Patent ID: 8197976

Claim:
A solid oxide fuel cell system comprising: a stack including a bundle of tubular cells; a feed tube extending through the stack for providing an anode feed stream; an inlet end tube sheet for retaining a position of the tubular cells; a partial cylinder end cap sealed to the inlet end tube sheet to form an anode feed plenum having a reducing environment, wherein the anode feed plenum is in fluid communication with the feed tube so that the anode feed stream passes through the stack to become an anode exhaust; a main plate supporting the stack and forming an exhaust plenum into which the anode exhaust flows, the main plate defining at least one feed hole; an inner cylinder attached to the main plate and enclosing the stack and end cap to form a cathode feed plenum so that a cathode gas stream mixes with the anode exhaust in the exhaust plenum to form an exhaust flow; and a hot zone boundary element coupled to the main plate and having: i) a cap defining a flame space with the main plate; ii) a tail gas combustor at least partially located in the flame space, wherein the exhaust flow enters the tail gas combustor by the at least one feed hole and becomes a heated exhaust stream; and iii) an outer cylinder coupled to the cap and enclosing the inner cylinder to define an exhaust annular gap around the inner cylinder, wherein the heated exhaust stream exits through the exhaust annular gap and, in turn, exchanges heat with the cathode feed plenum.