Static equipment petrochemical equipment technology, 2011, 32 (2) Propane tower air cooler header pipe damping vibration reduction technology research Jiang Yang, He Lixi, Ren Wei (School of Mechanical and Electrical Engineering, Beijing University of Chemical Technology, Beijing 100029) using finite element analysis software The modal analysis of the piping system is compared with the measured data, and a solution to the piping vibration is proposed. In the case of non-stop, install the damper in the appropriate position of the pipeline, which effectively reduces the amplitude of the pipeline system and improves the operating life of the pipeline. In petrochemical enterprises, the vibration of the pipeline system poses a great threat to production safety. Strong pipeline vibration will cause the pipeline accessories, especially the connection parts of the pipeline and the connection parts of the pipeline and the accessories to loosen and rupture, causing leakage at least, and explosion at heavy. Therefore, solving the vibration problems of the pipeline system can effectively prevent the hidden safety hazards such as weld seam breakage, medium leakage, system shutdown, and explosion, which are of great significance to the safety production of the enterprise. The main reasons for the vibration of the pipeline system are air flow pulsation excitation, resonance of the pipeline structure, poor dynamic balance of the unit, or improper foundation design. Pipeline vibration damping mainly controls the pressure pulsation of the fluid in the pipeline so that it does not produce resonance or changes the natural frequency of the pipeline system so that it does not produce resonance. The above vibration reduction methods need to be implemented in the state of shutdown, or need to be implemented in the overall design stage of the piping system. Pipeline damping and vibration reduction technology can dissipate the vibration energy of the pipeline system, so that the kinetic energy is converted into heat energy and released. The damping and vibration reduction technology can install a damper at a suitable position (usually at the maximum amplitude) of the pipe system without stopping the machine and changing the structure of the pipe system to carry out vibration reduction transformation of the pipe system. In this paper, the amplitude and frequency of the pipe vibration of the propane tower air cooler manifold of a refinery in Jinan were measured on site, and the modal analysis of the pipeline system was performed using finite element software. From the analysis, it was found that resonance caused strong vibration of the pipeline system. Using damping and vibration reduction technology, install a damper at the appropriate position of the pipeline to greatly reduce the amplitude of the pipeline and achieve a good vibration reduction effect. 1 Vibration of the air cooler manifold pipe of the propane tower As shown in the pipeline of the air cooler manifold of a propane tower in Jinan, as shown in the figure, the pipeline space direction is complicated, there are many elbows and valves, and the medium velocity and flow direction have changed drastically, causing pipeline Excited vibration. The amplitude of the pipeline varies at different positions, its maximum value exceeds 1mm, the acceleration exceeds 1.72m / s2, and the vibration impact is large. The pipeline vibration direction is mainly the horizontal y direction, vibration frequency mechanical specialty, currently studying for master degree, mainly engaged in the research work of pipeline vibration problems in petrochemical enterprises. 2 Piping system vibration parameter measurement and vibration principle analysis 2.1 Piping system vibration parameter measurement A portable vibration meter is used to measure the amplitude and frequency of the piping system. The location of the measuring point is selected as shown. The measured data shows that the measured frequency is 9.610.67 Hz. Comparing the modal analysis results with the actual measurement, it can be concluded that the piping system is in the resonance region, so the vibration amplitude of the piping system is large. It can be seen that the amplitude of the elbow and the connection of the outlet pipe of the air cooler manifold is relatively large, which is consistent with the measured pipeline vibration. (Horizontal direction> schematic diagram of the location of the measuring points of the pipeline system. Table 1 Actual measured value of each point of the pipeline system. 1 measuring point: horizontal amplitude rnm frequency HzI 2.2 Analysis of vibration principle Due to the many elbows and valves of the collecting pipe pipeline system, the impact of airflow Piping system vibration. When the pulsation frequency of the airflow coincides with the natural frequency of the piping system, it will cause the piping system to resonate. 2.2.1 Modal analysis of the piping system using the software Modal analysis of the piping system using the finite element software to determine the installation location of the damper. See the piping model, see the modal. Piping system model The fifth-order natural frequency of the piping system is 10.331 Hz, and its resonance frequency region is 8.2612.40 Hz, and the actual vibration analysis of the piping system 2.2.2 Damping and damping principle analysis Install the damper at the location where the piping system amplitude is large, The mechanical energy of the pipe vibration is transferred to the damping fluid of the damper, and the vibration energy of the pipe is dissipated by the movement friction of the damping fluid to finally achieve the purpose of damping the vibration. The damper is a flexible support, which does not change the rigidity of the original system and has no free motion. Its damping effect on low-frequency vibration is very significant. According to Newton's law of motion, the vibration differential equation can be obtained: r-viscous damping coefficient; suitable, so that the welding line energy is small, which can reduce sensitization. However, the reduction of sensitization should not only consider the control of the welding line energy, but also the sensitization effect caused by the multi-layer welding on the front layer. Therefore, the final cover welding should be used on the side that contacts the medium. For this purpose, the A-type and B-type joints of the tower should use V-shaped inner bevels. Welding electrode arc welding should be applied from the inner side to the inner side. The thickness of the cover layer is welded. Covering layer on the inside. Weld the test piece according to the proposed welding procedure instruction book. At this time, the welding procedure evaluation should be based on the mechanical properties of the welded joint (especially the normal temperature yield strength ipo.2) and the intergranular corrosion performance as the judgment criteria. The previous (according to B / T4708) assessment rules, parameter division, steel classification grouping, thickness replacement (coverage), etc. are not fully applicable, because the B / T4708-2000 assessment standard only considers the mechanical properties of the welded joints, and does not consider the intergranular Corrosion performance. 21433 stipulates that for the evaluation of the intergranular corrosion performance of welded joints, the welded test pieces shall be those welded with the same batch of base metal, the same batch of welding consumables, and the same welding process (including the joint type). The arc welding electrode determined after passing the welding procedure qualification is the A002 electrode in GB / T 983-1995 stainless steel electrode. Standards are the crystallization of theory and practice, and are the detailed rules for the implementation of standardization. They are public welfare and should be specific, clear, and feasible. Correct understanding and application of standards are fundamental to ensure the quality of container construction. White Double Windows Envelope,Envelope of Double Windows,Mailers of Double Windows,Check Double Windows Envelope Sun Kee Envelopes Limited , https://www.sunkeeenvelope.com
Research on Damping and Vibration Reduction Technology of the Collector Pipe of Propane Tower Air Cooler