Selective Matrimid Membranes Containing Mesoporous Molecular Sieves

2002 ◽  
Vol 752 ◽  
Author(s):  
Kenneth J. Balkus ◽  
Kyle Cattanach ◽  
Inga H. Musselman ◽  
John P. Ferraris
Keyword(s):  
Molecular Sieves ◽  
Molecular Sieve ◽  
High Performance ◽  
Gas Permeability ◽  
Amorphous Material ◽  
Polymer Chains ◽  
Mesoporous Molecular Sieves ◽  
Permeability Characteristics ◽  
High Performance Polymer ◽  
The Ideal

ABSTRACTWe have employed mesoporous molecular sieves in polymer membranes in an effort to enhance the permselectivity. The principal advantage of these materials is that the polymer chains can penetrate the pores reducing the nonselective voids that are often observed with inorganic additives. In this study, we have prepared Matrimid® membranes with various loadings of the all silica molecular sieve DAM-1 (Dallas Amorphous Material) as well as DAM-1 functionalized with amines in the channel wall, to enhance the gas permeability characteristics of a high performance polymer. For all gases tested (N2, O2, CO2, CH4), the permeability increased in proportion to the wt % of the amine DAM-1 present in the membrane. The addition of the amine DAM-1 resulted in modest ideal O2/N2 permselectivity, while the ideal CO2/CH4 permselectivity values were >100, depending upon the moisture content of the feed. The ideal CO2/CH4 permselectivity values are among the highest for this type of composite membrane. Details of membrane fabrication as well as permeability and permselectivity results will be presented for a range of Matrimid®/molecular sieve composites.

scholarly journals On-Board Oxygen Generation Using High Performance Molecular Sieve

2017 ◽  
Vol 2 (4) ◽  
pp. 380 ◽  
Author(s):  
Ajaz A. Bhat ◽  
H. Mang ◽  
Rajkumar S. ◽  
T. M. Kotresh ◽  
U. K. Singh
Keyword(s):  
Molecular Sieves ◽  
Molecular Sieve ◽  
High Performance ◽  
Environmental Control ◽  
Solenoid Valve ◽  
Limiting Factors ◽  
Liquid Oxygen ◽  
Gaseous Oxygen ◽  
System Pressure ◽  
Pipe Line

<p class="p1">The majority of high performance combat aircrafts presently being operated by Indian air Force are fitted with conventional oxygen systems in which a replenishable store of oxygen is carried, most often as liquid oxygen and the flow of gas to each crew member is controlled by an individual pressure demand regulator in which the oxygen is diluted with cabin air to provide breathing gas.Moreover, in-flight refueling capability of present generation fighter aircraft has made it possible to fly for long durations (6 to 8 hours). In such case, the oxygen source becomes one of the limiting factors. In order to meet this requirement, a large supply of Gaseous Oxygen (GASOX) or Liquid Oxygen (LOX) have proven to be a costly affair and the Onboard Oxygen Generating System (OBOGS) has become a very convenient and attractive proposal. The OBOGS employs molecular sieves to adsorb nitrogen from engine bleed air using pressure swing adsorption (PSA) technique, wherein two molecular sieve beds are continuously cycled between steps of pressurization (adsorption) and depressurization (desorption) to generate oxygen enriched breathing gas for aircrew. This paper describes the design of OBOGS using high performance Lithium based Low Silica X-type (Li-LSX) molecular sieves and its performance characteristics. It consists of two Zeolite beds filled with Li-LSX material which adsorbs nitrogen fromengine bleed air tapped from Environmental Control System pipe line. The two beds are cycled by a 5/2 way solenoid valve. The input air is supplied to the solenoid valve through a coalescent filter to reduce moisture from it and a pressure regulator is fitted at the upstream of solenoid valve to regulate the system pressure. The experimental setup for evaluation of OBOGS is also discussed. The OBOGS, presented in this paper, meets all the performance requirements as specified in MIL-C-85521 (AS).<span class="Apple-converted-space"> </span></p>

Synthesis and Catalytic Property of V-MCM-41 Mesoporous Molecular Sieves by Atrane Route

