Tubular Support Research Articles

Separation of Helium from Gases Using the Synthesized Hydroxy Sodalite Membrane

The goals of this work are to synthesize and evaluate the potential of hydroxy sodalite membrane in the separation of helium from natural gas. Sodalite membrane was synthesized via direct hydrothermal method (conventional heating) on tubular alumina support. It was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and single gas permeation using helium and N2. After drying of the membrane, permeances of single gases were found to be of the order Helium > CH4 > N2 > CO2 at low temperatures and the membrane was impermeable to N2, CO2 and CH4 at high temperatures (>85 °C). In the investigated range of temperature 35-180 °C, membrane performance tended to high selectivity. The maximum separation factors (helium/N2 ~ 8.8, helium/CO2 ~ 16.5 and helium/CH4 ~ 5) with acceptable permeance were observed at 85 °C.

DME conversion using high flux tubular membrane reactors

ABSTRACTHigh flux tubular membrane reactors were designed for dimethyl ether (DME) steam reforming. Considering the facile scale-up and high flux of hydrogen, tubular stainless steel supports were employed for the membrane reactors. At 500°C, DME conversion reached ~100%, while hydrogen recovery reached 20%. However, contamination by CO was rather high (>1%), making this process unsuitable for proton exchange membrane fuel cell applications, which require a CO concentration of <100 ppm. This result showed that an additional polishing step was needed to reduce the CO concentration. Membrane reactors were further modified to perform an water–gas shift reaction on the permeate of the membrane reactors by employing a fixed bed reactor, which yielded high-purity hydrogen (~99%) along with a low CO content (<20 ppm).

Thin Hydrogen-Selective SAPO-34 Zeolite Membranes for Enhanced Conversion and Selectivity in Propane Dehydrogenation Membrane Reactors

We demonstrate significantly enhanced conversion and selectivity in high-temperature propane dehydrogenation (PDH) membrane reactors via the synthesis and use of small-pore SAPO-34 zeolite membranes. The reduction of SAPO-34 membrane thickness to ∼1 μm levels while maintaining good H2 selectivity is challenging. Initial reductions in membrane thickness were achieved using a single structure-directing agent (SDA) and concentrated precursor solution, leading to a large permeance increase and good H2/hydrocarbon selectivity. We further show that thinner (∼1 μm) SAPO-34 membranes can be fabricated on a large area (∼18 cm2) tubular ceramic supports by the use of both base and salt forms of the SDA to independently control the SDA concentration and pH. EDX analysis and elemental mapping confirmed the formation of micrometer-thin (∼1 μm) SAPO-34 zeolite membrane layers on α-alumina tubular supports. Micrometer-thin SAPO-34 membranes reach propylene selectivities greater than 80% as well as high propane conversio...

Preparation and characterization of ZnO microfiltration membrane and its support using kaolin (DD3) and CaCO3

Abstract The objective of the present paper was to prepare a ceramic support with membrane. Tubular ceramic supports prepared from kaolin (DD3) and calcium carbonate with 6 and 10 mm inner and outer diameters, respectively, were extruded and sintered at 1200 °C. It has been found that sintered supports had interesting characteristics: average pore size of about 5µm, porosity of about 50%, and monomodal pore size distribution. This support was used to be substrate for a membrane layer of microfiltration. This membrane layer was elaborated from zinc oxide, using slip casting technique. The specimens were subsequently sintered at 1000 °C. The microstructure and porosity as well as the permeability have also been studied. It has been found that the average pore size was about 1.2µm, the layer thickness was ~33µm, and the water permeability measured was about 880 L.h-1.m-2.bar-1.

Fabrication of metal-supported tubular solid oxide fuel cell by phase-inversion method and in situ reduction

Ni–Fe alloy supported tubular solid oxide fuel cells (SOFCs) were successfully fabricated by a low cost and simple process involving phase-inversion, co-sintering and in situ reduction. The tubular metal supports have a special structure consisting of uniformly distributed sponge-like pores. It has proven that co-sintering the as-prepared tubular supports together with half cells (anode and electrolyte layers) is in favor of obtaining the YSZ crack-free electrolyte film. In addition to the support for SOFC, the Ni–Fe alloy tube also serves as current collector at the anode side after fully in situ reduction. The maximum power densities of the Ni–Fe alloy supported tubular SOFCs are 0.26 W cm−2 at 800 °C, using moist hydrogen as fuel and ambient air as oxidant. The present work demonstrates the feasibility for the fabrication of metal-supported SOFCs with acceptable performance using economical techniques.

