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Yi Hua - One of the best experts on this subject based on the ideXlab platform.
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cfd study of heat and mass transfer in ethanol steam reforming in a Catalytic Membrane Reactor
International Journal of Hydrogen Energy, 2017Co-Authors: Bernardo Castrodominguez, Anthony G. Dixon, Yi HuaAbstract:Abstract This work shows the analysis of ethanol steam reforming process within a Catalytic Membrane Reactor. A 2-D non-isothermal CFD model was developed using Comsol Multiphysics, based on previous experimentally validated isothermal model. A comprehensive heat and mass transfer study was carried out utilizing the model. Operating conditions such as liquid hourly space velocity (LHSV) (3.77–37.7 h −1 ), temperature (673–823 K), reaction side pressure (4–10 bar) and permeate side sweep gas flow pattern were discussed. A temperature gradient along the Reactor was observed from the model and a “cold spot” was seen at the Reactor entrance area, which is unfavorable for the highly endothermic ethanol steam reforming process. By changing the sweep gas pattern to counter-current, the “cold spot” appears to be smaller with a reduced temperature drop. By studying the individual reaction rates, reverse methane steam reforming (methanation) was observed, caused by the low temperature in the “cold spot”. Optimal operating conditions were found to be under LHSV = 37.7 h −1 and counter-current sweep gas conditions.
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experimental and simulation studies of the production of renewable hydrogen through ethanol steam reforming in a large scale Catalytic Membrane Reactor
Chemical Engineering Journal, 2016Co-Authors: Bernardo Castrodominguez, Anthony G. Dixon, Ivan P Mardilovich, Yi HuaAbstract:Abstract The diversification of hydrogen production sources has tremendous energy and environmental implications, making ethanol steam reforming (ESR) an essential process that requires further investigation. Hence, the purpose of this work is to investigate the performance of a large-scale Catalytic Membrane Reactor (CMR) used to enhance the efficiency of ESR by the in-situ removal of H2 from the Reactor module. The Reactor consisted of a tubular Membrane located at the center and surrounded by a commercial nickel-based catalyst. A thin, defect-free composite asymmetric Membrane was prepared as a Pd/Au/Pd/Au structure, then characterized and tested under reacting conditions. Ethanol steam reforming was conducted under different conditions such as steam-to-carbon ratios, liquid hourly space velocities (LHSV), operating pressures and temperatures. A 1-D model and a 2-D computational fluid dynamics (CFD) model were developed, validated experimentally and used to explore further the features of this reaction. The CMR module was operated for 300 h showing 100% conversion of ethanol in all conditions and producing H2 with a purity of 99.9%.
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hydrogen production in a large scale water gas shift pd based Catalytic Membrane Reactor
Industrial & Engineering Chemistry Research, 2013Co-Authors: Jacopo Catalano, Federico Guazzone, Ivan P Mardilovich, Nikolaos Kazantzis, Yi HuaAbstract:Composite palladium and Pd-based Membranes represent an appealing technology option to increase the CO conversion and the H2 recovery in the water–gas shift (WGS) Reactor as a result of the continuous removal of hydrogen over the course of the reaction. Even though many studies have been performed in this area, their outcome typically represents a proof-of-concept involving Reactors with small Membrane area. The present study therefore addresses the scaling up of the process to obtain high hydrogen production rates through the use of large surface area, ∼0.02 m2, composite Pd Membranes. Two thin, δ < 10 μm, defect-free composite Membranes were prepared by the electroless plating method on porous stainless steel tubular supports and tested under pure gases and water–gas shift reaction conditions. Syngas similar to the actual gasifier reacting mixture (40% H2, 42.2% CO, and 17.8% CO2 and steam to carbon ratio varying between 2.5 and 3.5) was fed to the WGS Catalytic Membrane Reactor (WGS-CMR) with a total f...
