Deformation Characteristic Evaluation of Large Oil Storage Tanks under the Planar Inclined Foundation

2013 ◽  
Vol 351-352 ◽  
pp. 786-789
Author(s):  
Da Wei Ji ◽  
Li Xin Wei ◽  
Xiao Yan Li

Oil storage tank plays an important role in modern oil industry. The development of large-scale oil storage tanks has resulted in the complexity of stress distribution and deformation situation of tank wall and tank bottom. Especially in soft foundations, the tank structure is susceptible to various types of settlement deflections. The most common type is planar inclined foundation. In this paper, the finite element model of large-scale oil storage tank was built according to the pattern of design and the deformation characteristic and stress distribution of large storage tank under the planar inclined foundation was obtained. Considering the floating roof, the ultimate value of large storage tank under the planar inclined foundation is determined.

Author(s):  
Lei Shi ◽  
Xiaolin Wang ◽  
Jian Shuai ◽  
Kui Xu ◽  
Ming Li

It is well known that foundation settlement of tank is particularly severe, and can produce distortion and stress of the tank, especially differential settlement around the circumference of the foundation below the shell of large-volume tank. The settlement standards involving European EEMUA 159-2003, American API 653-2009, and Chinese codes SH/T 3123-2001, SY/T 5921-2011 for in-service assessment of large-scale storage tank were reviewed and discussed. Finite element model for strength assessment of large-scale oil storage tank was developed based on actual field data of tank foundation settlement. The whole stress distributions and deformation of seven large-scale oil storage tanks in a depot in China were analyzed under the conditions of the practical pressure test through finite-element method. It also provides a comparison between an analytical model based on settlement criteria and a finite element model that replicates field operating loading and settlement conditions of storage tanks. A basis for comparison between models was established from the maximum allowable settlement and stress values. It was found that results from settlement standards of tank in China and other countries were more conservative than those from FEA, and SY/T 5921 in China made most stringent requirements for the tank settlement. The evaluation indicators of differential foundation settlement around the tank circumference are unreasonable in standards and rules mentioned above, the structural response of tank such as stress and deformation under foundation settlement should be considered sufficiently.


2018 ◽  
Vol 878 ◽  
pp. 95-103
Author(s):  
Joko Wisnugroho ◽  
Sutomo

Inspection and maintenance are necessary to maintain the continuity of critical equipment operations such as oil storage tank. The criteria for the various types of settlement specified in American Petroleum Institute (API) 653. However, the criteria for planar settlement could not be determined. In this paper, a finite element model is developed to study the hoop stress of the tank during planar settlement. In this paper, 384 finite element models were built in order to predict the most effective allowable planar settlement at oil storage tanks. Each model is variation of the tank size, shell plate thickness, seismic zone and planar tilt of the tank. Based on size of tank population in Pertamina, 8 of standard tank size from 500-10.000 m3 were simulated. The simulation results are validated by case study in 500-5.000 m3 full scale oil storage tank. From the results, equation for criteria of planar settlement has been created.


2006 ◽  
Vol 324-325 ◽  
pp. 1031-1034
Author(s):  
Yang Du ◽  
Jian Feng Gao ◽  
Xin Sheng Jiang

The fuel-air mixture explosion incidents in the large-scale metal oil storage tank are frequent occurrence and rapidly extend because of the tank structure being fractured and damaged by the fuel-air mixture explosion. In this paper, the simulation experiment and numerical simulation has been carried out for the fuel-air mixture explosion in the large-scale metal storage tank. The shock waves characteristic of the explosive pressure has been studied and discussed. The fracture and damage effects caused by the shock waves characteristic to the tank structure has been analyzed and discussed too.


