Selective Deposition of Pd on Porous Alumina Support Using Supercritical CO2

2002 ◽  
Vol 752 ◽  
Author(s):  
Masahiko Matsukata ◽  
Takashi Nishizuka ◽  
Yasushi Sekine ◽  
Eiichi Kikuchi
Keyword(s):  
Thermal Decomposition ◽  
Supercritical Co2 ◽  
Hydrogen Permeation ◽  
Porous Alumina ◽  
Diffusion Mechanism ◽  
Pore Filling ◽  
Alumina Support ◽  
Hydrogen Flux ◽  
Pd Membrane ◽  
High Separation

ABSTRACTA Pd/α-Al2O3 composite membrane was prepared on a porous α-Al2O3 disk via the thermal decomposition of bis(hexafluoroacetylacetonato)Pd(II), Pd(hfac)2. Pd(hfac)2 was dissolved in supercritical CO2 at 303 K, supplied to the substrate, and thermally decomposed at 403 and 443 K. The decomposition of Pd(hfac)2 at 443 K resulted in a sufficient pore filling of substrate with Pd as well as the formation of a thin Pd top layer. The hydrogen flux through this membrane was about 1.7 times than that of a electro-less plating Pd membrane with about 20 μm thick. Hydrogen permeation was governed by the solution-diffusion mechanism which gave a high separation selectivity.

Fabrication and Microstructure of ZnO-TiO2 Composite Membranes by a Reverse Micelle and Sol-Gel Processing

2006 ◽  
Vol 510-511 ◽  
pp. 786-789 ◽  
Author(s):  
Dong Sik Bae ◽  
Byung Ik Kim ◽  
Kyong Sop Han
Keyword(s):  
Particle Size ◽  
Reverse Micelle ◽  
Porous Alumina ◽  
Sol Gel ◽  
Average Particle Size ◽  
Composite Membranes ◽  
Dip Coating ◽  
Narrow Particle Size Distribution ◽  
Average Particle ◽  
Alumina Support

ZnO-TiO2 nanoparticles were synthesized by a reverse micelle and sol-gel process. The average particle size of the colloid was below 30 nm and well dispersed in the solution. ZnOTiO2 composite membranes were fabricated by using the dip-coating method on a porous alumina support. ZnO-TiO2 composite membranes showed a crack-free microstructure and narrow particle size distribution even after the heat treatment up to 600°C. The average particle size of the membrane was 30-40nm, and the pore size of ZnO-TiO2 composite membrane was below 10 nm.

scholarly journals Flux-Reducing Tendency of Pd-Based Membranes Employed in Butane Dehydrogenation Processes

Membranes ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 291 ◽  
Author(s):  
Thijs A. Peters ◽  
Marit Stange ◽  
Rune Bredesen
Keyword(s):  
Competitive Adsorption ◽  
Prolonged Exposure ◽  
Hydrogen Permeation ◽  
State Of The Art ◽  
Operating Temperature ◽  
Operating Conditions ◽  
Maximum Temperature ◽  
Hydrogen Flux ◽  
Membrane Performance ◽  
Wide Range

We report on the effect of butane and butylene on hydrogen permeation through thin state-of-the-art Pd–Ag alloy membranes. A wide range of operating conditions, such as temperature (200–450 °C) and H2/butylene (or butane) ratio (0.5–3), on the flux-reducing tendency were investigated. In addition, the behavior of membrane performance during prolonged exposure to butylene was evaluated. In the presence of butane, the flux-reducing tendency was found to be limited up to the maximum temperature investigated, 450 °C. Compared to butane, the flux-reducing tendency in the presence of butylene was severe. At 400 °C and 20% butylene, the flux decreases by ~85% after 3 h of exposure but depends on temperature and the H2/butylene ratio. In terms of operating temperature, an optimal performance was found at 250–300 °C with respect to obtaining the highest absolute hydrogen flux in the presence of butylene. At lower temperatures, the competitive adsorption of butylene over hydrogen accounts for a large initial flux penalty.