Response to “Comments on ‘Influence of Zeolite Protective Overlayer on the Performances of Pd Thin Film Membrane on Tubular Asymmetric Alumina Supports’”

Response to “Comments on ‘Influence of Zeolite Protective Overlayer on the Performances of Pd Thin Film Membrane on Tubular Asymmetric Alumina Supports’”

Comments on “Influence of Zeolite Protective Overlayer on the Performances of Pd Thin Film Membrane on Tubular Asymmetric Alumina Supports”

ADVERTISEMENT RETURN TO ISSUEPREVCorrespondenceNEXTComments on “Influence of Zeolite Protective Overlayer on the Performances of Pd Thin Film Membrane on Tubular Asymmetric Alumina Supports”Jiafeng Yu*View Author Information Dalian Institute of Chemical Physics, Chinese Academy of Sciences—Dalian National Laboratory for Clean Energy, Zhongshan Road 457#, Dalian, Liaoning 116023, China*E-mail: [email protected]Cite this: Ind. Eng. Chem. Res. 2016, 55, 21, 6260Publication Date (Web):May 23, 2016Publication History Published online23 May 2016Published inissue 1 June 2016https://doi.org/10.1021/acs.iecr.6b01716Copyright © 2016 American Chemical SocietyRIGHTS & PERMISSIONSArticle Views281Altmetric-Citations1LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (125 KB) Get e-AlertsSUBJECTS:Alkyls,Membranes,Mixtures,Palladium,Zeolites Get e-Alerts

Ceramic filters for oil emulsion treatments

AbstractThis work focused on obtaining low-cost macroporous ceramic tubes to be used as filters or as supports for the preparation of multilayer ceramic membranes. A Tunisian natural clay was used as raw material and cellulose as porogen agent. Cellulose fibers obtained from paper were used. The tubular supports were shape formed by extrusion in order to obtain a low-cost material with high porosity low shrinkage. The characterization of the process has been carried out studying the phase evolution, microstructure, pore structure, mechanical strength, and water permeability at various sintering temperatures. The porosity was improved adding 10 wt.% of cellulose to the clay and sintering temperatures were between 800 and 900°C. The sintered macroporous support with 10 wt.% cellulose, sintered at 850°C exhibited good performance such as porosity 40%, mechanical strength 6.5 MPa, and water permeability 8.5 L/h m3. Finally, an emulsion of oil was significantly cleaned. A rejection rate of 50% for 10 min of tr...

Interim pressure garment therapy (4-6mmHg) and its effect on donor site healing in burn patients: study protocol for a randomised controlled trial.

BackgroundPressure garment therapy (PGT) is well accepted and commonly used by clinicians in the treatment of burns scars and grafts. The medium to high pressures (24–40 mmHg) in these garments can support scar minimisation, and evidence is well documented for this particular application. However, PGT specifically for burn donor sites, of which a sequela is also scarring, is not well documented. This study protocol investigates the impact of a low pressure (4–6 mmHg) interim garment on donor site healing and scarring. With a primary purpose of holding donor dressings in place, the application of the interim pressure garment (IPG) appears to have been twofold. IPGs for donor sites have involved inconsistent application with a focus on securing wound dressing rather than scar management. However, anecdotal and observational evidence suggests that IPGs also make a difference to some patient’s scar outcomes for donor sites. This study protocol outlines a randomised controlled trial designed to test the effectiveness of this treatment on reducing scarring to burn donor sites.Methods/designThis study is a single-centre, single (assessor)-blinded, randomised control trial in patients with burns donor sites to their thighs. Patients will be randomly allocated to a control group (with no compression to donor sites) or to an experimental group (with compression to donor sites) as the comparative treatment. Groups will be compared at baseline regarding the important prognostic indicators: donor site location, depth, size, age, and time since graft (5 days). The IPG treatment will be administered post-operatively (on day 5). Follow-up assessments and garment replacement will be undertaken fortnightly for a period of 2 months.DiscussionThis study focuses on a unique area of burns scar management using a low-pressure tubular support garment for the reduction of donor site scars. Such therapy specifically for donor scar management is poorly represented in the literature. This study was designed to test a potentially cost-effective scar prevention for patients with donor sites to the thigh. No known studies of this nature have been carried out to date, and there is a need for rigorous clinical evidence for low-pressure support garments for donor site scar minimisation.Trial registrationAustralian New Zealand Clinical Trials Registry identifier ACTRN12610000127000. Registered 8 Mar 2010.

