Download or read book Novel Composite Hydrogen Permeable Membranes for Non Thermal Plasma Reactors for the Decomposition of Hydrogen Sulfide written by John F. Ackerman and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The goal of this experimental project is to design and fabricate a reactor and membrane test cell to dissociate hydrogen sulfide (H{sub 2}S) in a non-thermal plasma and recover hydrogen (H{sub 2}) through a superpermeable multi-layer membrane. Superpermeability of hydrogen atoms (H) has been reported by some researchers using membranes made of Group V transition metals (niobium, tantalum, vanadium, and their alloys), although it has yet to be confirmed in this study. A pulsed corona discharge (PCD) reactor has been fabricated and used to dissociate H{sub 2}S into hydrogen and sulfur. A nonthermal plasma cannot be produced in pure H{sub 2}S with our reactor geometry, even at discharge voltages of up to 30 kV, because of the high dielectric strength of pure H{sub 2}S ({approx}2.9 times higher than air). Therefore, H{sub 2}S was diluted in another gas with lower breakdown voltage (or dielectric strength). Breakdown voltages of H{sub 2}S in four balance gases (Ar, He, N{sub 2} and H{sub 2}) have been measured at different H{sub 2}S concentrations and pressures. Breakdown voltages are proportional to the partial pressure of H{sub 2}S and the balance gas. H{sub 2}S conversion and the reaction energy efficiency depend on the balance gas and H{sub 2}S inlet concentrations. With increasing H{sub 2}S concentrations, H{sub 2}S conversion initially increases, reaches a maximum, and then decreases. H{sub 2}S conversion in atomic balance gases, such as Ar and He, is more efficient than that in diatomic balance gases, such as N{sub 2} and H{sub 2}. These observations can be explained by the proposed reaction mechanism of H{sub 2}S dissociation in different balance gases. The results show that nonthermal plasmas are effective for dissociating H{sub 2}S into hydrogen and sulfur.
Download or read book Novel Composite Hydrogen Permeable Membranes for Non Thermal Plasma Reactors for the Decomposition of Hydrogen Sulfide written by John F. Ackerman and published by . This book was released on 2006 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The goal of this experimental project is to design and fabricate a reactor and membrane test cell to dissociate hydrogen sulfide (H{sub 2}S) in a non-thermal plasma and recover hydrogen (H{sub 2}) through a superpermeable multi-layer membrane. Superpermeability of hydrogen atoms (H) has been reported by some researchers using membranes made of Group V transition metals (niobium, tantalum, vanadium, and their alloys), although it has yet to be confirmed in this study. Several pulsed corona discharge (PCD) reactors have been fabricated and used to dissociate H{sub 2}S into hydrogen and sulfur. Visual observation shows that the corona is not uniform throughout the reactor. The corona is stronger near the top of the reactor in argon, while nitrogen and mixtures of argon or nitrogen with H{sub 2}S produce stronger coronas near the bottom of the reactor. Both of these effects appear to be explainable base on the different electron collision interactions with monatomic versus polyatomic gases. A series of experiments varying reactor operating parameters, including discharge capacitance, pulse frequency, and discharge voltage were performed while maintaining constant power input to the reactor. At constant reactor power input, low capacitance, high pulse frequency, and high voltage operation appear to provide the highest conversion and the highest energy efficiency for H{sub 2}S decomposition. Reaction rates and energy efficiency per H{sub 2}S molecule increase with increasing flow rate, although overall H{sub 2}S conversion decreases at constant power input. Voltage and current waveform analysis is ongoing to determine the fundamental operating characteristics of the reactors. A metal infiltrated porous ceramic membrane was prepared using vanadium as the metal and an alumina tube. Experiments with this type of membrane are continuing, but the results thus far have been consistent with those obtained in previous project years: plasma driven permeation or superpermeability has not been observed. A new test cell specially designed to test the membranes has been constructed to provide basic science data on superpermeability.
