Study Concerning Numerical Simulation Of Temperature And Stress Field Of Electromagnetic Induction Partial Heat Treatment On Hydrogenation Reactor

The procedure of hydrotreating has been applied in industry from 1927. Raw oilis hydrogenated at about 175 - 455 under the conditions of activator and high℃pressure hydrogen gas. Hydrocarbon changes into products with low molecularweight. The role that hydrogenation reactor vessel plays in the procedure ofHydrotreating is offering a location for the reaction of raw oil and hydrogen gas underthe conditions of activator and a certain temperature and pressure.Hydrogenation reactor is welded by many tubular courses with more than 4meters in internal diameter, 200mm in thickness and 2m in axial length. To reduce thewelding residual stress and improve the integration mechanical properties of weldingseam and thermal affected zone structures, post-weld heat treatment is required. Thetraditional treatment is to dispose the whole sample in the heat treatment stove, whichis heated to a certain temperature, kept a certain time and then cooled. That is the bestway to eliminate the residual stress, but it is difficult to find the right stove suitablefor the size of the hydrogenation reactor vessel, in which case the partial heattreatment of electromagnetically induced heating stands out with its remarkableadvantages.First of all, this paper investigates the theory of finite element calculation onelectromagnetically induced heating. From the view of electromagnetics and calorifics,a mathematical method for this particular magnetic - heat coupling phenomena isobtained, and the computational model is given. Then, bonded with the finite elementtheory, the way of using ANSYS software to achieve numerical simulation ofinduction heating is discussed. Finally, the APDL is compiled.Through the numerical simulation calculation, the optimum combination ofparameters of heating width and heat preservation width for electromagnetic inductionpartial heat treatment is found, which helps to keep the difference in temperature ofhydrogenation reactor Vessel's welding seam within a certain range during the processof Partial Heat Treatment. As a result, extra residual stress will not be generatedowing to excessively high temperature gradient in the process of Partial HeatTreatmentLastly, based on the distribution of temperature field, the relationship betweenheating width and residual stress during partial heat treatment is calculated. And more,with different heating width, the values of new residual stress brought by thedisproportionation of heating are compared. The best heating width of partial heattreatent, gained from the calculation of temperature field Simulation,is estimatedfrom the viewpoint of residual stress. The shortage in the ASME standards that thequality of partial heat treatment is controlled only by the value of heat width has beensupplemented and improved.