苯储罐事故后果模拟计算与分析

Analysis over the simulated calculation of the consequences caused by explosive accidents in the benzene tanks

苯储罐区是石油化工生产中事故后果危害较大的场所。基于对苯储罐事故特性的分析,选择典型工程案例,利用ALOHA软件对苯储罐的蒸气云爆炸、BLEVE事故、蒸气云闪火、池火灾、中毒事故以及泄漏产生的池火的热辐射等的影响进行模拟计算,分析了不同场景下事故后果的严重程度,并根据事故后果进行危险区域划分。结果表明:对于爆炸和火灾事故,BLEVE事故造成的危害最大,其次是池火灾,最后是闪火;对于中毒事故,56 m范围内为死亡区域;1601号苯储罐发生池火灾时,约3 min时对距离5m的1603号罐产生的热辐射达37.5 kW/m2,该热辐射会严重损坏工艺设备,连续暴露30min以上,很可能造成钢结构断裂或坍塌,也可能导致热辐射效应类型的多米诺事故。

The paper is aimed at pursuing the regularity of the disastrous consequences caused by explosive accidents in the benzene tank areas. As is known, there always exist hazardous accidental consequences in petrochemical production due to the accidental explosion in the tanks. Based on the analyses of the characteristic features of such accidental consequences, we have chosen a typical case study sample, in which we have done some simulated calculations including vapor cloud explosion, BLEVE accident, flash fire, pool fire, poisoning accidents and radiation effects of pool fire during the leakage to its adjacent naphtha tanks. The relative results in different models we have gained, including the damage radius in different accidents, the variation of diffusion concentrations of toxic gases with time and distance and heat radiation to the adjacent tanks. Based on the analysis of the results of the various consequences from the simulation under different accident scenarios, we have divided the dangerous areas into different levels. And, finally, we have made comprehensive analyses of the multi-level sorts in the light of simulated calculation results. For the explosive and fire accidents, the BLEVE is the key factor leading to the accidents, which is followed by the pool fire, with the flash fire being the last. As to the poisoning accidents, the death radius proves to be 56 m. When No.1601 tank comes on the pool fire, its heat radiation to the adjacent tank No.1603 five meters away from it can be so strong as to reach 37.5 kW/m2 in about three minutes, which is potential to destroy the processing equipment and installations and make the steel structure crack or blown up, and it is possible to cause the dominant accidents of the heat radiation type. All the above research results show that the application of ALOHA software shall be able to provide a lot of useful scientific guides such as the on-site emergency disposal strategies in benzene tank fires.