Numerical Simulation/Experimental Study And Structural Improvement On Steel Rectangular Vessel In A Pilot Plant Of Seawater Desalination

With the advantages of simple manufacture,high space utilization and heat transfer efficiency,rectangular cross-section vessels are widely used in low-pressure vessels.Steel rectangular vessel is a classic pressure vessel,which is usually used for oil,gas and water storage in energy industry.With the development of technology and the demand of high-efficiency production,the structure of steel rectangular vessel tends to be larger and more complex,which also puts forward higher requirements for structure and load.At present,there is no mature theoretical calculation method and appropriate specification for the design of rectangular vessels with complex structure,which limits the development of its design.With the development of computer and finite element analysis technology,the analytical design method is widely used in the design of steel rectangular vessels.In addition,the strain electrical measurement technology is mature and widely used in the stress test of engineering structure.In this paper,the finite element analysis and stress test of a large steel rectangular vessel in a seawater desalination pilot plant are carried out,and the structure is improved.The main research contents are as follows:(1)According to the relevant literature and standards,the stress analysis of the large steel rectangular vessel under various working conditions was carried out by using the finite element analysis method based on ANSYS,and the verification was carried out according to JB 4732 analysis and design specification,which verifies the safety and reliability of the equipment in normal use.(2)According to the actual test conditions and requirements,a complete stress test system was developed,including hardware and software;At the same time,the field test of the steel rectangular vessel was carried out,and the stress intensity in the test process was monitored by the stress test system,which verifies that the vessel meets the design requirements;By comparing the finite element analysis results with the experimental data and based on the error analysis,the accuracy of the finite element analysis results and the applicability of the analysis design method are further verified.(3)Considering the high vacuum degree inside the steel rectangular vessel during operation,the stability of the vessel under external pressure was analyzed by the method of eigenvalue buckling analysis;The influence of shell thickness,reinforcement size and arrangement on the bearing capacity of steel rectangular vessel structure was studied,and the rectangular vessel structure was further improved;In order to verify the rationality of the structure improvement,the strength and stability of the improved structure are analyzed.(4)Based on the finite element analysis method,the influence of uneven settlement on the steel rectangular vessel was studied,and the change trend of strength and deformation with the settlement of each support point was obtained;Furthermore,according to the different characteristics of the influence of the settlement of different support points on the vessel stress,the allowable settlement was given.(5)According to the relevant design specifications,combined with the three moment equation in the mechanics of materials,the theoretical calculation method of the strength of nine points braced reinforced rectangular plate structure was explored;The feasibility of this method was verified by comparing the calculated data with the results of finite element analysis.