Hydrocarbon fuelled fuel cell power system

Claim 2

A hydrocarbon fuelled fuel cell power system comprising a fuel cell stack having a plurality of anode chambers and a plurality of cathode chambers, a supply of hydrocarbon fuel, a reformer arranged to produce hydrogen from a hydrocarbon fuel, pipe means to supply hydrocarbon fuel from the supply of hydrocarbon fuel to the reformer, pipe means to supply hydrogen from the reformer to the anode chambers of the fuel cell stack, a hydrogen store arranged to store hydrogen produced by the reformer, pipe means to supply hydrogen from the reformer to the hydrogen store, pipe means to supply hydrogen stored in the hydrogen store to the anode chambers of the fuel cell stack, means for periodically starting the reformer, and valve means in the pipe between the supply of hydrocarbon fuel and the reformer for periodically allowing the supply of hydrocarbon fuel to the reformer for a period of time to produce sufficient hydrogen to recharge the hydrogen store with hydrogen or to directly supply the fuel cell stack during an increased load demand on the fuel cell stack and for terminating the supply of hydrocarbon fuel after the period of time, said reformer and said hydrogen store having a common supply pipe to supply hydrogen to the anode chambers of the fuel cell stack, and in which a hydrogen pump is provided to supply hydrogen between the common supply pipe and the hydrogen store, said means for periodically starting the reformer comprising a burner for burning hydrogen to raise the temperature in said reformer to a temperature sufficient for reforming the hydrocarbon fuel, pipe means to supply hydrogen stored in the hydrogen store to said burner, valve means in said pipe means for periodically allowing the supply of stored hydrogen from the hydrogen store to said burner.

Claim 3

A hydrocarbon fuelled fuel cell power system as claimed in claim 1 in which the hydrogen store comprises a metal hydride.

Claim 4

A hydrocarbon fuelled fuel cell power system as claimed in claim 2 in which the metal hydride is selected from the group consisting of an iron -titanium alloy, and a misch-metal-nickel-iron-titanium alloy.

Claim 5

A hydrocarbon fuelled fuel cell power system as claimed in claim 1 in which the hydrogen store is a pressure vessel for storing compressed hydrogen.

Claim 6

A hydrocarbon fuelled fuel cell power system as claimed in claim 1 in which a hydrogen pump interfaces between the hydrogen store and the reformer to supply hydrogen into the hydrogen store.

Claim 7

A hydrocarbon fuelled fuel cell power system as claimed in claim 5 in which the hydrogen pump comprises an electrochemical pump.

Claim 8

A hydrocarbon fuelled fuel cell power system as claimed in claim 6 in which the hydrogen pump comprises a proton exchange membrane interface between the hydrogen store and the hydrogen produced by the reformer, the proton exchange membrane has surfaces facing in opposite directions, the proton exchange membrane has electrodes mounted on said oppositely facing surfaces, the electrodes are connected to an electrical source, and the electrical potential of the electrical source controls the flow of hydrogen through the proton exchange membrane.

Claim 9

A hydrocarbon fuelled fuel cell power system as claimed in claim 2 in which the metal hydride hydrogen store has a heater to desorb hydrogen.

Claim 10

A hydrocarbon fuelled fuel cell power system as claimed in claim 8 in which the heater is an electrical heater connected to an electrical source.

Claim 11

A hydrocarbon fuelled fuel cell power system as claimed in claim 1 in which the hydrogen store is arranged to supply hydrogen to the reformer by a supply pipe such that the hydrogen is burnt to produce energy to preheat the reformer to a temperature sufficient for reforming the hydrocarbon to hydrogen, the third supply pipe has a third control valve to control the supply of hydrogen to the reformer.

Claim 12

A hydrocarbon fuelled fuel cell power system as claimed in claim 10 wherein a control means is arranged to control the operation of the first valve, the second valve, the third valve the hydrogen pump and the heater.

Claim 13

A hydrocarbon fuelled fuel cell power system as claimed in claim 11 in which voltage sensor means are provided to measure the voltage produced across the fuel cell stack, the voltage sensor means supplying a voltage signal to the control means, the control means analysing the voltage across the fuel cell stack and controlling the operation of the first valve, the second valve, the third valve the hydrogen pump and/or the heater.

Claim 14

A hydrocarbon fuelled fuel cell power system as claimed in claim 11 in which current sensor means are provided to measure the current produced by the fuel cell stack, the current sensor means supplying a current signal to the control means, the control means analysing the current produced by the fuel cell stack and controlling the operation of the first valve, the second valve, the third valve the hydrogen pump and/or the heater.

Claim 15

A hydrocarbon fuelled fuel cell power system as claimed in claim 11 in which pressure sensor means are provided to measure the partial pressure of hydrogen in the reformate supplied to the anode chambers of the fuel cell stack, the pressure sensor means supplying a partial pressure signal to the control means, the control means analysing the partial pressure of hydrogen in the reformate supplied to the fuel cell stack and controlling the operation of the first valve, the second valve, the third valve the hydrogen pump and/or the heater.

