氮封拱顶化工储罐“大小呼吸”过程职业危害评估

Occupational Hazard Assessment in the Process of Big and Small Breathing Loss on Nitrogen Sealed Vault Tank

目的研究氮封拱顶化工储罐"大小呼吸"过程中的职业危害特征。方法使用高斯分段烟羽模型,模拟分析2 500 m3储罐储存的苯、甲苯二异氰酸酯(TDI)等高毒化学品"大小呼吸"损失量及在最不利气象条件下厂区浓度分布状况。结果大气F级稳定度情况,在静小风状态下,距离泄露点100 m处浓度最高,且随与泄露点距离增加呈依次递减关系;在小风状态下,且400～600 m范围内浓度最高,浓度与泄露点距离呈正偏态分布关系。结论在最不利的气象条件下,储罐存储慢性毒性物质后果严重,或无明显的阈剂量的高毒物品(如苯或TDI等),其"大小呼吸"过程对评估员工接触状况具有不可忽视的实际意义;同时可对化工储罐行业厂区总平面布置中功能分区评价提供量化参考。

Objective To study the occupational hazards characteristics in the process of big and small breathing loss on nitrogen sealed vault tank.Methods Big and small breathing loss was simulated with the concentration distribution of high toxic chemicals（benzene and TDI）on 2 500 m3 storage tank in the most adverse weather conditions based on Gaussian plume model.Results In the F-level atmospheric stability situations and the static wind,the highest concentration was shown from the leak point 100 m,and the concentration was followed by decreasing relationship with increasing distance.But the highest concentration was shown from the leak point 400-600 m,and the concentration was positively skewed distribution of basic relations with increasing distance in the light wind the same as atmospheric stability level.Conclusion The concentration distribution of chronic toxicity with serious consequences or no apparent threshold dose toxicity in the tank has practical significance to assess exposure status of employees in the most adverse weather conditions.Meanwhile,the references are given to quantitative evaluation of the functional division on general layout.