Characteristics of VOCs Emissions from Circulating Water of Typical Petrochemical Enterprises and Their Impact on Surroundings

Abstract

The petrochemical industry is regarded as the main source of anthropogenic VOCs emissions in China. As one of the main sources of unorganized emissions, circulating water is scarcely studied and reported. In this research, six circulating water systems (LC2X, HGLY, YJ, XJ, LC4X and LC5X) of a typical petrochemical enterprise were selected as targets to characterize VOCs emitted from such unorganized emissions. The results showed that there was a great difference in the VOCs disorganized emissions from the six circulating water systems, among which the main VOCs of HG2X, HGLY and YJ were oxygen-containing VOCs (OVOCs), accounting for about 48.0–81.2%. The main compounds of XJ, LC4X and LC5X were alkynes (89.1%), aromatic hydrocarbons (69.7%) and alkane (50.1%), respectively. TVOCs ranged from 276.0 to 23,009.6 µg·m−3. Based on POC test results, VOCs emissions of the circulating water system were 1237.5 tons, indicating further control was needed. As for their ambient impact, XJ had higher OFP contribution, and the OFP values of the six systems ranged from 823.3 to 145,739.0 µg·m−3, among which the major contributors were aromatic hydrocarbons (0.2–85.1%), OVOCs (0.1–77.2%) and alkynes (1.7–97.6%). In addition, aromatic hydrocarbons showed the largest contribution of the potential of SOA generation, which was more than 88.0%. As far as control was concerned, the replacement of an open cooling tower to closed cooling tower combined with regular POC detection will be an efficient way to control VOCs from such sources.

Keywords

• petrochemical industry
• volatile organic compounds (VOCs)
• emission characteristic
• ozone formation potential (OFP)
• secondary organic aerosol (SOA)