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SCO 8000 Skimmer Separator Hybrid at Preem Refinery

How to Reduce Emissions from Oil Refinery API Separators with SurfCleaner Skimmer Separator Hybrids

Oil refineries and petrochemical plants use massive amounts of water in their operations. An estimated 7.5 barrels of wastewater are produced for every 1 barrel of crude oil. Oil contaminants and other pollutants must be removed or stabilized before refinery wastewater can be safely discharged or reused. One way to remove and recover more oil from wastewater and stormwater at refineries is to install a SurfCleaner Skimmer Separator Hybrid in the API separators. SurfCleaner devices are ideal for floating oil removal, both thin and thicker layers, with a direct oil/water separation function.

How SurfCleaner Skimmer Separator Hybrids can be used in oil refinery API separators

In petrochemical plants, an oil water API separator is one of the first steps in the wastewater treatment process. The API separator removes oil from the water using gravity. Oil rises to the top of the API tank, while solids sink to the bottom. The surface oil is skimmed off the top of the water for recycling or disposal. 

Water temperature, the density of the oil, and the amount of suspended materials all impact how effectively an API separator works. For instance, API separators by themselves are not effective for: removing oil droplets larger than 150 microns, working in water temperature less than 5 degrees Celsius, or removing oil thin sheen from the water surface. Without additional treatment, API separator effluent generally still might have around  50 mg/l of oil in it and must undergo further treatment stages to comply with regulations. 

The SurfCleaner SCO 8000 is a device that can be installed in the API separator or another type of oil water separator and operates continuously, capturing oil before it evaporates and produces harmful and costly volatile organic compounds (VOCs) and greenhouse gas (GHG) emissions. SurfCleaners also improve worker safety since their automated oil-water separation functionality means there is minimal need for manual operation or supervision. 

SurfCleaner devices operate by using gravimetric separation to draw the oil into an internal storage tank where the oil floats to the top of the tank and water exits the bottom of the device. When the unit is full, the pure oil is pushed out a discharge pipe into an external tank or floating bag to be refined and reused later. The SurfCleaner devices can be used in different types of oil water separators, both with or without a floating cover. 

Refinery infographic

VOC emissions from API separators

When the lighter hydrocarbons, such as oil, diesel, and petrol rise to the surface of the water, a layer of oil forms on the top of the water in the API tank. This oil layer can vary in thickness from a very thin sheen to several inches thick if there are a lot of crude oil compounds in the wastewater. The topmost sheen evaporates into the air, producing volatile organic compounds (or VOC) emissions. One example study which measured VOCs of ambient air at an oil refinery found a total hydrocarbon concentration between 5.0-13.8 ppm with significant concentrations of benzene, toluene, ethylbenzene, and xylenes in the evaporated air. VOCs are known to be carcinogenic and harmful to humans, animals, and the environment. 

16% of global VOCs come from the crude oil industry, and VOC emission from effluent treatment is about 9% of the total refinery VOC emissions. To comply with regulations, refineries must limit VOC emissions, and their facilities are required to implement treatment processes that reduce benzene and hydrocarbon emissions. 

Benefits of using SurfCleaner Skimmer Separator Hybrids in refineries

SCO 8000 removes close to 100% of floating oil and pollutants

The SurfCleaner SCO 8000 is a skimmer separator hybrid designed for industrial wastewater treatment in oil refineries, oil ports, and petrochemical plants. While traditional API separation methods remove between 52% and 87% of the oil content from effluent, SurfCleaner skimmer separator hybrids have the capacity to recover very nearly 100% of the floating oil, petrol, diesel, and other pollutants. SurfCleaner devices have been used for industrial oil-water separation since the early 2000s. 

SurfCleaners cut VOC and GHG emissions significantly

By installing a SurfCleaner Skimmer Separator Hybrid in a covered API separator, refineries can reduce VOC and GHG emissions considerably. In one large refinery, VOC emissions were reduced by nearly 95% using two SCO 8000 units, combined with covering the API separators. 

The API separator cover helps reduce emission-causing evaporation of the floating diesel and petrol. Meanwhile, the SurfCleaner device captures and removes the hydrocarbons mechanically from the water and discharges them to a storage tank where they can be re-refined. In the case of the refinery mentioned, the recovered oil was pure and ready for reuse, providing an additional revenue stream for the refinery. The case study is available by request from SurfCleaner.

SurfCleaners reduce hydrocarbons in wastewater far below regulation limits

Using a covered API separator helps refineries reduce VOCs and GHG emissions to the air by preventing evaporation. Instead, the hydrocarbons are trapped in the water. This is where the SurfCleaner can have the biggest impact.

SurfCleaner SCO 8000 removes floating oil in a covered API separator
SurfCleaner SCO 8000 removes floating oil in a covered API separator

SurfCleaners capture and remove hydrocarbons from the water beneath the API cover, helping refineries reduce wastewater emissions and comply with regulations. 

The combination of an API separator cover and a SurfCleaner skimmer separator hybrid efficiently and effectively removes harmful emissions from both water and air.

SurfCleaner devices operate continuously and automatically to remove hydrocarbons from the wastewater, maintaining ppm levels far below regulation limits. Refineries can either reuse the water or send it to wastewater treatment plants. In any case, refineries reduce negative environmental impact and avoid paying external wastewater treatment plants for additional treatment of the wastewater to remove hydrocarbons.


SurfCleaners reduce carbon emissions for lower carbon taxes

Many refineries are working hard to reduce carbon emissions so that they can limit negative impacts on both the environment and their profits. As governments regain ground toward Paris Agreement commitments, carbon taxes are used in many countries as a lever to reduce emissions. Carbon taxes cost refineries in the EU €0.15 per barrel in 2020 and could increase to €2.05 per barrel by 2030.  

In addition to lowering VOC emissions and recovering oil for reuse, another benefit of using a skimmer separator hybrid is that carbon emissions are also reduced which means lower carbon taxes. 

Carbon emission reduction is accomplished largely by reducing the need for additional carbon-emitting wastewater treatment stages such as dissolved air flotation, parallel plate separators, and biological treatments. Lowering energy use and reducing the need for flaring are additional carbon tax reduction benefits of SurfCleaner devices.

The same refinery mentioned previously was able to keep their wastewater hydrocarbons within 20-40 ppm by using two SCO 8000 skimmer separator hybrids. This result was well within their emissions compliance requirement for hydrocarbons below 50 ppm in their wastewater effluent.

SurfCleaners improve worker safety and decrease maintenance

SCO 8000 is ATEX certified for Zone 0, meaning it is safe to operate where there is a continuous presence of explosive or flammable gasses. The device can operate continuously 24/7 and self-adjusts to accommodate the speed of the flow and thickness of the oil in the influent, requiring very little manual intervention and operation. 

Remote control and diagnostics features enable personnel to monitor and operate the SCO 8000 device remotely from another location, maintaining a safe distance. There are minimal maintenance requirements for the device itself, and installing the device in an API tank reduces toxic VOC fumes considerably in the proximity of the tank where workers may be present.

SCO 8000 provides industrial-scale oil water separation and can be installed in existing API separators and wastewater basins

The SCO 8000 can be installed in existing API separator tanks to separate hydrocarbons of light and medium viscosity. Floating solids up 150 mm (5.9”) are also captured and removed. The SCO 8000 removes, separates and discharges up to 8,000 litres (2,100 gallons) of oil per hour. Depending on the size of the separator chamber and the flow rate, one or more units can be used. 

In addition to installation in API separators, SurfCleaner skimmer separator hybrids can also be used in other types of oil-water separators, clarifiers, oil ponds, and wastewater tanks.


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