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Modelling of ethylbenzene dehydrogenation in a Catalytic Membrane Reactor
Journal of Membrane Science, 1993Co-Authors: Ying L. Becker, Anthony G. Dixon, William R. Moser, Yi HuaAbstract:Abstract A two-dimensional mathematical model was formulated and solved for a Catalytic Membrane Reactor in a tube-and-shell configuration. The model was compared to experimental conversions for the reversible gas-phase Catalytic dehydrogenation of ethylbenzene to styrene. No adjustable parameters were used; the ceramic Membrane diffusion coefficients and the reaction kinetics for the iron oxide catalyst were determined from independent experiments. The model correctly predicted the 20% increase in conversion over conventional fixed bed operation, when a permselective alumina Membrane was used as the fixed bed Reactor tube. The porous tube wall allowed the selective removal of hydrogen from the catalyst bed. Changes in conversion that occurred when tube- and shell-side flow rates were changed were also correctly predicted. The model predicted a small increase in conversion (2%) when catalyst was deposited in the Membrane wall, which was less than the experimentally observed increase (an average of 10%).
Leon Lorenzen - One of the best experts on this subject based on the ideXlab platform.
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extractor type Catalytic Membrane Reactor with nanocomposite mfi alumina Membrane tube as separation unit prospect for ultra pure para xylene production from m xylene isomerization over pt hzsm 5 catalyst
Applied Catalysis A-general, 2010Co-Authors: M O Daramola, S. Miachon, A J Burger, Anne Giroirfendler, Leon LorenzenAbstract:Abstract This paper is a follow-up on our recent study on the applications of extractor-type zeolite Catalytic Membrane Reactor (herewith referred to as e-ZCMR) for m-Xylene isomerization. In this paper, results of a preliminary investigation on the possibility of producing ultra-pure p-Xylene (PX) (purity > 99%) via m-Xylene (MX) isomerization over Pt-HZSM-5 catalyst in an e-ZCMR with a “defect-free” nanocomposite MFI-alumina Membrane tube as the separation unit is presented. Unlike “film-like” architectures, in nanocomposite architectures zeolite crystals are embedded within the pores of the supports. During m-Xylene isomerization conducted at a temperature range 473–573 K, liquid meta-Xylene (99% purity) saturated in N2 gas was fed into the Reactor and N2 gas was swept over the outer surface of the Membrane on the shell side of the Reactor. Analysis of results was based on permeate-only mode (products in permeate stream only) and combined mode (products in both permeate and retentate) operations. At 473 K, e-ZCMR gave a maximum p-Xylene yield of 2.7% at permeate-only mode and 19.0% at combined mode. Throughout the temperatures investigated, the purity of PX approached 100% in the permeate and the Membrane displayed 100% PX selectivity. These results indicate that there is a possibility of cutting down operational costs through a reduction in energy consumption during ultra-pure PX production and that this becomes feasible with the application of e-ZCMR having nanocomposite MFI-alumina Membrane as separation unit. However, high flux defect-free nanocomposite MFI-alumina Membranes are necessary to make this technology attractive and competitive with those currently in use.
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Xylene isomerization in an extractor type Catalytic Membrane Reactor
Catalysis Today, 2005Co-Authors: Lizelle Van Dyk, Leon Lorenzen, Sylvain Miachon, Jean-alain DalmonAbstract:Abstract A zeolite/alumina pore plugging Membrane was used to successfully separate xylene isomers. It was then applied, as a selective Membrane, in an extractor type Catalytic Membrane Reactor (CMR), used to enhance the xylene isomerization reaction selectivity towards para-xylene. The results of the CMR in different configurations (permeate-only and combined permeate-and-retentate mode) were compared to conventional fixed-bed Reactor results. In both cases, the selectivity was significantly enhanced (up to 100% in permeate-only mode). In the combined mode, the CMR also provided a net increase in productivity over the conventional Reactor.
