Ethylene cracker tube damage and life prediction m

yxfbbiedtj · Wysłany: Czw 15:03, 31 Mar 2011

Ethylene cracker tube damage and life prediction methods thinning

Maximum hoop stress is 3.39/MPa, at this time did not consider radial stress, axial stress caused by heavy white, inside and outside tube wall thermal stress and thermal stress such as heating and cooling. Therefore, a certain selection in the design of the safety factor, the design of the hoop stress of 0.5MPa, the safety factor of 1.48. Wall thinning caused by the increased stress the safety performance should also be considered,[link widoczny dla zalogowanych], the net 9 also listed considering the safety factor of stress. Figure 8 different thickness hoop stress distribution when the running time and the Inner Ring 9 to stress if the systems 3.3Lar '= on-Miller song push the listless life of sewing section B and D will be a lasting performance on pipe using the formula P-10T (23 + lgtr) P index of stress and do figure lO, D segment decline curve in the most, it should be D-meter section of pipe to predict the life of the P values determined how much life depends on D section of pipe Larsoa-Miller curve and the stress of running intersection. Anatomical analysis in the preceding paragraph tubes found in D all the coarsening of secondary carbides Pat, in a later operation, the organization will not change significantly the position so the same curve. Thinning of tube wall thickness, hoop stress will increase, that is, the position of point P along the curve upward change. Exhausted from the perspective of life life expectancy, can be considered as the residual life of less than one year duration of use is its life. Figure lO in the furnace after the stress of running 5.3a corresponds to P = 6.3MPa 35.8 at this time, such as the operating temperature is 1000 * C, can be calculated by the formula P value of remaining life at this time. But this life did not consider continuing to run-time tube wall thinning also caused by the stress increased. Therefore, the dynamic method to use the remaining life prediction. Table 4 lists the use of time, stress and circumferential residual life, the furnace if the work can continue to operate under the 7-8a. P: l0'T (23 ten Igr,) store and the LM curve of the stress lO, P index curve of Dalian University of Science report 4 and the stripping section operating life, asked God f, between 30 a. Volume 4 Conclusion 5.3a cracking tube after thinning in the run, the most severe thinning of parts of 1.8mm, the original wall thickness of about 20. b. The furnace is running 5.3a, the section of pipe in the organization of the precipitation of secondary carbon 『seven and growing up. D section of pipe http organization of secondary carbides have been rented, carbide chain distribution network. c. Thinning of tube wall thickness is high temperature oxidation and gas combined result of erosion. d. With the effective hoop stress in the L-M curve extrapolated for the remaining life of the tube 7 ~ 8B.