Pharmaceuticals & Biotechnology
Chemistry & Metallurgy
Oil & Gas
CFD designed internals for Produced Water Tanks
Dr. Eng. Eduard Sarbu
Outline
1. Introduction
2. Case Study – existing PWT
3. Pilot Tank
• concept and results
4. Improvements
• concept, results and applications
5. Conclusions
1. IntroductionProduced Water Tanks (PWTs) and Phase Separation
• PWTs used as
− 1st stage separators
− buffer tanks
− storage volume
• Simple design with few or no
internals
• Stoke’s law for gravity separation:
𝒗𝒔 =𝒅𝒅𝟐 × (𝝆𝒘 − 𝝆𝟎)
𝟏𝟖 × 𝜼𝟎
• larger diameters, greater density
difference, higher temperatures
→ faster separation
• for better phase separation
→ maximize residence time
Slide 3/13
2. Case study Existing PWT
Old Pilot Tank Design and Residence Time Distribution (RTD)
Original tank design with single change in flow direction
Slide 4/13
3. Pilot TankConcept
Tangential Flow Pattern
Tangential injection of oil – water phase via diverter; central outlet pipes
Slide 5/13
3. Pilot TankResults
CFD Simulation and Tracer Test Results
• CFD model used to perform virtual
tracer test
• Tracer test for new tank internals
• Sufficient consistency between real
tank and CFD model
• RTD increased by factor 8
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3. Pilot TankResults
Completed Internals
Oil in water (OIW) concentration reduced from 1000 ppm to 250 ppm
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4. ImprovementsConcept
Symmetrical internals
• 2 inlet diverters, 1 central outlet • Internals design based on tank geometry
Inlet 1
Inlet 2
Outlet
Inlet 1
Inlet 2
Outlet
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4. ImprovementsResults
Flow Pattern for Symmetrical Arrangement
No short circuits and low flow velocities in cm/sec
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4. ImprovementsResults
RTD for Symmetrical Setup
CFD Tracer Test Results for Symmetrical Internals
Slide 10/13
4. ImprovementsApplications
Additional Applications for PWT CFD Models
Predict separation efficiencies and outlet concentrations
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5. Conclusions
• Symmetrical tangential flow patterns improve PWT performance
• CFD optimized internals reduce velocities and short circuiting
• Optimal use of tank volume, less mixing, better coalescence
• Tailor-made solutions based on CFD models
• Reduces overall number of separation stages/equipment
• Reduces plant footprint and total CAPEX
Slide 12/13
Contact data
• Eduard Sarbu, [email protected] (+40731 336 537)
Acknowledgements:Nikolas Trofaier, VTUBernhard Puchner, VTUJaroslaw Konieczny, VTUAnne Steinbrugger, VTU Alexander Weilhartner, OMVGeorg Kuemmel, OMV Oscar Perez, OMV PetromNikolaus Friedl, CAERichard Markl, CAE
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