Multifuel fuel cell system and a method for its operation

A multifuel fuel cell system, comprising:

• a hydrogen production unit;
• at least one fuel cell;
• a catalytic converter element in the hydrogen production unit;
• a heater for the catalytic converter element;
• a liquid fuel pipe leading from a fuel tank to the catalytic converter element and an air pipe leading from a compressor to the catalytic converter element;
• a pipe leading from the catalytic converter element to at least one of a high-temperature heat exchanger;
• at least one shift stage;
• a selective oxidizer;
• a catalytic burner;
• a high-pressure compressor;
• or an evaporator for passing a synthetic gas mixture;
• and
• a switch between the catalytic converter element and the fuel cell that switches the fuel cell system between a first operating mode, where the hydrogen production unit is raised to a predetermined operating temperature, and a second operating mode, wherein the hydrogen production unit and the at least one fuel cell are disconnected during the first operating mode and are connected during the second operating mode and wherein the switch switches the fuel cell system from the first operating mode to the second operating mode upon the hydrogen production unit reaching the predetermined operating temperature and further wherein reformate can be transferred from the hydrogen production unit to the at least one fuel cell only during the second operating mode.

A method for operating a multifuel fuel system having a hydrogen production unit and at least one fuel cell, comprising:

• heating a catalytic converter element in the hydrogen production unit to a required operating temperature;
• metering a liquid fuel and air to the catalytic converter element, thereby producing a synthetic gas mixture containing hydrogen;
• passing the synthetic gas mixture to additional components of the hydrogen production unit which are connected between the catalytic converter element and the at least one fuel cell;
• feeding a reformate to the at least one fuel cell by operating a switch disposed between the catalytic converter element and the at least one fuel cell only when at least one of the catalytic converter element or at least one of the additional components has reached a predetermined operating temperature.