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e CO conversion versus reactor length for cases of dense PdeAg MR, silica MR and TR at 623 K, H 2 O/CO ¼ 1 and 3 bar pressure.
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The main purpose of present study is the theoretical analysis and the comparison of inorganic membrane reactor (MR) performances, namely, silica MR performance with respect to dense Pd-Ag MR during water gas shift (WGS) reaction. To this target, a one-dimensional, isothermal numerical model was developed and its validation was realized by literatur...
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... the other hand, Fig. 7 indicates the CO conversion along both MRs length and also versus traditional reactor (TR) length. As corresponding curve for the TR case, in which no membrane is used, it effectively depict the role of membrane in enhancing the conversion. In particular, by using PdeAg membrane, around 10% conversion enhancement was ob- tained with ...
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The main aim of this work is a comprehensive study on a new Hybrid Sorption-Enhanced Membrane Reactor (HSE-MR) concept, in which a Pd-Ag membrane during water gas shift (WGS) reaction was applied. This purpose was performed by integrating both the WGS and CO2 absorption reactions. To avoid the high experimental test costs, for evaluating the HSE-MR...
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... The results of Ethanol steam reforming over a Co/Al 2 O 3 catalyst in a catalytic Pd-Ag membrane reactor indicated that continuous removal of hydrogen from the retentate is necessary to achieve high performance of the reactor. Ghasemzadeh et al. [104] simulated and compared the performance of a water gas shift reaction in a silica membrane reactor and a Pd-Ag reactor. The performance of the silica membrane reactor was 5% lower than that of the dense type. ...
Hydrogen is one of the most efficient and attractive energy carriers that can fulfill current and future energy requirements and address the drawbacks of conventional energy resources. Hydrogen as a fuel is nonmetallic, carbon-free, non-toxic, and has higher specific energy than gasoline (on a mass basis). Hydrogen production, storage, safety, and utilization are the four main aspects that should be considered in hydrogen energy-based systems. This review extensively analyzes the literature on fundamental, technological, and environmental aspects of various hydrogen applications and production techniques as well as theoretical and practical challenges. The global demand for hydrogen is mainly for its utilization in oil refineries (33%), chemical production (40%), metallurgical industries (3%), and the rest is in applications such as fuel, glass manufacturing, welding processes, and food industries. Natural gas, crude oil, coal, and electrolysis processes are the main feedstock sources for hydrogen production, with shares of 49, 29, 18, and 4%, respectively. Currently, hydrocarbon and alcohol reforming, gasification (coal and fossil fuels), and fossil fuel partial oxidation have the greatest shares of the hydrogen production methods. The main challenges for these methods are the high total energy consumption and carbon emissions to the environment. Water electrolysis technologies are still under development and can be combined with renewable energy resources, such as solar, geothermal, wind, and tidal to achieve eco-friendly technologies. Biohydrogen production through biological approaches such as direct and indirect biophotolysis, and photo and dark fermentation processes can be sustainable and promising technologies for bioenergy production worldwide. This review investigates the various thermochemical cycles for hydrogen production and presents the process flow diagram of each cycle. It discusses the different chemical and physical methods and materials for hydrogen storage. In fact, hydrogen storage materials are still lacking in both volumetric and gravimetric density, and in some cases, they do not have promising storage capacity. The current status of hydrogen production, available resources, various challenges in the field of hydrogen production, storage and transportation, and government regulations in North America are discussed.
... Compared to the cryogenic distillation and pressure swing adsorption (PSA) which have been extensively applied as the state of art technology in industry for H 2 separation, the membrane technology is a more economically effective method since no phase change is involved in the separation process if the H 2 -permselective membranes with high performance and low material cost can be achieved. Amongst various hydrogen selective membranes, metallic Pd-based membranes have been studied extensively due to their significant resistance at elevated temperature, high permeability and selectivity towards hydrogen and good mechanical strength [5][6][7][8][9][10][11][12]. However, the Pd-based membranes also have the unavoidable shortcomings such as high price of precious metal palladium, susceptibility to damage by CO and sulfur contaminants and coking, and hydrogen embrittlement as a consequence of the phase transition caused by cycling at different temperatures or hydrogen pressures [13,14]. ...
... Finally, these authors modeled a silica MR during an WGS reaction, theoretically comparing its performance with a Pd-Ag MR [46]. For this purpose, a 1-D isothermal mathematical model was developed and its validation was carried out by using experimental data coming from literature, achieving a good matching between simulation and experimental results. ...