Download or read book NOVEL COMPOSITE HYDROGEN PERMEABLE MEMBRANES FOR NON THERMAL PLASMA REACTORS FOR THE DECOMPOSITION OF HYDROGEN SULFIDE written by and published by . This book was released on 2004 with total page 32 pages. Available in PDF, EPUB and Kindle. Book excerpt: The goal of this experimental project is to design and fabricate a reactor and membrane test cell to dissociate hydrogen sulfide (H2S) in a non-thermal plasma and recover hydrogen (H2) through a superpermeable multi-layer membrane. Superpermeability of hydrogen atoms (H) has been reported by some researchers using membranes made of Group V transition metals (niobium, tantalum, vanadium, and their alloys), although it has yet to be confirmed in this study. Experiments involving methane conversion reactions were conducted with a preliminary pulsed corona discharge reactor design in order to test and improve the reactor and membrane designs using a non-toxic reactant. This report details the direct methane conversion experiments to produce hydrogen, acetylene, and higher hydrocarbons utilizing a co-axial cylinder (CAC) corona discharge reactor, pulsed with a thyratron switch. The reactor was designed to accommodate relatively high flow rates (655 x 10−6 m3/s) representing a pilot scale easily converted to commercial scale. Parameters expected to influence methane conversion including pulse frequency, charge voltage, capacitance, residence time, and electrode material were investigated. Conversion, selectivity and energy consumption were measured or estimated. C2 and C3 hydrocarbon products were analyzed with a residual gas analyzer (RGA). In order to obtain quantitative results, the complex sample spectra were de-convoluted via a linear least squares method. Methane conversion as high as 51% was achieved. The products are typically 50%-60% acetylene, 20% propane, 10% ethane and ethylene, and 5% propylene. First Law thermodynamic energy efficiencies for the system (electrical and reactor) were estimated to range from 38% to 6%, with the highest efficiencies occurring at short residence time and low power input (low specific energy) where conversion is the lowest (less than 5%). The highest methane conversion of 51% occurred at a residence time of 18.8 s with a flow rate of 39.4 x 10−6 m3/s (5 ft3/h) and a specific energy of 13,000 J/l using niobium and platinum coated stainless steel tubes as cathodes. Under these conditions, the First Law efficiency for the system was 8%. Under similar reaction conditions, methane conversions were (almost equal to)50% higher with niobium and platinum coated stainless steel cathodes than with a stainless steel cathode.
Download or read book Novel Composite Hydrogen Permeable Membranes for Nonthermal Plasma Reactors for the Decomposition of Hydrogen Sulfide written by and published by . This book was released on 2007 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The goal of this experimental project was to design and fabricate a reactor and membrane test cell to dissociate hydrogen sulfide (H2S) in a nonthermal plasma and to recover hydrogen (H2) through a superpermeable multi-layer membrane. Superpermeability of hydrogen atoms (H) has been reported by some researchers using membranes made of Group V transition metals (niobium, tantalum, vanadium, and their alloys), but it was not achieved at the moderate pressure conditions used in this study. However, H2S was successfully decomposed at energy efficiencies higher than any other reports for the high H2S concentration and moderate pressures (corresponding to high reactor throughputs) used in this study.
Download or read book Low Cost Hydrogen novel Membrane Technology for Hydrogen Separation from Synthesis Gas Phase 1 Poly etherimide and Poly ether ester amide Membranes written by and published by . This book was released on 1986 with total page 19 pages. Available in PDF, EPUB and Kindle. Book excerpt: During the last quarter several high performance membranes for the separation of hydrogen from nitrogen, carbon monoxide, hydrogen sulfide and carbon dioxide. The heat-resistant resin poly(etherimide) has been selected as the polymer with the most outstanding properties for the separation of hydrogen from nitrogen and carbon monoxide. Flat sheet and hollow fiber poly(etherimide) membranes have been prepared and evaluated with pure gases and gas mixtures at elevated pressures and temperatures. Multilayer composite poly(ether-ester-amide) membranes were also developed. These membranes are useful for the separation of carbon dioxide and hydrogen sulfide hydrogen. They have very high selectivities and extremely high normalized carbon dioxide and hydrogen sulfide fluxes. Separation of carbon dioxide/hydrogen streams is a key problem in hydrogen production from coal. The development of the two membranes now gives us two approaches to separate these gas streams, depending on the stream's composition. If the stream contains small quantities of hydrogen, the hydrogen- permeable poly(etherimide) membrane would be used to produce a hydrogen-enriched permeate. If the stream contains small quantities of carbon dioxide or hydrogen sulfide, the poly(ether-ester-amide) membrane would be used to produce a carbon dioxide/hydrogen sulfide-free, hydrogen-enriched residue stream. 6 fig., 4 tabs.
