scholarly journals Efficiency Separation Process of H2/CO2/CH4 Mixtures by a Hollow Fiber Dual Membrane Separator

Processes ◽  
2020 ◽  
Vol 8 (5) ◽  
pp. 560 ◽  
Author(s):  
Wu Xiao ◽  
Pei Gao ◽  
Yan Dai ◽  
Xuehua Ruan ◽  
Xiaobin Jiang ◽  
...  
Keyword(s):  
Hollow Fiber ◽  
Power Plants ◽  
Separation Efficiency ◽  
Operating Temperature ◽  
Gas Permeation ◽  
Area Ratio ◽  
Separation Performance ◽  
Operating Pressure ◽  
Membrane Area ◽  
Membrane Separator

Hydrogen purification and CO2 capture are of great significance in refineries and pre-combustion power plants. A dual membrane separator offers an alternative approach for improving H2/CO2 separation efficiency. In this work, H2/CO2/CH4 ternary gas mixtures separation can be achieved by a dual membrane separator with an integrated polyimide (PI) membrane and polydimethylsiloxane/polyetherimide (PDMS/PEI) composite membrane. A hollow fiber dual membrane separation equipment is designed and manufactured. Through the self-designed device, the effects of stage cut, operating temperature, operating pressure, and membrane area ratio on separation performance of dual membrane separator have been studied. The results indicate that, at a high stage cut, a dual membrane separator has obvious advantages over a single membrane separator. Operating temperature has a significant impact on gas permeation rates. At 25 °C, a dual membrane separator can obtain the highest purity of H2 and CO2. By increasing operating pressure, the purity and recovery of H2 and CO2 can be improved simultaneously. The effect of the membrane area ratio on the performance of the dual membrane separator was studied. When the permeate flows of two membranes are approximately equal by changing the membrane area ratio, the overall performance of the dual membrane separator is the best. On the basis of its synergy in promoting separation, the dual membrane separator holds great industrial application potential.

Miscible blend polyethersulfone/polyimide asymmetric membrane crosslinked with 1,3-diaminopropane for hydrogen separation

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Nur’ Adilah Abdul Nasir ◽  
Ameen Gabr Ahmed Alshaghdari ◽  
Mohd Usman Mohd Junaidi ◽  
Nur Awanis Hashim ◽  
Mohamad Fairus Rabuni ◽  
...  
Keyword(s):  
Separation Efficiency ◽  
Chemical Characterization ◽  
Gas Permeation ◽  
Separation Performance ◽  
Membrane Composition ◽  
Asymmetric Membrane ◽  
Wet Phase Inversion ◽  
Pair Performance ◽  
Improved Performance ◽  
Physical And Chemical

Abstract Efficient purification technology is crucial to fully utilize hydrogen (H2) as the next generation fuel source. Polyimide (PI) membranes have been intensively applied for H2 purification but its current separation performance of neat PI membranes is insufficient to fulfill industrial demand. This study employs blending and crosslinking modification simultaneously to enhance the separation efficiency of a membrane. Polyethersulfone (PES) and Co-PI (P84) blend asymmetric membranes have been prepared via dry–wet phase inversion with three different ratios. Pure H2 and carbon dioxide (CO2) gas permeation are conducted on the polymer blends to find the best formulation for membrane composition for effective H2 purification. Next, the membrane with the best blending ratio is chemically modified using 1,3-diaminopropane (PDA) with variable reaction time. Physical and chemical characterization of all membranes was evaluated using field emission scanning electron microscope (FESEM), X-ray diffraction (XRD), and Fourier transform infrared (FTIR). Upon 15 min modification, the polymer membrane achieved an improvement on H2/CO2 selectivity by 88.9%. Moreover, similar membrane has demonstrated the best performance as it has surpassed Robeson’s upper bound curve for H2/CO2 gas pair performance. Therefore, this finding is significant towards the development of H2-selective membranes with improved performance.

