Performance Analysis Of The SOFC-GT-Kalina Integrated Power Generation System

Electricity is necessary for industrial enterprises and residents' life,with the rapid development of China's economy,the demand for electricity has also increased rapidly.But the traditional power generation method has the characteristics of low efficiency,serious pollution,more energy waste etc.,so the design and optimization of clean and high efficiency thermodynamic cycle system has been an important development direction of thermodynamics.Based on the "temperature counterparts,cascade utilization of energy" principle to improve the shortcomings of large combustion heat loss and exhaust underutilized in conventional integrated cycle,in this paper a new system is proposed: the SOFC-GT-Kalina integrated power generation system.In this paper we use Aspen Plus and the built-in Fortran program to simulate,also propose some performance evaluation indexes based on energy and exergy analysis method,including electrical power?electrical efficiency?exergy efficiency of SOFC and the integrated system.Effects of main operating parameters on the system performance is studied,operating parameters include the SOFC operating pressure,current density,air flow and fuel utilization etc.Results show that the electrical and exergy efficiency of the integrated system in certain conditions can be up to 73.13% and 70.69% respectively,fully proving its high efficiency.By EUD analysis,Kalina cycle heat exchange processes has been improved,its exergy destruction is smaller.By variable condition analyzing,with the SOFC operation pressure increases,SOFC power and electrical efficiency both increase,the overall system electrical efficiency and exergy efficiency both increase and reach a peak at 10 bar then decrease.The optimum current density is 349.5 mA/cm2 and the optimum fuel utilization is 0.8.Taking Kalina cycle efficiency and economy into account as the objective functions,a multi-objective optimization design is conducted.Results show that there exists an optimum ammonia concentration 0.65 and AT pressure ratio 33 to make Kalina cycle running at its best performance.In addition,the exergy destruction of each component is studied,showing that the largest exergy destruction occurs in the SOFC and after-burner.