... The simulations showed lower performance for the silica MR in terms of CO conversion and hydrogen recovery with respect to those of the Pd-Ag MR, while the reaction temperature evidenced dual effects at various space velocities for both MRs (Figures 12 and 13). Finally, these authors modeled a silica MR during an WGS reaction, theoretically comparing its performance with a Pd-Ag MR [46]. For this purpose, a 1-D isothermal mathematical model was developed and its validation was carried out by using experimental data coming from literature, achieving a good matching between simulation and experimental results. ...
... CO conversion and hydrogen recovery vs. reaction pressure for the dense Pd-Ag and silica MRs and TR at 623 K, H2O/CO = 1 and three different space velocity values. With permission to reprint from Elsevier by Ghasemzadeh al.[46]. ...
Hydrogen is seen as the new energy carrier for sustainable energy systems of the future. Meanwhile, proton exchange membrane fuel cell (PEMFC) stacks are considered the most promising alternative to the internal combustion engines for a number of transportation applications. Nevertheless, PEMFCs need high-grade hydrogen, which is difficultly stored and transported. To solve these issues, generating hydrogen using membrane reactor (MR) systems has gained great attention. In recent years, the role of silica membranes and MRs for hydrogen production and separation attracted particular interest, and a consistent literature is addressed in this field. Although most of the scientific publications focus on silica MRs from an experimental point of view, this review describes the progress done in the last two decades in terms of the theoretical approach to simulate silica MR performances in the field of hydrogen generation. Furthermore, future trends and current challenges about silica membrane and MR applications are also discussed.
... This reaction provides high theoretical hydrogen yield by extracting more hydrogen atoms from ethanol and water molecules, which provides an important advantage in hydrogen production applications. ESR is the most widely used reaction to generate hydrogen not only with nonrenewable fossil fuels like coal, natural gas, and petroleum but also with renewable raw materials such as ethanol (Kumar et al., 2014;Ghasemzadeh et al., 2016a). The general form of the reaction is as shown: ...
... The layers in graphite interact weakly through van der Waals forces. In terms of properties, graphene is unique; it is a soft membrane and, at the same time, it possesses a high Young's modulus, and good thermal and electrical conductivities (Dreyer et al., 2010;Ghasemzadeh et al., 2016Ghasemzadeh et al., , 2018a. In addition, a single-layer graphene is a zero band gap material and highly transparent, exhibiting an optical transmittance of 97.7%. ...
... These ceramic membranes can be applied at temperatures higher than 600 C, but their flux is too low for practical applications. 6 Metallic membranes for hydrogen separation have been widely probed with Pd-alloy membranes as the state of the art due to their high permeability and infinite selectivity toward H 2 at intermediate temperature regime (300 C-500 C). [11][12][13][14][15][16][17][18] Supporting Information Table S1 (in Appendix S1) summarizes the hydrogen flux values of several typical metallic membranes including Pd, Pd-Ag, Pd-Cu, and Ni reported in literature. [19][20][21][22][23][24][25] Pd-based membranes have the unavoidable shortcomings such as high material cost, susceptibility to damage by CO, hydrocarbon, and sulfur contaminants, and significant hydrogen embrittlement. ...
Cost‐effective and robust nickel (Ni) membrane for H2 separation is a promising technology to upgrade the conventional H2 industries with improved economics and environmental benignity. In this work, Ni hollow fibers (HFs) with one closed end were fabricated and assembled into a membrane module for pure H2 separation by applying vacuum to the permeate side. The separation behavior of the HF module was investigated both experimentally and theoretically. Results indicate that H2 recovery can be improved significantly by changing the operation conditions (temperature or feed pressure). Ni HF is a promising membrane geometry, but the negative effect of pressure drop when H2 passes through the lumen cannot be ignored. Under the vacuum operation mode, there is little difference in term of H2 recovery efficiency whether the feed gas flow is controlled in countercurrent or recurrent operation. This work provides important insight to the development of superior membrane H2 separation system.
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... It should be noted that the main reason of this affinity is that the membrane technology can successfully separate gas mixtures under low pressure, obviously reducing the required industry area and minimizing the necessary energy consumption with relatively low contamination, compared to traditional separation technologies [2][3][4]. Up till now, numerous papers about gas separation membranes are focused on achieving high flux and surprising selectivity [see for example : 5-7]. ...
