VOC emission from oil refinery and petrochemical wastewater treatment plant estimation

Abstract

As a consequence of environmental legislation improvement in Serbia for industrial producers, especially future holders of Integrated Pollution Prevention Control (IPPC) license, it is necessary to report annually on emissions of pollutants emitted into the environment and pay certain environmental fees. Wastewater treatment plants can be significant sources of volatile organic compounds (VOCs) diffuse emissions, which are difficult to measure directly. Reporting obligations may also expand to benzene and other VOCs in the near future. This paper deals with gaseous emissions calculations from an API separator, based on emission factors and adequate software applications. The analyses results show that the estimated emission values are significantly different, depending on the applied method. VOC emissions have been estimated using US EPA and CONCAWE emissions factors. Calculated emissions range from 40 to 4500 tons/year for oil refinery WWTP of 2,000,000 m3/year. The calculations of benzene and toluene emissions have been performed using three methods: U.S. EPA emission factors, and WATER9 and Toxchem+ software. The calculated benzene and toluene emissions range from 5.5-60 and 0.7-20 tons/year, respectively. U.S. EPA emission factors give the highest values and Toxchem+ the lowest estimation values. Sensitivity analysis of obtained results included the following parameters: flow, temperature, oil content and the concentration of benzene and toluene in the effluent. The wide range of results indicates the need for their official interpretation for the conditions that are typical for Serbia if, in the future, the "polluter pays" principle should be applied to VOC and benzene emissions. The proposal is that adequate national emission factors should be established.

Stupanjem na snagu novih zakonskih akata, industrijski zagađivači u Srbiji - budući nosioci integrisane dozvole, dužni su da na godišnjem nivou izveštavaju o emisijama štetnih gasova koji se ispuštaju u životnu sredinu i da u skladu sa time plaćaju određene ekološke naknade. Obaveza izveštavanja u skorijoj budućnosti može se proširiti na benzen i druge lako isparljive ugljovodonike. Predmet analize ovog rada su primena emisionih faktora i softverske simulacije za proračun gasovitih emisija iz postrojenja za tretman otpadnih voda. Rezultati pokazuju da se izračunate vrednosti emisija značajno razlikuju od metode do metode, a u diskusiji se posebna pažnja obraća na procenu pouzdanosti svake od njih.