Preparation and performance characterization of novel PVA blended with fluorinated polyimide membrane for gas separation

2020 ◽  
pp. 095400832095970
Author(s):  
Yunwu Yu ◽  
Peng Lin ◽  
Ye Zhao ◽  
Changwei Liu ◽  
Changwei Xu ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Hydrogen Bonds ◽  
Gas Separation ◽  
Amic Acid ◽  
Gas Permeation ◽  
Separation Performance ◽  
Hydroxyl Groups ◽  
Operating Pressure ◽  
Polyimide Membrane ◽  
Fluorinated Polyimide

Fluorinated polyimide and PVA blending membranes were prepared by aqueous solution casting. We chose a poly (amic acid) ammonium salt (PAAS) in aqueous solution based on a novel green strategy as the PI precursor. The blending membranes were characterized by ATR-FTIR, DSC, TGA and gas permeation measurement. The ATR-FTIR analysis revealed that the imidization reaction of 6FPI based on aqueous precursor was completed at 180°C and hydrogen bonds formed between PVA and 6FPI. 6FPI showed good compatibility with PVA segment in blending membranes without obvious separated phase structure. The blending membranes showed high separation properties, for blending with 6FPI the gas separation performance stability was improved due to the hydrogen bonds between hydroxyl groups of PVA and carbonyl groups of 6FPI, and the rigid structure of 6FPI. At high operating pressure 10 bar, the CO2 permeability and CO2/N2 selectivity remained rather high. Using water as the solvent in the PAAS synthesis and membrane preparation is more environmentally friendly and less costly.

scholarly journals Experimental Investigation of the Gas/Liquid Phase Separation Using a Membrane-Based Micro Contactor

2018 ◽  
Vol 2 (4) ◽  
pp. 55 ◽  
Author(s):  
Kay Marcel Dyrda ◽  
Vincent Wilke ◽  
Katja Haas-Santo ◽  
Roland Dittmeyer
Keyword(s):  
Phase Separation ◽  
Liquid Phase ◽  
Pressure Gradient ◽  
Separation Efficiency ◽  
Gas Permeability ◽  
Separation Process ◽  
Methanol Solution ◽  
Liquid Phase Separation ◽  
Separation Performance ◽  
Membrane Area

The gas/liquid phase separation of CO2 from a water-methanol solution at the anode side of a µDirect-Methanol-Fuel-Cell (µDMFC) plays a key role in the overall performance of fuel cells. This point is of particular importance if the µDMFC is based on a “Lab-on-a-Chip” design with transient working behaviour, as well as with a recycling and a recovery system for unused fuel. By integrating a membrane-based micro contactor downstream into the µDMFC, the efficient removal of CO2 from a water-methanol solution is possible. In this work, a systematic study of the separation process regarding gas permeability with and without two-phase flow is presented. By considering the µDMFC working behaviour, an improvement of the overall separation performance is pursued. In general, the gas/liquid phase separation is achieved by (1) using a combination of the pressure gradient as a driving force, and (2) capillary forces in the pores of the membrane acting as a transport barrier depending on the nature of it (hydrophilic/hydrophobic). Additionally, the separation efficiency, pressure gradient, orientation, liquid loss, and active membrane area for different feed inlet temperatures and methanol concentrations are investigated to obtain an insight into the separation process at transient working conditions of the µDMFC.

scholarly journals Preparation and characterization of polysulfone membrane coated with poly(ether block amid) for oxygen enrichment process

2019 ◽  
Vol 15 (1) ◽  
pp. 50-53
Author(s):  
Kok Chung Chong ◽  
Yin Yin Chan ◽  
Woei Jye Lau ◽  
Soon Onn Lai ◽  
Ahmad Fauzi Ismail ◽  
...  
Keyword(s):  
Gas Separation ◽  
Hollow Fiber ◽  
Phase Inversion ◽  
Membrane Surface ◽  
Gas Permeation ◽  
Separation Performance ◽  
Hollow Fiber Membranes ◽  
Polysulfone Membrane ◽  
Fiber Membranes ◽  
Gas Separation Performance

