M-TYPE PULVERIZED COAL BOILER SUITABLE FOR SUPER-HIGH STEAM TEMPERATURE

摘要

An M-type pulverized coal boiler suitable for super-high steam temperature comprises a hearth (10), a slag discharge opening (11) disposed in the bottom of the hearth (10), a tail downtake flue (30), a smoke outlet (33) disposed in the lower part of the tail downtake flue (30) and a middle flue (20) communicated between the hearth (10) and the tail downtake flue (30). The middle flue (20) comprises an updraught flue (23) and a hearth outlet downtake flue (21) whose bottoms are communicated with each other and upper ends are respectively communicated with the upper end of the hearth (10) and the upper end of the tail downtake flue (30) to form a U-shaped circulation channel. The middle flue (20) extending downwards and enabling circulation of smoke along the U-shaped circulation channel is disposed between the hearth outlet and the tail downtake flue (30), so as to introduce high temperature smoke from the hearth (10) to a low level through the hearth outlet downtake flue (21), so that it is possible to arrange last stage convection heating surfaces (41, 42, 43) at low positions. Therefore, the length of a super-high temperature steam pipeline (70) between a high temperature superheater (41) as well as a high temperature reheater (42) and a steam turbine (60) is greatly decreased, thereby reducing the manufacturing cost of the boiler.