The CANMET Hydrocyclone: An Innovative Technology for the ...

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know-how gained by CANMET staff led to the development of innovative hydrocyclone designs and flowsheet configurations to meet the requirements of the heavy oil industry in western Canada.The new CANMET hydrocyclone design has already proved highly effective in treating heavy oilproduction fluids in the Canadian provinces of Alberta and Saskatchewan. This success has led to theinstallation of commercial-scale multi-hydrocyclone systems at the Husky Energy refinery and upgrader inLloydminster, Alberta. Other operators are considering the installation of CANMET hydrocyclone systemsin their operations.HYDROCYCLONE ADVANTAGESLiquid-liquid hydrocyclone technology offers unique advantages over gravity-based separation methods.Hydrocyclones produce centrifugal forces more than 500 times the gravitational force, resulting in muchmore rapid separation than conventional methods.• Elegantly simple in design – Hydrocyclones are highly compact and portable compared to theequipment they replace (FWKO vessels, skim tanks, etc.). Residence time in hydrocyclones istypically about 2 seconds compared to hours in conventional treatment units. It is easy to relocate ahydrocyclone system, offering a much higher salvage value.• Simple to operate – The absence of moving parts ensures a minimum of maintenance and downtime.Wide fluctuations in feed rate can be handled without serious effects on efficiency or oil recovery.• Environmentally friendly – Hydrocyclone systems are energy efficient and generate no wastes. Theyreduce heating requirements and readily accommodate the recycling of heated fluids.THE CANMET HYDROCYCLONEENHANCED PERFORMANCEDesign advances in the CANMET hydrocyclone give superior performance compared to conventionaldesigns. Figure 1 shows a working model of an available commercial (conventional) hydrocyclone. Asoil/water separation occurs in the hydrocyclone, the lighter (dark-coloured) oil phase migrates towards thecentre of the vortex to form an oil core that exits the unit via an overflow orifice located at the centre of theupstream (left) end of the unit. As can be seen in Figure 1, the conventional design produces an oil corewith a corkscrew shape. This off-centred oil core hinders the removal of concentrated oil from the unit,regardless of orifice size.In contrast, the CANMET hydrocyclone, shown in Figure 2, produces a straight, symmetrical oil core thatreadily exits through the overflow orifice. For an added degree of operator control, the advanced CANMETdesign also features variable orifice size to ensure efficient oil removal and the desired overflow qualityover a range of feed properties.Schematic and component drawings of the CANMET hydrocyclone can be found in the patent documents(U.S. 5,858,237 and International PCT/CA98/00403). The following are unique features of the CANMEThydrocyclone:Multiple inlet ports. Unlike conventional hydrocyclones, which generally have one inlet port, theCANMET version has two, three, or four ports, evenly spaced around the involute. This produces a morestable vortex flow and oil core.Adjustable overflow orifice. Changing the diameter of the overflow orifice during operation adds anelement of performance control.Solids separation. An attachment can be installed at the downstream end of the hydrocyclone to removesolids that would otherwise report with the water stream.Heating jacket. Hot liquid or steam can be circulated around the hydrocyclone body to reduce oilviscosity and increase separation efficiency.The Environment & Energy 2003 Conference 468
ENIVIRONMENTAL ADVANTAGESReduced CO 2 emissions. Reduced heating requirements reduce CO 2 emissions.Example: For the treatment of 70% water cut production, each barrel of oil produced usingconventional gravity-based systems requires the consumption of approximately 100 standard cubicfeet (SCF) of natural gas to heat the wellhead production from ambient temperature to about 65 O C.This heating releases about 5.25 kg CO 2 to the atmosphere per barrel of treated oil. Usinghydrocyclones, the separation can be achieved at 40 O C; therefore, CO 2 emissions are reduced byan estimated 25%. For a typical 7500-bpd treatment facility, this would result in a reduction ofCO 2 emissions of nearly 10 tonnes per day.Reduced site degradation. Hydrocyclone systems have a much smaller footprint than conventionaltreatment trains and are less subject to accidental spills. For environmental and safety reasons,hydrocyclone installations include shutoffs that are automatically activated in the event of a leak or processupset. Inadvertent releases of process fluids or wash water are therefore no larger than a few litres, andthese are entirely recoverable since the hydrocyclone setup incorporates a drainage pan that drains to apumpable sump. In contrast, the potential spillage of tank volumes in conventional treatment schemesrequires large containment areas that still carry the risk of harmful seepage into surface and ground waters.Clean water. CANMET hydrocyclone systems are capable of producing oil-free water streams suitable forreuse or safe disposal, thus reducing the consumption of fresh water and the negative impacts of wastewaterdisposal.ECONOMIC ADVANTAGESJoint projects with oil industry clients demonstrated that, for the treatment of produced waters, and slop oil,and oily effluents from desalters, capital and operating costs are reduced as compared to conventionalseparators (FWKO vessels, skim tanks, etc.), which are bulky and require frequent maintenance.Capital costs. Hydrocyclone systems are relatively simple in design, require much less plant space thanthe equipment they replace, and are easily transportable.Example: For deoiling refinery desalter effluent, a CANMET hydrocyclone system with a capacityof 1000 m 3 /d and standard instrumentation, the construction cost would be approximately$300,000 CAD. This is about half the cost of a conventional separator installation of matchingcapacity. For systems with larger capacities, even greater cost savings per unit volume ofthroughput can be expected.Operating costs. Operating costs are reduced in several ways: Energy inputs are reduced, the absence ofmoving parts ensures a minimum of maintenance and downtime.Example: CANMET hydrocyclone system installed at a refinery for the treatment of 500 m 3 /d ofdesalter effluent:• Operating costs for servicing of water disposal wells were reduced by 50%.• Chemical costs were reduced by 30%.• Slop production was substantially reduced and nearly all of it was transformed intosaleable oil product.Prior to the installation of the CANMET hydrocyclone system, the total average operating cost forthe above items was approximately $300,000 CAD annually. As a result of the changeover, thiswas reduced to about $200,000.In high-water-cut oil production, the reduced operating costs associated with hydrocyclones effectivelyincrease total oil recovery by extending the economic lifetime of the production wells.The Environment & Energy 2003 Conference 469
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