The Stress And Strain Analysis Of Coke Tower

Delayed coking belongs to secondary processing way. It is widely used in heavy oil processing because of its simple technique and low cost. At the same time, delayed coking is the important means of increasing the light oil yield. Coke tower is the key equipment of the device. The safe operation of coke tower is the premise of stabilization of coking unit. Software ABAQUS was used in this article and user subroutines were defined to conduct the dynamic analysis and analyzing the changes of temperature as well as stress during the working period.The transient modal method was used in the dynamic analysis of the coke tower. Lanczos eigensolver was firstly used to request 100 eigenvalues and the modal superposition technique was used to calculate the dynamic response to loads. The results indicate that, the first mode with significant mass in the x-direction is mode 8, and that in z-direction is mode 7, while the response of y-direction is not significant. With the effect of wind, the maximal nodal displacement appears at the top of the tower, which is 0.788mm. After loading and unloading, the structure engenders vibration along the loading direction. The frequency is lOHz. This is decided by the natural frequency of the tower.Sequentially coupled thermal-stress analysis was employed in this article. Thermal analysis of the five periods was conducted firstly. According to the results, the radial temperature difference of the whole course is small, which is 1?4?. The axial temperature difference is different in different periods. The uniform temperature distribution is observed in pressure test and coking period. And the axial temperature difference is around 10?. In oil preheating and steam blowing, temperature of the top is higher than that of the bottom. Temperature difference of the former is 51?, and the latter is 18?. The tower is cooled from bottom to top in water cooling stage. There is a high temperature gradient section at this moment. The section rises with the increase of the water until the temperature of the tower dropped to 80?.The stress results have a close relationship with the thermal results. There is a temperature rising during the period of pressure test, oil preheating and coking. So the stress of these three periods is similar. The max stress locates in the skirt and the maximum is 183.6MPa,242.7MPa and 250.4MPa, respectively. The stress of the weld is greater than that of the cylinder. The temperature reduces at the stage of steam blowing, and the stress of the weld is less than that of the cylinder. The stress distribution is similar to the temperature at water cooling. There is a high stress gradient section which is moving with the water. The max stress is 400.4MPa, which is exceeded the yield limit of the material. This leads to the local plastic deformation. Thermal stress ratchet will occur after lots of processes. The plastic deformation accumulates constantly, which eventually leads to the distortion of the tower.