In the last five recent years, molecular-sieve Graphene Oxide (GO) membranes have shown a great potential to realize high-flux and high-selectivity mixture separation, at low energy cost. Hence, in this study, GO nanocomposite membranes were fabricated on modified -alumina
tubes for hydrogen separation. As a high-performance process, H2-permselective GO membrane derived from graphite source was developed by using a modified hummer method.
In fact, the GO nanocomposite membranes, referred to here as carbon membranes, were prepared via vacuum dip coating of the modified γ-alumina tubes using single-layer GO solution. Special attention was devoted to obtain high H2/CO2 selectivity, high H2 permeance,
and good stability in separation process. Hence, the effects of the operating conditions (temperature, and pressure on quality and performance of the GO membranes) were investigated. At the best condition, the synthesized GO membrane exhibited good H2/CO2
selectivity (>57) and high H2 permeance (in the order of 7.9×10-7 mol.Pa-1.m-2.s-1). Moreover, it was found that the GO membrane selectivities (H2/CO2 and H2/N2) were decreased by temperature increasing, while selectivity trends were improved by increasing pressure gradient. It should be noted that all permeation tests were reported after time durability of around 48 h.
... Angelo Basile is a senior researcher at ITM of the Italian national research council (CNR). His research area includes membrane for gas separation [50,[229][230][231], inorganic membrane reactors [232][233][234][235][236], modelling and simulation aspects [237][238][239][240]. Adolfo Iulianelli, as a researcher at the ITM-CNR works on membrane reactors [240][241][242], fuel cells [243][244][245], gas separation [246,247] and hydrogen production from reforming reactions of renewable sources through inorganic membrane reactors [234,248,249]. Naotsugu Itoh at Utsunomiya University works mainly on functional membranes [250][251][252] and innovative chemical and separation processes [197,[253][254][255][256]. J. Douglas Way in Colorado University focused on application, study, and synthesis of new materials such as metals, microporous oxides and ionic polymers for use in novel separation processes include inorganic membranes and catalytic membrane reactors for fuel cells, applied to energy, environmental and chemical processing applications [21,[257][258][259]. ...
Application of palladium-based membrane technology in chemical reactions is currently focused on producing ultrapure hydrogen. Due to the environmental concerns and undesirable side effects of greenhouse gases, hydrogen has great potential as an alternative future fuel. Pd-alloy membranes have demonstrated tremendous potential for the hydrogen extraction in hydrogen-dependent reactions. Numerous studies have been done investigating the diffusion of hydrogen through palladium membranes. In this review, the ability of Pd-alloy membrane reactors in the removal of hydrogen from water gas shift, steam reforming, and dehydrogenation reactions is evaluated. This review is divided into several sections including palladium membranes, Pd-alloy membranes, composite Pd-based membranes, and their preparation methods Moreover, the hydrogen permeation rate, Sieverts’ law, Damkohler-Peclet product design parameter, and various membrane reactors will be discussed in detail. There is also an overview of the last-decade researches on Pd-based membrane reactors. Finally, some essential ideas for the improvement of future membrane technology are proposed.
... Several simulation or modeling experiments of WGS reaction has been studied to know the performance of WGS reactor. Ghasemzadeh et al.[64] studied the modeling of inorganic membrane reactor performance to WGS reaction. The results showed hydrogen recovery and CO ...
Hydrogen is considered as a promising energy vector which can be obtained from various renewable sources. However, an efficient hydrogen production technology is still challenging. One technology to produce hydrogen with very high capacity with low cost is through water gas shift (WGS) reaction. Water gas shift reaction is an equilibrium reaction that produces hydrogen from syngas mixture by the introduction of steam. Conventional WGS reaction employs two or more reactors in series with inter-cooling to maximize conversion for a given volume of catalyst. Membrane reactor as new technology can cope several drawbacks of conventional reactor by removing reaction product and the reaction will favour towards product formation. Zeolite has properties namely high temperature, chemical resistant, and low price makes it suitable for membrane reactor applications. Moreover, it has been employed for years as hydrogen selective layer. This review paper is focusing on the development of membrane reactor for efficient water gas shift reaction to produce high purity hydrogen and carbon dioxide. Development of membrane reactor is discussed further related to its modification towards efficient reaction and separation from WGS reaction mixture. Moreover, zeolite framework suitable for WGS membrane reactor will be discussed more deeply.
