Chemical Rotary Kiln Type Self Return Alkali Steam Calcination Furnace

Changes and considerable progress Of Cement Rotary Kiln

Firstly, to address the issues of discontinuous alkali return and poor premixing effect, the furnace body is extended into the furnace head, and forward and reverse push spiral plates and chains are added to the extended part as the premixing section. The alkali return in the furnace is changed to alkali return at the end of the furnace body. The returned dry alkali is pushed into the premixing section of the furnace head through several material guiding screws in the exhaust hood. Not only has it solved the problems of discontinuous alkali return and poor premixing effect, but it has also effectively addressed the issue of scarring on the furnace head.

Secondly, change the disc-shaped air chamber into a circular tubular air chamber, and connect the intake pipe and the return pipe end to end to form a closed circulation system. Whether the condensate water is discharged smoothly or not will directly affect the production capacity of the calcination furnace. The initial gas chamber structure of the calcination furnace was complex, which not only made the processing difficult but also made the condensate water discharge not smooth. The improved heating system has increased the drainage channel of the air intake box. The steam in the front keeps condensing, and the subsequent steam constantly compensates. While the steam flows, it also promotes the flow of condensate water. In addition, the heating temperature and heating area are the prerequisites for enhancing the production capacity of the furnace. Therefore, various manufacturers and users are all working hard to increase the steam pressure and expand the heating area. Meanwhile, the fin height of the finned tube is reduced and the pitch is decreased, which significantly increases the heat transfer intensity per unit area.

Thirdly, the characteristic of mechanical seals is that the moving and stationary rings are in close contact with each other. The sealing surface is provided with oil grooves and lubricated with molybdenum disulfide grease, providing excellent sealing performance for gases. The feature of the floating ring is that its processing accuracy is relatively low, but it can play a sealing role for solid materials. At present, most manufacturers organically combine the two, that is, the flexible joint compensates for the expansion and contraction of the furnace body, and the combined sealing structure is compressed by the compression wheel or cylinder.

After continuous improvement in recent years, the output of the self-alkali return steam calcination furnace has increased by about 30% compared with the initial stage. The concentration of furnace gas can reach 85-90%, and the minimum steam consumption can be reduced to 1.24 tons per ton of alkali. With the advancement of design and manufacturing technologies, the specifications of furnaces have been continuously increasing, ranging from φ1800, φ2000, φ2500, φ2800 to φ3200. They have been adopted by most large and medium-sized new and old soda ash plants in China, and the light and heavy soda ash produced by them all meet the national standards for high-quality products.