Influence of Zeolite Protective Overlayer on the Performances of Pd Thin Film Membrane on Tubular Asymmetric Alumina Supports

The role of zeolite overlayer in the performance of Pd thin film membranes on asymmetric alumina tubular supports is analyzed. These novel multilayer membranes have a ceramic base support (asymmetric α-Al2O3 tubes) on which a crack-free Pd dense thin film was deposited by electroless plating deposition followed by creation of a further zeolite (titanium silicalite, TS-1) membrane compact layer on the top of the Pd thin film. The TS-1 layer was prepared by a two-step procedure: (i) the preseeding with TS-1 nanocrystals by dip-coating, eventually assisted by a polymer (PEI or PDADMAC), followed by (ii) a secondary growth. The composite membranes are crack-free and homogeneous, and show good mechanical properties, in terms of adhesion between metallic film and substrate, and between the zeolitic film and Pd thin film. The composite membranes were evaluated in terms of H2 permeance with respect to bare Pd membrane. The zeolite overlayer induces a change in the rate-limiting step in H2 transport, due to the pa...

Electrochemical Performance of H2o-CO2 Co-Electrolysis with a Tubular Solid-Oxide Co-Electrolysis (SOC) Cell

The H2O-CO2 electrochemical conversion process in solid-oxide co-electrolysis (SOC) cells may be one of the most efficient ways to reduce CO2 emissions and to store renewable power simultaneously. In this study, a tubular solid-oxide co-electrolysis (SOC) cell based on a general electrode support solid-oxide fuel cell was fabricated and investigated. For this purpose, we fabricated tubular electrode support tubes through an extrusion process, and after which the essential SOC cell components, i.e., the electrolyte and the electrode, were coated onto the surface of the ceramic support consecutively using a vacuum slurry and dip-coating method. The cell was operated while varying the operating temperature, cathode gas flow rate, and the supplied amount of H2O. The results demonstrate that the fabricated tubular SOC cell is a promising candidate for many practical applications, such as technology to mitigate climate change and power fluctuations associated with renewable energy.

Microwave synthesis of zeolite CHA (chabazite) membranes with high pervaporation performance in absence of organic structure directing agents

Thin and compact zeolite chabazite membranes were prepared by microwave heating using symmetric stainless steel tubular supports. The microstructures (crystal size and membrane thickness) and separation performances of supported chabazite layers were strongly affected by heating method, synthesis time and synthesis temperature. The best membrane prepared by microwave heating under optimized conditions showed fluxes of 7.3 and 9.1 kg/(m2 h) and separation factors of 2000 and 2500 for 90 wt.% ethanol and isopropanol aqueous solutions at 348 K, respectively. These fluxes were twice as high as those of the chabazite membranes prepared by conventional heating due to the thinner zeolite layers and lower resistance of the support layer in the microwave heating system. The membrane prepared on the 3-time-reused stainless steel support showed comparable separation performance with the membrane on the fresh support, suggesting that the stainless steel supports had a good reuse prospect for chabazite membrane preparation. Synthesis reproducibility and hydrothermal stability of chabazite membranes by microwave heating were also investigated.

