Riser for preparing chlorinated polyvinyl chloride through circulating fluidized bed

The invention relates to a riser for preparing chlorinated polyvinyl chloride through a circulating fluidized bed. The riser is formed by connecting devices, a riser body, fixing devices and purging devices in a connected mode. The riser is characterized in that the riser body is square, and the two ends of the riser body are communicated with the connecting devices with circular-to-square structures; at least two corresponding fixing devices are arranged on any diagonal plane of the side walls of the square riser body, the fixing devices are distributed on the surfaces of the square riser body in a staggered and arrayed mode, and the distance between the centers of the fixing devices is 1.5-4 times the diameter of a lamp tube. According to the riser, the purposes of ultraviolet-induced uniformity and material activation uniformity are effectively achieved, the problems of material sintering, carbonization and the like caused by material gathering or clustering in the industrialized enlargement process are av