2011 ◽  
Vol 284-286 ◽  
pp. 936-939 ◽  
Author(s):  
Wen Ming Liu ◽  
Jia Jia Cao ◽  
Chun Ling Fan ◽  
Zhao Ping Chen
Keyword(s):  
Gas Phase ◽  
Atmospheric Pressure ◽  
Molecular Sieves ◽  
Molecular Sieve ◽  
Space Velocity ◽  
Vanadium Content ◽  
Mesoporous Molecular Sieves ◽  
Active Centers ◽  
Partial Oxidation Of Toluene ◽  
Mcm 41

V-MCM-41 molecular sieve with high vanadium content has been prepared by the atrane route. Gas phase partial oxidation of toluene to benzaldehyde on the V-MCM-41 molecular sieves catalysts was studied. The structure and characteristic of catalyst were characterized by means of XRD, UV-vis and so on. The experimental results showed that the vanadium content in the framework related to mole ratio of silica to vanadium. The vanadium content in the framework was the highest, when the mole ratio of Si to V was 30. And the vanadium in the framework may be active centers of catalytic oxidation of toluene to benzaldehyde. Under the condition of atmospheric pressure, mole ratio of Si to V 30, space velocity 800 h-1, n(air):n(toluene)=5 and reaction temperature 450°C，the conversion of toluene, selectivity to benzaldehyde and its yield were 20.8%, 41.8% and 8.7% respectively.

High-Performance Polymer Molecular Sieve Membranes Prepared by Direct Fluorination for Efficient Helium Enrichment

2021 ◽  
Author(s):  
Xiaohua Ma ◽  
Kaihua Li ◽  
Zhiyang Zhu ◽  
Hao Dong ◽  
Jia Lv ◽  
...  
Keyword(s):  
Natural Gas ◽  
Molecular Sieve ◽  
High Performance ◽  
Separation Membranes ◽  
Direct Fluorination ◽  
High Performance Polymer

One of the biggest challenges facing membrane-based helium (He) recovery from natural gas is the lack of efficient He separation membranes featuring both high He permeability and He/CH4 selectivity (>...

The Effect of Type of Acid Sites in Molecular Sieves on Activity and Selectivity in Acylation Reactions

2007 ◽  
Vol 72 (5-6) ◽  
pp. 728-746 ◽  
Author(s):  
Martina Bejblová ◽  
Josef Vlk ◽  
Dana Procházková ◽  
Helena Šiklová ◽  
Jiří Čejka
Keyword(s):  
Molecular Sieves ◽  
Molecular Sieve ◽  
Acid Sites ◽  
Acid Strength ◽  
Zeolite Beta ◽  
Mesoporous Molecular Sieves ◽  
Lewis Acid Sites ◽  
Mcm 41 ◽  
Acylation Reactions

The role of the type of acid site (Broensted vs. Lewis) on the activity and selectivity of molecular sieve catalysts was investigated in ferrocene and toluene acylation. H-, Zn-, Fe-, Al- and La-forms of zeolite Beta, USY and mesoporous molecular sieves (Al)MCM-41, (Al)SBA-15 were tested. It was observed that addition of metal cations acting as Lewis acid sites can increase the acidity of various molecular sieve catalysts. No general relationship between the type of cation and conversion of individual substrate was found. While the highest activity in ferrocene acylation was observed after addition of Zn, in the case of toluene acylation Al-forms of catalysts were the most active. The results indicate that the acid strength of cationic Lewis sites controls their activity in acylation reactions.

Comparison of Two Evaluating Methods for Establishing the Marginal Fit on Four Heat - Pressed Resin Inlays

2018 ◽  
Vol 69 (4) ◽  
pp. 890-893
Author(s):  
Sorana Baciu ◽  
Cristian Berece ◽  
Adrian Florea ◽  
Andrada Voina Tonea ◽  
Ondine Lucaciu ◽  
...  
Keyword(s):  
High Performance ◽  
Clinical Results ◽  
Marginal Fit ◽  
High Performance Polymer ◽  
Investigation Methods ◽  
Evaluating Methods

In this study were compared two investigation methods, a bi- and tri-dimensional techniques by examining the marginal fit pressed in (BioHPP) Inlays. The study pruved that the BioHPP is a high performance polymer which provides very good clinical results.

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