Electrochemical Properties of Tubular SOFC Based on a Porous Ceramic Support Fabricated by Phase-Inversion Method

In this work, a tubular ceramic-supported solid oxide fuel cell (SOFC) was successfully fabricated by a low cost and simple process involving phase-inversion, brush coating and co-sintering. Properties including sintering behavior, microstructure of the tubular support as well as the electrochemical properties of single cell were investigated. The results show that a porous tubular support with finger-like pores and macrovoids was obtained after phase-inversion process. The tubular support is proved to be gas-permeable after sintering at 1400 °C with shrinkage of about 34%. The maximum power density of single tubular SOFC is 100 mW/cm2 and 122 mW/cm2 at 850 °C when fed with wet methane and hydrogen, respectively. The current collection, thickness of electrolyte and gas permeability of tubular support should account for the large total resistance. The present tubular design could be expected to deliver a higher voltage for longer support with several segmented-in-series cell stacks.

Electrochemical performance of H2O–CO2 coelectrolysis with a tubular solid oxide coelectrolysis (SOC) cell

The H2O–CO2 electrochemical conversion process in solid oxide coelectrolysis (SOC) cells is potentially an efficient way to reduce CO2 emissions and to store renewable power simultaneously. In this study, a tubular solid oxide coelectrolysis (SOC) cell based on a general electrode support solid oxide fuel cell was fabricated and investigated. We fabricated tubular electrode support tubes through an extrusion process, and the essential SOC cell components, i.e., the electrolyte and the electrode, were then coated onto the surface of a ceramic support consecutively using a vacuum slurry and dip-coating method. The cell was operated while varying the operating temperature, cathode gas flow rate, and the supplied amount of H2O. The results demonstrate that the fabricated tubular SOC cell is a promising candidate for many practical applications, such as technology to mitigate climate change and power fluctuations associated with renewable energy.

Design and Performance Evaluation of Hybrid Nanofiltration Membranes Based on Multiwalled Carbon Nanotubes and Polyelectrolyte Multilayers for Larger Ion Rejection and Separation

A polyelectrolyte multilayer (PEM) membrane of poly(diallyldimethylammonium chloride) (PDADMAC) and poly(sodium 4‐styrenesulfonate) (PSS) is deposited on top of a thick‐layer micrometer range of multiwalled carbon nanotubes (MWCNTs) assembled on a porous silicon carbide (SiC) tubular membrane support. MWCNTs are assembled “layer‐by‐layer” alternating oxidized CNTs and poly(allylamine hydrochloride)‐modified CNTs. The MWCNTs layer is crosslinked by annealing after the assembly. The MWCNT layer acts as a spacer between the PDADMAC/PSS PEM and the SiC support. The MWCNT support increases water permeability in 42% compared with the PEMs deposited without MWCNTs. Hybrid MWCNT–PEM membranes show high rejection for divalent ions, which increases directly with flux. A rejection up to 92% is measured for MgSO4 and there is up to a 60% rejection difference between MgCl2 and NaCl, making the hybrid MWCNT–PEMs highly appealing for nanofiltration and monovalent and divalent ion separations image

Carbon molecular sieve membranes on porous composite tubular supports for high performance gas separations

Carbon molecular sieve (CMS) membranes on the inside of porous composite stainless steel supports were developed for gas separation in this research effort. The intermediate alumina layer was introduced to reduce the pore size of the porous stainless steel tube and subsequently provide uniform surface roughness. Viscosity of the phenolic polymer solution was varied from 10 to 30 centipoises (cP) to maximize performance of the CMS membranes. Pyrolysis temperature was also varied from 700 °C to 900 °C to optimize the fabrication of uniform CMS membranes on porous composite stainless steel supports. High performance CMS membranes were obtained from triple coatings and subsequent pyrolysis at 700 °C. The viscosity of precursor solutions played a critical role to determine the performance of CMS membranes in terms of gas permeance and ideal gas separation factor. The highest separation performance of the CMS membranes was shown with viscosity of 20 cP, resulting in gas separation factor of 462 for He/N2, 97 for CO2/N2, and 15.4 for O2/N2.

