某退役油罐氮气惰化数值模拟

Numerical Simulation of Nitrogen Inerting in a Decommissioned Oil Tank

目前我国很多油库油罐是20世纪60—70年代修建,已达到退役年限,随之而来这些退役油罐面临封存停用问题。基于湍流k-ε标准模型,对某退役覆土1000 m3立式拱顶油罐进行氮气惰化数值模拟研究。重点研究了油罐氮气惰化过程中随氮气进口流量变化时,氧气体积分数分布和油罐拱顶压力变化规律。研究结果表明:相同氮气进口流量时,油罐内氧气体积分数随时间不断降低,且开始阶段降低速度较快,之后较为平缓;氮气进口流量越大惰化时间越短,同时为保护油罐拱顶对流量有相应限制;工程实践中油罐惰化对氧气体积分数提出了安全临界值。为大量退役油罐安全处置提供参考方案。

Many of the oil tanks in our country have been built in 1960 s-1970 s,now they have been decommissioned,and these decommissioned tanks are facing the mothballing problem.Based on the turbulent k-εstandard model,the numerical simulation of nitrogen inerting method was carried out for a 1000 m^3 decommissioned vertical arch tank.The distribution of oxygen volume fraction and the change law of pressure of oil tank dome were studied when nitrogen inlet flow changed in the process of nitrogen inerting in oil tank.The results showed that,with the same nitrogen inlet flow rate,the volume fraction of oxygen in the tank decreased continuously with time,and the decrease rate was faster in the initial stage,and then was relatively stable;The larger the nitrogen inlet flow rate,the shorter the inerting time.At the same time,the flow was limited to protect the oil tank dome;In engineering practice,the safety critical value of oxygen volume fraction in nitrogen inerting was proposed.It provides a reference scheme for the safe disposal of large number of decommissioned oil tanks.