Steam reforming of heptane in a fluidized bed membrane reactor

Rakib, Muntaha; Grace, John R.; Lim, C. Jim; Elnashaie, S.S.E.H.

doi:10.1016/j.jpowsour.2010.03.072

Cited by 29 publications

(21 citation statements)

References 45 publications

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“…Partil et al, Chen et al, Andrés et al, Rakib et al, Roses et al, and Arratibel et al experimentally explored the topic of hydrogen production from an FBMR by steam or autothermal reforming of methane with in situ removal of hydrogen via Pd‐based dense membranes. H 2 perm‐selective membranes also have been utilized for the water–gas shift reaction and steam reforming of higher hydrocarbons in a fluidized bed reactor to promote the hydrogen yield. Hydrogen perm‐selective membranes can also be used to enhance the dehydrogenation reaction .…”

Section: Introductionmentioning

confidence: 99%

“…Additionally, the bubble‐to‐emulsion phase mass transfer limitation also tends to become more pronounced in an FBMR . The reduction in the volumetric flow rate caused by the gas extraction can affect the bubble properties in the bed . Therefore, explorations of the hydrodynamic effects of the membrane, especially the interaction of the gas extraction/addition with the in‐bed hydrodynamics, are required to improve the performance of FBMR.…”

Section: Introductionmentioning

confidence: 99%

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Effect of gas extraction on the hydrodynamics in a fluidized bed membrane reactor at elevated temperatures

Xiao

Chun

Chen

et al. 2019

Asia-Pacific J Chem Eng

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This study describes experimental explorations on the effects of gas extraction on hydrodynamics in a pilot-scalegas fluidized bed membrane reactor (FBMR) at high temperatures. Differential pressure signals were measured at different vertical intervals in bed and were then characterized by multiscale resolution and power spectra analysis. The experimental results showed that the relative amplitude of σ r (σ/x av ) of pressure signal tended todecrease with the increase of gas extraction fraction.At room temperature, 20% gas extraction caused defluidization at an inlet velocity of 2U mf . However, athigh temperatures the gas extraction simultaneously decreased the magnitude of the low-frequency components and the numbers of the medium-to small-sized structures, mainly due to the decreased number of small-sized structures and the integration of bubbles. This effect of gas extraction increased with increase of gas extraction fraction and slightly decreased at higher inlet gas velocities. At elevated temperatures, the D6 sub-signals (0.781~1.562Hz) possessed the highest wavelet energy distribution percentage of the pressure signals, which meant that the medium-to small-sized bubbles dominated the gas-solid flow dynamics. Gas extraction was observed to enhance the dominance of the D6 scale components..

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Effect of gas extraction on the hydrodynamics in a fluidized bed membrane reactor at elevated temperatures

Xiao

Chun

Chen

et al. 2019

Asia-Pacific J Chem Eng

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“…18,19 In addition, the fluidized bed membrane reactor, which is very linked to the membrane reactor, has been proposed and developed recently by Grace and coworkers and Elnashaie and coworkers. [20][21][22] This type of reactor is similar in that the produced hydrogen is simultaneously extracted by using the membrane. And this reactor can take advantages of fluidized bed reactor in terms of effective utilization of catalysts and maintaining uniformity of reactor temperature.…”

Section: Introductionmentioning

confidence: 99%

Stable equilibrium shift of methane steam reforming in membrane reactors with hydrogen-selective silica membranes

et al. 2010

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Equilibrium shifts of methane steam reforming in membrane reactors consisting of either tetramethoxysilane-derived amorphous hydrogen-selective silica membrane and rhodium catalysts, or hexamethyldisiloxane-derived membrane and nickel catalysts is experimentally demonstrated. The hexamethyldisiloxane-derived silica membrane showed stable permeance as high as 8 Â 10À8 mol m À2 s À1 Pa À1 of H 2 after exposure to 76 kPa of vapor pressure at 773 K for 60 h, which was a much better performance than that from the tetramethoxysilane-derived silica membrane. Furthermore, the better silica membrane also maintained selectivity of H 2 /N 2 as high as 10 3 under the above hydrothermal conditions. The degree of the equilibrium shifts under various feedrate and pressure conditions coincided with the order of H 2 permeance. In addition, the equilibrium shift of methane steam reforming was stable for 30 h with an S/C ratio of 2.5 at 773 K using a membrane reactor integrated with hexamethyldisiloxane-derived membrane and nickel catalyst.

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“…Sci. 2019, 9, 67 2 of 22 separation with reforming reactions, higher reactant conversions were achieved at lower temperatures, and ultra-pure hydrogen flow with purity >99.995% were obtained in the permeate lines [2][3][4][5][6][7]. Another interesting application of membranes is the selective dosing of reactant-mostly oxygen-into a chemical reactor.…”

mentioning

confidence: 99%

“…Additionally, the bubble-to-emulsion phase mass transfer limitation also tends to become more pronounced in a FBMR [1,10]. Variation in the volumetric flowrate caused by gas extraction or addition could affect the pressure drop in the bed [7]. Therefore, research on the hydrodynamic effects of the membrane processes, especially the interaction of gas extraction/addition with in-bed hydrodynamics, is required to improve the performance of FBMRs.…”

mentioning

confidence: 99%

Analysis of the Hydrodynamic Effects of Gas Permeation in a Pilot-Scale Fluidized Bed Membrane Reactor

et al. 2018

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This study experimentally investigates the effects of gas extraction/addition, via multiple vertical membrane panels, on the hydrodynamics in different regions of a pilot-scale gas fluidized bed membrane reactor (FBMR), based on differential pressure signals measured at different vertical bed sections at high temperature. In a bed section where membrane panels were installed and activated, the extraction of gas caused the average bubble size to increase, but decreased the number of small- and medium-sized bubbles. This effect of gas extraction penetrated into bed sections above the active membrane panel, but attenuated with increasing distance away from the extraction location. The attenuation rate was much faster in FBMR with lower bed voidage, mainly due to the large decrease of the drag force exerted by gas extraction on fluidizing gas in a denser bed. With the same inlet gas velocity, gas addition favored the growth of bubbles, especially in the upper bed sections compared with operation without gas permeation. The increase of the effective fluidizing velocity was the major reason for the increase of the bubble size during gas addition. These findings preliminarily suggest that membrane units should not be installed in or below fast-reacting zones in a scale-up FBMR, and operation with a lower bed voidage is preferable to avoid the formation of large bubbles enhanced by gas extraction.

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Steam reforming of heptane in a fluidized bed membrane reactor

Cited by 29 publications

References 45 publications

Effect of gas extraction on the hydrodynamics in a fluidized bed membrane reactor at elevated temperatures

Effect of gas extraction on the hydrodynamics in a fluidized bed membrane reactor at elevated temperatures

Stable equilibrium shift of methane steam reforming in membrane reactors with hydrogen-selective silica membranes

Analysis of the Hydrodynamic Effects of Gas Permeation in a Pilot-Scale Fluidized Bed Membrane Reactor

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