Synthesis at several length scales of zeolite A membranes using a continuous flow method

ABSTRACTZeolite A membranes were synthesized in the inner side of porous TiO2 and α-Al2O3 tubular supports by a continuous method. The methodology was then used at several scales for preparing membranes on TiO2 and α-Al2O3 supports with lengths of 6, 12 and 25 cm. Formation of an homogeneous zeolite film was confirmed by XRD and SEM in all supports. Single-gas permeation experiments (He, H2, N2 and n-C3H8) indicated that Knudsen diffusion was the predominant mechanism in both supports. All the synthesized membranes present high flux and moderate selectivity to water in water–ethanol mixtures.

Characterization of NaA Zeolite Oxygen Permeable Membrane on TiO2/α-Al2O3Composite Support

The NaA zeolite membrane was synthesized on the surface of TiO 2 /α-Al 2 O 3 composite support with TiO 2 as modifier of α-Al 2 O 3 porous tubular ceramic membrane support by crystallization method. The structure characterization indicated that the TiO 2 of the support surface could effectively improve the surface properties of the support. It didn’t affect the crystallization of NaA synthesis liquid and synthesis process of NaA zeolite membrane. There were no obvious defects between the crystal particles with size of approximate 6μm. The perfect and complete membrane with thickness of approximate 15μm combined closely with support to connection together by TiO 2 modified. The oxygen permeability of the membrane on TiO 2 /α-Al 2 O 3 composite support improves of 47% compared with that of α-Al 2 O 3 support. So the process of TiO 2 modifying the surface of α-Al 2 O 3 support should increase the oxygen permeability of the NaA zeolite membrane.

Development of an Asymmetric Ultrafiltration Membrane from Naturally Occurring Kaolin Clays: Application for the Cuttlefish Effluents Treatment

This work concerns to the development and characterization of support and ultrafiltration membranes from naturally occurring- kaolin clays as principal components. The preparation and characterization of porous tubular supports, using kaolin powder with corn starch as poreforming agent, were reported. It has been found that the average pore size was about 1 μm while the pore volume was 44% for supports sintered at 1150°C with a flexural strength of about 15 MPa. The deposition of the active layer was performed by slip casting method. The rheological study of various coatings with different concentration of kaolin powder, polyvinyl alcohol (PVA) and water under different conditions regarding temperature and stirring time was done. After drying at room temperature for 24 h, the membrane was sintered at 650°C. The average pore diameter of the active layer was 11 nm and the thickness was around 9 μm. The determination of the water permeability shows a value of 78 l/h.m2.bar. This membrane can be used for crossflow ultrafiltration. The application of the cuttlefish effluent treatment shows an important decrease of turbidity, inferior to 1.5 NTU and chemical organic demand (COD), retention rate of about 87%. So, it seems that this membrane is suitable to use for wastewater treatment.

Characterization of Metal-Doped Methylated Microporous Silica for Molecular Separations

Novel silica xerogels are prepared and developed by sol-gel method in the present study. The preparation involves cobalt-doping within the organic templated silica matrices, where methyltriethoxysilane (MTES), which contains methyl groups as a covalently bonded organic template is used. The synthesis and surface properties of cobalt-doped methylated microporous silica xerogels with different MTES and cobalt content are revealed by surface and microstructural techniques, such as TGA, FTIR, X-ray and N2 adsorption measurements. The doping process enhances the thermal stability of the silica xerogels up to ~ 560 °C in oxidizing atmosphere. Besides, this process has no significant effect on the incorporation of the organic template within the silica matrix. As result of the promoted densification of the xerogels either by increasing MTES content and heat treatment, there is structural change of the silica xerogels such as decreasing the micropore volume and broadening of the pore size distribution. Heat treatment and increasing the cobalt oxide content from 5 to 10% weight ratio resulted in samples with approximately the same structural parameters. This suggests that the cobalt particles are homogeneously dispersed in the silica matrix. The novel silica xerogels exhibit trend toward micropores formation suggesting that these doped silica xerogels can be precursor materials for molecular sieve silica membranes applications. Two silica membranes, hydrophobic and cobalt-doped hydrophobic, are prepared and their performance is examined by the study of transport of He, H2 and N2. Preliminary results show that the microporous structure obtained in the unsupported cobalt-doped hydrophobic material are preserved after coating inside the tubular support.