Performance analysis of solid oxide fuel cell-gas turbine hybrid system

Official URL: http://risc01.sabanciuniv.edu/record=b2058069 (Table of Contents)

Fossil fuels which includes coal, natural gas and oil, have been the main sources of energy since the beginning of industrial revolution as they are used in various instruments (gas turbine, internal combustion engines, thermal power plants) for power production. Fossil fuels may offer good efficiencies and high performance, but the fact that they are finite and have severe effects on the environment has always left the researchers of exploring alternative techniques for energy production to overcome the growing energy demands of the world. Although Fuel Cells (FCs) were first introduced more than 170 years ago, but it has been only the last three decades since they have shown great prospects of being commercially suitable. FCs particularly Solid Oxide Fuel Cells (SOFCs) are high efficiency electrical power, heat generating and environment friendly devices which offers a great promise of overtaking the traditionally existing power generating technologies and they have the potentials to meet the uncontrollable increasing energy demands around the globe. Apart from their good performance as a stand-alone power and heat generating units, the performance efficiency can be improved even more when SOFCs are integrated with the waste heat recovery units. Solid Oxide Fuel Cell-Gas Turbine (SOFC-GT) Combined Heat and Power (CHP) hybrid systems are becoming a promising solution to the future energy demands. Integrating the recuperative Gas Turbine (GT) with SOFC, the overall efficiency of up to 70 percent could be achieved. Looking to the rising interest of hybrid system, a detailed thermodynamic and thermal model of SOFC-GT is simulated in MATLAB in this thesis. This thesis aims to analyze the performance of SOFC-GT by investigating the effect of fuel flow rates, current density and pressure ratio change on the temperature and electrical power output of SOFC stack, gas turbine. The model also investigates the effects of the aforementioned parameters on the stack voltage and the efficiency of the whole plant. The results of the tests are compared with the results available in the literature.