Poor Pretreatment Can Increase Refinery Wastewater Load and Variability
The desalter is the gateway into the refinery and is one of the most critical unit operations, cleaning and processing all crudes entering the refinery. The high temperature desalter effluent is a brine stream, high in impurities and flow volume. Impurities removed by the desalter that are transferred into the effluent include salts, solids, metals and amines. Underperforming desalters can be a major contributor to downstream wastewater treatment plant upsets due to high flows and impurities. Challenging desalter operating conditions result from crude slate changes and/or opportunity crudes which may increase “mud washes”. These purge emulsified material to protect the crude unit and maintain refinery production. When oil, grease and total suspended solids (TSS) are not effectively separated, they pass through the refinery’s primary oil separation treatment (such as API or DAF) directly to the secondary biological treatment. This increases cleaning, treatment and disposal costs and may potentially result in permit non-compliance.
Improving refinery performance
Desalter effluent pretreatment increases the capacity of the wastewater treatment plant and improves its operations by reducing load and flow variability to the plant. Recovered water may be returned to the desalter, improving its performance. Increasing capacity in the wastewater treatment plant often enables the refinery to pursue opportunity crude slates to unlock additional profitability. Fewer Total Petroleum Hydrocarbons (TPH) entering the wastewater treatment plant reduces the biosolids to dewater and dispose of. An improvement in OPEX due to reduced tank and equipment cleanings reduces maintenance and chemical spend. Finally, enabling more stable wastewater treatment operations reduces the permit compliance risk.
A Trusted Partner
Veolia provides Design Build Own Operate Maintain (DBOOM) services to address the variability associated with desalter upsets and impacts to the wastewater treatment plant performance. With 40+ years of onsite operational experience handling oily waste streams in 30 refineries, Veolia provides a solution to reduce the risk of upsets & compliance exceedances.
Part of a Complete Refinery Solution
Desalter effluent pretreatment is the most recent addition to Veolia’s offering to manage challenging refinery oily sludge and wastewater flows. Additional offerings include oily sludge management, coker quench or coker injection which result in savings to the refinery through disposal cost avoidance. From the oily water streams, Veolia recovers oil as slop oil for the crude unit and solids that can be fed to the coker (either as quench or feed). The water recovered is sent to the wastewater plant. In areas with water scarcity or strict environmental discharge requirements, these operations may also incorporate water reuse, which could result in significant savings for the refinery in terms of reduced city water and discharge costs.