Design Of Shell-and-tube Heat Exchanger With Research And Optimization Of Tube-sheet

Shell-and-tube heat exchanger is a kind of chemical equipment for heat exchange in the chemical industry.Because both sides of the tube-sheet in the device are affected by temperature load and pressure load,the stress of the tube-sheet is very complex.Therefore,it is necessary to analyze the stress distribution of tube-sheet accurately under different forces.In this paper,the tube-sheet structure is optimized when the tube-sheet strength meets the design requirements,so that the safety and economic performance of the tube-sheet in the heat exchanger will achieve a better balance.The specific research contents of this project are as follows:Firstly,according to the requirements of GB151-2014 heat exchanger and GB150-2011 pressure vessel,the overall structure design and material selection of the heat exchanger are carried out.The three-dimensional model of heat exchanger with parameterization is established by Solid Works software,and the simplified model of tube-sheet finite element is established by ANSYS.Secondly,the heat transfer mode of the tube-sheet of the heat exchanger is analyzed,and the steady-state heat transfer mode is determined.The distribution of temperature field under the influence of temperature load on both sides of tube-sheet is analyzed.The result shows that there is a very thin layer on the shell side of the tube-sheet,the temperature is close to the shell side temperature,and the remaining thickness changes rapidly to the working medium temperature on the tube side,which is called the "skin effect".Thirdly,the different working conditions of the heat exchanger and the different combinations of temperature load and pressure load on the tube-sheet are analyzed.The stress analysis of tube-sheet under different working conditions of heat exchanger is carried out to find out the stress distribution law of tube-sheet.According to JB4732,the membrane stress,membrane stress plus bending stress and total stress on different paths are evaluated.The result shows that the designed tube-sheet of heat exchanger can meet the requirements under all working conditions.Under the condition of temperature load,the stress of tube-sheet is large,the stress of the connection between tube-sheet and other components is large.In the seven working conditions,when the shell side stops first,the stress on the tube-sheet appears the maximum value,which is the most dangerous in all working conditions.Finally,in order to study which design factors have influence on the stress distribution of tube-sheet,parametric analysis is carried out for tube-sheet layout,process parameters and tube-sheet thickness when the heat exchanger is working to find out the influence degree of different factors on the stress distribution of tube-sheet.The result shows that the triangle layout has the characteristics of compact layout and low stress.The thickness of tube-sheet has the greatest influence on the stress of tube-sheet,followed by the temperature load,and the pressure load has the least influence on the stress of tube-sheet.According to the above analysis results,the optimization analysis of tube-sheet shows that the process parameters of heat exchanger are fixed,and it is not advisable to optimize the temperature load.Therefore,the thickness of the tube-sheet is optimized,and 43% of the tube-sheet thickness is optimized,achieving the goal of both economic and safety.The buckling analysis of the optimized tubesheet is carried out to verify the buckling stability of the tube-sheet.The results show that there is no instability of the tube-sheet.