Download or read book NOVEL COMPOSITE MEMBRANES FOR HYDROGEN SEPARATION IN GASIFICATION PROCESSES IN VISION 21 ENERGY PLANTS written by and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This report describes the work performed, accomplishments and conclusion obtained from the project entitled ''Novel Composite Membranes for Hydrogen Separation in Gasification Processes in Vision 21 Energy Plants'' under the United States Department of Energy Contract DE-FC26-01NT40973. ITN Energy Systems was the prime contractor. Team members included: the Idaho National Engineering and Environmental Laboratory; Nexant Consulting; Argonne National Laboratory and Praxair. The objective of the program was to develop a novel composite membrane structure for hydrogen separation as a key technology module within the future ''Vision 21'' fossil fuel plants. The separation technology module is targeted for use within the gasification module of the ''Vision 21'' fossil fuel plant. The high performance and low-cost manufacturing of the proposed technology will benefit the deployment of ''Vision 21'' fossil fuel plant processes by improving the energy efficiency, flexibility and environmental performance of these plants. Of particular importance is that this technology will also produce a stream of pure carbon dioxide. This allows facile sequestration or other use of this greenhouse gas. These features will benefit the U.S. in allowing for the continued use of domestic fossil fuels in a more energy efficient and environmentally acceptable manner. The program developed and evaluated composite membranes and catalysts for hydrogen separation. Components of the monolithic modules were fabricated by plasma spray processing. The engineering and economic characteristics of the proposed Ion Conducting Ceramic Membrane (ICCM) approach, including system integration issues, were also assessed. This resulted in a comprehensive evaluation of the technical and economic feasibility of integration schemes of ICCM hydrogen separation technology within Vision 21 fossil fuel plants. Several results and conclusion were obtained during this program. In the area of materials synthesis, novel pyrochlore-based proton conductors were identified, synthesized and characterized. They exhibited conductivity as high as 0.03 S/cm at 900 C. Long-term stability under CO2 and H2 atmospheres was also demonstrated. In the area of membrane fabrication by plasma spray processing, the initial results showed that the pyrochlore materials could be processed in a spray torch. Although leak-tight membranes were obtained, cracking, most likely due to differences in thermal expansion, remained a problem. More modeling and experimental work can be used to solve this problem. Finally the techno-economic analyses showed that the ITN ICCM approach for separating H2 is comparable to conventional pressure swing adsorption (PSA) technology in efficiency and economics. Enhanced membrane flux and lower operating temperatures may make the ICCM approach superior to PSA.
Download or read book Hydrogen permeable Composite Metal Membrane and Uses Thereof written by and published by . This book was released on 1993 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Various hydrogen production and hydrogen sulfide decomposition processes are disclosed that utilize composite metal membranes that contain an intermetallic diffusion barrier separating a hydrogen-permeable base metal and a hydrogen-permeable coating metal. The barrier is a thermally stable inorganic proton conductor.
Download or read book NOVEL COMPOSITE MEMBRANES FOR HYDROGEN SEPARATION IN GASIFICATION PROCESSES IN VISION 21 ENERGY PLANTS written by Michael Schwartz and published by . This book was released on 2003 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: ITN Energy Systems, along with its team members, the Idaho National Engineering and Environmental Laboratory, Nexant Consulting, Argonne National Laboratory and Praxair, propose to develop a novel composite membrane structure for hydrogen separation as a key technology module within the future ''Vision 21'' fossil fuel plants. The ITN team is taking a novel approach to hydrogen separation membrane technology where fundamental engineering material development is fully integrated into fabrication designs; combining functionally graded materials, monolithic module concept and plasma spray manufacturing techniques. The technology is based on the use of Ion Conducting Ceramic Membranes (ICCM) for the selective transport of hydrogen. The membranes are comprised of composites consisting of a proton conducting ceramic and a second metallic phase to promote electrical conductivity. Functional grading of the membrane components allows the fabrication of individual membrane layers of different materials, microstructures and functions directly into a monolithic module. Plasma spray techniques, common in industrial manufacturing, are well suited for fabricating ICCM hydrogen separation modules inexpensively, yielding compact membrane modules that are amenable to large scale, continuous manufacturing with low costs. This program will develop and evaluate composite membranes and catalysts for hydrogen separation. Components of the monolithic modules will be fabricated by plasma spray processing. The engineering and economic characteristics of the proposed ICCM approach, including system integration issues, will also be assessed. This will result in a complete evaluation of the technical and economic feasibility of ICCM hydrogen separation for implementation within the ''Vision 21'' fossil fuel plant. The ICCM hydrogen separation technology is targeted for use within the gasification module of the ''Vision 21'' fossil fuel plant. The high performance and low-cost manufacturing of the proposed technology will benefit the deployment of ''Vision 21'' fossil fuel plant processes by improving the energy efficiency, flexibility and environmental performance of these plants. Of particular importance is that this technology will also produce a stream of pure carbon dioxide. This allows facile sequestration or other use of this greenhouse gas. These features will benefit the U.S. in allowing for the continued use of domestic fossil fuels in a more energy efficient and environmentally acceptable manner.
