Strength Analysis And Comparison Of Polyester Final Polymerization Kettles With Two Different Jacket Structures

Final polymerization kettle provides necessary reaction conditions for the PET final polycondensation reaction, which directly influences the quality of PET products. In order to ensure the reaction process, the strength and stiffness of the final polymerization kettle should be guaranteed in the production process. In this thesis, the finite element method software ANSYS is performed to analyze polyester final polymerization kettles with two engineering applied jacket structures, namely the whole cylindrical shell jacket and the semicircle pipe jacket.The finite element models of the two jacket final polymerization kettles are established. Stress and deformation of two structures under normal operating conditions with combined design loads are analyzed and strength and stiffness are checked based on the analysis results. In addition, strength check is also performed under the hoisting loading as well as seismic loading conditions for the semicircle pipe jacket structure. Results indicate that all the requirements of strength and stiffness according to JB4732-1995Steel Pressure Vessels—Design by Analysis are satisfied for the both structures.As the deformation of the inner cylinder is critical for the smooth operation of the stirring frame inside, the deformation and affecting factors of the inner cylinder are studied and compared for the two final polymerization kettles. It is found that in term of the radial deformation of the inner cylinder, the whole cylindrical shell jacket structure is better than the semicircle pipe jacket structure, but the whole cylindrical shell jacket structure consumes more material and has a bigger equipment weight. In order to increase the stiffness and decrease the deformation of the inner cylinder, thus conducive to the rotational operation of the stirring cage, a "T" shape stiffening ring with equal mass is proposed for the semicircle pipe jacket structure.It is suggested that if the steam outlet is jointly reinforced by the reinforcing rib and supporting tube, the reinforcing structure can not only guarantee the strength of the steam outlet, but also avoid the disadvantages of thick wall pipe reinforcement, and as a result, consumes less materials and reduce the difficulty of manufacture.