Howari Fares M
College of Sustainability and Human Sciences, Zayed University, P.O. Box 144534, Abu Dhabi, United Arab Emirates,
Environ Monit Assess. 2015 May;187(5):273. doi: 10.1007/s10661-015-4456-z. Epub 2015 Apr 19.
The present study is an application of a Gaussian dispersion model to evaluate volatilization losses from tank farms. It reports methodology to estimate evaporation losses of volatile organic compounds (VOCs) from organic liquid in storage tanks. This study used fixed roof and floating roof equations for breathing and working losses. Total loss, the breathing loss, vapor pressure, molecular weight of the product, tank diameter, diurnal temperature, paint factor, tank capacity, and number of turnovers were considered and factored in the calculation. AERMOD and ALOHA softwares were used to simulate the dispersion of VOCs under normal and accidental scenarios. For the modeling purposes, meteorological data such as annual average ambient temperature, annual average atmospheric pressure, daily minimum ambient temperature, daily maximum ambient temperature, solar insulation factor, and average wind speed were included as input in the calculation and modeling activities. The study took place in Sharjah Emirate in United Arab Emirates, which borders Dubai to the south and Ajman to the north, and the three form a conurbation. The reported method was used to estimate evaporation losses for baseline and hypothetical leak scenarios. Results of this research show that liquid storage tanks in the study area emit a low concentration of VOC under the studied and assumed conditions, e.g., new tanks with high performance sealing as well as the noted earlier climatic conditions. The dispersion of those concentrations is controlled by the prevailing wind direction. The predicted VOCs concentrations were within the range of the measured VOCs values in air. The study found that the spatial distributions of the predicted concentration attenuate with time and distance. Under the reported accidental spill scenario, the Gaussian model indicates that the danger area starts within the zone of less than 10 m. The danger area is subjected to flame pockets, and the VOC concentrations in this area will exceed 19,800 ppm.
本研究应用高斯扩散模型评估油库的挥发损失。报告了估算储油罐中有机液体挥发性有机化合物（VOCs）蒸发损失的方法。本研究使用固定顶罐和浮顶罐的呼吸损失和工作损失方程。计算中考虑并纳入了总损失、呼吸损失、蒸气压、产品分子量、罐直径、日温度、涂料系数、罐容量和周转次数。使用AERMOD和ALOHA软件模拟正常和意外情况下VOCs的扩散。为进行建模，计算和建模活动中纳入了诸如年平均环境温度、年平均大气压力、日最低环境温度、日最高环境温度、太阳辐射系数和平均风速等气象数据作为输入。该研究在阿拉伯联合酋长国的沙迦酋长国进行，沙迦南接迪拜，北邻阿治曼，三者形成一个城市集聚区。所报告的方法用于估算基线和假设泄漏情况下的蒸发损失。本研究结果表明，在研究和假设条件下，例如具有高性能密封的新罐以及上述气候条件下，研究区域内的储液罐排放的VOC浓度较低。这些浓度的扩散受主导风向控制。预测的VOCs浓度在空气中测量的VOCs值范围内。研究发现，预测浓度的空间分布随时间和距离而衰减。在所报告的意外泄漏情况下，高斯模型表明危险区域始于小于10米的区域内。该危险区域存在火焰区，该区域内的VOC浓度将超过19,800 ppm。