Download or read book Nonporous Inorganic Membranes written by Anthony F. Sammells and published by Wiley-VCH. This book was released on 2006-12-13 with total page 291 pages. Available in PDF, EPUB and Kindle. Book excerpt: This reference book addresses the evolution of materials for both oxygen and hydrogen transport membranes and offers strategies for their fabrication as well as their subsequent incorporation into catalytic membrane reactors. Other chapters deal with, e.g., engineering design and scale-up issues, strategies for preparation of supported thin-film membranes, or interfacial kinetic and mass transfer issues. A must for materials scientists, chemists, chemical engineers and electrochemists interested in advanced chemical processing.
Download or read book Low Cost Hydrogen novel Membranes Technology for Hydrogen Separation from Synthesis Gas Phase 1 Palladium silver poly etherimide Polysulfone poly dimethylsiloxane poly ether esteramide composite Membranes written by and published by . This book was released on 1987 with total page 10 pages. Available in PDF, EPUB and Kindle. Book excerpt: During this quarter, work continued on the development of high-flux palladium-silver membranes for the separation of hydrogen from carbon dioxide. Palladium-silver/poly(etherimide) composite membranes were prepared by a vacuum sputtering technique. The influence of different poly(etherimide) support membranes on the performance of palladium-silver membranes was investigated. All membranes tested showed a hydrogen/carbon dioxide selectivity lower than that of the uncoated poly(etherimide)/poly(dimethylsiloxane) membranes. This is probably due to damage of the skin layer of the asymmetric poly(etherimide) support membranes during the palladium-silver electron bombardment. Polysulfone/poly(dimethylsiloxane)/poly(ether-ester-amide) composite membranes were also prepared. Membrane samples consistently showed a carbon dioxide/hydrogen selectivity of 9 to 10 and a normalized carbon dioxide flux of 2 to 4 × 10−4 cm3 (STP)/cm2{center dot}sec{center dot}cmHg. These are extremely good values, superior to any commercially available membranes for this separation. 2 figs., 4 tabs.
Download or read book Material and Operational Considerations for Effective Use of Palladium Composite Hydrogen Separation Membranes in Ammonia Decomposition Membrane Reactors written by Sean-Thomas B. Lundin and published by . This book was released on 2017 with total page 105 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Low Cost Hydrogen novel Membrane Technology for Hydrogen Separation from Synthesis Gas written by and published by . This book was released on 1990 with total page 137 pages. Available in PDF, EPUB and Kindle. Book excerpt: The production of hydrogen from synthesis gas made by gasification of coal is expensive. The separation of hydrogen from synthesis gas is a major cost element in the total process. In this report we describe the results of a program aimed at the development of membranes and membrane modules for the separation and purification of hydrogen from synthesis gas. The performance properties of the developed membranes were used in an economic evaluation of membrane gas separation systems in the coal gasification process. Membranes tested were polyetherimide and a polyamide copolymer. The work began with an examination of the chemical separations required to produce hydrogen from synthesis gas, identification of three specific separations where membranes might be applicable. A range of membrane fabrication techniques and module configurations were investigated to optimize the separation properties of the membrane materials. Parametric data obtained were used to develop the economic comparison of processes incorporating membranes with a base-case system without membranes. The computer calculations for the economic analysis were designed and executed. Finally, we briefly investigated alternative methods of performing the three separations in the production of hydrogen from synthesis gas. The three potential opportunities for membranes in the production of hydrogen from synthesis gas are: (1) separation of hydrogen from nitrogen as the final separation in a air-blown or oxygen-enriched air-blown gasification process, (2) separation of hydrogen from carbon dioxide and hydrogen sulfide to reduce or eliminate the conventional ethanolamine acid gas removal unit, and (3) separation of hydrogen and/or carbon dioxide form carbon monoxide prior to the shift reactor to influence the shift reaction. 28 refs., 54 figs., 40 tabs.
