Fuel cell stack module shell with integrated heat exchanger

1. A fuel cell stack module, comprising:

a fuel inlet conduit;

a fuel outlet conduit;

a plurality of fuel cell stacks, wherein the fuel cell stacks are configured to receive a fuel cell stack fuel inlet stream via the fuel inlet conduit and output a fuel cell stack anode exhaust stream to the fuel outlet conduit;

a splitter, wherein the splitter is configured to separate a portion of the fuel cell stack anode, exhaust stream from the fuel outlet conduit and recycle the separated portion of the fuel cell stack anode exhaust stream to the fuel cell stack fuel inlet stream in the fuel inlet conduit;

an anode tail gas oxidizer (ATO), wherein the ATO is configured to receive the remaining fuel cell stack anode exhaust stream from the splitter and oxidize the fuel cell stack anode exhaust stream and a fuel cell stack cathode exhaust stream to generate an ATO exhaust stream;

a base supporting the plurality of fuel cell stacks, wherein the base contains a first heat exchanger located under the fuel cell stacks, the fuel inlet conduit, and the fuel outlet conduit, the first heat exchanger configured to transfer heat to the fuel cell stack fuel inlet stream in the fuel inlet conduit from the ATO exhaust stream; and

a metal shell located over the base and the fuel cell stacks, wherein the metal shell contains a second heat exchanger integrated into the metal shell such that the metal shell and the second heat exchanger comprise a single component, the second heat exchanger configured to transfer heat to a fuel cell stack air inlet stream from the ATO exhaust stream.

2. The module of claim 1 , wherein the second heat exchanger comprises a wall configured to separate the metal shell from the fuel cell stacks thereby forming a first air conduit comprised of the shell and the wall and a second air conduit located between the fuel cell stacks and the wall such that the wall forms a wall of the second air conduit.

3. The module of claim 2 , wherein:

the plurality of fuel cell stacks comprise 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; and

a fuel inlet manifold is located in a middle of the annular array of the fuel cell stacks.

4. The module of claim 1 , wherein the base comprises a single manifold.

5. The module of claim 2 , wherein the wall includes heat exchanger fins and flow passages.

6. The module of claim 2 , wherein the first air conduit is an air inlet conduit and the second air conduit is an air exhaust conduit.

7. The module of claim 2 , wherein the metal shell and the wall are configured to be attached to the base as a single unit.

8. The module of claim 2 , wherein the wall contains at least one of fins, ridges, groves or any combination thereof.

9. The module of claim 2 , wherein the wall is corrugated.

10. The module of claim 6 , wherein the air exhaust conduit is an exhaust conduit of the ATO.