Flameless fuel gas combustion device and method with extremely low nitrogen oxide emission

The invention relates to a flameless fuel gas combustion device and method with the extremely low nitrogen oxide emission. The flameless fuel gas combustion device with extremely low nitrogen oxide emission comprises an L-shaped air spray pipe, a central fuel gas spray pipe, an outer fuel gas spray pipe and a flame holder, wherein one section of the air spray pipe is arranged horizontally, a spray pipe outlet is formed a the tail end of the horizontal section of the air spray pipe, a horizontal branch pipe is arranged at the bent position of the L-shaped pipe, the central fuel gas spray pipe is a straight pipe and stretches into the horizontal section of the air spray pipe after penetrating through the horizontal branch pipe, and an annular gap is reserved between the air spray pipe and the central fuel gas spray pipe, so that an air channel is formed; the central fuel gas spray pipe and the horizontal branch pipe are connected through a sealing connector; the outer fuel gas spray pipe is arranged in a sleeved mode and is connected to the outer side of the horizontal section of the air spray pipe in a sealed mode, a spray pipe inlet is formed in one side of the outer fuel gas spray pipe, and an annular gap is reserved between the outer fuel gas spray pipe and the air spray pipe, so that an outer fuel gas channel is formed; the outer fuel gas spray pipe, the horizontal section of the air spray pipe and the central fuel gas spray pipe are coaxial, the end face of an outlet of the outer fuel gas spray pipe is flush with the end face of the outlet of the air spray pipe, and the flame holder is installed at the outlet end of the central fuel gas spray pipe.