R. Hughes - One of the best experts on this subject based on the ideXlab platform.
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The Efficient Combustion of O-Xylene in a Knudsen Controlled Catalytic Membrane Reactor
Process Safety and Environmental Protection, 2002Co-Authors: Y. Yildirim, R. HughesAbstract:Catalytic inorganic Membrane preparation and the Catalytic oxidation of o-xylene contained in air streams on Catalytic Membrane tubes are presented in this study. Boehmite prepared sols were deposited onto porous alumina tubes from the outside using a filtration coating technique. The coatings were characterized by nitrogen gas permeations at the same temperatures used for the o-xylene experiments. Single gas permeabilities indicated a best separation factor for the modified Membrane for H 2 /N 2 of 3.6, which is very close to the Knudsen value. Pt loading was estimated as 1.6%w/w based on Membrane material weight by using both weighing and atomic absorption spectrophotometry (AAS) methods. O-xylene Catalytic oxidation of o-xylene contained in air streams with concentrations between 0.146–0.220% (v/v) was carried out in a Catalytic Membrane Reactor at temperatures between 150–290°C and 97% conversion was achieved for 0.146% o-xylene in air at a temperature of 285°C.
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Ethane dehydrogenation in a Catalytic Membrane Reactor coupled with a reactive sweep gas
Chemical Engineering Science, 1995Co-Authors: Edward Gobina, Kaihu Hou, R. HughesAbstract:Abstract An experimental and simulation study has been carried out for the dehydrogenation of ethane to ethylene in a Catalytic Membrane Reactor, with and without reaction on the permeate side. The Membrane comprised a palladium-silver alloy deposited as a thin film on a Vycor glass support and palladium catalyst pellets were packed inside the Membrane tube. Permeation data for the model were determined separately. The differential equations for transport and reaction within the Membrane module were solved using orthogonal collocation to give concentration profiles as a function of contact time, Reactor length and radius. The simulation was validated with experimental data and was observed to correctly predict the increase in conversion with contact time for the range of experimental conditions investigated.
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Equilibrium-shift in alkane dehydrogenation using a high-temperature Catalytic Membrane Reactor
Catalysis Today, 1995Co-Authors: Edward Gobina, Kaihu Hou, R. HughesAbstract:Abstract This study involves the application of a tubular fixed-bed Catalytic Membrane Reactor to effect equilibrium-shift during the Catalytic dehydrogenation of ethane to ethylene and hydrogen. The specific characteristic behaviour of the Reactor to shift the equilibrium was analysed using a two-dimensional mathematical model which was solved using the orthogonal collocation method. An important extrinsic variable, the time factor (W/F Ao ) was manipulated to yield results which were then used to explain Reactor performance. Experimental results showed that under optimal conditions an eight-fold shift in the equilibrium conversion could be attained. Generally, good agreement was obtained between model and experimental predictions for Reactor operation using pure nitrogen as sweep gas. When air was employed as sweep, the agreement was not as expected; possibly due to oxidation of the Pd surface.
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Ethane dehydrogenation using a high-temperature Catalytic Membrane Reactor
Journal of Membrane Science, 1994Co-Authors: Edward Gobina, R. HughesAbstract:Abstract Experiments have been conducted for the dehydrogenation of ethane to ethylene using a high-temperature Catalytic Membrane Reactor under isothermal conditions. Typically, conversions of up to 7 times (cocurrent mode) and 8 times (countercurrent mode) higher than the equilibrium value achievable in conventional fixed-bed Reactors have been attained at high sweep flow rates. The Membrane used in this study was a thin layer of Pd-23 wt% Ag on porous Vycor glass. The significant improvement in the ethane conversion is attributed to the exclusive and continuous permeation of hydrogen through the Membrane.
