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Methane Coupling By Membrane Reactor Quarterly Technical Progress Report December 25 1994 March 24 1995
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Book Synopsis Methane Coupling by Membrane Reactor. Quarterly Technical Progress Report, December 25, 1994--March 24, 1995 by :
Download or read book Methane Coupling by Membrane Reactor. Quarterly Technical Progress Report, December 25, 1994--March 24, 1995 written by and published by . This book was released on 2001 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Research efforts during this quarter concentrated on two issues. The first issue is related to the chemistry of oxygen conducting materials that could be used as dense membranes in the membrane reactors. Mixed oxides of La, Sr, Fe, Ce, Yb etc., were synthesized, characterized and studied for their catalytic activity towards the oxidative coupling of methane. Heavy metal oxides of lanthanum, strontium and iron, which form good oxygen conductors, showed very poor methane coupling activity. Perovskites of the Strontium-Cerium-Yitribium series showed moderate activity for methane coupling. These could be potential candidates for dense membrane synthesis, since they also have moderate oxygen conduction properties. The second area of research focus was the development of a radial flow catalytic membrane reactor in which methane coupling was carried out over a catalyst that was deposited inside the pores of a ceramic porous membrane. Catalytic results from the high temperature oxidative coupling of methane in these radial flow membrane reactors are presented in this report. By exploring the reactor performance in membranes of pore diameters of 2.0[mu]m, 0.2[mu]m, and 0.02[mu]m, the effect of the diffusional regime on the methane. coupling activity was demonstrated. The smallest pore diameter membranes exhibited lowest hydrocarbon selectivities.
Book Synopsis Methane Coupling by Membrane Reactor. Quarterly Technical Progress Report, December 25, 1995--March 24, 1996 by :
Download or read book Methane Coupling by Membrane Reactor. Quarterly Technical Progress Report, December 25, 1995--March 24, 1996 written by and published by . This book was released on 1996 with total page 15 pages. Available in PDF, EPUB and Kindle. Book excerpt: Methane oxidative coupling experiments were conducted in a packed-bed reactor using La/MgO catalyst. The results were in agreement with those reported in the literature. Oxygen permeability through an oxygen-conductive dense membrane was measured. The oxygen permeability was about 20% of the reported values and increased with the sweep flow rate of helium in the tube side. Blank runs under methane coupling conditions were carried out with no catalyst packed in the dense membrane tube. Nearly 100% CO2 selectivity was observed, suggesting that the membrane material is a facile total oxidation catalyst. After the experiment the membrane tube was analyzed by scanning electron microscopy.
Book Synopsis Neue Kommunalverfassung des Landes Brand ... by :
Download or read book Neue Kommunalverfassung des Landes Brand ... written by and published by . This book was released on with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Methane Coupling by Membrane Reactor. Quarterly Technical Progress Report, March 25, 1995--June 24, 1995 by :
Download or read book Methane Coupling by Membrane Reactor. Quarterly Technical Progress Report, March 25, 1995--June 24, 1995 written by and published by . This book was released on 2001 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Research focus, for the development of a radial flow catalytic membrane reactor for studying methane coupling concentrated on understanding the effects of pore size on improving the hydrocarbon selectivity for the reaction. The effect of pressure on the reaction was also investigated. Experimental results from the catalytic studies of oxidative coupling of methane in the radial flow membrane reactors presented in this report augment earlier work on membranes of pore diameters of 2.0[mu]m, 0.2[mu]m, and 0.02[mu]m, indicating better performance with the larger pore diameter membranes. Higher operating pressures seem to enhance gas phase non-selective reactions during methane coupling. The chemistry of oxygen conducting materials that could be used as dense membranes in the membrane reactors was investigated by studying the catalytic activity of several oxygen conducting perovskites for methane coupling. Heavy metal oxides of lanthanum, strontium and iron, which form good oxygen conductors, showed very poor methane coupling activity. Perovskites of the Strontium-Cerium-Yttribium series showed moderate activity for methane coupling. These could serve as candidates for dense membrane synthesis, since they also have moderate oxygen conduction properties.
