Filter Media for Separation of Water from Ultra Low Sulfur Diesel Sarfaraz Patel Multiphase Group Department of Chemical Engineering The University of Akron, Akron Ohio
Outline Motivation Background Hypothesis Experimental Results Future Work 2
Motivation Fuel contamination Corrosion of engine parts Strict emission standards set for the diesel engines by EPA 3
Background Water drops in fuel stream Water & fuel emulsion flow in Fuel flow with enlarged water drops Fuel Out Gravity settling tank Droplet capture on fibers Droplets moves on fibers and coalesce to form bigger drops Migration and release of enlarged droplets from the media 4
Superhydrophobic Filter Membrane Glassfiber Mat Superhydrophobic Fibers Diesel+Water Wire Mesh Gravity Diesel Water 5
Experimental Outline Experimental Parameters: Layer of superhydrophobic electrospun fibers (porosity) Filtration Face Velocity (Q/A): 2, 4, 6 cm/min Layer of superhydrophilic and superhydrophobic fibers Filtration Performance Separation Efficiency Pressure Drop Quality Factor 6
Hypothesis Pressure required to push a drop of water through superhydrophobic fiber layer is much higher than pressure required for diesel fuel to flow through the membrane. Superhydrophilic membrane will absorb water from flow stream and cleaner fuel is obtained. 7
Experimental Results Poly (vinylidene fluoride-co-hexafluoropropene) (PVDF-HFP) Tecophilic polyurethane (TPU) Preparation of superhydrophobic and superhydrophilic surfaces Filter characterization Filtration experiment 8
Electrospinning Syringe with Polymer Solution Needle Electrospinning Jet High Voltage Power Supply Glassfiber Mat Grounded Collector 9
Electrospinning PVDF HFP to Solvent Conc. (% wt) 10% PVDF- HFP Solvent Vtg (kv) Tip to collect or dist (cm) Flow rate (ml/hr) Fiber dia range (nm) Acetone 30 15 15 123-760 Log normal mean dia (nm) 334 2%TPU THF/EtOH (80:20) by weight 25 10-220- 1190 694 10
SEM Characterization a b a) SEM image of PVDF-HFP nanofibers; b) SEM image of TPU nanofibers with Waterlock particles. 11
Fiber Size Distribution: PVDF-HFP 0.03 0.025 Frequency f 0.02 0.015 0.01 0.005 0 0 100 200 300 400 500 600 700 800 Fiber Diameter (nm) 12
Fiber Size Distribution:TPU Frequency f 0.0018 0.0016 0.0014 0.0012 0.001 0.0008 0.0006 0.0004 0.0002 0 0 500 1000 1500 2000 Fiber Diameter (nm) 13
Water Contact Angle Water Contact Angle Water Contact Angle in Diesel 14
Filter Membrane Properties Polymer to Solvent Conc. % (wt) or Glass Fibers Porosity (ε) WCA in air (Degree) Hysteresis (Degree) WCA in ULSD (Degree) Glassfiber membrane 0.96 009±2 Water spreads Water spreads 10 % PVDF-HFP 0.94 170.3 ± 2 6 162.4 ± 3 2% TPU 0.73 Water spreads Water spreads Water spreads 15
Electrospinning of Superhydrophilic Surfaces: Tecophilic Polyurethane (TPU) Water uptake (%) 600 500 400 300 200 100 TPU+Waterlock 402 448 476 487 495 0 0 10 20 30 40 Waterlock Particles (by wt% of TPU) 16
Filtration Experiment 17