Download or read book Membrane Engineering for the Treatment of Gases Volume 1 written by Enrico Drioli and published by Royal Society of Chemistry. This book was released on 2017-10-06 with total page 312 pages. Available in PDF, EPUB and Kindle. Book excerpt: Volume 1. Gas-separation issues with membranes -- volume 2. Gas-separation issues combined with membrane reactors.
Download or read book Separation of Hydrogen Using Thin Film Palladium ceramic Composite Membrane written by and published by . This book was released on 1995 with total page 8 pages. Available in PDF, EPUB and Kindle. Book excerpt: The primary objective of this study was to prepare and characterize a hydrogen permselective palladium-ceramic composite membrane for high temperature gas separations and catalytic membrane reactors. Electroless plating method was used as a potential route to deposit a thin palladium film on microporous ceramic substrate. The objectives of the work presented here were to characterize the new Pd-ceramic composite membrane by SEM and EDX analysis and to carry out fundamental permeability measurements of the membrane at elevated temperatures and pressures. The potential application of membranes in high temperature gas separation and reactor technology have been recognized by many investigators. In the coal gasification process, the exit gases are normally hydrogen, carbon monoxide, carbon dioxide, hydrogen sulfide, and water vapor. The objective is to obtain hydrogen from this gas mixture.
Download or read book Palladium Composite Membranes for Hydrogen Production and Separation written by Samhun Yun and published by LAP Lambert Academic Publishing. This book was released on 2012-04 with total page 148 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this work, we developed a new preparation technique for palladium composite membranes which results in an ultra-thin and defect-free selective layer with outstanding performance properties and long life. In the method, a palladium precursor and a reducing agent on opposite sides of a substrate of porous alumina hollow fibers were placed and used an electric field to cause migration of metal ions to the outer surface where they are reduced to form seeds at high concentration in a narrow spatial region. The ethanol steam reforming was conducted in a membrane reactor with the Pd membrane and the performance of this reactor was compared with results from a packed bed reactor under identical conditions. For all conditions studied, enhancement of ethanol conversion and hydrogen yield were observed in the membrane reactor compared to the packed bed reactor.
Download or read book Membrane for Hydrogen Recovery from Streams Containing Hydrogen Sulfide written by and published by . This book was released on 2007 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: A membrane for hydrogen recovery from streams containing hydrogen sulfide is provided. The membrane comprises a substrate, a hydrogen permeable first membrane layer deposited on the substrate, and a second membrane layer deposited on the first layer. The second layer contains sulfides of transition metals and positioned on the on a feed side of the hydrogen sulfide stream. The present invention also includes a method for the direct decomposition of hydrogen sulfide to hydrogen and sulfur.
Download or read book Low Cost Hydrogen novel Membrane Technology for Hydrogen Separation from Synthesis Gas Phase 1 Polyetherimide Cellulose Acetate and Ethylcellulose written by and published by . This book was released on 1986 with total page 8 pages. Available in PDF, EPUB and Kindle. Book excerpt: The goal of this program is to develop polymer membranes useful in the preparation of hydrogen from coal-derived synthesis gas. During this quarter the first experiment were aimed at developing high performance composite membranes for the separation of hydrogen from nitrogen and carbon monoxide. Three polymers have been selected as materials for these membranes: polyetherimide cellulose acetate and ethylcellulose. This quarter the investigators worked on polyetherimide and cellulose acetate membranes. The overall structure of these membranes is shown schematically in Figure 1. As shown, a microporous support membrane is first coated with a high flux intermediate layer then with an ultrathin permselective layer and finally, if necessary, a thin protective high flux layer. 1 fig., 4 tabs.
