Cement kiln tail flue gas treatment device and technological method characterized by combination of bypass air release and staged combustion

The invention provides a cement kiln tail flue gas treatment device characterized by combination of bypass air release and staged combustion. The cement kiln tail flue gas treatment device characterized by the combination of bypass air release and staged combustion comprises a kiln tail flue gas chamber of a rotary kiln, a decomposition furnace, a cyclone preheater, a double-cyclone separator, a layered cooling desulfurizing tower and a bag type dust collector. The kiln tail flue gas chamber of the rotary kiln is connected with the decomposition furnace and connected with the double-cyclone separator through a bypass flue gas pipeline. Hot raw materials in a feeding pipe of the cyclone preheater are divided into two parts, one part enters the kiln tail flue gas chamber along the existing path, and the other part enters bypass flue gas which is pumped out of the kiln tail flue gas chamber. The double-cyclone separator is connected with the top of the layered cooling desulfurizing tower. The bottom of the layer