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.
Solutions
- 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.
Highlights
- 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.
Project numbers
A 650 gpm permanent system for desalter washwaterSystem designed to remove 3,000 mg/l of asphaltenes
250 gpm temporary/pilot system