Hydrogen generator, fuel cell system comprising hydrogen generator, and operation method of hydrogen generator, and operation method of fuel cell system

A method of operating a hydrogen generator comprising:

• at shutdown of the hydrogen generator,
• a step (A) for stopping supply of a material gas from a material gas supplier to a reformer via a material gas supply passage;
• a step (B) for stopping supply of water from a water supplier to an evaporator;
• a step (C) for closing the material gas supply passage using a first valve;
• a step (D) for closing a communicating passage for allowing the reformer to communicate with atmosphere, using a second valve;
• and
• a step (E) for opening the second valve prior to opening the first valve, when the material gas supplier resumes supply of the material gas to the reformer, after performing the step (A) to step (D).

A method of operating a fuel cell system including a hydrogen generator including a reformer for generating a hydrogen-containing gas through a reforming reaction in an internal space thereof using a material gas and steam;

• a material gas supply passage through which the material gas is supplied to the reformer;
• a first valve which opens and closes the material gas supply passage;
• an evaporator for generating a steam which is supplied to the reformer;
• a water supplier for supplying water to the evaporator;
• a communicating passage for providing communication between the reformer and atmosphere;
• a second valve which opens and closes the communicating passage;
• and a fuel cell;
• the method comprising:
• at shut-down of the fuel cell system,
• step (A) for stopping supply of the material gas from the material gas supplier to the reformer via the material gas supply passage;
• step (B) for stopping supply of water from the water supplier to the evaporator;
• step (C) for closing the material gas supply passage using the first valve;
• and
• step (D) for closing a communicating passage for providing communication between the reformer and atmosphere via an oxidizing gas exhaust passage through which the oxidizing gas exhausted from the fuel cell flows, using the second valve;
• the method further comprising:
• step (E) for opening the second valve prior to opening of the first valve when supply of the material gas from the material gas supplier to the reformer resumes, after the step (A)˜step (D).