Source profile study of VOCs unorganized emissions from typical aromatic devices in petrochemical industry

Abstract

Volatile organic compounds (VOCs) are significant pollutants generated during the processes of petroleum refining and chemical production. Aromatic hydrocarbons, in particular, pose a great risk to human health. Nevertheless, unorganized emissions of VOCs from typical aromatics units remain poorly studied and reported. Therefore, it is vital to achieve precise control over aromatic hydrocarbons while managing VOCs. In this study, two typical aromatics production devices in petrochemical enterprises, namely aromatics extraction devices and ethylbenzene devices, were selected. The fugitive emissions of VOCs from the process pipelines in the units were investigated. Samples were collected and transferred using the EPA bag sampling method and HJ 644 and analyzed using gas chromatography–mass spectrometry. The results indicated that a total of 112 VOCs were emitted during the six rounds of sampling in the two types of devices, with alkanes (61 %), aromatic hydrocarbons (24 %), and olefins (8 %) being the primary types of VOCs emitted. The results also revealed the unorganized emissions characteristic substances of VOCs in the two types of devices, with slight differences in the types of VOCs emitted. The study found significant differences in the detection concentrations of aromatic hydrocarbons and olefins, as well as the types of detected chlorinated organic compounds (CVOCs), between the two sets of aromatics extraction units in distinct regions. These differences were closely related to the processes and leakages in the devices and can be effectively controlled by enhancing leak detection and repair (LDAR) and other measures. This article offers guidance for compiling VOCs emission inventories and improving the management of VOCs emissions in petrochemical enterprises by refining the source spectrum at the device scale. The findings are significant for analyzing VOCs unorganized emission factors and promoting safe production in enterprises.