Book Synopsis Methane Coupling by Membrane Reactor. Quarterly Technical Progress Report, September 25, 1995--December 24, 1995 by :
Download or read book Methane Coupling by Membrane Reactor. Quarterly Technical Progress Report, September 25, 1995--December 24, 1995 written by and published by . This book was released on 1996 with total page 45 pages. Available in PDF, EPUB and Kindle. Book excerpt: The performance of the third type of catalytic membrane reactor configuration, with catalyst deposited in the membrane and no catalyst or inert materials in the tube side, was evaluated. The C2 selectivity obtained was about 10% due to the gas phase reaction in the empty tube side of the reactor. The membrane reactor with an oxygen-permeable dense membrane has been built. The use of a dense membrane will eliminate the loss of hydrocarbon from the tube side to the shell side, as observed in the Vycor glass membrane reactor. Also, air can be used as the oxygen source without contaminating the product. La/MgO was synthesized and will be used as the catalyst for the dense membrane reactor. This catalyst was reported in the literature to show significant improvement of C2 selectivity and yield for oxidative coupling of methane in a packed-bed reactor by using the operation mode of staged-feed of oxygen. A reactor mode for methane oxidative coupling in reactors with both distributed oxygen feed and C2 product removal was developed based on the general model of cross-flow reactors reported in the last quarterly report. A distributed oxygen feed could give rise to much higher C2 yield than the co-feed reactor as long as the space time is long enough. In the case of a two-membrane reactor, where oxygen is supplied by one membrane and products are removed through the other membrane, a high separation factor of C2 product to methane for the product-removal membrane is critical to achieve high C2 yield.
Book Synopsis Methane Coupling by Membrane Reactor. Quarterly Technical Progress Report, June 25, 1995--September 24, 1995 by :
Download or read book Methane Coupling by Membrane Reactor. Quarterly Technical Progress Report, June 25, 1995--September 24, 1995 written by and published by . This book was released on 1995 with total page 15 pages. Available in PDF, EPUB and Kindle. Book excerpt: The research focus, for the development of a radial flow catalytic membrane reactor for studying methane coupling, concentrated on understanding the effects of pore size, catalyst loading and catalyst distribution inside the membrane, on the hydrocarbon selectivity. The experimental results from the catalytic studies of oxidative coupling of methane in the radial flow membrane reactors are summarized in this report and the reactor performances of three radial flow reactors with pore sizes of 0.02 [mu]m are interpreted by the energy dispersive X-ray digital mapping (EDX) technique. A conventional fixed bed catalytic reactor was set up and run under the same conditions as were used for the radial flow reactor studies. Two sources of samarium oxide catalysts were used in these experiments and their performances were compared in terms of C2 selectivity at same methane conversion. Compared to the monoclinic form of samarium oxide, the catalyst with cubic form was more active and selective for methane oxidative coupling. A general reactor model for oxidation reactions with distributed feed of oxygen and product removal strategies was proposed. Six types of feeding modes were analyzed and their feed distributions were optimized such that the desired product yields at the reactor outlet were maximized.
Book Synopsis Methane Coupling by Membrane Reactor. Quarterly Technical Progress Report, June 25, 1994--September 24, 1994 by :
Download or read book Methane Coupling by Membrane Reactor. Quarterly Technical Progress Report, June 25, 1994--September 24, 1994 written by and published by . This book was released on 1995 with total page 23 pages. Available in PDF, EPUB and Kindle. Book excerpt: This quarterly report describes results from the experimental studies on oxidative coupling of methane, oxygen conducting perovskite dense membrane synthesis and modeling studies of the methane coupling reaction. The focus of the experimental study is to explore the effects of varying catalyst loading, varying methane to oxygen ratios and feed conditions when the oxygen conversion is much less than 100%. Results from these studies help in understanding the effects of various parameters controlling methane coupling. Dense membrane synthesis and characterization results are presented which describe new approaches to the synthesis and characterization of these membranes. The modeling results described in this report present a theoretical fit to the experimental data on oxidative coupling of methane in fixed bed reactors. The parameters from the fit are used to predict the trends in experimental data obtained from VYCOR membrane reactors. The predicted trends are based on a theoretical model employing simplified methane coupling kinetics.
Book Synopsis Methane Coupling by Membrane Reactor, Quarterly Technical Progress Report, September 1994--December 24, 1994 by :
Download or read book Methane Coupling by Membrane Reactor, Quarterly Technical Progress Report, September 1994--December 24, 1994 written by and published by . This book was released on 1995 with total page 18 pages. Available in PDF, EPUB and Kindle. Book excerpt: Experimental studies presented in this report discuss the performance of porous VYCOR membrane reactors in which the oxidative coupling of methane was carried out in an excess of oxygen. This was accomplished by shortening the porous section of the membrane reactor and operating at lower W/F ratios. Results are also discussed from experiments in which methane gas flow was metered in from the high pressure shell side into the oxygen stream on the tube side of the membrane reactor. These studies indicated that the presence of gas phase oxygen downstream to the catalyst bed was detrimental for the C2 selectivity in the methane coupling reaction. Dense membrane synthesis and characterization results are presented which describe new approaches to dense membrane synthesis. Modifications to the 40 Angstrom pore diameter gamma alumina membranes to enhance their stability and pore filling of micron size pores on alpha alumina supports are discussed. Sr{sub 0.8}La{sub 0.2}FeO3, an oxygen conducting perovslcite synthesized in the Microfluidizer showed interesting DSC (Differential Scanning Calorimetry) and TGA (Thermo Gravimetric Analysis) spectra that indicated a change in the crystal structure at relatively moderate temperatures of 150°C and 350°C. This report also presents details of the design and experimental set-up of a catalytic membrane reactor in which the porous membrane is doped with the active catalyst and methane coupling occurs as the reactant gases pass through the membrane pores.
