Figure 1.
Capillary Pressure
for water at 20 °C,
, dependent on channel geometry, surface properties, and material combination. Rectangular I (wall contact angle: 60°, width: 1 mm, height: 0.5 mm) without a hydrophobic membrane on the top of the micro channel. Rectangular II (wall contact angle: 60°, width: 1 mm, height: 0.5 mm) with hydrophobic membrane made of PTFE (contact angle: 120° [
20]) on the top of the micro channel. Round Capillary I (wall contact angle: 60°, diameter: 1 mm). Round Capillary II (wall contact angle: 60°, diameter: 0.5 mm).
Figure 1.
Capillary Pressure
for water at 20 °C,
, dependent on channel geometry, surface properties, and material combination. Rectangular I (wall contact angle: 60°, width: 1 mm, height: 0.5 mm) without a hydrophobic membrane on the top of the micro channel. Rectangular II (wall contact angle: 60°, width: 1 mm, height: 0.5 mm) with hydrophobic membrane made of PTFE (contact angle: 120° [
20]) on the top of the micro channel. Round Capillary I (wall contact angle: 60°, diameter: 1 mm). Round Capillary II (wall contact angle: 60°, diameter: 0.5 mm).
Figure 2.
Cross and longitudinal section of the separation process.
Figure 2.
Cross and longitudinal section of the separation process.
Figure 3.
Theoretical trend according to a maximum separable gas feed amount of , , and calculated by Darcy’s law with , , , , and .
Figure 3.
Theoretical trend according to a maximum separable gas feed amount of , , and calculated by Darcy’s law with , , , , and .
Figure 4.
Mass balance model of the separation process.
Figure 4.
Mass balance model of the separation process.
Figure 5.
Exploded-view of the membrane based micro contactor with integrated T-junction for two-phase flow generation.
Figure 5.
Exploded-view of the membrane based micro contactor with integrated T-junction for two-phase flow generation.
Figure 6.
Scheme of the experimental setup.
Figure 6.
Scheme of the experimental setup.
Figure 7.
Transmembrane pressure at different for all membranes at and calculated average permeabilities for all membranes at .
Figure 7.
Transmembrane pressure at different for all membranes at and calculated average permeabilities for all membranes at .
Figure 8.
Measured sweep gas loss through a Aspire® QL217 membrane for different sweep gas flows at and .
Figure 8.
Measured sweep gas loss through a Aspire® QL217 membrane for different sweep gas flows at and .
Figure 9.
Degree of condensation of the evaporated and diffusively transported liquid species at within the sweep gas channel on the supporting material, observed for different operating times. Illustrated pictures are for following operating times 0 s, 150 s, 300 s, and 600 s using , , and .
Figure 9.
Degree of condensation of the evaporated and diffusively transported liquid species at within the sweep gas channel on the supporting material, observed for different operating times. Illustrated pictures are for following operating times 0 s, 150 s, 300 s, and 600 s using , , and .
Figure 10.
Comparison of the separation performance for different at , , and (, , and .
Figure 10.
Comparison of the separation performance for different at , , and (, , and .
Figure 11.
Images of the membrane surface by scanning electron microscopy after usage as separation layer for all experimental investigations.
Figure 11.
Images of the membrane surface by scanning electron microscopy after usage as separation layer for all experimental investigations.
Figure 12.
Diffusive liquid loss for water and methanol under single phase flow conditions (liquid) of the porous membrane depending on the sweep gas volume flow for Aspire® QL217 at 20 °C and .
Figure 12.
Diffusive liquid loss for water and methanol under single phase flow conditions (liquid) of the porous membrane depending on the sweep gas volume flow for Aspire® QL217 at 20 °C and .
Figure 13.
Overall liquid loss for water and for all porous membrane under two-phase flow conditions for different feed inlet temperatures ( and feed gas volume flows .
Figure 13.
Overall liquid loss for water and for all porous membrane under two-phase flow conditions for different feed inlet temperatures ( and feed gas volume flows .
Figure 14.
Overall liquid loss for methanol and for all porous membrane under two-phase flow conditions for different feed inlet temperatures ( and feed gas volume flows .
Figure 14.
Overall liquid loss for methanol and for all porous membrane under two-phase flow conditions for different feed inlet temperatures ( and feed gas volume flows .
Figure 15.
Orientation independence tests for Aspire® QL217 (, , , and ).
Figure 15.
Orientation independence tests for Aspire® QL217 (, , , and ).
Figure 16.
Active membrane area (calculated with Equation (9)) of membrane QL 217 at , , , and for different methanol concentrations and different (left image). Development of the transmembrane pressure gradient with increasing (right image).