Claim 16

A hydrocarbon fuelled fuel cell power system as claimed in claim 1 in which the fuel cell stack comprises a plurality of solid polymer fuel cells.

Claim 17

A hydrocarbon fuelled fuel cell power system as claimed in claim 1 in which the reformer is a steam reformer, a partial oxidation reformer or an autothermal reformer.

Claim 18

A hydrogen fuelled fuel cell power system as claimed in claim 5 wherein a control means is arranged to control the operation of at least the hydrogen pump, the first valve means and the means for periodically starting the reformer.

Claim 19

A hydrogen fuelled fuel cell power system as claimed in claim 1 in which the reformer and the hydrogen store are arranged to supply hydrogen to the anode chambers of the fuel cell stack by a common supply pipe, the hydrogen store is arranged to supply hydrogen to the anode chambers of the fuel cell stack by a second supply pipe, the second supply pipe has a second control valve to control the flow of hydrogen from the hydrogen store to the fuel cell stack and a control means is arranged to control the operation of the first valve, the second valve the hydrogen pump and the means for periodically starting the reformer.

Claim 20

A hydrocarbon fuelled fuel cell power system as claimed in claim 1 in which the means for periodically starting the reformer comprises a pipe to supply hydrogen from the hydrogen store to the reformer such that the hydrogen is burnt to produce energy to heat the reformer to a temperature sufficient for reforming the hydrocarbon to hydrogen, the pipe has valve means to control the supply of hydrogen to the reformer.

Claim 21

A hydrocarbon fuelled fuel cell power system comprising a fuel cell stack having a plurality of anode chambers and a plurality of cathode chambers, a supply of hydrocarbon fuel, a reformer arranged to produce hydrogen from a hydrocarbon fuel, pipe means to supply hydrocarbon fuel from the supply of hydrocarbon fuel to the reformer, pipe means to supply hydrogen from the reformer to the anode chambers of the fuel cell stack, a hydrogen store arranged to store hydrogen produced by the reformer, pipe means to supply hydrogen from the reformer to the hydrogen store, pipe means to supply hydrogen stored in the hydrogen store to the anode chambers of the fuel cell stack, means for periodically starting the reformer and valve means in the pipe between the supply of hydrocarbon fuel and the reformer for periodically allowing the supply of hydrocarbon fuel to the reformer for a period of time to produce sufficient hydrogen to recharge the hydrogen store with hydrogen or to directly supply the fuel cell stack during an increased load demand on the fuel cell stack and for terminating the supply of hydrocarbon fuel after the period of time.

Claim 22

A hydrocarbon fuelled fuel cell power system comprising a fuel cell stack having a plurality of anode chambers and a plurality of cathode chambers, a supply of hydrocarbon fuel, a reformer arranged to produce hydrogen from a hydrocarbon fuel, pipe means to supply hydrocarbon fuel from the supply of hydrocarbon fuel to the reformer, pipe means to supply hydrogen from the reformer to the anode chambers of the fuel cell stack, a hydrogen store arranged to store hydrogen produced by the reformer, pipe means to supply hydrogen from the reformer to the hydrogen store, pipe means to supply hydrogen stored in the hydrogen store to the anode chambers of the fuel cell stack, means for periodically starting the reformer and valve means in the pipe between the supply of hydrocarbon fuel and the reformer for periodically allowing the supply of hydrocarbon fuel to the reformer for a period of time to produce sufficient hydrogen to recharge the hydrogen store with hydrogen or to directly supply the fuel cell stack during an increased load demand on the fuel cell stack and for terminating the supply of hydrocarbon fuel after the period of time.

Claim 23

A hydrocarbon fuelled fuel cell power system comprising a fuel cell stack having a plurality of anode chambers and a plurality of cathode chambers, a supply of hydrocarbon fuel, a reformer arranged to produce hydrogen from a hydrocarbon fuel, pipe means to supply hydrocarbon fuel from the supply of hydrocarbon fuel to the reformer, pipe means to supply hydrogen from the reformer to the anode chambers of the fuel cell stack, a hydrogen store arranged to store hydrogen produced by the reformer, pipe means to supply hydrogen from the reformer to the hydrogen store, pipe means to supply hydrogen stored in the hydrogen store to the anode chambers of the fuel cell stack, means for periodically starting the reformer, and valve means in the pipe between the supply of hydrocarbon fuel and the reformer for periodically allowing the supply of hydrocarbon fuel to the reformer for a period of time to produce sufficient hydrogen to recharge the hydrogen store with hydrogen or to directly supply the fuel cell stack during an increased load demand on the fuel cell stack and for terminating the supply of hydrocarbon fuel after the period of time, said reformer and said hydrogen store having a common supply pipe to supply hydrogen to the anode chambers of the fuel cell stack, and in which a hydrogen pump is provided to supply hydrogen between the common supply pipe and the hydrogen store, said means for periodically starting the reformer comprising a burner for burning hydrogen to raise the temperature in said reformer to a temperature sufficient for reforming the hydrocarbon fuel, pipe means to supply hydrogen stored in the hydrogen store to said burner, valve means in said pipe means for periodically allowing the supply of stored hydrogen from the hydrogen store to said burner, said hydrogen pump comprising a proton exchange membrane interface between the hydrogen store and the hydrogen produced by said reformer, the proton exchange membrane having surfaces facing in opposite directions, the proton exchange membrane having electrodes mounted on said oppositely facing surfaces, said electrodes being connected to an electrical source with the electrical potential of the electrical source controlling the flow of hydrogen through said proton exchange membrane.