Book Synopsis International Software for Strategic Systems Conference Proceedings ; 3 by :
Download or read book International Software for Strategic Systems Conference Proceedings ; 3 written by and published by . This book was released on 1990 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Methane Coupling by Membrane Reactor. Quarterly Technical Progress Report, March 25--June 24, 1996 by :
Download or read book Methane Coupling by Membrane Reactor. Quarterly Technical Progress Report, March 25--June 24, 1996 written by and published by . This book was released on 1996 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt: The experimental study was continued on methane oxidative coupling using an oxygen-permeable dense membrane reactor. The oxygen permeance through the dense membrane was measured and preliminary experiments were conducted with the catalytic membrane reactor. The oxygen permeance was found to be similar to that obtained earlier without catalyst packing. No C2 hydrocarbons were observed in the catalytic membrane reactor for methane coupling. In order to reduce the non-selective, total oxidation activity of the dense membrane material, the inner surface of the dense membrane tube was deposited by the sol-gel technique with BaCe{sub 0.6}Sm{sub 0.4}O3, which is a catalytic, oxygen-conductive material without total oxidation catalytic activity. The dense membrane tube was examined by XRD before and after the deposition. Catalytic experiments with the coated dense membrane reactor were carried out and higher C2 selectivity was observed than with the co-feed reactor.
Book Synopsis Methane Coupling by Membrane Reactor. Quarterly Technical Progress Report by :
Download or read book Methane Coupling by Membrane Reactor. Quarterly Technical Progress Report written by and published by . This book was released on 1993 with total page 15 pages. Available in PDF, EPUB and Kindle. Book excerpt: Several membranes have been investigated for use in a membrane reactor. Porous VYCOR has been tested for permeability changes with temperature. Three-sectional VYCOR membranes, with a porous central section, have been fabricated and tested in the experimental setup. Catalysts for methane coupling have been reviewed in the literature and five catalysts have been selected. Modeling studies of the methane oxidative coupling reaction in different reactor configurations shows higher C2 selectivity and yield with membrane reactors as compared to conventional packed bed reactors.
Book Synopsis Methane Coupling by Membrane Reactor. Quarterly Technical Progress Report, June 25--September 24, 1997 by :
Download or read book Methane Coupling by Membrane Reactor. Quarterly Technical Progress Report, June 25--September 24, 1997 written by and published by . This book was released on 1997 with total page 19 pages. Available in PDF, EPUB and Kindle. Book excerpt: A new reactor module was constructed as a porous membrane reactor or radial flow reactor for the study of methane oxidative coupling. A Mn-W-Na/SiO2 catalyst was prepared by the slurry mixing method and its catalytic activity was evaluated in a porous alumina membrane reactor. Experimental results showed that the Mn-W-Na/SiO2 catalyst calcined at 900 C was not stable during methane oxidative coupling. After 1,050 C calcination the catalyst became stable, however its activity was not as good as the one prepared by incipient wetness impregnation. The dense membrane tube obtained from Eltron Research Inc. was tested in a membrane reactor for the catalytic oxidative coupling of methane. The Mn-W-Na/SiO2 catalyst prepared by the incipient wetness impregnation method was packed inside the membrane tube. The initial oxygen flux was 0.02 cc/cm2-min. It increased to 0.34 cc/cm2-min after reaction and remained unchanged during a period of 31 days on stream. In a temperature range of 688 C to 977 C, the increase in oxygen flux with temperature obeyed the Arrhenius law. The C2 yield was about 10% at a methane conversion of 20%. The yield of the membrane reactor with Eltron membrane tube was higher than that with the Argonne membrane tube.
