Abstract: A combustion air supply apparatus 9 of alternating heat exchange type supplies combustion air and discharges combustion exhaust gas at a flow velocity of 80 to 200 m/sec. A burner assembly 4 is configured in such a manner that low-caloric fuel gas is pre-heated with heat of pre-combusting high-caloric fuel gas before the low-caloric fuel gas reaches a mixing starting space CA in the combustion chamber where the pre-combusting high-caloric fuel gas and the low-caloric fuel gas come to burn together in a full scale in the mixing starting space CA. When an air amount of the combustion air supplied through the high-temperature air supply ports of the plurality of fuel gas combustion apparatuses is defined as Q1 and an air amount of the pre-combustion air to be mixed with the high-caloric fuel gas, supplied from the fuel gas combustion apparatuses, is defined as Q2, a total air amount (Q1+Q2) is 1.02 to 1.10 times more than a theoretical air amount QS required for combustion, and a ratio of Q2/(Q1+Q2) is 0.

Abstract: A fuel nozzle assembly is provided. The assembly includes an outer nozzle body having a first end and a second end and at least one inner nozzle tube having a first end and a second end. One of the nozzle body or nozzle tube includes a fuel plenum and a fuel passage extending therefrom, while the other of the nozzle body or nozzle tube includes a fuel injection hole slidably aligned with the fuel passage to form a fuel flow path therebetween at an interface between the body and the tube. The nozzle body and the nozzle tube are fixed against relative movement at the first ends of the nozzle body and nozzle tube, enabling the fuel flow path to close at the interface due to thermal growth after a flame enters the nozzle tube.

Abstract: In a combustion unit, a fuel collision member is disposed between a fuel injection valve and a combustion chamber. The fuel collision member is positioned so that, a part of fuel injected from said fuel injection valve is introduced into the combustion chamber while colliding with the fuel collision member, and the other part of fuel is directly introduced into the combustion chamber without colliding with the fuel collision member. Thus, fuel introduced into the combustion chamber is atomized while being introduced into the combustion chamber in a wide range.