Mass and energy balance of an integrated solid oxide fuel cell system

A fully integrated solid oxide fuel cell system is described. Tubular fuel cells are mounted on a base plate and placed inside a number of concentric tubes. These serve as heat exchangers to provide the heat for the electrochemical process. Gases are drawn through the system by exploiting the chimney effect. The system also comprises a pre-reforming chamber, which is heated by the process exhaust gas. A design study is carried out for a 360 W system. The effect of variation of fuel inlet temperatures, cell voltage, current and utilization on system dimensions is studied. The system uses two consecutively placed pipe heat exchangers. In one of the heat exchangers heat is transferred, firstly on air, which then passes part of its acquired heat on to the fuel. Temperature profiles for this exchanger are derived. Using a chimney to draw the gases through the system, it is found that the system will stand approximately 1.5 m tall, and including insulation will have a diameter of approximately 200 mm.