油罐泄漏扩散过程中罐区油气浓度分布规律数值模拟

Numerical simulation on concentration distribution law of oil and gas in tank farm during leakage diffusion

储罐油品一旦发生泄漏事故,将会对罐区安全、大气环境、社会经济等造成不利影响,甚至引发安全事故。利用改进的高斯烟团模型对储罐油气泄漏扩散过程进行模拟,确定了不同环境风速、大气稳定度下罐区的油气浓度分布规律,并根据油气浓度危险程度,将罐区划分为爆炸危险区、闪火危险区以及窒息危险区。通过分析环境风速、大气稳定度对油气烟团迁移扩散的影响,得出罐区环境条件对油气浓度分布、危险区域范围的影响规律:随着环境风速的增大,油气烟团迁移扩散加剧,罐区油气浓度降低,不同等级的危险区域相应减小;大气稳定度越高,油气烟团扩散越弱,油气浓度沿下风向影响范围增加,横风向影响范围减少;油气烟团因环境风速变化有出现聚集的可能,形成浓度较高的油气聚集区,环境风速越低或大气稳定度越高时,油气烟团越容易聚集。改进的高斯烟团模型能更加准确地反映油气泄漏扩散规律,并预测油气浓度分布情况,可为储罐安全运行管理提供指导。

The leakage of tank oils,once occurred,will bring about adverse effect to ambient environment,social economy and safety of tank farm,and even cause safety accident.Herein,the leakage diffusion process of oil and gas was simulated with the improved Gaussian puff model to find out the concentration distribution law of oil and gas in tank farm under different environmental wind speeds and atmospheric stability.Meanwhile,the tank farm was divided into the explosive hazardous area,flash fire hazardous area and suffocation hazardous area according to the risk level of oil and gas concentration.By analyzing the influence of environmental wind speed and atmospheric stability on migration and diffusion of oil and gas puff,the influence law of environmental conditions of tank farm on concentration distribution of oil and gas,as well as the scope of hazardous area,was obtained.Specifically,the migration and diffusion of oil and gas puff is intensified with the increasing of environmental wind speed,but the concentration of oil and gas in the tank farm is reduced,and the hazardous areas of different grades are reduced accordingly.With the increase of atmospheric stability,the diffusion of oil and gas puff becomes weaker,the influence range of concentration along the downwind direction increases,but the influence range along the crosswind direction decreases.Because of the fluctuation of wind speed,the oil and gas puff may gather and form an oil and gas accumulation area at high concentration.Generally,the lower the environmental wind speed and the more stable the atmosphere,the easier the oil and gas puff to gather.The improved Gaussian puff model may more accurately reflect the leakage diffusion law of oil and gas,and predict the concentration distribution of oil and gas,which could provide guidance to the safe operation and management of tanks.