A burner system includes a plurality of burners, each having a nozzle positioned to emit a stream of fuel into a combustion volume, and a perforated flame holder, including a plurality of apertures extending between first and second faces thereof, and positioned to receive a stream of fuel from the respective nozzle. In operation, the flame holders are configured to hold a flame substantially within the plurality of apertures.

A burner system includes a plurality of burners, each having a nozzle positioned to emit a stream of fuel into a combustion volume, and a perforated flame holder, including a plurality of apertures extending between first and second faces thereof, and positioned to receive a stream of fuel from the respective nozzle. In operation, the flame holders are configured to hold a flame substantially within the plurality of apertures.

Proposed is a heat pipe unit and a waste heat recovery boiler including the same, wherein a heat pipe unit includes a plurality of heat pipes provided inside a casing part of a waste heat recovery boiler and a plurality of connection pipes connecting the plurality of heat pipes to each other. The heat pipes are disposed in a plurality of rows along a direction in which the exhaust gas flows. The connection pipes include a plurality of first connection pipes disposed in oblique directions and connecting the plurality of heat pipes disposed in corresponding front and rear side rows, and a plurality of second connection pipes connecting the plurality of heat pipes disposed in corresponding front and rear side rows and disposed not to be parallel with the plurality of first connection pipes.

Proposed is a heat pipe unit and a waste heat recovery boiler including the same, wherein a heat pipe unit includes a plurality of heat pipes provided inside a casing part of a waste heat recovery boiler and a plurality of connection pipes connecting the plurality of heat pipes to each other. The heat pipes are disposed in a plurality of rows along a direction in which the exhaust gas flows. The connection pipes include a plurality of first connection pipes disposed in oblique directions and connecting the plurality of heat pipes disposed in corresponding front and rear side rows, and a plurality of second connection pipes connecting the plurality of heat pipes disposed in corresponding front and rear side rows and disposed not to be parallel with the plurality of first connection pipes.