S. Miachon - One of the best experts on this subject based on the ideXlab platform.
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extractor type Catalytic Membrane Reactor with nanocomposite mfi alumina Membrane tube as separation unit prospect for ultra pure para xylene production from m xylene isomerization over pt hzsm 5 catalyst
Applied Catalysis A-general, 2010Co-Authors: M O Daramola, S. Miachon, A J Burger, Anne Giroirfendler, Leon LorenzenAbstract:Abstract This paper is a follow-up on our recent study on the applications of extractor-type zeolite Catalytic Membrane Reactor (herewith referred to as e-ZCMR) for m-Xylene isomerization. In this paper, results of a preliminary investigation on the possibility of producing ultra-pure p-Xylene (PX) (purity > 99%) via m-Xylene (MX) isomerization over Pt-HZSM-5 catalyst in an e-ZCMR with a “defect-free” nanocomposite MFI-alumina Membrane tube as the separation unit is presented. Unlike “film-like” architectures, in nanocomposite architectures zeolite crystals are embedded within the pores of the supports. During m-Xylene isomerization conducted at a temperature range 473–573 K, liquid meta-Xylene (99% purity) saturated in N2 gas was fed into the Reactor and N2 gas was swept over the outer surface of the Membrane on the shell side of the Reactor. Analysis of results was based on permeate-only mode (products in permeate stream only) and combined mode (products in both permeate and retentate) operations. At 473 K, e-ZCMR gave a maximum p-Xylene yield of 2.7% at permeate-only mode and 19.0% at combined mode. Throughout the temperatures investigated, the purity of PX approached 100% in the permeate and the Membrane displayed 100% PX selectivity. These results indicate that there is a possibility of cutting down operational costs through a reduction in energy consumption during ultra-pure PX production and that this becomes feasible with the application of e-ZCMR having nanocomposite MFI-alumina Membrane as separation unit. However, high flux defect-free nanocomposite MFI-alumina Membranes are necessary to make this technology attractive and competitive with those currently in use.
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Extractor-type Catalytic Membrane Reactor with nanocomposite MFI-alumina Membrane tube as separation unit: Prospect for ultra-pure para-Xylene production from m-Xylene isomerization over Pt-HZSM-5 catalyst
Applied Catalysis A : General, 2010Co-Authors: M O Daramola, S. Miachon, A J Burger, A. Giroir-fendler, L. LorenzenAbstract:This paper is a follow-up on our recent study on the applications of extractor-type zeolite Catalytic Membrane Reactor (herewith referred to as e-ZCMR) for m-Xylene isomerization. In this paper, results of a preliminary investigation on the possibility of producing ultra-pure p-Xylene (PX) (purity > 99%) via m-Xylene (MX) isomerization over Pt-HZSM-5 catalyst in an e-ZCMR with a "defect-free" nanocomposite MFI-alumina Membrane tube as the separation unit is presented. Unlike "film-like" architectures, in nanocomposite architectures zeolite crystals are embedded within the pores of the supports. During m-Xylene isomerization conducted at a temperature range 473-573 K, liquid meta-Xylene (99% purity) saturated in N-2 gas was fed into the Reactor and N-2 gas was swept over the outer surface of the Membrane on the shell side of the Reactor. Analysis of results was based on permeate-only mode (products in permeate stream only) and combined mode (products in both permeate and retentate) operations. At 473 K, e-ZCMR gave a maximum p-Xylene yield of 2.7% at permeate-only mode and 19.0% at combined mode. Throughout the temperatures investigated, the purity of PX approached 100% in the permeate and the Membrane displayed 100% PX selectivity. These results indicate that there is a possibility of cutting down operational costs through a reduction in energy consumption (luring ultra-pure PX production and that this becomes feasible with the application of e-ZCMR having nanocomposite MFI-alumina Membrane as separation unit. However, high flux defect-free nanocomposite MFI-alumina Membranes are necessary to make this technology attractive and competitive with those currently in use. (C) 2010 Elsevier B.V. All rights reserved.
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Catalytic Membrane structure influence on the pressure effects in an interfacial contactor Catalytic Membrane Reactor applied to wet air oxidation
Catalysis Today, 2005Co-Authors: E. E. Iojoiu, Henrik Raeder, J. C. Walmsley, S. Miachon, J A DalmonAbstract:This paper deals with the influence of Catalytic Membrane structure on the way the gas pressure affects the efficiency of a Catalytic Membrane Reactor (CMR). The CMR is an interfacial contactor, used for wet air oxidn., formic acid soln. and air being fed sep. from both sides of the Catalytic Membrane. The gas overpressure can shift the gas-liq. interface into the Membrane wall, closer to the Catalytic zone, and therefore greatly increase the reaction rate. It has been confirmed that this was not an oxygen partial pressure effect. When compared to a conventional slurry Reactor, the contactor CMR showed a reaction rate more than three times higher.
