基于遥感FTIR-扩散模式反推模型的中国北方某石化企业石脑油罐区VOCs源强反演

Inversion research in VOCs source emission of naphtha tank farm in a petrochemical enterprise in North China

储罐是石化企业最常用的生产装置,更是最主要的无组织排放源之一,自储罐排放的无组织排放VOCs,一方面降低了油品质量、造成了资源的大量浪费,另一方面排放的大气污染物也严重危害了人们的生命健康和生态环境.针对于石化罐区无组织排放VOCs,建立了同时具备遥感FTIR和扩散模式反推法两者优势的源强反演模型,并在我国北方某石化企业20万m3石脑油罐区进行了6 d的外场监测,详尽的检验源强反演模型的实际应用状况,同时为我国石油化工行业储罐区VOCs排放特征提供参考,为工业面源VOCs排放量计算方法的构建提供数据支撑.研究结果表明,该石脑油罐区VOCs排放体量大,对周边大气环境影响明显;以扣除背景点的受体点VOCs作为该罐区的VOCs排放化学成分谱,其体积浓度百分比分别为:乙烯(8.48%)、乙烷(22.73%)、丙烷(10.35%)、异丁烷(8.10%)、己烷(7.11%)、庚烷(24.22%)、甲基叔丁基醚(6.90%);根据源强反演模型,20万m3石脑油罐区的VOCs排放量约为0.41 g·s^(−1),比指南公式法计算结果高45%,分析是由于指南公式法相关系数尚未实现“本土化”及监测时段的气象条件共同造成的.

Storage tank is the most commonly used production device in petrochemical enterprises,and also one of the most important unorganized emission sources.On the one hand,the unorganized VOCs emission from the storage tank reduces the quality of oil products and causes a large amount of waste of resources,on the other hand,the emission of air pollutants also seriously endangers people's life,health and ecological environment.In view of the unorganized VOCs emission from the petrochemical tank farm,a source strength calculation method with the advantages of both remote sensing FTIR and inverse dispersion modeling was established.Six-day field monitoring was carried out in a tank farm of a petrochemical enterprise in northern China to test the actual application of the source strength calculation method in detail,and to provide a reference and data support for the VOCs emission characteristics of the tank farm.The results showed that the VOCs emission volume in this area was large,which had a significant impact on the surrounding atmospheric environment;Taking VOCs subtracted in background from those in receptors as the emission chemical composition spectrum of VOCs in the tank farm,the volume concentration percentages of VOCs were ethylene(8.48%),ethane(22.73%),propane(10.35%),isobutane(8.10%),hexane(7.11%),heptane(24.22%)and methyl tert butyl ether(6.90%);According to the source strength calculation method,the VOCs emission of the tank farm was about 0.41 g·s^(−1),which was 45%higher than the calculation result of the guide formula method,owning to the influence of the unlocalized emission factor and the changeable meteorological conditions.