Patent ID: 8904790

Claim:
A pulverized coal boiler suitable for ultrahigh steam temperature, comprising: a hearth including a lower end comprising a slag hole; a tail downward flue including a lower end comprising a flue gas outlet; wherein the pulverized coal boiler further comprises a middle flue arranged to permit flue gas communication between the hearth and the tail downward flue, and the middle flue comprises: a hearth outlet downward flue and an upward flue, wherein a bottom of the hearth outlet downward flue is arranged in flue gas communication with a bottom of the upward flue, wherein an upper end of the hearth outlet downward flue is arranged in flue gas communication with an upper end of the hearth, and wherein an upper end of the upward flue is arranged in flue gas communication with an upper end of the tail downward flue, to form a U-shaped circulation channel; wherein multi-stage convection heating surfaces are arranged inside the middle flue, the multi-stage convection heating surfaces comprise final-stage convection heating surfaces connected with a steam turbine, and the final-stage convection heating surfaces are arranged below other stages of the multi-stage convection heating surfaces.