Water Drop Distribution Drop Count (Number/ml) 3000 2500 2000 1500 1000 500 Upstream Downstream with PVDF-HFP Downstream Glass fibers only 0 0 5 10 15 20 25 30 35 40 45 50 55 Drop Diameter (µm) 18
Filtration Performance Filter performance is measured by separation efficiency and pressure drop Separation Efficiency = Quality Factor (QF) = 1 C ( C Pressure drop is related to energy expenditure QF is a measure of separation performance achieved against energy expended out in ) Cout ln( ) / P C in Π Ci = ΣNi 6 di 3 ρ water 19
Separation Efficiency Separation Effciency (%) 100 90 80 70 60 50 40 30 20 10 0 97.63 74.06 91.79 66.74 PVDF-HFP Nanofibers Glass Fibers 77.46 43.91 2.00 4.00 6.00 Face velocity (cm/min) 20
Pressure Drop Pressure Drop (kpa) 3.50 3.00 2.50 2.00 1.50 1.00 0.50 0.00 PVDF-HFP nanofibers Glass Fibers 2.88 2.60 1.79 1.38 0.83 1.03 2.00 4.00 6.00 Face Velocity (cm/min) 21
Quality Factor (1/kPa) 4.00 3.50 3.00 2.50 2.00 1.50 1.00 0.50 0.00 3.40 Quality Factor 1.93 0.92 1.10 PVDF-HFP nanofibers Glassfibers 0.59 2.00 4.00 6.00 Face Velocity (cm/min) 0.33 22
Separation Efficiency Drop Size Separation Efficiency (%) 100 90 80 70 60 50 40 30 20 10 0 Glassfibers Face Velocity 2 cm/min Face Velocity 4 cm/min Face Velocity 6 cm/min 0 10 20 30 40 50 60 Drop Diameter (µm) 23
Observations Water collected on upstream of membrane Emulsion on upstream side Emulsion on downstream side 24
Filter Membrane Reuse 100 97.63 97.33 95.59 95.12 2 Separation Efficiency (%) 80 60 40 20 1.38 1.75 1.68 1.71 1.6 1.2 0.8 0.4 Pressure Drop (kpa) 0 Fresh Reuse 1 Reuse 2 Reuse 3 0 25
Reuse Interfacial Tension Sample IFT (mn/m) Fresh Membrane 22.32 ± 0.24 Reuse 1 21.66 ± 0.31 Reuse 2 22.40 ± 0.23 Reuse 3 21.54 ± 0.43 26
Critical Pressure Drop PP cccccccc = 2ΓΓ oo/ww cos θθ [1 { rr pppppppp 2+3 cccccccc cccccc 3 θθ rrpppppppp )3 cccccc 3 θθ (2 ssssssss +ssssss 3 θθ) }1 3] 4( rr dddddddd Γ o/w is interfacial tension θ is contact angle of water on the surface of membrane r pore is the pore diameter of membrane r drop is average drop size of the oil PVDF-HFP layer average pore diameter 1µm F.F. Nazzal, M.R. Wiesner, Microfiltration of oil-in-water emulsions, Water Environ. Res. 68, 1996, 1187 27
Critical Pressure Drop Sample Porosity of membrane (ε) WCA in ULSD (Degree) P crit (kpa) P expt (kpa) 10%PVDF- HFP 0.94 162.4 17-70 2.86 28
Composite Membrane Filter Superhydrophilic Fibers Glassfiber Mat Superhydrophobic Fibers Diesel+Water Wire Mesh Gravity Water Diesel Porosity ε 0.84 29
Superhydrophilic Membranes Drop Count (Number/ml) 5000 4500 4000 3500 3000 2500 2000 1500 1000 500 0 Face Velocity- 6 cm/min Upstream PVDF-HFP TPU-WL 0 10 20 30 40 50 60 Drop Diameter (µm) 30
Performance Comparison 100 99.1 3.6 Separation Efficiency (%) 80 60 40 20 77.46 2.6 3.36 3.2 2.8 2.4 2 1.6 1.2 0.8 0.4 Pressure Drop (kpa) 0 PVDF-HFP TPU/Waterlock 0 Filter Media 31
Future Work Separation efficiency at lower IFT Reuse of composite filter membrane 32
Acknowledgements Dr George Chase Machinist Frank Pelc Multiphase Group Members Cummins Filtration 33
Thank You 34