Development of pilot WGS/multi-layer membrane for CO 2 capture

Lee, See Hoon; Kim, Jung Nam; Eom, Won Hyun; Ryi, Shin-Kun; Park, Jongsoo; Baek, Il Hyun

doi:10.1016/j.cej.2012.07.013

Cited by 20 publications

(7 citation statements)

References 14 publications

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“…In turn, the equilibria of eqs – were shifted toward the products side, and a high purity of H 2 could be derived directly at the permeation side . Membrane reactors have been extensively employed in steam reforming of natural gas − or higher hydrocarbons, − water shift reaction, , dry reforming of methane, and so forth. A sorption-enhanced reactor where in situ adsorption of CO 2 was integrated with reforming reactions was another available technology to shift the reforming reactions toward the hydrogen side. − Sorption enhanced steam reforming of COG (SE-SRCOG) has been demonstrated to be able to achieve 4.0-fold H 2 amount amplification at 550–650 °C. − A more compact and efficient technique was the membrane-assisted sorption-enhanced steam reforming method (MA-SE-SR), which incorporated sorbents into a membrane reactor, so an extra-high-purity hydrogen stream could be directly obtained, and CO 2 could also be easily enriched by the cyclic reforming/calcination process.…”

Section: Introductionmentioning

confidence: 99%

“…In turn, the equilibria of eqs 1−3 were shifted toward the products side, and a high purity of H 2 could be derived directly at the permeation side. 22 Membrane reactors have been extensively employed in steam reforming of natural gas 23−26 or higher hydrocarbons, 27−29 water shift reaction, 30,31 dry reforming of methane, 32 and so forth. A sorption-enhanced reactor where in situ adsorption of CO 2 was integrated with reforming reactions was another available technology to shift the reforming reactions toward the hydrogen side.…”

Section: ■ Introductionmentioning

confidence: 99%

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Comprehensive Modeling of Sorption-Enhanced Steam Reforming of Coke Oven Gas in a Fluidized Bed Membrane Reactor

et al. 2020

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Integration of membrane hydrogen separation and carbon dioxide capture with fuel steam reforming efficiently promoted hydrogen production and feedstock conversion. In this study, catalytic steam reforming of coke oven gas in a sorption-enhanced fluidized bed membrane reactor (MA-SE-SRCOG) was simulated using a reactive three-fluid model under the Euler framework. The numerical studies provided insights into details about interactions of multiscale subprocesses, including hydrogen permeation, carbon dioxide adsorption, catalytic reforming, and multiphase flow dynamics, during MA-SE-SRCOG. Concentration polarization caused by hydrogen separation was also examined. Meanwhile, impacts of several operating parameters, such as reaction pressure, steam concentration, membrane position, and reactor scale, on the performance of MA-SE-SRCOG were evaluated in terms of CH4 conversion, CO selectivity, hydrogen recovery factor, and CO2 fix factor. The simulation results demonstrated that membrane hydrogen separation and carbon dioxide adsorption promoted reforming kinetics and reactant conversions in the fast reaction zone, and also extended the reactive zone, thus efficiently improving the overall reforming efficiencies. Fast CO2 adsorption kinetics showed more profound enhancements on reducing CO selectivity compared to membrane separation, which instead had greater potential to facilitate high CH4 conversion when membrane effectiveness (a parameter representing impacts of membrane area, layer thickness and composite on permeation rates) was sufficiently large, particularly at high operation pressures. With membrane effectiveness increasing from 1 to 5, a CH4 conversion of 91.3% was achieved by MA-SE-SRCOG at 0.33 MPa and 560 °C, while the H2 permeation flux was augmented from 0.077 mol/(m2·s) to 0.192 mol/(m2·s). However, the increase of membrane effectiveness would cause more serious H2 concentration polarization in FBMR, which inhibited the effective H2 separation rates, so membrane effectiveness >10 has been observed to not remarkably benefit CH4 conversion and H2 production further. High S/C (>6) enhanced the occurrence of larger bubbles, and decreased the driving force (hydrogen partial pressure) for hydrogen permeation, both of which degraded the reforming performances and reduced yield of high purity H2. The more closely membrane units were installed to the fast reaction zone, the larger the enhancements of membrane expected to exert on COG-steam reforming reactions. With the given dimensions of the membrane tube, the decrease of reactor diameter helped to decrease concentration polarization, so higher CH4 conversion and H2 separation factors were achieved.

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Section: Introductionmentioning

confidence: 99%

Section: ■ Introductionmentioning

confidence: 99%

Comprehensive Modeling of Sorption-Enhanced Steam Reforming of Coke Oven Gas in a Fluidized Bed Membrane Reactor

et al. 2020

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“…To shift the steam reforming reaction toward the products side and achieve high conversion of feedstocks at mild operating temperatures, different enhancing technologies were developed. The sorption-enhanced reforming method, which used the proper high-temperature sorbent to capture CO 2 in situ during steam reforming, can achieve high H 2 production and fuel conversion at mild temperature and lower steam/carbon ratio. − Another available technology is the membrane-assisted reforming method, which uses a selective dense metal membrane, usually palladium-based membranes, to separate H 2 from the reactive bed during the reforming process. − To avoid damage of the membrane, the membrane reactor was mostly operated under a temperature < 600 °C. , To achieve a more compact and efficient reforming system, a novel technique has been proposed such as membrane-assisted sorption-enhanced steam reforming (MA-SE-SR), which combined membrane separation and in situ CO 2 sorption into single units. − MA-SE-SR exhibits advantages including the following. (i) The conversion of reactants and selectivity to hydrogen was expected to be further promoted by the synergetic enhancements of CO 2 adsorption and H 2 separation.…”

