Study of Hydrogen Combustion in the Off-Gas Burner of Solid Oxide Fuel Cell System

摘要

The afterburner is an important components for thermal balance in a solid oxide fuel cell system. The chemical energy of the off-gases from anode and cathode is changed to heat energy for thermal balance of system and further heat recovery and reuse. This study uses the computational fluid dynamics to simulate the combustion flow field in the afterburner. The flue gas is mixed by hydrogen and nitrogen carrying gases at different ratio. The effects of afterburner geometric size is also studied in this researches. The results show that the amount of nitrogen gases significantly affects the thermal uniformity and outlet temperature. In the study cases, the temperature of exhaust gases is reduced to be less than 950 degrees C as the hydrogen components is less than 60% of the mixing fuel gas. In the case, the system cost can be reduced by using common materials which cannot be operated at high temperature above 1000 degrees C.