Numerical evaluation of deoxygenation towers under blast loadings

Onshore facilities in the oil and gas industry are high risk structures because of their exposure to hazardous and flammable hydrocarbon materials, which can lead to fire and explosion accidents. Deoxygenation towers, typically made from steel plates with strengthening rings, are one of the common onshore facilities. In the literature, evaluations of onshore facilities subjected to fire or explosion actions were mainly on storage tanks with large diameters but shorte heights, while little research was conducted for deoxygenation towers. Therefore, this paper investigates the response of the deoxygenation tower subjected to blast loadings. Prototype towers with four different heights commonly used in onshore facilities in China were selected. Nonlinear finite element models were developed for the prototype towers with rate-dependent plasticity materials. Implicit dynamic analyses were performed with the input of blast loading. The blast loading was applied as a pressure wave on the tower surface which changes with location and time. The tower structural responses were evaluated in terms of roof drift, base shear, and plastic strain. By comparing the maximum demands with the code limits, it can be concluded that in general, the tower structures can withstand the pressure from explosion accidents with considerable damage, particularly local buckling of the steel plate.