Security Analysis And Lifetime Evaluation Of The Coke Drum - The Structural Strength Of The Coke Drum

Strength problem in practical engineering contains extensive range, and usually comes down to considering many factors relating to structural bearing capacity, such as obvious shape variation due to plastic deformation, material damage due to load over nominal scale and stability loss, etc. The stress state of material under high temperature is more complex, where temperature stress combines with mechanical stress, which produces huge effects on strength of device. So researching their strengths under high temperature has important value.Coke drum is the key device of delayed coking in petrochemical industry. But due to the severe service conditions, it's easy to raise some kinds of failure relating to structural strength. So analyzing its strength completely has great practical meaning and economic value.In order to study structural strength of the coke drum in working, paper emphasizes the study on the thermal deformations and thermal stresses of the wall. Sets up analytic models for the transient temperature field, based on theory of finite element. Makes good use of the powerful software ANSYS to calculate the temperature fields and thermal stress fields on different stages in its operation. In order to compare the effect of different structural patterns to structural strength, the improved skirt structure is studied.All mechanical loads are considered, including internal pressure, gravity, wind load and earthquake load, in which the modal analysis of the drum, functional wind load and temporal analysis for earthquake are the innovations of this paper.The analysis results indicate that not only radial temperature gradient but also a major axial one exist in temperature field of the drum wall, and the thermal stresses generated by them are the essential components of the combined stress onthe wall. Comparing the combined stress of mechanical and thermal stress with the stability criterion, conclusion is drawn that the structure of coke drum contents the qualification of stability. Checking the axial compressive stress of the skirt, deduces that it is stable. The simulation results got in this study are reasonable and match the practical perfectly. So the methods employed in this paper is useful for the failure analysis and structural improvement of coke drum.