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Over the past 15 years, environmental standards for the discharge of refinery effluent back into the environment has become extremely stringent and are currently at 15 ppm.  This can put alot of pressure on oil companies to comply.

Industrial wastewater found in the internal collection sewers and basins of oil refineries contains petroleum by products and raw crude oil. Installing oil skimming technology helps recover these valuable products, returning them to the refining process. Besides the financial return, there is a positive benefit to the environment by reducing the amount of hydrocarbons in the effluent.

In 2008, Chevron approached Aqua-Guard to design a custom solution to replace the outdated and inefficient pipe weir skimming system at a refinery’s API separation basins. Chevron was looking to upgrade their system to fully meet all effluent discharge requirements.

In order to cut down the amount of chemicals used in the secondary processing stage, the skimming system would need to remove most of the surface hydrocarbons in the primary separation ponds. This would reduce the amount of carry over hydrocarbons into the secondary treatment ponds.

Aqua-Guard proposed installing oil skimming systems equipped with RBS TRITON™ skimming technology. This recovers up to 98% of the surface oil, thereby increasing efficiency of the primary separation stage by almost 99%. To withstand the highly corrosive API environment, industrial skimmers must be constructed of stainless steel.

The system relies on adhesion of oil to the surface of a rotating stainless steel disc. As the disc rotates through the oil/water surface, oil adheres to the disc and is removed by a scraper. Recovered product is collected in a common sumpand pumped back into the refinery system for use. Discs can be interchanged
with either drums or brushes, for recovering various types of oil. 

Since the site had an adequate air power source, the unit is 100% pneumatically powered, from the oil skim-mer head and the rotating stainless steel disc recovery system, to the double diaphragm pump used to recover the product.  The fully automated floating oil-skimming systems were installed in the primary separation ponds. Each skimmer is capable of recovering up to 63 m3/hour of surface hydrocarbons. They were paired with two externally mounted pneumatic pumps, each capable of 20 m3/hour. To adapt to fluctuating basin levels, reduce wastewater circulation and maximize oil recovery, the skimmers needed to be self-adjusting.

Between 2008 and 2014, the system has run trouble free for over 50,000 hours. The skimmers are serviced only twice a year, primarily for maintenance purposes. The estimated maximum hydrocarbon recovery of these systems is 870,000 m3.

Shell oil refineries in Asia and other national oil companies in Latin America now also employ this patented oil skimming technology in their industrial processes to help optimize their refining.  Aqua-Guard recently launched and supplied a new RBS TRITON 100 industrial oil skimming system capable of recovering over 100 m3/hour. These systems have been specifically designed for export to countries where higher amounts of oil are present in their primary separation ponds and require higher recovery rates from skimming systems.

See full story in Environmental Science and Engineering magazine December 17th 2014 issue on page 61 (Link below)

About Aqua-Guard

Aqua-Guard provides a range of state-of-the-the-art oil spill response solutions including the URO Skimmer System and the RBS TRITON™ range of oil skimmers—all built on Aqua-Guard’s patented RBS TRITON™ technology to deliver some of the highest efficiency and recovery rates in the industry.