Oxygen enriched air (OEA) is widely applied in various areas such as chemical and medical applications. Currently, cryogenic distillation and pressure swing adsorption are the two common technologies that being commercially used for i the production of OEA. However, these two techniques are not economically favorable due to required intensive energy and large built-up area. With the advancement of membrane technology in separation process, it garners the interest from both industrial and academic to explore the feasibility of membrane in gas separation. In this study, polysulfone (PSF) hollow fiber membranes with poly(ether block amide) (PEBAX) coating were used for the separation of O2/N2 gas. The hollow fiber membranes used in this work were fabricated by phase inversion spinning process using PSF pellet, along with N,N-dimetyhlacetamide (DMAc) and ethanol (EtOH) as solvent and co-solvent, whereas tetrahydrofuran (THF) as additive. The fabricated membrane exhibited dense structure in the inner layer whereas finger like layer at the outer surface. The formation of this structure was attributed by rapid phase inversion of the solution arose from strong solvent used. The EDX surface mapping analysis confirmed the formation of PEBAX coating on the membrane surface. Gas permeation study in this work illustrated that the pristine PSF membrane exhibited better gas separation performance relative to the PEBAX coated membrane with 20% higher in terms of permeance. The results obtained from this work suggested that the PEBAX coating enhanced the membrane surface but not certain to improve the gas separation performance. Further study on the PEBAX materials for the membrane coating is essential to polish its potential in gas separation.

scholarly journals Elaboration of High Permeable Macrovoid Free Polysulfone Hollow Fiber Membranes for Air Separation

Fibers ◽  
2019 ◽  
Vol 7 (5) ◽  
pp. 43 ◽  
Author(s):  
George Dibrov ◽  
Mikhail Ivanov ◽  
Mikhail Semyashkin ◽  
Vladislav Sudin ◽  
Nikita Fateev ◽  
...  
Keyword(s):  
Hollow Fiber ◽  
Packing Density ◽  
Fiber Diameter ◽  
Hollow Fiber Membrane ◽  
Air Separation ◽  
Solution Temperature ◽  
Separation Performance ◽  
Practical Application ◽  
Membrane Area ◽  
Dope Solution

In this work, polysulfone hollow fibers with oxygen permeance 70 L (STP)/(m2·h·bar) and selectivity α(O2/N2) = 6 were obtained. A decrease in the dope solution temperature allowed to diminish macrovoids due to the increase of the dope viscosity from 15.5 Pa·s at 62 °C to 35 Pa·s at 25 °C. To reduce the fiber diameter, thereby increasing the packing density, they were spun at high linear velocities. A hollow fiber membrane element was produced with effective membrane area 2.75 m2 and packing density 53%. Its air separation performance was evaluated to bridge laboratory studies and practical application.

Effect of Superficial Gas Velocity on the Separation Efficiency of Inline Horizontal Swirl Tube Separator

2014 ◽  
Vol 625 ◽  
pp. 566-569
Author(s):  
Nurhayati Mellon ◽  
Mohd Shariff Azmi
Keyword(s):  
Natural Gas ◽  
Centrifugal Force ◽  
Separation Efficiency ◽  
Fluid Velocity ◽  
Maximum Velocity ◽  
Separation Performance ◽  
Operating Pressure ◽  
Gas Velocity ◽  
Liquid Load ◽  
Superficial Gas Velocity

The use of compact, inline separator has gain interest in the effort of reducing the size of topside facilities to reduce the capital cost associated with natural gas exploration. This paper discusses the effect of superficial gas velocity on the separation performance of an inline horizontal swirl tube separator. In this study, the superficial velocity is varied from a minimum of 5 m/s up to a maximum velocity of 12 m/s at different operating pressure. The pressure is varied from 40, 50 and 60 bars, corresponding to different centrifugal force on the incoming gas stream. Results shows that the best separation performance is achieve at higher operating pressure, in this case at 60 bar, regardless of the incoming fluid velocity and liquid load (of up to 30% by mass).

