5000m^3立式拱顶储罐应力分析与弱顶性能评价

根据国内外相关设计标准与规范,石油天然气等易燃易爆气体的储罐必须设计成弱顶结构,以最大限度地降低因内部超压而发生事故的危害程度。为了得到合适的弱顶结构设计方法,以常见的5 000 m^3立式拱顶储罐为对象展开分析。首先,根据GB 50341-2014《立式圆筒形钢制焊接油罐设计规范》,对储罐结构参数进行设计并对其弱顶性能进行初步评价;然后,利用有限元分析方法对储罐结构进行分析,获得储罐在空罐、半罐、满罐工况下的提离高度、提离半径、最大等效应力和薄膜应力等关键参数,并在此基础上对储罐强度、稳定性、破坏形式和弱顶性能进行综合评价;最后,分析了顶壁连接焊角高度、罐顶曲率半径、边缘板厚度和罐体高径比等关键参数对储罐弱顶性能的影响。结果表明:基于GB 50341-2014设计的5 000 m^3立式拱顶储罐并不具备弱顶性能,顶壁连接焊角高度减小到3.75 mm,或罐顶曲率半径增大到3.0D(D为储罐直径),或边缘板厚度增大到15 mm,或罐体高径比增大到2.0都能使该储罐满足弱顶结构的设计要求。研究结果可为储罐弱顶结构的改进提供参考。

Stress analysis and weak roof performance evaluation for 5 000 m3vertical dome storage tank

In order to minimize the extent of injury caused by internal overpressure, storage tanks for flammable and explosive substances such as oil and natural gas must be designed as weak roof structures according to the relevant design standards and specifications at home and abroad. The common 5 000 m³ vertical dome storage tank was analyzed to obtain a suitable design method of weak roof structure. Firstly, the structural parameters of the storage tank were designed and its weak roof performance was preliminarily evaluated by the GB 50341—2014 Code for the Design of Vertical Cylindrical Steel Welded Oil Tanks. Secondly, the structure of the storage tank was analyzed by the finite element method to obtain the key parameters such as lifting height, lifting radius, maximum equivalent stress and film stress under the conditions of empty, half and full tank. The strength， structural stability, failure mode and weak roof performance of the storage tank were evaluated on these key parameters. Finally, it was conducted to analyze the influence of key parameters such as the roof-wall connection weld angle height, the tank roof curvature radius, the boundary plate thickness and the tank height-diameter ratio on the weak roof performance. The results showed that the 5 000 m³ vertical dome storage tank designed by the GB 50341—2014 did not meet the weak roof performance. However, some methods which could enable the tank to meet the weak roof structure were proposed: the roof-wall connection weld angle height was increased to 3.75 mm, the tank roof curvature radius was increased to 3.0D (D was the tank diameter), the boundary plate thickness was increased to 15 mm, or the tank height-diameter ratio was increased to 2.0. The research results can provide a reference for improving the weak roof structure of the storage tank.