Abstract: As the main process equipment of PTA plant, the reliability of the mechanical seal of PTA purification crystallizer has a direct impact on the stable operation of the whole plant. This paper analyzed the causes of mechanical seal failure in the purification crystallizer of a PTA plant. And finite element software was adopted to simulate the conditions of the mechanical seal before and after the structural improvement and optimization so as to know the temperature field and deformation of the dynamic and static rings. According to the results of the simulation analysis, the structure of the mechanical seal was improved. This has effectively reduced the ambient temperature of the components, especially the dynamic and static rings, improved the seal lubrication conditions and solved the failure problem of the original mechanical seal.

Key words: mechanical seal, leakage, improvement and optimization, deformation of dynamic and static rings, finite element analysis