浮顶储罐设置PVV的必要性与计算方法探讨

DISCUSSION ON THE NECESSITY OF SETTING PVV IN FLOATING ROOF TANKS AND CAL­CULATION METHOD

大型浮顶储罐经过几十年的发展基本趋于成熟,但是迄今为止仍然没有任何一部标准规定浮顶储罐边缘呼吸阀(简称PVV)的设置原则和计算方法.文章通过详细分析浮顶结构特点和运行过程,提出环形气相空间的4种正、负压工况;通过分析各工况下受压元件的损伤风险得出PVV是浮顶储罐不可或缺的安全附件的结论;借助一定的推理和假定搭建了4种工况的计算模型,参考API2000计算出各工况下的通气量,并最终确定了PVV的安装数量.

Large floating roof storage tanks have basically matured after decades of development.But up to now,there is still no standard for the setting principles and calculation method of PVV.In this paper,four kinds of positive and negative pressure working conditions of annular gas phase space are put forward by analyzing the structural characteristics and operation process of floating roof in detail.Through analyzing the damage risk of pressure components under each working condition,the paper arrived at the conclusion that PVV is an indispensable safety accessory of floating roof storage tank.With the help of certain reasoning and assumption,the calculation model of four working conditions is built.Referring to API 2000,the ventilation under various conditions is calculated,and finally the nstallation number of PVV is determined.