Numerical Simulation And Experimental Study On Post - Weld Heat Treatment Of Large Pressure Vessel

Post-welding heat treatment of large pressure vessels has three properties:integrity, one-off and finality. At present there are many shortcomings in the post-welding heat treatment industry. No more than the preservation temperature, holding time and the rising and cooling process is required in the standard of post-welding heat treatment. There is rarely any requirement in the technology implementation, such as thermodynamic calculation. Such key technologies as the range of insulation and heating areas, the distribution and quantity of the thermocouple point, the error of temperature-measuring system, heatproof material selection and laying thickness, deformation control and such others can only rely on the operators’experience. The more experienced, the better the effect is.Otherwise, it is difficult to guarantee the quality of post-welding heat treatment. Development of post-welding heat treatment can’t keep up with the requirement of pressure vessel manufacturing. It has been the weakest link in the pressure vessel construction process. The flowing field, temperature field and thermal distortion field are analyzed by computer simulation during post-welding heat treatment, which is of active significance for improving the level of post-welding heat treatment of domestic pressure vessels.This project makes a steady-state thermal analysis of the post-welding heat treatment phase of a 10000m3 spherical tank and tower equipment, based on ANSYS simulation technology for the flowing field, temperature field and thermal distortion field as well as the theory of the fluid-thermal coupling and thermal-structure coupling analysis. With simulation of different inlet velocity and thickness of insulation layer, the effects of different heat treatment process parameters are analyzed and illustrated.The practice of post-welding heat treatment of the 10000 m3 spherical tank goes as follows. Since the internal space is too large, it is necessary to install flame-diverting arrangement in the high-speed electromagnetic valve and timely maintain micro positive pressure internally, for the purpose of ensuring all parts’ temperature uniformity and stability of the spherical tank. Temperature monitoring system is used in the actual measure of spherical tank shell. After the simulation results contrast with the real ones, the accuracy of numerical simulation model is proved. Proving the research is beneficial for the quality of the large spherical tank after the post-welding heat treatment, and it is applied in the actual engineering practice successfully.Analyzing the similarities and differences with the spherical tank and tower equipment, corresponding modification to the validated numerical simulation model of spherical tank is applied to the numerical simulation of tower equipment. Combining with qinghai salt lake magnesium integration project, aspen plus tower be modeled properly. Thus, the blanks of the numerical simulation of tower equipment are filled.