3.23%for the proposed Kalina Cycle-12A cycle and 3.94%for the proposed Kalina Cycle-12B cycle.In terms of second law efficiency,Kalina Cycle-12A is 3.68 percent more efficient than Kalina Cycle-12,while Kalina Cycle-12B is 4.04 percent more efficient.Furthermore,2nd law analysis also reveals,maximum destruction of exergy occurs at the condensers of the cycles.展开更多
文摘As an alternative to the conventional steam Rankine Cycle,Kalina Cycle has witnessed a growing interest over the past years for high-temperature applications(A working fluid temperature of 500◦C at the turbine inlet).However,the possibility of implementing an additional multi-phase expander on the weak ammonia-water solution loop of the Kalina cycle was hardly analyzed in the available literatures.In this research,two novel Kalina cycles(Kalina cycle-12A and Kalina cycle-12B)have been presented by integrating a multi-phase expander in addition to the turbine installed downstream of the Kalina evaporator.For Kalina cycle-12A,this additional multi-phase expander is positioned downstream of the Kalina separator and on the weak ammonia-water solution loop for Kalina Cycle-12B.A detailed mathematical model based on the thermodynamic laws has been developed to solve and optimize the Kalina Cycles.The influence of critical decision parameters,specifically the ammonia concentration on working fluid and evaporation pressure,were investigated.The optimization was performed based on the objective to maximize the net power output from the multi-phase expander under steady-state operating conditions.When the performance of the proposed Kalina cycles was compared with the conventional Kalina Cycle-12,both of them demonstrated superior performance,i.e.,net power output and peak thermal efficiency increased by a maximum value of 3.23%for the proposed Kalina Cycle-12A cycle and 3.94%for the proposed Kalina Cycle-12B cycle.In terms of second law efficiency,Kalina Cycle-12A is 3.68 percent more efficient than Kalina Cycle-12,while Kalina Cycle-12B is 4.04 percent more efficient.Furthermore,2nd law analysis also reveals,maximum destruction of exergy occurs at the condensers of the cycles.
