Five-stage preheating system of rotary cement kiln

The utility model provides a five-stage preheating system of a rotary cement kiln. The five-stage preheating system comprises a decomposing furnace, a first-stage preheater, a second-stage preheater, a third-stage preheater, a fourth-stage preheater and a fifth-stage preheater. Each stage of preheater is correspondingly provided with an air inlet, an air outlet pipe and a discharging pipe; the second-stage to the fifth-stage preheaters are also correspondingly provided with a feeding opening; the second-stage air outlet pipe is communicated with the first-stage air inlet; the third-stage air outlet pipe is communicated with the second-stage air inlet; the fourth-stage air outlet pipe is communicated with the third-stage air inlet; the fifth-stage air outlet pipe is communicated with the fourth-stage air inlet; the air outlet pipe of the decomposing furnace is communicated in parallel to the fifth-stage air inlet of the fifth-stage preheater; the third-stage feeding opening is communicated to the first-stage discharging pipe; the fourth-stage feeding opening is communicated to the second-stage discharging pipe; the fifth-stage feeding opening is communicated to the third-stage discharging pipe; the fourth-stage discharging pipe, the fifth-stage discharging pipe and the decomposing furnace are communicated to a feeding chamber in the tail end of the rotary kiln, and the five-stage preheating system is characterized in that a sampling hole is formed in a position, which is 300mm to 600mm away from the air inlet end, of the fifth-stage air outlet pipe, and a sensing probe of a sampling pipe gas analyzer is arranged in a sampling pipe. The five-stage preheating system has the characteristics of good rotation effect and high reliability.