Failure Analysis of a Double-Cyclone located in a Cement Production Line

The main objective of the paper herein presented is to analyze an equipment failure in a cement production line, namely the existence of cracking of the concrete inside the cyclone towers (with the fall of this coating). The observed failures are recurrent and responsible for reducing the period between stops of the production line. The equipment is a double cyclone that makes up the fourth stage of a preheating tower; this is composed of a set of cyclones arranged at various levels, which use the hot exhaust gases from the kiln to pre-heat and partially decompose the raw material before it enters the kiln. Cyclones are exposed to high temperatures; for this reason, their metallic structure is covered with an insulating material and a refractory material (concrete). It was identified that the refractory material cracks and falls due to its thermal degradation and due to the temperature gradients, which range from 24oC to 750oC. Also, repeated thermal cycling could affect the bond strength between the concrete and the steel reinforcements. One solution passes by developing a new brick support layout that replaces the concrete, taking advantage of the internal steel framework of the cyclones.