Integrated solid oxide fuel cell and fuel processor

1. A fuel cell unit comprising:

a plurality of angularly spaced fuel cell stacks arranged to form a ring-shaped structure about a central axis, each of the fuel cell stacks having a stacking direction extending parallel to the central axis;

an annular cathode feed manifold surrounding the fuel cell stacks;

an annular cathode feed flow passage surrounding the annular cathode feed manifold; and

at least one radial cathode feed flow passage connecting the annular cathode feed flow passage to the annular cathode feed manifold surrounding the plurality of fuel cell stacks; and

wherein each of the fuel cell stacks includes a plurality of cathode feed flow paths open to a radially outer face of the stack to receive a radially directed cathode feed flow from said cathode feed flow passages.

2. The fuel cell unit of claim 1 further comprising an annular cathode exhaust flow passage in heat exchange relation with said annular cathode feed flow passage to define a cathode recuperator heat exchanger.

3. The fuel cell unit of claim 2 further comprising another annular cathode feed flow passage in heat exchange relation with an annular anode exhaust flow passage to define an anode exhaust cooler.

4. The fuel cell unit of claim 2 further comprising a steam generating heat exchanger connected downstream from the cathode recuperator heat exchanger to receive the cathode exhaust flow therefrom and upstream from a steam reformer to provide a steam flow thereto.

5. A fuel cell unit comprising:

a plurality of angularly spaced fuel cell stacks arranged to form a ring-shaped structure about a central axis, each of the fuel cell stacks having a stacking direction extending parallel to the central axis;

an annular cathode feed manifold surrounding the fuel cell stacks to deliver a cathode feed flow thereto;

an annular cathode exhaust manifold surrounded by the fuel cell stacks to receive a cathode exhaust flow therefrom;

an annular cathode recuperator heat exchanger located radially outboard from the fuel cell stacks to transfer heat between the cathode feed flow and the cathode exhaust flow; and

an annular anode recuperator heat exchanger located radially inboard from the fuel cell stacks to transfer heat between an anode feed flow and an anode exhaust flow.

6. The fuel cell unit of claim 5 further comprising an annular anode exhaust cooler connected upstream of the cathode recuperator to direct the cathode feed flow thereto and downstream from the anode recuperator to receive the anode exhaust flow therefrom.

7. The fuel cell unit of claim 5 further comprising a steam generating heat exchanger connected downstream from the cathode recuperator heat exchanger to receive the cathode exhaust flow therefrom and upstream from a steam reformer to provide a steam flow thereto.

8. A fuel cell unit comprising:

an annular array of fuel cell stacks surrounding a central axis, with each of the fuel cell stacks having a stacking direction extending parallel to the central axis, wherein each of the stacks has a rectangular cross section;

an annular cathode feed manifold surrounding the annular array of fuel cell stacks to deliver a cathode feed flow thereto;

a plurality of baffles extending parallel to the central axis, each of the baffles located between an adjacent pair of the fuel cell stacks to direct a cathode feed flow from the annular cathode feed manifold and radially inwardly through the adjacent pair;

an annular cathode exhaust manifold surrounded by the annular array of fuel cell stacks to receive a cathode exhaust flow therefrom;

at least one radial cathode feed flow passage connected with an annular cathode feed flow passage surrounding the plurality of fuel cell stacks; and each of the fuel cell stacks includes a plurality of cathode feed flow paths, wherein the baffles cooperate with the at least one radial cathode feed flow passage and the annular feed flow passage to direct cathode feed flow to the cathode feed flow paths;

an annular cathode exhaust flow passage in heat exchange relation with said annular cathode feed flow passage to define a cathode recuperator heat exchanger; and

another annular cathode feed flow passage in heat exchange relation with an annular anode exhaust flow passage to define an anode exhaust cooler.

9. A fuel cell unit comprising:

an annular array of fuel cell stacks surrounding a central axis, with each of the fuel cell stacks having a stacking direction extending parallel to the central axis, wherein each of the stacks has a rectangular cross section;

an annular cathode feed manifold surrounding the annular array of fuel cell stacks to deliver a cathode feed flow thereto;

a plurality of baffles extending parallel to the central axis, each of the baffles located between an adjacent pair of the fuel cell stacks to direct a cathode feed flow from the annular cathode feed manifold and radially inwardly through the adjacent pair;

an annular cathode exhaust manifold surrounded by the annular array of fuel cell stacks to receive a cathode exhaust flow therefrom;

an annular cathode recuperator heat exchanger located radially outboard from the fuel cell stacks to transfer heat between a cathode feed flow and a cathode exhaust flow; and

an annular anode recuperator heat exchanger located radially inboard from the fuel cell stacks to transfer heat between an anode feed flow and an anode exhaust flow.

10. The fuel cell unit of claim 9 further comprising an annular anode exhaust cooler connected upstream of the cathode recuperator to receive the cathode feed flow therefrom and downstream from the anode recuperator to receive the anode exhaust flow therefrom.

11. The fuel cell unit of claim 9 further comprising a steam generating heat exchanger connected downstream from the cathode recuperator heat exchanger to receive the cathode exhaust flow therefrom and upstream from a steam reformer to provide a steam flow thereto.