The Failure Analysis And Management Of MAN Gas Holder

The MAN type gas holder is widely used in steel plants, chemical plants and civil equipments. There is great meanning of the using of MAN type gas holder to balance the pressure fluctuation of the pipeline system, and the generation and consumption of secondary energy sources. During use of MAN type gas holder, many plants were confronted with the problem of leaking sealing oil. It’s difficult to find out the failure reason. In the thesis, the failure reason is studyed in using of FE method.Firstly, the stress and displacement of gas holder are obtained, when exerted kinds of loads in operation condition. And the accuracy of FE result is verified by the theoretical and analytical solution of side plant and wind-pressure rib. The stress of 4 direction change slightly along circumferential, so the influence of structure load have no relation with orientation. The failure problem has showed its orientational, so structure loads have little effect on gas holder’s failure.The solar temperature field is obtained by using ANSYS according to ASHRAE sunshine model and the coefficient of solar radiation intensity is chosen according to the test result of our local place. The structure temperature field obtained from the "converted outdoor temperature tz description method" has a good agreement with the FE results. The displacement and and thermal stress of gas holder are obtained based on the solar temperature field caculated above. The stress distribution at the edge of side plate is nonuniform and have point mutation. But this kind of stress distribution can’t lead to the failure of the structure because of the stress is below the maximum allowable stress of materials. We can just regard the thermal stress as an important factor of the failure problem of gas holder.The welding between side plate and guideway is calculated by using dedicated welding simulation software. The residual stress shows the structure have plastic deformation already, which lead to the increase of its friability and the load bearing capacity decrease. Along the welding line, contraction deformation occured, which led to the weakest position of the structure, so the welding quality have the key effect on the gas holder’s normal use.