Solid oxide fuel cell

1. A solid oxide fuel cell comprising an inlet for fuel, an inlet for air, an outlet for product gas, an outlet for depleted air, a fuel flow path between the inlet for fuel and the outlet for product gas, an air flow path between the inlet for air and the outlet for air, and a plurality of elements each having an upstream part and a downstream part, wherein the upstream part comprises an anode layer, a cathode layer and an oxygen ion-conductive layer between the anode and the cathode layer, and wherein the downstream part comprises an oxygen ion- and electron-conductive layer.

2. The solid oxide fuel cell of claim 1 , wherein the downstream part of the elements further comprises a porous layer supporting the oxygen ion- and electron-conductive layer.

3. The solid oxide fuel cell of claim 2 , wherein the cathode layer of the upstream part of the element and the porous layer supporting the oxygen ion- and electron-conductive layer of the downstream part of the element are the same layer.

4. The solid oxide fuel cell of claim 3 , wherein the elements are flat plates.

5. The solid oxide fuel cell of claims 1 , wherein the elements are tubes and the anode layer is located at the outside of the upstream part of the tube and the cathode layer at the inside of the upstream part of the tube.

6. The solid oxide fuel cell of claim 5 , wherein the upstream part and the downstream part of each tube are distinct tubes that are connected to each other by means of a high-temperature resistant, gas-tight joint.

7. The solid oxide fuel cell of claim 5 , wherein each tube is closed at its upstream end.

8. A process for the generation of electricity and the production of carbon dioxide from a hydrocarbonaceous fuel, wherein, in a solid oxide fuel cell comprising an inlet for fuel, an inlet for air, an outlet for product gas, an outlet for depleted air, a fuel flow path between the inlet for fuel and the outlet for product gas, an air flow path between the inlet for air and the outlet for air, and a plurality of elements each having an upstream part and a downstream part, wherein the upstream part comprises an anode layer, a cathode layer and an oxygen ion-conductive layer between the anode and the cathode layer, and wherein the downstream part comprises an oxygen ion- and electron-conductive layer, the process comprising:

a) contacting the cathode layer with air; and, contacting a hydrocarbonaceous fuel or a partially reformed hydrocarbonaceous fuel with the anode layer;

b) allowing the cathode and anode reactions to take place in the upstream part of the elements; generating electricity and an anode off-gas comprising hydrogen, carbon oxides, water and fuel; and, forming partially-depleted air at the cathode side of the elements;

c) reacting the anode off-gas with oxygen ions at the surface of the oxygen ion- and electron-conductive layer facing the fuel flow path to form a product gas mainly comprising carbon dioxide and water; and forming depleted air at the surface of the oxygen ion- and electron-conductive layer facing the air flow path.

9. The process of claim 8 , further comprising partially condensing the product gas; and, removing water from it to produce a stream rich in carbon dioxide.

10. The process of claim 8 , further comprising converting at least part of the hydrocarbonaceous fuel into a mixture comprising hydrogen and carbon monoxide prior to contacting it with the anode surface of the upstream part of the elements.

11. The solid oxide fuel cell of claim 2 , wherein the elements are tubes and the anode layer is located at the outside of the upstream part of the tube and the cathode layer at the inside of the upstream part of the tube.

12. The solid oxide fuel cell of claim 3 , wherein the elements are tubes and the anode layer is located at the outside of the upstream part of the tube and the cathode layer at the inside of the upstream part of the tube.

13. The solid oxide fuel cell of claim 12 , wherein the upstream part and the downstream part of each tube are distinct tubes that are connected to each other by means of a high-temperature resistant, gas-tight joint.

14. The solid oxide fuel cell of claim 6 , wherein each tube is closed at its upstream end.

15. The process of claim 9 , further comprising converting at least part of the hydrocarbonaceous fuel into a mixture comprising hydrogen and carbon monoxide prior to contacting it with the anode surface of the upstream part of the elements.

16. The process of claim 9 , wherein in the solid oxide fuel cell the downstream part of the elements further comprises a porous layer supporting the oxygen ion- and electron-conductive layer.

17. The process of claim 16 , wherein the cathode layer of the upstream part of the element and the porous layer supporting the oxygen ion- and electron-conductive layer of the downstream part of the element are the same layer.

18. The process of claim 17 , wherein in the solid oxide fuel cell the elements are flat plates.

19. The process of claim 9 , wherein in the solid oxide fuel cell the elements are tubes and the anode layer is located at the outside of the upstream part of the tube and the cathode layer at the inside of the upstream part of the tube.

20. The process of claim 9 , wherein in the solid oxide fuel cell, the upstream part and the downstream part of each tube are distinct tubes that are connected to each other by means of a high-temperature resistant, gas-tight joint.