Low-nitrogen combustion boiler with built-in tuyere circulation structure and method

The invention relates to the technical field of low-nitrogen combustion boilers, in particular to a low-nitrogen combustion boiler with a built-in tuyere circulation structure and a method. The low-nitrogen combustion boiler with the built-in tuyere circulation structure and the method aim at solving the problems that the over-low oxygen content in flue gas possibly enables primary air not to reflect the effect of fuel air, so that pulverized coal cannot be completely combusted, and the targeted low-nitrogen combustion cannot be conducted on the pulverized coal with different mass. The low-nitrogen combustion boiler comprises a hearth, the low-nitrogen combustion boiler comprises an air pressure adjusting air distribution plate used for controlling air pressure, a primary air outlet pipe provided with a hot air inlet, a secondary air outlet pipe set, an air supply proportion controller used for controlling the air inlet amount of a primary air outlet pipe set and the secondary air outlet pipe set, and an air