Fuel cell system and method for its operation

Abstract

A fuel cell system (1) comprising a fuel cell (2), a liquid fuel supply (3) for providing liquid fuel, an evaporator (6) for evaporating the liquid fuel to fuel vapor, a reformer (7) for catalytic conversion of the fuel vapor to syngas for the fuel cell and a burner (8) for heating the reformer (7). The burner (8) comprises a catalytic monolith (21) down-stream of a mixing chamber (31) in which air is mixed with evaporated fuel or rest gas prior to entering the monolith (21). The mixing chamber (31) is surrounded by a sleeve (23), which comprises a plurality of openings (29A, 29B) around the mixing chamber (31) for supply of fuel vapor through the openings (29A, 29B) in the startup phase and for supply of rest gas through the openings (29A, 29B) during normal operation. Optionally, a heat exchanger (17) is provided between the burner (8) and the reformer (7) for reducing the temperature of the exhaust gas from the burner (8) before it reaches the reformer (7). This temperature reduction prevents degradation of the reformer (7) by hot exhaust gas during start-up of the fuel cell system (1).

Dependencies are inferred from the claim text.