Synthesis of MCM-22 Zeolite Membrane on a Porous Alumina Support

2014 ◽  
Vol 805 ◽  
pp. 272-278 ◽  
Author(s):  
Antonielly dos S. Barbosa ◽  
Antusia dos S. Barbosa ◽  
Meiry Glaucia F. Rodrigues
Keyword(s):  
Porous Alumina ◽  
Mercury Porosimetry ◽  
Secondary Growth ◽  
Molecular Size ◽  
Zeolite Membrane ◽  
X Ray Diffraction ◽  
Alumina Support ◽  
X Ray ◽  
Ceramic Support ◽  
Separation Of Mixtures

Much interest has been aroused in the application in industrial processes using zeolite membrane, due to its crystalline structure, and narrow pore diameters. These features enable the continuous separation of mixtures based on differences in molecular size and shape and also based on different adsorption properties. This paper reports the synthesis of MCM-22 zeolite membrane, using the method of secondary growth. The MCM-22 zeolite was synthesized by the hydrothermal method and characterized by spectroscopy Energy Dispersive X-ray (EDX), X-Ray Diffraction (XRD) and Scanning Electron Microscopy (SEM).The ceramic support (α-alumina) was prepared using the technique of forming powder and then subjected to the sintering temperature of 1400 °C/1h and characterized by XRD. The zeolite membrane preparation was performed by the method of secondary growth and characterized by XRD, SEM and mercury porosimetry. The obtained zeolite membrane could be confirmed by X-ray diffraction. From, the obtained SEM pictures it was possible to observe the formation of a homogeneous film on the zeolite surface of the ceramic support (α-alumina).

Fabrication and Properties of Alumina Flat Sheet Membrane Surports

2014 ◽  
Vol 955-959 ◽  
pp. 601-604
Author(s):  
De Xiang Liao ◽  
An Chao Geng ◽  
Peng Hao Su ◽  
Dao Lun Feng ◽  
Lin Lin Wang
Keyword(s):  
Sintering Temperature ◽  
Porous Alumina ◽  
Pure Water ◽  
Porous Ceramic ◽  
Water Flux ◽  
Carbon Powder ◽  
Pore Former ◽  
Alumina Support ◽  
Ceramic Support ◽  
Flat Sheet Membrane

The porous ceramic support was realized at various temperature range from 1200°C~1300°C using α-Al2O3 as main material, carbon powder as pore-former, kaolin clay and titanium dioxide as sintering aids and polyvinyl alcohol (PVA) as adhesives. The microstructures of sintered body were significantly affected by the amount of pore-former and sintering temperature. The results indicated that the porosity dramatically increased and the pore radius increased from 2.9 μm to 3.2 μm as carbon powder addition increased from 3 wt.% to 12 wt.%. Correspondingly, their pure water flux depending on the pore structure parameters of the support increased from 1.37 to 4.53 m3.m-2.h-1.bar-1. To prepare porous alumina support with 40% open porosity, carbon powder up to 10 wt.% is appropriate. Sintering experiments showed that the optimum sintering conditions are the sintering temperature of 1300 °C and 2 h holding time at this temperature.

The Effect of the Partial Pressure of H2S and CO2 on the Permeation of Hydrogen in Carbon Steel by Using Pressure Buildup Techniques

CORROSION ◽  
10.5006/3128 ◽  
2019 ◽  
Vol 75 (10) ◽  
pp. 1207-1215
Author(s):  
Nayef M. Alanazi ◽  
Abdullah A. Al-Enezi
Keyword(s):  
Steady State ◽  
Carbon Steel ◽  
Corrosion Rate ◽  
Partial Pressure ◽  
Hydrogen Permeation ◽  
Measurement Techniques ◽  
Permeation Rate ◽  
Pressure Buildup ◽  
Hydrogen Flux ◽  
The Relationship

