Marathon Petroleum Desalter Blowdown Process and Treatment Facilities

New processes remove asphaltenes from desalter effluent

Canadian bitumen-based crude oil can be used

Costs savings realized

Challenges

Canadian heavy sour crude is a cost-effective solution for combating rising crude-oil market prices. Unfortunately, it can create significant problems for a refinery’s wastewater treatment system.
Marathon Petroleum was facing a potential shutdown due to its violations of publicly owned treatment works (POTW) resulting from using this crude oil in its refining slate.

Marathon Petroleum contracted our engineering, pilot testing, and design/build services to construct treatment facilities for its desalter blowdown. The goal was to eliminate the POTW violations resulting from treating Canadian crude oil stock.
The Hatch desalter effluent pretreatment process (DEPP) was developed with the on-site treatability testing of desalter washwater over a period of several months. Because the crude slate changed from day to day, the process needed to be able to treat a wide variety of Canadian crudes.
Following on-site testing, a full-scale pilot system was provided for the temporary treatment of Canadian crude desalter blowdown on an expedited design-build basis. The system was designed to treat 250 gallons per minute (gpm) of desalter washwater while removing up to 3,000 mg/l of asphaltenes.

The temporary system consistently removed an average of 98 percent of the asphaltene solids.
With this process, mercury was also removed and the washwater returned to non-detect levels.
The full-scale pilot system was completed in 2007. It operated until the permanent system was installed by Hatch on a design-build basis.
This process has allowed Marathon to use less costly Canadian heavy crudes, thus improving its bottom line.