Abstract: In order to explore the emission characteristics and secondary pollution of volatile organic compounds (VOCs) from petrochemical enterprises, based on the distribution of the oil transportation pipeline network, a large petrochemical enterprise in the south, north and central China was selected as the research object to analyze the concentration characteristics and treatment efficiency of its organized emissions, collect data from the flare emission components monitored by southern enterprises, and carry out research on the component characteristics, ozone generation potential (OFP) and health risk assessment. The results showed that the organized outlets of the three enterprises all met the discharge standards, and the concentration was 0—85.16 mg/m³. The inlet concentration of some treatment facilities could be detected, and the concentration range was 20.08—245 071.11 mg/m³. The removal efficiency of biological treatment facilities was low, about 30%, and the removal efficiency of CO was high, both of which were greater than 99%. The proportion of alkanes emitted from the flare of southern enterprises exceeded 60%. The main components of flare combustion 1 were isobutane and n-butane , while the main components of flare combustion 2 were hexane and heavier, all pentene, all butene, n-pentane and isopentane. The OFP value of flare emissions ranged from 1.32 kg/m³ to 16.95 kg/m³, with olefins accounting for more than 76% of the total, and ethylene and all butenes accounted for the largest contribution rate of the second combustion, respectively. The human health risk assessment shows that the concentration of 1,3-butadiene is greater than 1.42×10^-2 mg/m³ and the LCR value is between 1×10^-5 and 1×10^-4 within the range of 300 m to 600 m from the torch, which is a high probability carcinogenic risk. In addition, there is a low probability carcinogenic risk within the range of 200 m to 15 000 m from the torch, and the rest are negligible risks. Enterprises need to include 1,3-butadiene in the carcinogenic risk species for control.

Key words: petrochemical enterprises, torch, volatile organic compounds, emission characteristics, ozone generation potential, health risk