Section: Introductionmentioning

confidence: 99%

Efficient Hydrogen Production from Coke Oven Gas by Sorption-Enhanced Steam Reforming in a Membrane-Assisted Fluidized Bed Reactor

et al. 2019

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High-purity hydrogen was produced by catalytic steam reforming of coke oven gas (COG) in a fluidized bed membrane reactor (FBMR), assisted by calcined dolomite and a tubular palladium membrane. This membrane-assisted and sorption-enhanced steam-COG reforming process was denoted as MA-SE-SRCOG. A novel bimetallic Ni–Fe/mayenite (Ca12Al14O33) catalyst was first tested in a fixed bed reactor and was then applied to steam reforming of COG in the pilot-scale FBMR. The Ni-0.1Fe/mayenite catalyst showed good sulfur tolerance during steam reforming of COG, and no carbon deposition was detected on the catalyst surface. Partial substitution of “free oxygens” in Ca12Al14O33 by sulfur to form Ca12Al14O32S was observed by XRD characterization. With hydrogen being separated by palladium membrane and CO2 being captured by calcined dolomite, a hydrogen recovery efficiency > 1.7 along with a CH4 conversion of 0.93 and near-zero CO selectivity was achieved by steam reforming of COG at 560 °C, S/C = 4 in the FBMR. Initial CO and H2 contents suppressed conversion of CH4 during steam reforming of COG at specific operating temperature, and restrictions from initial CO were more serious than initial H2. MA-SE-SRCOG efficiently overcame the restrictions of initial CO and H2 and was able to produce over 4.0-fold H2 from COG. A hydrogen permeation flux of 2.14 × 10–2–3.34 × 10–2 mol/m2·s having a purity of >99.9 vol % (with deletion of N2) was obtained at the permeation side. Excessive steam (S/C > 4) was observed to decrease CH4 conversion, which could be ascribed to the decreased residence time of reactants and increased bypassing of reactants through large voids in the reactor at a high S/C ratio. Over high concentration of steam in the reactor side also inhibited permeation of H2. Strong attachment of filler particles on the Pd membrane surface was detected by EPMA analysis, but no metal contents from the catalyst/sorbent were found inside the Pd layer yet after 30 h serving in FBMR.

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“…Steam and some corrosive gases are included, such as H 2 S. Therefore, high thermal, mechanical and chemical stability of the membranes are required for the WGS membrane reactors. To date, several types of inorganic membranes, such as Pd and Pd-based alloy membranes [9][10][11][12][13], silica membranes [14][15][16], and zeolite membranes [17][18][19][20][21], have been studied as WGS membrane reactors for H 2 production.…”

Section: Introductionmentioning

confidence: 99%

“…al. [10] developed a pilot-scale WGS reactor (1 Nm 3 •h -1 feed gas) using Pd-Cu membranes. The CO 2 concentration of retentate flow reached 80 vol.% and the H 2 concentration of permeate flow was over 99 vol.%.…”

Section: Introductionmentioning

confidence: 99%

Tubular dual-layer MFI zeolite membrane reactor for hydrogen production via the WGS reaction: Experimental and modeling studies

Dong

Wang

Rui

et al. 2015

Chemical Engineering Journal

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Water-gas shift (WGS) reaction is an important intermediate step in converting fossil fuels to hydrogen (H 2) for chemical production or power generation. Catalytic membrane reactor with a H 2 perm-selective membrane can improve WGS reaction conversion and separate H 2 from carbon dioxide (CO 2) simultaneously. In this work, experimental work and modeling analysis were performed on WGS in a tubular ZSM-5/silicalite bilayer membrane composed of a 3µm ZSM-5 layer, a 8µm silicalite base layer and a 2µm YSZ barrier layer supported on α-alumina substrate. The experimental and modeling studies demonstrated that temperature, H 2 O/CO ratio, gas hourly space velocity (GHSV) and feed pressure are key factors that determine the WGS performance in the tubular zeolite membrane reactor. At 500 o C and under 5 atm with the H 2 O/CO ratio of 3.0 and GHSV of 72000 h-1 , the CO conversion and H 2 recovery reached 89.8% and 28.5%, respectively. Appropriate temperature, pressure, H 2 O/CO ratio and GHSV are crucial to obtain high reaction performance. Modeling analysis coupled with experimental data identifies the optimum operation conditions (550 o C, feed pressure of 20 atm, H 2 O/CO ratio of 2.0, GHSV of 60000 h-1) under which one can achieve both high CO conversion (>95%) and H 2 recovery (>90%) for WGS in this zeolite membrane reactor.

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Development of pilot WGS/multi-layer membrane for CO 2 capture

Cited by 20 publications

References 14 publications

Comprehensive Modeling of Sorption-Enhanced Steam Reforming of Coke Oven Gas in a Fluidized Bed Membrane Reactor

Comprehensive Modeling of Sorption-Enhanced Steam Reforming of Coke Oven Gas in a Fluidized Bed Membrane Reactor

Efficient Hydrogen Production from Coke Oven Gas by Sorption-Enhanced Steam Reforming in a Membrane-Assisted Fluidized Bed Reactor

Tubular dual-layer MFI zeolite membrane reactor for hydrogen production via the WGS reaction: Experimental and modeling studies

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