Fuel reforming system

A fuel reforming system of a fuel cell system, comprising:

• a combustor comprising:
• a main combustion part adapted to perform premixed lean combustion;
• a sub-combustion part provided upstream of the main combustion part, the sub-combustion part being adapted to perform a first lean combustion;
• a fuel pre-vaporization part between the main combustion part and the sub-combustion part, the fuel pre-vaporization part adapted to pre-vaporize fuel;
• a main fuel injection valve adapted to supply liquid fuel to the fuel pre-vaporization part;
• and
• a sub-fuel injection valve adapted to supply fuel to the sub-combustion part;
• and
• a fuel reforming device provided downstream of the combustor, the fuel reforming device comprising:
• a fuel reformer adapted to generate hydrogen-rich gas by a steam reforming reaction of fuel and an oxidation reaction of fuel,
• wherein the fuel reforming system is adapted to, (a) subject, when the fuel cell system starts, predetermined amounts of fuel and air for generating heat required in the fuel pre-vaporization part to the first lean combustion in the sub-combustion part, (b) pre-vaporize fuel to be combusted in the main combustion part in the fuel pre-vaporization part by use of a first combustion gas generated by the first lean combustion in the sub-combustion part, (c) subject air and the pre-vaporized fuel obtained by the pre-vaporization in the fuel pre-vaporization part to a second lean combustion in the main combustion part, and (d) heat, with a second combustion gas generated by the second lean combustion in the main combustion part, the fuel reformer of the fuel reforming device.