Artykuły w czasopismach: „Methane Conversion - Hydrogen”

1

Kushch, S. D., V. E. Muradyan i N. S. Kuyunko. "Methane Conversion over Vacuum Carbon Black: Influence of Hydrogen". Eurasian Chemico-Technological Journal 3, nr 3 (5.07.2017): 163. http://dx.doi.org/10.18321/ectj560.

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Methane pyrolysis over vacuum carbon black has been studied in the temperature range 550–1000 °C. The methane conversion degree and selectivity with respect to ethene and propene do not depend on the initial concentration of methane i.e. the process order with respect to methane is first. The selectivity with respect to pyrolytic carbon is antibate to the methane initial concentration. Hydrogen introduced to methane inhibits formation of pyrolytic carbon and aromatics especially in methane pyrolysis. The methane conversion degree in pyrolysis of methane/hydrogen mixture is inversely proportional to the initial concentration of hydrogen while the selectivity with respect to ethene being symbate to the one. A hypothesis on the reason of inhibition of pyrolytic carbon formation by hydrogen is proposed. Methane pyrolysis is a homogeneous-heterogeneous reaction up to 850°C, but homogeneous reaction is prevalent at the temperature range of maximal selectivity with respect to alkenes.

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Vodopyanov A.V., Mansfeld D.A., Sintsov S.V., Kornev R.A., Preobrazhensky E.I., Chekmarev N.V. i Remez M.A. "Plasmolysis of methane using a high-frequency plasma torch". Technical Physics Letters 48, nr 12 (2022): 29. http://dx.doi.org/10.21883/tpl.2022.12.54942.19383.

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The possibility of converting methane into hydrogen using a high-frequency induction plasma torch at the atmospheric pressure has been experimentally studied. The dependencies of the degree of methane conversion and the rate of hydrogen production were studied depending on the process conditions. It has been demonstrated that the degree of the methane-to-hydrogen conversion can reach values close to 100%. Keywords: methane plasmolysis, HF plasma torch, hydrogen.

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Jin, Zhu, Liang Wang, Erik Zuidema, Kartick Mondal, Ming Zhang, Jian Zhang, Chengtao Wang i in. "Hydrophobic zeolite modification for in situ peroxide formation in methane oxidation to methanol". Science 367, nr 6474 (9.01.2020): 193–97. http://dx.doi.org/10.1126/science.aaw1108.

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Selective partial oxidation of methane to methanol suffers from low efficiency. Here, we report a heterogeneous catalyst system for enhanced methanol productivity in methane oxidation by in situ generated hydrogen peroxide at mild temperature (70°C). The catalyst was synthesized by fixation of AuPd alloy nanoparticles within aluminosilicate zeolite crystals, followed by modification of the external surface of the zeolite with organosilanes. The silanes appear to allow diffusion of hydrogen, oxygen, and methane to the catalyst active sites, while confining the generated peroxide there to enhance its reaction probability. At 17.3% conversion of methane, methanol selectivity reached 92%, corresponding to methanol productivity up to 91.6 millimoles per gram of AuPd per hour.

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Водопьянов, А. В., Д. А. Мансфельд, С. В. Синцов, Р. А. Корнев, Е. И. Преображенский, Н. В. Чекмарев i М. А. Ремез. "Плазмолиз метана при помощи высокочастотного плазмотрона". Письма в журнал технической физики 48, nr 23 (2022): 34. http://dx.doi.org/10.21883/pjtf.2022.23.53950.19383.

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The possibility of converting methane into hydrogen using a high-frequency induction plasma torch at atmospheric pressure has been experimentally studied. The dependencies of the degree of methane conversion and the rate of hydrogen production were studied depending on the process conditions. It has been demonstrated that the degree of conversion of methane to hydrogen can reach values close to 100%.

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Myltykbayeva, L. K., K. Dossumov, G. E. Yergaziyeva, M. M. Telbayeva, А. Zh Zhanatova, N. А. Assanov, N. Makayeva i Zh Shaimerden. "Catalysts for methane conversion process". BULLETIN of the L.N. Gumilyov Eurasian National University. Chemistry. Geography. Ecology Series 134, nr 1 (2021): 44–53. http://dx.doi.org/10.32523/2616-6771-2021-134-1-44-53.

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The article describes current trends in the catalytic processing of natural gas such as partial and deep, also steam oxidation of methane and methane decomposition. Kazakhstan is rich in large energy resources. Therefore, it is important to create new gas chemical technologies that will allow gas resources to produce valuable chemical products. Currently, processes based on these reactions have not been introduced into production. There are highlighted catalyst systems for each reaction that provides good performance. The oxide catalysts based on metals of variable valency are effective in all processes. In the future, it is important to increase the activity of these catalysts. The catalysts were prepared by impregnating the carrier capillary (γ-Al2O3) by incipient wetness and subsequently dried at 2000C (2 h) and calcination at 5000C for three hours. In this article, a catalyst based on nickel-zirconium (3%NiО-2%ZrО2) is active in the partial oxidation of methane to obtain synthesis gas. On this catalyst, the reaction products are H2 - 60.5 vol.%, CO - 30.5 vol.%. On a 3%NiО-7%Со2О3-0,5%Сe2O3 catalyst in the reaction of DRY conversion methane 95.6% and the yield of hydrogen and carbon monoxide is 47.0 and 45.9 vol%, respectively. 29.6% methane is converted even at low temperatures (350°C) on catalyst 3%NiО-2%СеО2/γ-Al2O3 modified with cerium oxide in the reaction of deep oxidation of methane. Iron-based catalysts for the reaction of decomposition of methane to hydrogen gas are effective. On 5 wt.% Fe/ɣ-Al2O3 catalyst at 700°C of reaction of methane conversion was 2%, with an increase in the reaction temperature to 850°C, the methane conversion reached 13%, and the hydrogen yield is increased to 5.8 vol.%.

