Study On The Thermal Performance Of Effective SOFC-CCHP Polygeneration System Fueled By Coke Oven Gas

With the growing shortage of energy supplies,all kinds of advanced energy supply systems become the target to chase for,wherein the distributed energy system,as an efficient energy supply system,will be widely applied in the future.Hence research on various potential distributed energy systems become one of the hot topics nowadays.In this paper based on the idea of energy cascade utilization,one distributed energy system has been proposed,i.e.,the integrated combined cooling heating and power system,which is driven by solid oxide fuel cell and fueled by coke oven gas.The designed syetem can simultaneously generate a certain amount of electric power,cooling and heating.Accordingly the specific research on SOFC-CCHP system is carried out by the following aspects.Firstly the direct kinetics calculation and indirect thermodynamics calculation models are built for the individual system of SOFC stack and then the commercial software ASPEN PLUS is adopted to simulate SOFC system,which validates the numerical method and models.Secondly the mathematical models of SOFC-CCHP system are established.Whereafter two different classical schemes are designed and put forward.The performance comparison between them indicates that the steam type heat power steam generator system is better.Then the influences of some major controlled operating parameters on the improved type of SOFC-CCHP system are investigated.The results imply that SOFC system is an efficient thermodynamic cycle system because the power generation efficiency,the total system power efficiency and the overall system thermal efficiency can be achieved 60%,70% and 90% respectively.Furthermore by means of exergy analysis under various operation conditions,some basic performance influence laws are concluded including fuel flow rate,current density,fuel efficiency,operating pressure and operating temperature.Finally in order to further improve the system efficiency and the power density,the orthogonal design method is applied to optimize and get preferably the best combination of parameters,which realizes the improvement of the system performance while saving costs.The comprehensive analysis of SOFC-CCHP system performance in this research will provide good theoretical guidance for designing and efficient operation of the SOFC-CCHP system.