ENV-01-19 Maximizing Desalter Recycle To Minimize Process Wastewater Flow And Subsequent NESHAP Benzene Emissions

Description:

Desalter wash water effluent is the largest producer of wastewater in the oil refining process. In an attempt to minimize refinery wastewater discharge volumes, Williams Alaska Petroleum refinery recycles desalter wash water effluent. Minimizing the wastewater discharged was necessary due to limitations with the wastewater treatment facilities, increased costs, and the arctic environment. In a recent study it was found that by optimizing variables in the desalter operation, the effluent could be reduced by 2% to 4% of the crude charge. The Refinery’s reduced desalter wash water flow in turn decreases facility hazardous air pollutant emissions, and in particular, benzene. Emission control requirements in 40 CFR part 61 subpart FF is based on the facilities total annual benzene generated in refinery aqueous waste streams (TAB). If the refinery’s total annual benzene quantity is less than 10 mega grams, Subpart FF’s reporting and record keeping provisions only apply, and not the control requirements. Williams’ North Pole refinery total annual benzene waste is below the regulatory threshold of 10Mg/yr where emission controls are required.