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Zeolite Membranes (zeolite + membrane)

Distribution by Scientific Domains
Chemistry100%

Selected Abstracts

Ceramic membranes for ammonia recovery

AICHE JOURNAL, Issue 6 2006
Olivier Camus
Abstract An extensive screening program has been performed to find a suitable membrane configuration and operating conditions for the effective recovery of ammonia from the syngas loop. All the experiments have been performed at steady state. MFI zeolite membranes in tubular and multi-channel fiber configurations have been tested along with tubular silica membranes. At 80°C, a high ammonia permeance (2.1 × 10,7 mol.m,2.s,1.Pa,1), and a selectivity of about 10 were found with the tubular zeolite membrane, whereas for the silica membrane an even higher ammonia permeance was measured (7.6 x 10,7 mol.m,2.s,1.Pa,1) with a selectivity of about 7. For both silica and zeolite membranes, the selectivity was found to increase with increasing temperature up to 80°C. This is a combined effect of weaker adsorption of ammonia and increased diffusion at higher temperature. The results have been modeled using both the well-mixed reactor and the log mean pressure difference approaches. To overcome their limitations in addressing changes in feed concentration along the membrane surface, a segmental model has been used to obtain suitable operating conditions and membrane areas required for an industrial application. © 2006 American Institute of Chemical Engineers AIChE J, 2006 [source]

Glycerol upgrading by ketalization in a zeolite membrane reactor

ASIA-PACIFIC JOURNAL OF CHEMICAL ENGINEERING, Issue 3 2009
Laura Roldán
Abstract Solketal, a valuable green solvent, has been produced from glycerol and acetone in a catalytic system, using K10 montmorillonite as a heterogeneous catalyst. The use of a zeolite membrane to remove water formed during the reaction gives rise to a significant improvement in the achievable glycerol conversion with a reduction in the excess of acetone needed because of the low equilibrium constant. Several zeolite membranes are compared, showing that the quality of the membrane is a key factor for this improvement, and that water/acetone separation is more difficult to achieve than the commonly used ethanol/water separation test. This method is compatible with a mixture of glycerol and fatty esters, showing the possible future application in an integrated system of biodiesel and solketal production. Copyright © 2009 Curtin University of Technology and John Wiley & Sons, Ltd. [source]

Ceramic membranes for ammonia recovery

AICHE JOURNAL, Issue 6 2006
Olivier Camus
Abstract An extensive screening program has been performed to find a suitable membrane configuration and operating conditions for the effective recovery of ammonia from the syngas loop. All the experiments have been performed at steady state. MFI zeolite membranes in tubular and multi-channel fiber configurations have been tested along with tubular silica membranes. At 80°C, a high ammonia permeance (2.1 × 10,7 mol.m,2.s,1.Pa,1), and a selectivity of about 10 were found with the tubular zeolite membrane, whereas for the silica membrane an even higher ammonia permeance was measured (7.6 x 10,7 mol.m,2.s,1.Pa,1) with a selectivity of about 7. For both silica and zeolite membranes, the selectivity was found to increase with increasing temperature up to 80°C. This is a combined effect of weaker adsorption of ammonia and increased diffusion at higher temperature. The results have been modeled using both the well-mixed reactor and the log mean pressure difference approaches. To overcome their limitations in addressing changes in feed concentration along the membrane surface, a segmental model has been used to obtain suitable operating conditions and membrane areas required for an industrial application. © 2006 American Institute of Chemical Engineers AIChE J, 2006 [source]

Boron-substituted ZSM-5 membranes: Preparation and separation performance

AICHE JOURNAL, Issue 6 2000
Vu A. Tuan
ZSM-5 zeolite membranes with boron substituted into the framework for silicon were prepared on porous stainless-steel and ,-alumina tubular supports. These membranes had higher n-C4H10/i-C4H10 separation selectivities, and effectively separated these isomer mixtures to higher temperatures than membranes with aluminum substituted into the framework. Membranes were prepared with Si/B ratios as low as 12, and the best membranes were prepared from alkali-free gels. The highest n-C4H10/i-C4H10 permselectivity at 473 K was 60, and the highest at 527 K was 24. For most alkali-free membranes, the n-C4H10/i-C4H10 permselectivities and separation selectivities increased with boron content, and membranes on ,-alumina supports had both higher permeances and separation selectivities. Membranes with the same permeances and selectivities can be reproducibly prepared, and they are stable at elevated temperatures. [source]

Glycerol upgrading by ketalization in a zeolite membrane reactor

ASIA-PACIFIC JOURNAL OF CHEMICAL ENGINEERING, Issue 3 2009
Laura Roldán
Abstract Solketal, a valuable green solvent, has been produced from glycerol and acetone in a catalytic system, using K10 montmorillonite as a heterogeneous catalyst. The use of a zeolite membrane to remove water formed during the reaction gives rise to a significant improvement in the achievable glycerol conversion with a reduction in the excess of acetone needed because of the low equilibrium constant. Several zeolite membranes are compared, showing that the quality of the membrane is a key factor for this improvement, and that water/acetone separation is more difficult to achieve than the commonly used ethanol/water separation test. This method is compatible with a mixture of glycerol and fatty esters, showing the possible future application in an integrated system of biodiesel and solketal production. Copyright © 2009 Curtin University of Technology and John Wiley & Sons, Ltd. [source]

A New, Yet Familiar, Lamellar Zeolite

CHEMCATCHEM, Issue 3 2010
Michael Tsapatsis Prof.
Compulsive layers: Lamellar zeolites are crystalline layered materials with porosity within the layers. A recent breakthrough regarding the synthesis of a new lamellar zeolite with the well-known ZSM-5 structure is highlighted in light of previous work on lamellar zeolites and the emerging applications of hierarchical zeolites and zeolitic layers, which include heterogeneous catalysis and zeolite membranes. [source]