Author(s):  
Jian Shuai ◽  
Kejiang Han

As an important production facility, storage tank plays a more and more important role in the storage and transportation of crude oil and chemical product. The remaining life prediction of storage tank is to forecast the thinning trend of plate thickness, and forecast remaining life on the premise that remaining strength of storage tank meets the tank operation and safety requirements. Maximum corrosion depths of tank bottom plate obey the maximum extreme value distribution. Based on maximum extreme value distribution and statistics of corrosion data, the calculation formula of the remaining life prediction for large-scale crude oil storage tank was obtained by formula derivation. Compared with API STD 653 and EEMUA 159, the inspection interval specified by China standard SY/T 5921 is relatively conservative. The remaining life of a certain crude oil storage tank (tank A) in china is determined by the remaining life of tank bottom plate. The remaining life of tank A at the reliability of 0.99, 0.999 and 0.9999 are 25 years, 20 years and 17 years, respectively. For the acceptable failure probability of 1×10−4, the inspection interval of tank A can be extended from required 5–7 years specified by China standard SY/T 5921 to 17 years. The remaining life of crude oil storage tank predicted by the method proposed in this paper can be used as an important reference in the determination of inspection interval and tank’s maintenance.


Author(s):  
Ken Hatayama

The Mw9.0 2011 Tohoku, Japan earthquake tsunami damaged 418 oil storage tanks located along the Pacific coast of the Hokkaido, Tohoku, and Kanto Districts of Japan. A wide variety of damage was observed, including movement and deformation of the tank body, scouring of the tank base and ground, and movement or structural fracture of the pipe. In total, 157 of the 418 tanks were moved by the tsunami. By comparing the severity of damage with the inundation depth of the tsunami experienced by the oil storage tank, a fragility curve projecting the damage rate for plumbing is presented, and a rough but easy-to-use method of predicting tsunami damage to an oil storage tank from a given inundation depth is also presented: (i) for inundation depths of 2–5 m, tanks suffer damage to their plumbing, and small tanks (capacity < 100 m3) and empty larger tanks may be moved; (ii) for inundation depths of greater than 5 m, most tanks are moved. The validity of the previously-proposed tsunami tank-movement prediction method is first examined. A comparison of the method’s predictions with the actual damage data from the 2011 Tohoku earthquake tsunami indicates a high hit rate of 76%.


Author(s):  
Haigui Fan ◽  
Zhiping Chen ◽  
Futeng Wan

Optimization calculation method determining wall thickness for large oil storage tank made of high strength steel is investigated in this paper. Taking three oil storage tanks with different volumes of 10×104 m3, 15×104 m3 and 20×104 m3 for examples, the wall thickness calculation methods of API 650, GB 50341, JIS B 8501 and BS EN 14015 have been analyzed and compared. Results show that as the volume of oil storage tank increases, some wall thickness calculation results of the standards have been larger than the allowable value, leading to the unreasonable distribution of the wall circumferential stress. The wall thickness calculation result applying the method of API 650 is more reasonable than other standards. While for the tanks made of high strength steel, like 12MnNiVR (GB 50341), the yield ratio of the steel has reached 0.803, which is larger than the upper limit value of API 650. In order to make up the deficiency, an optimization method based on API 650 is presented, which considers the effects of yield strength, tensile strength and yield ratio on the determination of allowable stress. Taking the 20×104 m3 oil storage tank and selecting a proper welded joint efficiency, the wall thickness is calculated by the presented optimization method. The wall thickness calculation result is more reasonable and the circumferential stress distribution is more homogeneous when the safety factor of tensile strength is taken to be 2.4. Results show that the optimization method is applicable to the thickness calculation of oil storage tanks made of high strength steel.


2011 ◽  
Vol 367 ◽  
pp. 467-474 ◽  
Author(s):  
R. Irughe Ehigiator ◽  
J.O. Ehiorobo ◽  
M.O. Ehigiator ◽  
Ashraf A. Beshr

In this paper the monitoring for subsidence in crude oil storage tanks by the method of Geodetic leveling is discussed. The monitoring network consisted of three control points established about 100m from the tank and 16 studs established at the base of the tank. From the control points, the stud locations were leveled using a geodetic level with parallel plate micrometer and telescopic staves. All levels were run in forward and reverse directions and the measurements were carried out in 2003, 2004 and 2008. Adjustment of observation was carried out using the least squares estimation model to determine the elevation of each stud position in the three measurement epochs together with their accuracy standards. Comparisons were made of the calculated movements from the three measurement epochs and the associated accuracies calculated from the least squares model. Analysis of the results indicated that with the exception of one stud ( stud 8), all other studs emplaced had moved and the movements ranged from 0.91mm to 13.06mm


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