The Particularity Of Pipe Flange Sealing Leakage Problem And Probability Research

Pressure pipe as an important petrochemical industry equipment,sealing performance has a direct impact on the national economy and personal safety.The forms of stress on pressure pipe flange are more complexed than it is on equipment flange.Equipment flange is mainly subjected to internal pressure and temperature load,pipe flange is subjected to not only internal pipeline pressure,high-temperature thermal stress but also a significant additional axial force and additional moment on the flange face generated by the internal pressure,temperature,gravity,installation errors etc.The size of the additional load is unpredictable.In the actual project pipeline flanges meet the design requirements,but the leakage accidents is a lot,this is because the flange design is without considering the influence of the additional load.So the research on pipeline flange sealing performance is important.This article mainly analyzes the following two cases.The first is that bolt flange sealing system is simulated though steady and transient state and analyzed for completeness and sealing performance.The pipe flange affected by particulariar load on the sealing performance is researched.The second is that considering the integral mechanical characteristics is complexed,the leakage failure limit state equation is created Monte Carlo method combined with probability statistics normal distribution random sampling theory is applied to calculate the pipeline flange sealing failure probability.A new method for guarantee the safe operation of the pipeline flange sealing system is proposed.The problem based on the traditional design method to design the pipe flange with uncertainty under additional loading of the poor sealing performance is solved.The disadvantages of this conservative approach increasing the bolt blindly pulling force to ensure the safety of the seal is eliminated.Firstly,according to the theory of heat transfer,heat transfer mode is created and the system steady-state thermal and thermal-structure coupling are analyzed,studying the flange system as a whole and its various components stress distribution.Secondly,studying the stress distribution of the whole and its components under bending moment and calculating the tightness of the flange by PVRC under different moments.Moreover,the system transient thermal was analyzed to study the temperature at different time of the flange system stress distribution.Finally,applying probability analys is method-Monte Carlo method to calculate flange leakage probability.