Filter Media for Separation of Water from Ultra Low Sulfur Diesel

Transcription

1 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

2 Outline Motivation Background Hypothesis Experimental Results Future Work 2

3 Motivation Fuel contamination Corrosion of engine parts Strict emission standards set for the diesel engines by EPA 3

4 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

5 Superhydrophobic Filter Membrane Glassfiber Mat Superhydrophobic Fibers Diesel+Water Wire Mesh Gravity Diesel Water 5

6 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

7 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

8 Experimental Results Poly (vinylidene fluoride-co-hexafluoropropene) (PVDF-HFP) Tecophilic polyurethane (TPU) Preparation of superhydrophobic and superhydrophilic surfaces Filter characterization Filtration experiment 8

9 Electrospinning Syringe with Polymer Solution Needle Electrospinning Jet High Voltage Power Supply Glassfiber Mat Grounded Collector 9

10 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 Log normal mean dia (nm) 334 2%TPU THF/EtOH (80:20) by weight

11 SEM Characterization a b a) SEM image of PVDF-HFP nanofibers; b) SEM image of TPU nanofibers with Waterlock particles. 11

12 Fiber Size Distribution: PVDF-HFP Frequency f Fiber Diameter (nm) 12

13 Fiber Size Distribution:TPU Frequency f Fiber Diameter (nm) 13

14 Water Contact Angle Water Contact Angle Water Contact Angle in Diesel 14

15 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 ±2 Water spreads Water spreads 10 % PVDF-HFP ± ± 3 2% TPU 0.73 Water spreads Water spreads Water spreads 15

16 Electrospinning of Superhydrophilic Surfaces: Tecophilic Polyurethane (TPU) Water uptake (%) TPU+Waterlock Waterlock Particles (by wt% of TPU) 16

17 Filtration Experiment 17

18 Water Drop Distribution Drop Count (Number/ml) Upstream Downstream with PVDF-HFP Downstream Glass fibers only Drop Diameter (µm) 18

19 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

20 Separation Efficiency Separation Effciency (%) PVDF-HFP Nanofibers Glass Fibers Face velocity (cm/min) 20

21 Pressure Drop Pressure Drop (kpa) PVDF-HFP nanofibers Glass Fibers Face Velocity (cm/min) 21

22 Quality Factor (1/kPa) Quality Factor PVDF-HFP nanofibers Glassfibers Face Velocity (cm/min)

23 Separation Efficiency Drop Size Separation Efficiency (%) Glassfibers Face Velocity 2 cm/min Face Velocity 4 cm/min Face Velocity 6 cm/min Drop Diameter (µm) 23

24 Observations Water collected on upstream of membrane Emulsion on upstream side Emulsion on downstream side 24

25 Filter Membrane Reuse Separation Efficiency (%) Pressure Drop (kpa) 0 Fresh Reuse 1 Reuse 2 Reuse

26 Reuse Interfacial Tension Sample IFT (mn/m) Fresh Membrane ± 0.24 Reuse ± 0.31 Reuse ± 0.23 Reuse ±

27 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,

28 Critical Pressure Drop Sample Porosity of membrane (ε) WCA in ULSD (Degree) P crit (kpa) P expt (kpa) 10%PVDF- HFP

29 Composite Membrane Filter Superhydrophilic Fibers Glassfiber Mat Superhydrophobic Fibers Diesel+Water Wire Mesh Gravity Water Diesel Porosity ε

30 Superhydrophilic Membranes Drop Count (Number/ml) Face Velocity- 6 cm/min Upstream PVDF-HFP TPU-WL Drop Diameter (µm) 30

31 Performance Comparison Separation Efficiency (%) Pressure Drop (kpa) 0 PVDF-HFP TPU/Waterlock 0 Filter Media 31

32 Future Work Separation efficiency at lower IFT Reuse of composite filter membrane 32

33 Acknowledgements Dr George Chase Machinist Frank Pelc Multiphase Group Members Cummins Filtration 33

34 Thank You 34