M O Daramola - One of the best experts on this subject based on the ideXlab platform.
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extractor type Catalytic Membrane Reactor with nanocomposite mfi alumina Membrane tube as separation unit prospect for ultra pure para xylene production from m xylene isomerization over pt hzsm 5 catalyst
Applied Catalysis A-general, 2010Co-Authors: M O Daramola, S. Miachon, A J Burger, Anne Giroirfendler, Leon LorenzenAbstract:Abstract This paper is a follow-up on our recent study on the applications of extractor-type zeolite Catalytic Membrane Reactor (herewith referred to as e-ZCMR) for m-Xylene isomerization. In this paper, results of a preliminary investigation on the possibility of producing ultra-pure p-Xylene (PX) (purity > 99%) via m-Xylene (MX) isomerization over Pt-HZSM-5 catalyst in an e-ZCMR with a “defect-free” nanocomposite MFI-alumina Membrane tube as the separation unit is presented. Unlike “film-like” architectures, in nanocomposite architectures zeolite crystals are embedded within the pores of the supports. During m-Xylene isomerization conducted at a temperature range 473–573 K, liquid meta-Xylene (99% purity) saturated in N2 gas was fed into the Reactor and N2 gas was swept over the outer surface of the Membrane on the shell side of the Reactor. Analysis of results was based on permeate-only mode (products in permeate stream only) and combined mode (products in both permeate and retentate) operations. At 473 K, e-ZCMR gave a maximum p-Xylene yield of 2.7% at permeate-only mode and 19.0% at combined mode. Throughout the temperatures investigated, the purity of PX approached 100% in the permeate and the Membrane displayed 100% PX selectivity. These results indicate that there is a possibility of cutting down operational costs through a reduction in energy consumption during ultra-pure PX production and that this becomes feasible with the application of e-ZCMR having nanocomposite MFI-alumina Membrane as separation unit. However, high flux defect-free nanocomposite MFI-alumina Membranes are necessary to make this technology attractive and competitive with those currently in use.
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Extractor-type Catalytic Membrane Reactor with nanocomposite MFI-alumina Membrane tube as separation unit: Prospect for ultra-pure para-Xylene production from m-Xylene isomerization over Pt-HZSM-5 catalyst
Applied Catalysis A : General, 2010Co-Authors: M O Daramola, S. Miachon, A J Burger, A. Giroir-fendler, L. LorenzenAbstract:This paper is a follow-up on our recent study on the applications of extractor-type zeolite Catalytic Membrane Reactor (herewith referred to as e-ZCMR) for m-Xylene isomerization. In this paper, results of a preliminary investigation on the possibility of producing ultra-pure p-Xylene (PX) (purity > 99%) via m-Xylene (MX) isomerization over Pt-HZSM-5 catalyst in an e-ZCMR with a "defect-free" nanocomposite MFI-alumina Membrane tube as the separation unit is presented. Unlike "film-like" architectures, in nanocomposite architectures zeolite crystals are embedded within the pores of the supports. During m-Xylene isomerization conducted at a temperature range 473-573 K, liquid meta-Xylene (99% purity) saturated in N-2 gas was fed into the Reactor and N-2 gas was swept over the outer surface of the Membrane on the shell side of the Reactor. Analysis of results was based on permeate-only mode (products in permeate stream only) and combined mode (products in both permeate and retentate) operations. At 473 K, e-ZCMR gave a maximum p-Xylene yield of 2.7% at permeate-only mode and 19.0% at combined mode. Throughout the temperatures investigated, the purity of PX approached 100% in the permeate and the Membrane displayed 100% PX selectivity. These results indicate that there is a possibility of cutting down operational costs through a reduction in energy consumption (luring ultra-pure PX production and that this becomes feasible with the application of e-ZCMR having nanocomposite MFI-alumina Membrane as separation unit. However, high flux defect-free nanocomposite MFI-alumina Membranes are necessary to make this technology attractive and competitive with those currently in use. (C) 2010 Elsevier B.V. All rights reserved.