Fuel reformer and exhaust gas purifier using the same

A fuel reformer comprising

• a carrier gas heating part that can adjust an amount of heat generation for heating a first carrier gas supplied from a carrier gas source through a first carrier gas supply pipe;
• a first carrier gas injection nozzle that injects the first carrier gas heated by the carrier gas heating part;
• a first fuel supply nozzle that supplies a fuel including a hydrocarbon-based liquid to a tip end of the first carrier gas injection nozzle so that the fuel is atomized with the first carrier gas injected from the first carrier gas injection nozzle;
• an exothermic catalyst part that includes an inlet facing the first carrier gas injection nozzle and the first fuel supply nozzle and that oxidizes the atomized fuel to further heat the first carrier gas and to increase a temperature thereof;
• a second carrier gas supply pipe that mixes a second carrier gas supplied from the carrier gas source with the first carrier gas heated by the exothermic catalyst part;
• a second carrier gas injection nozzle that injects the mixed carrier gas of the first and second carrier gases;
• a second fuel supply nozzle that supplies the fuel including the hydrocarbon-based liquid to a tip end of the second carrier gas injection nozzle so that the fuel is atomized with the mixed carrier gas injected from the second carrier gas injection nozzle;
• a reforming part that includes an inlet facing the second carrier gas injection nozzle and the second fuel supply nozzle and that decomposes the atomized fuel to reform the atomized fuel into a reducing gas including either or both of hydrogen and an oxygen-containing hydrocarbon;
• a reducing gas supply nozzle that is attached to an exhaust pipe of an engine so as to supply, to the exhaust pipe, the reducing gas discharged from an outlet of the reforming part;
• a first carrier gas temperature sensor that detects an outlet temperature of the carrier gas heating part;
• a second carrier gas temperature sensor that detects an outlet temperature of the exothermic catalyst part;
• and
• a controller that controls the amount of heat generation of the carrier gas heating part based on a detection output of the first carrier gas temperature sensor, that controls a supply flow rate of the fuel to the first fuel supply nozzle based on a detection output of the second carrier gas temperature sensor, and that further controls a supply flow rate of the fuel to the second fuel supply nozzle according to a flow rate of NOx flowing through the exhaust pipe.

An exhaust gas purifier for purifying an exhaust gas of an engine, the exhaust gas purifier comprising:

• a selective reduction catalyst that is provided in an exhaust pipe of the engine and that can reduce NOx in the exhaust gas to N2;
• a fuel reformer that heats a liquid fuel in a hermetically sealed reforming case by a heater to vaporize or vaporize and mist the liquid fuel and that further reforms the vaporized or vaporized and misted fuel with a reforming catalyst into a hydrocarbon-based gas, the fuel reformer including:
• a carrier gas injection nozzle that injects a carrier gas supplied from a carrier gas source;
• a carrier gas heating part provided between the carrier gas source and the carrier gas injection nozzle and that can adjust an amount of heat generation for heating the carrier gas supplied from the carrier gas source, the carrier gas heating part including:
• a coil holding part formed in a columnar shape,
• a heating coil embedded so as to extend along an outer peripheral surface of the coil holding part and not be exposed on the outer peripheral surface of the coil holding part, and
• a carrier gas passage coil that is helically wound around the outer peripheral surface of the coil holding part to thereby form a carrier gas passage through which the carrier gas flows helically along the outer peripheral surface of the coil holding part;
• a fuel supply device that supplies the fuel into the fuel reformer;
• an injecting nozzle that extends to an exhaust pipe on an exhaust gas upstream side of the selective reduction catalyst and that can inject the hydrocarbon-based gas reformed with the reforming catalyst;
• a catalyst temperature sensor that detects an exhaust gas temperature related to the selective reduction catalyst;
• a pressure sensor that detects an inlet pressure of the fuel reformer;
• and
• a controller, which in operation, controls operation of the fuel reformer and the fuel supply device based on respective detection outputs of the catalyst temperature sensor and the pressure sensor.