scholarly journals Highly Permeable Mixed Matrix Hollow Fiber Membrane as a Latent Route for Hydrogen Purification from Hydrocarbons/Carbon Dioxide

Membranes ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 865
Author(s):  
Yu-Ting Lin ◽  
Ming-Yen Wey ◽  
Hui-Hsin Tseng
Keyword(s):  
Hollow Fiber ◽  
Hollow Fiber Membrane ◽  
Gas Permeation ◽  
Flow Rate Ratio ◽  
Separation Performance ◽  
Hydrogen Purification ◽  
Fiber Membrane ◽  
Mixed Matrix ◽  
Alumina Particles ◽  
Separation Factors

This work reported on the fabrication and investigation of a mixed matrix hollow fiber membrane (MMHFM) by incorporating commercially available alumina particles into a polyetherimide (PEI) polymer matrix. These MMHFMs were prepared by the dry-wet spinning technique. Accordingly, optimizing the spinning parameters, including the air gap distance and flow rate ratio, is key to determining the gas separation performance. However, there are few studies regarding the effect of the filler dimensions. Consequently, three sizes of alumina particles, 20 nm, 30 nm, and 1000 nm, were respectively added into the PEI phase to examine the influence of filler size on gas permeation property. Moreover, the permeation properties of lower hydrocarbons (i.e., ethane and propane) were also measured to evaluate potential for emerging applications. The results indicated the as-synthesized membrane exhibited a remarkable hydrogen permeance of 1065.24 GPU, and relatively high separation factors of 4.53, 5.77, and 5.39 for H2/CO2, H2/C2H6, and H2/C3H8, respectively. This resulted from good compatibility between the larger fillers and the PEI polymer, as well as a reduction in the finger-like voids. Overall, the MMHFM in this work was deemed to be a promising candidate to separate hydrogen from gas streams, based on the comparison of the separation performance against other reported studies.

scholarly journals EFFECTS OF PEBAX COATING CONCENTRATIONS ON CO2/CH4 SEPARATION OF RGO/ZIF-8 PES MEMBRANES

2020 ◽  
Vol 82 (2) ◽  
Author(s):  
Najihah Jamil ◽  
Nur Hidayati Othman ◽  
Munawar Zaman Shahrudin ◽  
Mohd Rizuan Mohd Razlan ◽  
Nur Hashimah Alias ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Gas Separation ◽  
Dip Coating ◽  
Gas Permeation ◽  
Inorganic Materials ◽  
Mixed Matrix Membranes ◽  
Separation Performance ◽  
Operating Pressure ◽  
Performance Study ◽  
Coating Solution

The biggest challenge surrounding application of polymeric membranes for gas separation is their trade–off between gas permeation and selectivity. Therefore, the use of mixed matrix membranes (MMMs) comprising inorganic materials embedded into a polymer matrix can overcome this issue. In this work, PES flat sheet membrane and MMMs consists of 10 wt.% of rGO/ZIF-8 hybrid nanofillers were fabricated via dry/wet phase inversion process. Dip‐coating technique was then used to deposit PEBAX selective layer onto the surface of rGO/ZIF-8 PES support. The effects of PEBAX coating solution concentrations (2, 3 and 4 wt.%) on the permselectivity of CO2 and CH4 were investigated. The as-prepared rGO/ZIF-8 nanofillers and MMMs were characterized by fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA), X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (SEM) prior to gas separation performance study. Gas permeation testing was carried out at operating pressure of 1, 3 and 5 bar using CO2 and CH4 gasses. It was observed that the prepared PES membranes and rGO/ZIF-8 PES MMMs did not have any selectivity towards the gases although their permeability was high. As the concentration of PEBAX coating solution increased, thicker coating layer was formed. Therefore, the permeability of CO2 rapidly dropped but the CO2/CH4 selectivity increased significantly up to 38.4.  Results indicated that the use of 2 wt.% of PEBAX was not effective to form homogenous coating layers on PES membrane and to cover any defects on membrane surfaces, thus, possessing low selectivity of CO2/CH4. The high gas separation performances obtained in this work was due to the synergistic effect rGO and ZIF-8 crystals. In the rGO/ZIF-8 MMMs, the dispersibility are enhanced due to the presence of distorted rGO sheets, while the ZIF-8 component ensure the porosity of the nanofillers and permit gas interactions with the metallic sites and functional groups on the organic linker. These sites facilitate the reactive adsorption leading to enhanced CO2 adsorption as compared to CH4.