Figure 16.
Active membrane area (calculated with Equation (9)) of membrane QL 217 at , , , and for different methanol concentrations and different (left image). Development of the transmembrane pressure gradient with increasing (right image).
Table 1.
Examples of previous works on the gas/liquid separation in microstructured devices using polymeric membranes or inorganic microsieves as a separation layer.
Table 1.
Examples of previous works on the gas/liquid separation in microstructured devices using polymeric membranes or inorganic microsieves as a separation layer.
Investigator | Research Topic | Membrane | Material | Fluids | Mode |
---|
Meng et al. [9] | Distributed Breather | Microsieve | Silicon | CO2 (g)/H2O (l) | P |
Lee et al. [10] | Micro Bubble Separator | Microsieve | Silicon | CO2 (g)/H2O (l) | P |
Amon et al. [11] | Micro-electro-mechanical based µDMFC | Microsieve | Silicon | CO2/H2O + CH3OH (l) | P |
Alexander et al. [12] | Micro-breather (heat sink) | Microsieve | Silicon | H2O (g)/H2O (l) | P |
Kraus et al. [13] | Orientation indipendent microseparator | Membrane | PTFE | CO2 (g)/H2O (l) | A |
Meng et al. [14,15,16] | Membrane based micro separator in a µDMFC | Membrane | PTFE|PP | CO2 (g)/H2O + CH3OH (l) | A |
Xu et al. [17] | Active gas/liquid phase separation | Membrane | ACP | N2 (g)/H2O (l) | A |
David et al. [18] | Micro heat exchanger and microgas separator | Membrane | PTFE | Air (g)/H2O (l) | A |
Fazeli et al. [19] | Differential pressure on the gas/liquid separation | Membrane | PTFE | CO2 (g)/H2O + CH3OH (l) | A |
Table 2.
Data summary of the polymer based porous hydrophobic membranes. Data extracted from the data sheet provided by Clarcor Air for Aspire® QP955 and Aspire® QL217 and by Pall for Supor® 200PR and Versapor®. Contact angle of water determined by contact angle measurements at lab conditions against air with a measuring accuracy of ±2.5°.
Table 2.
Data summary of the polymer based porous hydrophobic membranes. Data extracted from the data sheet provided by Clarcor Air for Aspire® QP955 and Aspire® QL217 and by Pall for Supor® 200PR and Versapor®. Contact angle of water determined by contact angle measurements at lab conditions against air with a measuring accuracy of ±2.5°.
Hydrophobic Membranes | Functional Layer Material | Support Material | Thick-Ness | Pore Size | Contact Angle | Water Entry Pressure |
---|
Aspire® QP955 [30] | PTFE | Polyester | 200 µm | 100 nm | 120° | ≥4.5 bar |
Aspire® QL217 [31] | PTFE | Polypropylen | 200 µm | 200 nm | 120° | ≥1.0 bar |
Supor® 200PR [32] | Polyethersulfon | Polyester | 170 µm | 200 nm | 138° | ≥1.38 bar |
Versapor® 200PR [33] | Acrylic Copolymer | Nylon | 230 µm | 200 nm | 120° | ≥1.79 bar |
Table 3.
Summary of the experimental parameter for each evaluation criteria.
Table 3.
Summary of the experimental parameter for each evaluation criteria.
Evaluation Criteria | | | | | | |
---|
Separation Performance | 1 | 5 | 50 … 400 | 200 | 20, 40, 60 | 100 |
Liquid Loss | 0, 1, 2 | 5 | 50 … 400 | 200 | 20, 40, 60 | 100 |
Orientation Independence | 1 | 5 | 200, 350 | 200 | 40 | 100 |
Table 4.
Gas permeability values for single phase conditions.
Table 4.
Gas permeability values for single phase conditions.
Membrane | |
---|
Aspire® QL217 | 9.3 |
Aspire® QP955 | 14.0 |
Versapor® 200PR | 10.3 |
Supor® 200PR | 7.9 |
Table 5.
Comparison of the gas permeability under single and two-phase flow conditions.
Table 5.
Comparison of the gas permeability under single and two-phase flow conditions.
Membrane | | |
---|
| | | |
---|
Aspire® QP955 | 9.3 | 7.2 | 0.77 | 88.7 |
Aspire® QL217 | 14.0 | 10.6 | 0.76 | 86.7 |
Supor® 200PR | 10.3 | 9.0 | 0.87 | 100.0 |
Versapor® 200PR | 9.1 | 7.7 | 0.85 | 96.9 |