INORGANIC MEMBRANE PERVAPORATION … · pervaporation membranes and modules. • Experiments:...
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PS-P-99-050 BACKGROUND • Development of high flux (> 4 kg/m 2 hr) and high selective (> 200, 5% H 2 O-nBuOH) inorganic pervaporation membranes and modules. • Experiments: existence of strong mass and heat transfer resistances decrease the pervaporation efficiency. OBJECTIVE Increase the separation efficiency by improving the flow characteristics and design of the (lab scale) module. APPROACH Optimisation of the lab scale module by: • Chemical engineering calculations (Poster part I). • Computational Fluid Dynamic calculations (This poster). 1. understand physical transport phenomena in the module, 2. calculate pervaporation efficiency of proposed module designs. INORGANIC MEMBRANE PERVAPORATION MODULE DESIGN Optimisation by Computational Fluid Dynamics CFD MODEL • 2D and 3D modelling of feed side (concentration, temperature, flow, membrane length, and annular space). • Low Reynolds turbulence modelling (no wall function necessary). • Heat and mass transfer. • Membrane included as boundary condition on feed side: flux is function of concentration and temperature on membrane surface. • Transversal flow near inlet and outlet strongly increases local PV flux. CONCLUSIONS • Lab scale module: strong influence of temperature and concentration polarisation. • Bench scale module: need for e.g. baffles to enhance transversal flow/turbulence. • Detailed physical insight in heat and mass transport leads to better design of bench and pilot scale modules. • Local flux strongly depends on local flow conditions. 2D CFD RESULTS Flux decrease Concentration Temperature Combined due to polarisation polarisation effect at Re = 2400 27% 8% 31% at Re = 4700 n.a. n.a. 21% at Re = 9400 n.a. n.a. 14% Figure 1: Schematic view lab scale module Figure 4: PV flux on top, side and bottom of membrane surface. Figure 5: 2D/3D PV flux as function of axial distance • Increasing flux with feed flow rate, however still polarisation effects at high flow rates. 3D CFD RESULTS Figure 3: PV flux as function of axial distance Figure 2: 3D CFD mesh, approx. 300,000 computational cells Y.C. van Delft H.M. van Veen P.P.A.C. Pex Netherlands Energy Research Foundation, ECN, P.O. Box 1, 1755 ZG Petten, The Netherlands Tel. +31 224 564640, E-mail: [email protected] Work performed by: J.A. Lycklama à Nijeholt C.J.J. Beemsterboer NRG, P.O. Box 25, 1755 ZG Petten, The Netherlands E-mail: [email protected] S. Sommer B. Klinkhammer T. Melin Institut für Verfahrenstechnik, RWTH Aachen, Turmstrasse 46, Aachen, Germany This work is partially financed by the European Union and by Novem, the Dutch organisation for Energy and Environment.
Transcript of INORGANIC MEMBRANE PERVAPORATION … · pervaporation membranes and modules. • Experiments:...
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-P-9
9-05
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BACKGROUND• Development of high flux (> 4 kg/m2hr) and high
selective (> 200, 5% H2O-nBuOH) inorganic
pervaporation membranes and modules.• Experiments: existence of strong mass and heat
transfer resistances decrease the pervaporationefficiency.
OBJECTIVEIncrease the separation efficiency by improving theflow characteristics and design of the (lab scale)module.
APPROACHOptimisation of the lab scale module by:• Chemical engineering calculations (Poster part I).• Computational Fluid Dynamic calculations
(This poster).1. understand physical transport phenomena in the
module,2. calculate pervaporation efficiency of proposed
module designs.
INORGANIC MEMBRANEPERVAPORATION MODULE DESIGNOptimisation by Computational Fluid Dynamics
CFD MODEL• 2D and 3D modelling of feed side (concentration,
temperature, flow, membrane length, and annularspace).
• Low Reynolds turbulence modelling (no wallfunction necessary).
• Heat and mass transfer.• Membrane included as boundary condition on feed
side: flux is function of concentration andtemperature on membrane surface.
• Transversal flow near inlet and outlet stronglyincreases local PV flux.
CONCLUSIONS• Lab scale module: strong influence of temperature
and concentration polarisation.• Bench scale module: need for e.g. baffles to
enhance transversal flow/turbulence.• Detailed physical insight in heat and mass transport
leads to better design of bench and pilot scalemodules.
• Local flux strongly depends on local flowconditions.
2D CFD RESULTSFlux decrease Concentration Temperature Combined
due to polarisation polarisation effectat Re = 2400 27% 8% 31%at Re = 4700 n.a. n.a. 21%at Re = 9400 n.a. n.a. 14%
Figure 1: Schematic view lab scale module
Figure 4:PV flux on top, side and bottom of membrane surface.
Figure 5: 2D/3D PV flux as function of axial distance
• Increasing flux with feed flow rate, however stillpolarisation effects at high flow rates.
3D CFD RESULTS
Figure 3: PV flux as function of axial distance
Figure 2: 3D CFD mesh,approx. 300,000computational cells
Y.C. van Delft
H.M. van Veen
P.P.A.C. Pex
Netherlands Energy
Research Foundation, ECN,
P.O. Box 1, 1755 ZG Petten,
The Netherlands
Tel. +31 224 564640,
E-mail: [email protected]
Work performed by:
J.A. Lycklama à Nijeholt
C.J.J. Beemsterboer
NRG,
P.O. Box 25, 1755 ZG Petten,
The Netherlands
E-mail: [email protected]
S. Sommer
B. Klinkhammer
T. Melin
Institut für Verfahrenstechnik,
RWTH Aachen,
Turmstrasse 46, Aachen,
Germany
This work is partially financed bythe European Union and byNovem, the Dutch organisationfor Energy and Environment.