Field testing CFD-based predictions of storage chamber gross solids separation efficiency

1999 ◽  
Vol 39 (9) ◽  
pp. 161-168 ◽  
Author(s):  
Virginia R. Stovin ◽  
Adrian J. Saul ◽  
Andrew Drinkwater ◽  
Ian Clifforde
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Settling Velocity ◽  
Separation Efficiency ◽  
Flow Patterns ◽  
Total Efficiency ◽  
Separation Performance ◽  
Storage Chamber ◽  
Solids Separation ◽  
Simulated Flow

The use of computational fluid dynamics-based techniques for predicting the gross solids and finely suspended solids separation performance of structures within urban drainage systems is becoming well established. This paper compares the result of simulated flow patterns and gross solids separation predictions with field measurements made in a full size storage chamber. The gross solids retention efficiency was measured for six different storage chambers in the field and simulations of these chambers were undertaken using the Fluent computational fluid dynamics software. Differences between the observed and simulated flow patterns are discussed. The simulated flow fields were used to estimate chamber efficiency using particle tracking. Efficiency results are presented as efficiency cusps, with efficiency plotted as a function of settling velocity. The cusp represents a range of efficiency values, and approaches to the estimation of an overall efficiency value from these cusps are briefly discussed. Estimates of total efficiency based on the observed settling velocity distribution differed from the measured values by an average of ±17%. However, estimates of steady flow efficiency were consistently higher than the observed values. The simulated efficiencies agreed with the field observations in identifying the most efficient configuration.

"Recent Patents on the Triboelectrostatic Separation of Fly Ash"

2019 ◽  
Vol 13 ◽  
Author(s):  
Haisheng Li ◽  
Wenping Wang ◽  
Yinghua Chen ◽  
Xinxi Zhang ◽  
Chaoyong Li
Keyword(s):  
Fly Ash ◽  
Power Plants ◽  
High Efficiency ◽  
Separation Efficiency ◽  
High Reliability ◽  
Operating Conditions ◽  
Security Requirements ◽  
Unburned Carbon ◽  
Efficient Operation ◽  
Triboelectrostatic Separation

Background: The fly ash produced by coal-fired power plants is an industrial waste. The environmental pollution problems caused by fly ash have been widely of public environmental concern. As a waste of recoverable resources, it can be used in the field of building materials, agricultural fertilizers, environmental materials, new materials, etc. Unburned carbon content in fly ash has an influence on the performance of resource reuse products. Therefore, it is the key to remove unburned carbon from fly ash. As a physical method, triboelectrostatic separation technology has been widely used because of obvious advantages, such as high-efficiency, simple process, high reliability, without water resources consumption and secondary pollution. Objective: The related patents of fly ash triboelectrostatic separation had been reviewed. The structural characteristics and working principle of these patents are analyzed in detail. The results can provide some meaningful references for the improvement of separation efficiency and optimal design. Methods: Based on the comparative analysis for the latest patents related to fly ash triboelectrostatic separation, the future development is presented. Results: The patents focused on the charging efficiency and separation efficiency. Studies show that remarkable improvements have been achieved for the fly ash triboelectrostatic separation. Some patents have been used in industrial production. Conclusion: According to the current technology status, the researches related to process optimization and anti-interference ability will be beneficial to overcome the influence of operating conditions and complex environment, and meet system security requirements. The intelligent control can not only ensure the process continuity and stability, but also realize the efficient operation and management automatically. Meanwhile, the researchers should pay more attention to the resource utilization of fly ash processed by triboelectrostatic separation.

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