Electrochemical apparatus and hydrogen system

1. An electrochemical apparatus comprising:

a reformer that produces a first hydrogen-containing gas by reforming a raw material;

a combustor that heats the reformer;

an electrochemical device that includes an anode and a cathode, the electrochemical device operating by using the first hydrogen-containing gas supplied to the anode;

a first flow rate controller that controls a flow rate of the first hydrogen-containing gas and a flow rate of a second hydrogen-containing gas supplied from a supply source, the first hydrogen-containing gas and the second hydrogen-containing gas being to be supplied to the anode of the electrochemical device, the second hydrogen-containing gas being different from the first hydrogen-containing gas;

a second flow rate controller that controls a flow rate at which an anode-off gas exhausted from the anode of the electrochemical device is recycled to the anode of the electrochemical device and a flow rate at which the anode-off gas is supplied to the combustor; and

a controller that is programmed to control the first flow rate controller and the second flow rate controller by performing at least one of:

(i) when the controller controls the first flow rate controller so that the first hydrogen-containing gas is supplied to the anode more than the second hydrogen-containing gas, the controller controls the second flow rate controller so that the anode-off gas is supplied to the combustor at a flow rate which is higher than that at which the anode-off gas is recycled, or

(ii) when the controller controls the first flow rate controller so that the second hydrogen-containing gas is supplied to the anode more than the first hydrogen-containing gas, the controller controls the second flow rate controller so that the anode-off gas is recycled at a flow rate which is higher than that at which the anode-off gas is supplied to the combustor.

2. The electrochemical apparatus according to claim 1 , wherein the first flow rate controller is a first switcher that switches between the first hydrogen-containing gas and the second hydrogen-containing gas as fuel gas for the electrochemical device, and

the second flow rate controller is a second switcher that changes between recycling the anode-off gas and supplying the anode-off gas to the combustor.

3. The electrochemical apparatus according to claim 1 , wherein the first flow rate controller is a first switcher that switches between the first hydrogen-containing gas and the second hydrogen-containing gas as fuel gas for the electrochemical device,

the second flow rate controller is a second switcher that changes between recycling the anode-off gas and supplying the anode-off gas to the combustor, and

the controller is further programmed to perform, when the controller controls the first switcher so that the first hydrogen-containing gas is supplied to the electrochemical device, controlling the second switcher so that the anode-off gas is supplied to the combustor.

4. The electrochemical apparatus according to claim 1 , wherein the first flow rate controller is a first switcher that switches between the first hydrogen-containing gas and the second hydrogen-containing gas as fuel gas for the electrochemical device,

the second flow rate controller is a second switcher that changes between recycling the anode-off gas and supplying the anode-off gas to the combustor, and

the controller is further programmed to perform, when the controller controls the first switcher so that the second hydrogen-containing gas is supplied to the electrochemical device, controlling the second switcher so that the anode-off gas is recycled.

5. The electrochemical apparatus according to claim 1 , wherein in starting production of the first hydrogen-containing gas in the reformer while the electrochemical device is operating on the second hydrogen-containing gas, the controller is further programmed to control the second flow rate controller so that at least a portion of the anode-off gas is supplied to the combustor.

6. The electrochemical apparatus according to claim 1 , wherein the controller is further programmed to start production of the first hydrogen-containing gas in the reformer by supplying a part of the anode-off gas to the combustor, when an amount of the second hydrogen-containing gas in the supply source decreases while the electrochemical device is operating on the second hydrogen-containing gas.

7. The electrochemical apparatus according to claim 1 , wherein the controller is further programmed to activate the electrochemical device by controlling the first flow rate controller so that the second hydrogen-containing gas is more preferentially supplied to the electrochemical device than the first hydrogen-containing gas.

8. The electrochemical apparatus according to claim 1 , wherein the electrochemical device includes a fuel cell.

9. The electrochemical apparatus according to claim 1 , wherein the electrochemical device includes a hydrogen pump that causes hydrogen contained in the first hydrogen-containing gas supplied to the anode to move to the cathode via an electrolyte membrane and that boosts the hydrogen.

10. A hydrogen system comprising:

the electrochemical apparatus according to claim 1 ;

an electricity-generating apparatus that uses renewable energy to generate electricity; and

a water electrolysis apparatus that produces the second hydrogen-containing gas by electrolysis of water with electric power generated by the electricity-generating apparatus,

wherein the supply source stores the second hydrogen-containing gas produced in the water electrolysis apparatus.