A pre-reformer ( 10 ) comprises a non-electrically conducting gas tight duct ( 12 ) and an electrically conducting wire ( 14 ) arranged in the duct ( 12 ). The electrically conducting wire ( 14 ) is electrically isolated from the duct ( 12 ). The duct ( 12 ) has an inlet ( 16 ) for receiving a hydrocarbon fuel at a first end ( 18 ) and an outlet ( 20 ) for supplying a pre-reformed hydrocarbon fuel at a second end ( 22 ). At least the inner surface ( 24 ) of the duct ( 12 ) is chemically inert with respect to the hydrocarbon fuel. An electrical power supply ( 26 ) is electrically connected to the electrically conducting wire ( 14 ) and a control means ( 28 ) controls the supply of electrical current through the electrically conducting wire ( 14 ) to maintain the electrically conducting wire ( 14 ) at a temperature to provide selective thermal decomposition of higher hydrocarbons in the hydrocarbon fuel. The performer reduces coking in associated fuel cells and other parts of a fuel cell system.
1. A reformer arrangement comprising a pre-reformer and a reformer, said pre-reformer comprising a gas tight duct and at least one electrically conducting member arranged in the duct, the at least one electrically conducting member is electrically isolated from the duct, the duct has an inlet for receiving a hydrocarbon fuel at a first end and an outlet for supplying a pre-reformed hydrocarbon fuel at a second end, at least the inner surface of the duct is chemically inert with respect to the hydrocarbon fuel, an electrical power supply electrically connected to the at least one electrically conducting member and control means to control the supply of electrical current through the at least one electrically conducting member to maintain the at least one electrically conducting member at a temperature to provide selective thermal decomposition of higher hydrocarbons in the hydrocarbon fuel wherein the outlet of the duct is connected to a reformer via means to remove particulate carbon from the pre-reformed hydrocarbon fuel.
2. A reformer arrangement as claimed in claim 1 wherein the gas tight duct is non-electrically conducting.
3. A reformer arrangement as claimed in claim 1 wherein the gas tight duct comprises a ceramic, a glass-ceramic or a glass.
4. A reformer arrangement as claimed in claim 1 wherein a temperature sensor is arranged to measure the temperature in the duct and is electrically connected to the control means.
5. A reformer arrangement as claimed in claim 1 wherein the at least one electrically conducting member extends through the walls of the duct and is directly electrically connected to the electrical power supply.
6. A reformer arrangement as claimed in claim 5 wherein the electrically conducting member is electrically isolated from the duct by glass seals or glass-ceramic seals.
7. A reformer arrangement as claimed in claim 1 wherein the at least one electrically conducting member forms a loop, a second electrically conducting member is arranged outside the duct, the second electrically conducting member is electrically connected to the electrical power supply and the control means controls the supply of electrical current through the second electrically conducting member to maintain the at least one electrically conducting member at a temperature to provide selective thermal decomposition of higher hydrocarbons in the hydrocarbon fuel.
8. A reformer arrangement as claimed in claim 1 wherein the at least one electrically conducting member comprises a honeycomb.
9. A reformer arrangement as claimed in claim 1 wherein the at least one electrically conducting member comprises at least a portion of the duct.
10. A reformer arrangement as claimed in claim 1 wherein the at least one electrically conducting member comprises a metal or an alloy.
11. A reformer arrangement as claimed in claim 1 wherein the outlet of the duct is connected to a solid oxide fuel cell stack.
12. A reformer arrangement as claimed in claim 1 wherein the means to remove particulate carbon comprises an inertial separator.
13. A reformer arrangement as claimed in claim 12 wherein the inertial separator comprises a duct having an inlet at a first end and first and second outlets at a second end, a plurality of swirl vanes are provided in the inlet at the first end of the duct, a central duct is provided at the center of the duct at the second end of the duct, an outer duct is arranged around the central duct, the central duct is connected to the first outlet and the outer duct is connected to the second outlet.
14. A reformer arrangement as claimed in claim 1 wherein the means to remove particulate carbon comprises a filter or an electrostatic separator.
15. A fuel cell system comprising a fuel, a reformer, an electrical power supply, control means and a pre-reformer, said pre-reformer comprising a gas tight duct and at least one electrically conducting member arranged in the duct wherein the at least one electrically conducting member is electrically isolated from the duct, said duct having an inner surface, an inlet for receiving a hydrocarbon fuel at a first end and an outlet for supplying a pre-reformed hydrocarbon fuel at a second end, said outlet of the duct being connected to a fuel cell stack via means to remove particulate carbon from the pre-reformed hydrocarbon fuel, wherein at least said inner surface of the duct is chemically inert with respect to the hydrocarbon fuel, said electrical power supply being electrically connected to the at least one electrically conducting member and said control means being arranged to control the supply of electrical current through the at least one electrically conducting member to maintain the at least one electrically conducting member at a temperature to provide selective thermal decomposition of higher hydrocarbons in the hydrocarbon fuel, wherein said means to remove particulate carbon from the pre-reformed hydrocarbon fuel is connected to the fuel cell stack via a reformer.
16. A pre-reformer comprising an electrical power supply, control means, a gas tight duct having an inner surface and at least one electrically conducting member arranged in the duct, said at least one electrically conducting member being electrically isolated from the duct, said duct having an inlet for receiving a hydrocarbon fuel at a first end and an outlet for supplying a pre-reformed hydrocarbon fuel at a second end, said inner surface of said duct being chemically inert with respect to the hydrocarbon fuel, said electrical power supply being electrically connected to said at least one electrically conducting member and said control means being arranged to control the supply of electrical current through said at least one electrically conducting member to maintain said at least one electrically conducting member at a temperature to provide selective thermal decomposition of higher hydrocarbons in the hydrocarbon fuel wherein the outlet of said duct is connected to a fuel cell stack and wherein the outlet of said duct is connected to said fuel cell stack via means to remove particulate carbon from the pre-reformed hydrocarbon fuel, wherein the means to remove particulate carbon from the pre-reformed hydrocarbon fuel is connected to the fuel cell stack via a reformer.