Design And Analysis On The Stress Of The Discharge System And The Cycle-gas Compressor System For The Scale Of 300 Thousand Tons Polypropylene Plant

The calculation and design for the crucial pipelines in the recycle gas compressor system and the product discharge system of 300 thousand tons / year polypropylene unit are completed in this paper. Aiming at solving the conflicts between the security and economy of the crucial pipes, different support, hangers, and pipe accessories are designed and optimized, with CAESAR II stress analysis software utilized.The optimizing calculation and design of stress analysis for the pipe 42″-P-01, pipe 42″-P-02 and pipe 42″-P-03 in the recycle gas compressor system are executed in this paper. By comparing the calculated results of four design proposals which are brought up for the pipe 42″-P-01, the second proposal, which is the optimum design of stress analysis, is adopted ultimately. In the second proposal, large +Y heading whirling arm (+YROD) is set up at the elbow under the pipe, spring hangers are added in the double ends of the vertical component of the pipeline respectively, bearing supports and Z heading spacing supports are installed in the horizontal pipe of the inlet of compressor, expansion joint and two spring supports are set up in the inlet of compressor, and shock damper is fixed at the vertical component of the pipeline. According to this proposal's calculated result, not only the stability and security of pipes are ensured, but also achieves the economizing purpose. In the optimizing design for pipe 42″-P-02, which has expansion joint installed are optimizing calculated and designed. The result demonstrates that, by adding two multi universal hinge-shape expansion joints in the horizontal pipeline, setting up a angular expansion joint in the vertical pipeline, installing three spring hangers and two shock damper at the horizontal pipeline, setting up +Y heading support and Z heading restraint at the elbow, this design proposal can ensure the safety and stability of the pipes and pipe orifices of the equipment linking with the pipes. For the pipe 42″-P-03, it needs to set up bearing supports, hangers and spacing supports in the proper spots to make sure the safety and stability of pipelines.The pipe 8″-P-01 (A pipeline)in the product discharge system is the priority research area in this paper. The effect of pipeline A's length on the stress and moment of reactor's pipe orifices C and product vessel's pipe orifices A, and the effect of pipeline A's length on the different stresses and moments of the product vessel are compared. the conclusion of the the optimizing design and calculation: if the length of pipeline 8″-P-01 is set as 4300 mm, the extra stress can be reduced effectively, ensuring the safety of the entire pipeline. In order to decrease the heat expansion, optimum design proposal is adding four symmetrical spring supports and two XSNBs upper the product blow-off tank. This proposal gains the ends of proposal purpose.The engineering problems of optimizing proposal and design calculation of stress analysis for the crucial pipelines in the recycle gas compressor system and the product discharge system of 3 million tons / year polypropylene unit are solved by the research and design of this paper, which provides design reference and foundation for this kind of stress analysis calculation.