基于Gumbel极值分布的储罐使用状态评价方法研究

Research of Evaluation Method for Storage Tank Based on Gumbel Extreme Value Distribution

储罐的剩余寿命是其长期平稳运行的保证,目前国内尚无明确的方法处置服役期满的储罐。根据储罐腐蚀特点,底板是其腐蚀最严重的部位,而底板腐蚀的最大孔深度服从Gumbel I型最大极值分布。根据最大极值分布和概率统计,推导出储罐剩余寿命计算公式,建立储罐底板剩余寿命的极大值分布预测评价方法,得出某公司储罐在0.99、0.999和0.999 9的可靠度下的剩余寿命分别为40年、34年和25年,有效指导了储罐检修周期的确定。

The remaining life prediction of storage tank can ensure a long-term service of the storage tank, and at present time, no clear way at home can be applicable to the dispose of expired storage tank. The corro- sion characteristics of storage tank demonstrate that tank＇ s bottom plate is easy to be seriously corroded and its maximum corrosion depth conforms to the extreme value distribution of Gumbel I ~ Based on the maximum ex- treme value distribution and probability statistics of corrosion data, the calculation formula of the remaining life prediction for large-scale storage tank was deduced to present a prediction method for distribution of the remai- ning life＇ s maximum extreme value. Regarding the storage tank＇ s 25, 20 andl7-year remaining life at the re- liability of 0.99, 0. 999 and 0. 999 9 respectively, this method can be used to determine their repair period.