Book Synopsis Methane Coupling by Membrane Reactor. Quarterly Technical Progress Report, September 25--December 24, 1996 by :
Download or read book Methane Coupling by Membrane Reactor. Quarterly Technical Progress Report, September 25--December 24, 1996 written by and published by . This book was released on 1997 with total page 16 pages. Available in PDF, EPUB and Kindle. Book excerpt: A new catalyst, 1.9%(wt) Mn-5%(wt) Na2WO4/SiO2 was synthesized by the incipient wetness impregnation method. X-ray diffraction studies of the catalyst calcined at 800 C showed that cristobalite, Na2WO4, and Mn2O3 were the three phases that coexisted in the catalyst. Calcination at 1,000 C resulted in the formation of a new SiO2 phase (tridymite). The new catalyst was characterized by running the methane oxidative coupling reactions in a conventional packed bed reactor. The highest C2 yield obtained was 25%. The Mn-W-Na/SiO2 catalyst was coated on the inside wall of the SrFeCo{sub 0.5}O{sub 3-x} dense membrane tube. A methane oxidative coupling experiment was conducted with the new catalyst in a dense membrane reactor. The oxygen permeance of the dense membrane tube coated with the catalyst was about 0.05 cc/min/cm2 at 850 C. By co-feeding methane and oxygen to the tube side of the reactor, C2 yields up to 7% were observed in these runs. To prepare the membrane tube for the radial flow reactor, silica was deposited on a lanthanum stabilized gamma alumina membrane tube and gas permeances were measured after the membrane tube was calcined at different temperatures. The pressure drop across the membrane was high enough for the membrane to be used in the radial flow reactor.
Download or read book Energy Research Abstracts written by and published by . This book was released on 1995 with total page 782 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Government Reports Announcements & Index by :
Download or read book Government Reports Announcements & Index written by and published by . This book was released on 1996 with total page 756 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Methane Coupling by Membrane Reactor. Quarterly Report, June 25--September 24, 1996 by :
Download or read book Methane Coupling by Membrane Reactor. Quarterly Report, June 25--September 24, 1996 written by and published by . This book was released on 1996 with total page 16 pages. Available in PDF, EPUB and Kindle. Book excerpt: To prevent the deep oxidation of methane catalyzed by the direct contact between methane and the dense membrane material (SrFeCo{sub 0.5}O{sub 3-x}), BaCe{sub 0.6}Sm{sub 0.4}O3 perovskite was coated on the inner surface of the dense membrane tube by the sol-gel technique. Different pretreatment methods were tested to compare their effects on the coated film. The morphology of the coated membrane was studied by SEM. The BaCe{sub 0.6}Sm{sub 0.4}O3-coated membrane which was pretreated with a basic solution before coating was more evenly covered by the coating material. The oxygen permanence through the modified membrane tube were measured at different temperatures. The oxygen permanence were found to be about 70% lower than those of the unmodified tubes. The catalytic runs were carried out with La/MgO catalyst packed inside the membrane tube. The C2 yields obtained using the dense membrane reactor were less than 4%. This may have resulted from the fact that the methane fed to the tube side was still exposed to the uncoated area of the dense membrane surface due to the incomplete coverage of the coating material (BaCe{sub 0.6}Sm{sub 0.4}O3). A hybrid dense membrane reactor, in which the oxygen was supplied by co-feeding oxygen with methane to the tube side and feeding air to the shell side, was used for the oxidative coupling of methane. Again, the inner surface of the membrane tube was coated with BaCe{sub 0.6}Sm{sub 0.4}O3 by the sol-gel technique, and the La/MgO catalyst was packed inside the membrane tube. The oxygen permanence through the membrane tube was found to be about ten times higher than that under non-reaction conditions. C2 yields up to 12% were obtained using the coated dense membrane reactor. These yields are higher than those obtained in an uncoated dense membrane reactor setup with methane and oxygen co-fed into the tube side, where the same catalyst was packed.
Book Synopsis Methane Coupling by Membrane Reactor. First Quarterly Report, 1997 by :
Download or read book Methane Coupling by Membrane Reactor. First Quarterly Report, 1997 written by and published by . This book was released on 1997 with total page 23 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Mn-W-Na/SiO2 catalyst was studied by running the methane coupling reactions at different methane to oxygen ratios, temperatures and dilution gas flow rates. For methane to oxygen ratios less than 3, the C2 yield was almost the same; and C2 yield began to decrease as the methane to oxygen ratio was further increased. The optimal temperature observed was around 800°C, where the C2 yield reached a maximum value. Increasing the dilution gas (helium) flow rate resulted in higher C2 selectivity; however, after a certain dilution gas flow rate the C2 yield began to decrease due to a decrease in methane conversion as a result of the reduced contact time. The stability study of the catalyst showed that, after five successive run cycles, the C2 yield obtained decreased from 24% to 19% at 780 °C, and methane, oxygen and helium flow rates of 12.2, 4.1, and 44. 3 mm/min, respectively. XRD analysis showed that, after the reaction, the XRD peaks of the cristabolite and Na2WO4 phases in the catalyst became smaller than those in the fresh catalyst, and that at least one new, unidentified phase was observed. Mn-W-Na/SiO2 catalyst was used as the methane oxidative coupling catalyst in a porous membrane reactor and its performance was compared with a packed reactor operated at similar conditions. Although the membrane reactor showed lower methane conversion at the same reaction conditions, it gave higher C2 selectivity and C2 yield at similar methane conversions.
