Modeling And Simulation Of Fuel Cell And Microturbine Hybrid System

Fuel cell (FC) is a new energy conversion device featuring high efficiency and low pollution. Because its electrical efficiency can achieve 50%-60%, the foreground is very good, the research and development of fuel cell have been emphasized in many countries now. The exit gas temperature of Solid oxide fuel cell (SOFC) is high, if a SOFC and microturbine are integrated into a hybrid system, it will achieve greater efficiency and effectively reduce the exhaust emission, decrease the pollution. Therefore, the performance analysis of the hybrid system is significative to our society.Because SOFC operating in high temperature, close and complex conditions, it is difficult to survey. The cost of the experiment is very expensive, sometimes it is impossible. So this thesis establishing the mathematics model of the hybrid system and analyze the performance in order to ensure that it'll operate safely.This thesis includes there sections. In the first section, the theory of a natural gas-fed, tubular SOFC stack with internal reformer is analyzed. The calculation and analysis of the effects of the system parameter (current density, operating temperature, pressure, fuel flow-rate) on the cell performance (electrical power, electrical efficiency) is performed. Results show increasing operating temperature and pressure can improve the performance of SOFC. In the second section, the steady-state model of the Tubular SOFC is computed with a commercial Finite Element modeling package, FEMLAB. A CFD model for a tubular SOFC base on mass, momentum and energy balance coupled with fluid flow, heat generation and transfer and electrochemistry is presented, the model describes the fluid flow, heat and mass transfer in the SOFC, and also investigates the profile of temperature, concentration, gas flow rate and current density in the SOFC. Results show that increasing air flow-rate could decrease the SOFC temperature. In the last section, establishing the mathematic model of a SOFC-MGT hybrid system based on MATLAB/Simulink and integrates the CFD model of the SOFC with the process model of the microturbine to prosecute coordinated simulation, and analyzes the dynamic characteristic of the system.