There are concerns in the industry about using an electrochemical technique for actual hydrogen permeation measurements where charging current is not a field condition. The objective of this work is to use pressure buildup techniques to study the influence of H2S and CO2 partial pressure on the relationship between hydrogen permeation and corrosion rate measured by different techniques. Sulfide films formed on carbon steel in a solution containing 5 wt% NaCl and 0.5 wt% acidic acid at various H2S and CO2 partial pressures were characterized, and the effect of the film on hydrogen permeation was also investigated. Field conditions were included in this study for comparison purposes. The relationship was modeled at the steady state of both hydrogen flux and corrosion rate. The results confirmed by use of two hydrogen flux measurement techniques (eudiometer and high-pressure buildup probe) and two corrosion measurement methods (weight loss coupons and coupled multiarray electrode system), that there is no direct correlation between hydrogen flux and corrosion rate. Therefore, the hydrogen permeation rate in H2S and CO2 environments was found to be more controlled by partial pressure of H2S than corrosion rate. The amount of descent in hydrogen flux, after reaching maximum of hydrogen permeation rate and before reaching a steady state, depends on the morphology and structure of corrosion films which are mainly controlled by concentration of H2S.

A-1 Preparation of Micro-porous Alumina Support by Extrusion(Session: Ceramics I)

2006 ◽  
Vol 2006 (0) ◽  
pp. 1
Author(s):  
Khanthima Hemra ◽  
Duangduen Atong ◽  
Pavadee Aungkavattana
Keyword(s):  
Porous Alumina ◽  
Alumina Support

Fabrications and Evaluations of Hydrogen Permeation on TiN-5wt%Ni Membrane by Spark Plasma Sintering

2009 ◽  
Vol 620-622 ◽  
pp. 13-16
Author(s):  
Kyeong Il Kim ◽  
Tae Whan Hong
Keyword(s):  
High Temperature ◽  
Hydrogen Embrittlement ◽  
Spark Plasma Sintering ◽  
Fossil Fuel ◽  
Hydrogen Permeation ◽  
Pd Membrane ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
Hydrogen Selectivity ◽  
Vibration Mill

Many laboratories have researched membrane for gasification of coal technique, separating hydrogen from fossil fuel. In general, Pd membrane of separating hydrogen is very good a property of hydrogen selectivity on high temperature, but it has some problems, hydrogen embrittlement and costly material. So, we need some materials of good properties about hydrogen selectivity instead of Pd. In this research, we fabricate membrane for hydrogen permeation, that is great in resistance to acids and chemically steady TiN. Our laboratory investigated about hydrogen selectivity. TiN powder is milled 30, 60 and 240 minutes by vibration mill, respectively. After than the samples put in operate spark plasma sintering. We analyze XRD, SEM, BET and TG/DSC. Also, in this research take an inspect hydrogen selectivity by ourselves manufactured Sievert’s type hydrogen permeation membrane equipment.

Hydrogen Permeation Behavior of X-70 Pipeline Steel in a Near-Neutral pH Soil Environment

2000 ◽  
Author(s):  
Weixing Chen ◽  
Sheng-Hui Wang ◽  
Fraser King ◽  
Tom R. Jack ◽  
Martyn J. Wilmott
Keyword(s):  
Boundary Conditions ◽  
Hydrogen Permeation ◽  
Pipeline Steel ◽  
Soil Environment ◽  
Diffusible Hydrogen ◽  
Concentration Boundary ◽  
Hydrogen Flux ◽  
Neutral Ph ◽  
Best Fit ◽  
Galvanostatic Conditions

This paper reports the hydrogen permeation behavior of an X-70 pipeline steel in a synthetic near neutral pH field solution under both galvanostatic and potentiostatic conditions. The hydrogen flux through the steel exposed to the solution is influenced by the chemical reactions at the steel surface on the charging side. Results from tests done under potentiostatic and galvanostatic conditions were compared to predictions based on different boundary conditions assumed in solving Fick’s diffusion equations. Constant concentration boundary conditions gave the best fit. It was also found that the diffusible hydrogen generated in a near neutral pH soil environment is likely to be 3 to 10 times lower than the minimum hydrogen concentration required to initiate hydrogen blistering in pipeline steels.

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