Structure Design And Optimization Of Ammonia Synthetic Tower

The ammonia synthetic tower is important equipment in the ammonia synthetic industry,and it usually operates under high temperature, high pressure and corrosive medium conditions. The design pressure of the ammonia synthetic tower is approximately 10 ~100MPa, which belongs to the high pressure vessel. Due to withstand high pressure and high temperature, safety issue of high pressure vessel has been attracted the attention of researchers. To ensure the safety of the design for the vessel, a larger safety factor is applied in conventional high pressure vessel design according to the experience formula. Thus, the material utilization rate is very low, and the cost is very high. Moreover, the phenomenon of stress concentration often occurs because of multiple openings on the tower, and it is more dangerous. Therefore, in this paper, the strength analysis of key parts in the tower was calculated using the theoretical formula according to the GB.150.1~150.1-201 pressure vessel design basis. And the stress, strain and displacement situation of the parts were investigated by using the numerical simulation of finite element method. In this analysis, the thermal-structural coupled field was analyzed. The key parts in the ammonia synthetic tower are consist of cylinder, flat cap, double cone ring seal structure, the head and the bottom of the pore structure, and so on.The main contents of this research are listed as follows:(1) Manufacturing process and structural model of the cylinder of the ammonia synthesis tower were analyzed and established by using the finite element analysis method. The stress,displacement, strain and safety coefficient of the tower were discussed by using the finite element analysis method under different tube thicknesses.(2) Flat cap and double cone seal structures strength were analyzed by using the conventional formula, and the finite element model were established to analyze the double cone ring gasket stress with the change of internal tower pressure between cylinder and flat cap bearing surface.(3) A three-dimensional solid model of spherical head with one single hole was established based on the analysis of the stress distribution under reinforcement and without reinforcement structure cases. A finite element model of ammonia synthesis tower with three openings at the bottom was set up, and the distribution of stress in the structure of the mutant was analyzed.