Claim 24

A hydrocarbon fuelled fuel cell power system comprising a fuel cell stack having a plurality of anode chambers and a plurality of cathode chambers, a supply of hydrocarbon fuel, a reformer arranged to produce hydrogen from a hydrocarbon fuel, pipe means to supply hydrocarbon fuel from the supply of hydrocarbon fuel to the reformer, pipe means to supply hydrogen from the reformer to the anode chambers of the fuel cell stack, a hydrogen store arranged to store hydrogen produced by the reformer, pipe means to supply hydrogen from the reformer to the hydrogen store, pipe means to supply hydrogen stored in the hydrogen store to the anode chambers of the fuel cell stack, means for periodically starting the reformer, and valve means in the pipe between the supply of hydrocarbon fuel and the reformer for periodically allowing the supply of hydrocarbon fuel to the reformer for a period of time to produce sufficient hydrogen to recharge the hydrogen store with hydrogen or to directly supply the fuel cell stack during an increased load demand on the fuel cell stack and for terminating the supply of hydrocarbon fuel after the period of time, said reformer and said hydrogen store having a common supply pipe to supply hydrogen to the anode chambers of the fuel cell stack, and in which a hydrogen pump is provided to supply hydrogen between the common supply pipe and the hydrogen store, said means for periodically starting the reformer comprising a burner for burning hydrogen to raise the temperature in said reformer to a temperature sufficient for reforming the hydrocarbon fuel, pipe means to supply hydrogen stored in the hydrogen store to said burner, valve means in said pipe means for periodically allowing the supply of stored hydrogen from the hydrogen store to said burner, said hydrogen pump comprising a proton exchange membrane interface between the hydrogen store and the hydrogen produced by said reformer, the proton exchange membrane having surfaces facing in opposite directions, the proton exchange membrane having electrodes mounted on said oppositely facing surfaces, said electrodes being connected to an electrical source with the electrical potential of the electrical source controlling the flow of hydrogen through said proton exchange membrane.

Claim 25

A hydrocarbon fuelled fuel cell power system comprising a fuel cell stack having a plurality of anode chambers and a plurality of cathode chambers, a supply of hydrocarbon fuel, a reformer arranged to produce hydrogen from a hydrocarbon fuel, pipe means to supply the hydrocarbon fuel to the reformer, pipe means to supply hydrogen from the reformer to the anode chambers of the fuel cell stack, at least one hydrogen store for storing hydrogen, pipe means to supply hydrogen from the reformer to the at least one hydrogen store and pipe means for supplying hydrogen stored in the at least one hydrogen store to the anode chambers of the fuel cell stack to buffer the fast response of the fuel cell stack and the relatively slower response of the reformer during relatively large rapid load demands on the fuel cell stack, another pipe means to supply hydrogen stored in the at least one hydrogen store to the reformer, valve means for periodically allowing the supply of stored hydrogen from the at least one hydrogen store to the reformer, the reformer having means for burning the hydrogen in the reformer to raise the temperature in the reformer to a temperature sufficient for reforming the hydrocarbon fuel, and valve means for periodically supplying hydrocarbon fuel to the reformer for a period of time to produce sufficient hydrogen to recharge the hydrogen store with hydrogen.

Claim 26

A hydrocarbon fuelled fuel cell power system comprising a fuel cell stack having a plurality of anode chambers and a plurality of cathode chambers, a supply of hydrocarbon fuel, a reformer arranged to produce hydrogen from a hydrocarbon fuel, pipe means to supply the hydrocarbon fuel to the reformer, pipe means to supply hydrogen from the reformer to the anode chambers of the fuel cell stack, at least one hydrogen store for storing hydrogen, pipe means to supply hydrogen from the reformer to the at least one hydrogen store and pipe means for supplying hydrogen stored in the at least one hydrogen store to the anode chambers of the fuel cell stack to buffer the fast response of the fuel cell stack and the relatively slower response of the reformer during relatively large rapid load demands on the fuel cell stack, another pipe means to supply hydrogen stored in the at least one hydrogen store to the reformer, valve means for periodically allowing the supply of stored hydrogen from the at least one hydrogen store to the reformer, the reformer having means for burning the hydrogen in the reformer to raise the temperature in the reformer to a temperature sufficient for reforming the hydrocarbon fuel, and valve means for periodically supplying hydrocarbon fuel to the reformer for a period of time to produce sufficient hydrogen to recharge the hydrogen store with hydrogen.