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Marquardt, Tobias, Sebastian Wendt i Stephan Kabelac. "Impact of Carbon Dioxide on the Non-Catalytic Thermal Decomposition of Methane". ChemEngineering 5, nr 1 (3.03.2021): 12. http://dx.doi.org/10.3390/chemengineering5010012.

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Economically and ecologically, the thermal decomposition of methane is a promising process for large scale hydrogen production. In this experimental study, the non-catalytic decomposition of methane in the presence of small amounts of carbon dioxide was analyzed. At large scales, natural gas or biomethane are possible feedstocks for the thermal decomposition and can obtain up to 5% carbon dioxide. Gas recycling can increase the amount of secondary components even further. Experiments were conducted in a packed flow reactor at temperatures from 1250 to 1350 K. The residence time and the amounts of carbon dioxide and hydrogen in the feed were varied. A methane conversion of up to 55.4% and a carbon dioxide conversion of up to 44.1% were observed. At 1300 K the hydrogen yield was 95% for a feed of methane diluted in nitrogen. If carbon dioxide was added to the feed at up to a tenth with regard to the amount of supplied methane, the hydrogen yield was reduced to 85%. Hydrogen in the feed decreases the reaction rate of the methane decomposition and increases the carbon dioxide conversion.

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Wang, Chang Mei, Wu Di Zhang, Yu Bao Chen, Fang Yin, Shi Qing Liu, Xing Lin Zhao i Jing Liu. "The Efficiency of Material Utilization and Energy Conversion of Biogas Fermentation by Annua". Advanced Materials Research 621 (grudzień 2012): 273–77. http://dx.doi.org/10.4028/www.scientific.net/amr.621.273.

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This paper used annua as material to do a biogas fermentation experiment. The result suggests that biogas-fermentation by pretreated annua is a preferable approach compared with methane production followed by hydrogen production, only methane production, or only hydrogen production, due to its decreasing overall fermentation time, and increasing material utilization efficiency and energy conversion efficiency. It shows that the TS and VS utilization ratio of first hydrogen production then methane production is higher than that of first methane production then hydrogen production.

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Belikov, A. E., V. A. Mal’tsev, O. A. Nerushev, S. A. Novopashin, S. Z. Sakhapov i D. V. Smovzh. "Methane conversion into hydrogen and carbon nanostructures". Journal of Engineering Thermophysics 19, nr 1 (16.02.2010): 23–30. http://dx.doi.org/10.1134/s1810232810010042.

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Zhao, Te, Chusheng Chen i Hong Ye. "CFD Simulation of Hydrogen Generation and Methane Combustion Inside a Water Splitting Membrane Reactor". Energies 14, nr 21 (1.11.2021): 7175. http://dx.doi.org/10.3390/en14217175.

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Hydrogen production from water splitting remains difficult due to the low equilibrium constant (e.g., Kp ≈ 2 × 10−8 at 900 °C). The coupling of methane combustion with water splitting in an oxygen transport membrane reactor can shift the water splitting equilibrium toward dissociation by instantaneously removing O2 from the product, enabling the continuous process of water splitting and continuous generation of hydrogen, and the heat required for water splitting can be largely compensated for by methane combustion. In this work, a CFD simulation model for the coupled membrane reactor was developed and validated. The effects of the sweep gas flow rate, methane content and inlet temperature on the reactor performance were investigated. It was found that coupling of methane combustion with water splitting could significantly improve the hydrogen generation capacity of the membrane reactor. Under certain conditions, the average hydrogen yield with methane combustion could increase threefold compared to methods that used no coupling of combustion. The methane conversion decreases while the hydrogen yield increases with the increase in sweep gas flow rate or methane content. Excessive methane is required to ensure the hydrogen yield of the reactor. Increasing the inlet temperature can increase the membrane temperature, methane conversion, oxygen permeation rate and hydrogen yield.

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10

Le, Thong Nguyen-Minh, Thu Bao Nguyen Le, Phat Tan Nguyen, Trang Thuy Nguyen, Quang Ngoc Tran, Toan The Nguyen, Yoshiyuki Kawazoe, Thang Bach Phan i Duc Manh Nguyen. "Insight into the direct conversion of methane to methanol on modified ZIF-204 from the perspective of DFT-based calculations". RSC Advances 13, nr 23 (2023): 15926–33. http://dx.doi.org/10.1039/d3ra02650g.

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Catalytic oxidation of methane to methanol over oxo-doped ZIF-204 can occur with negligible transition energy barriers. High charge of the doped oxo is effective for methane capturing via hydrogen bonds and for C–H σ-bond weakening.

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Chen, Luning, Zhiyuan Qi, Shuchen Zhang, Ji Su i Gabor A. Somorjai. "Catalytic Hydrogen Production from Methane: A Review on Recent Progress and Prospect". Catalysts 10, nr 8 (2.08.2020): 858. http://dx.doi.org/10.3390/catal10080858.

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Natural gas (Methane) is currently the primary source of catalytic hydrogen production, accounting for three quarters of the annual global dedicated hydrogen production (about 70 M tons). Steam–methane reforming (SMR) is the currently used industrial process for hydrogen production. However, the SMR process suffers with insufficient catalytic activity, low long-term stability, and excessive energy input, mostly due to the handling of large amount of CO2 coproduced. With the demand for anticipated hydrogen production to reach 122.5 M tons in 2024, novel and upgraded catalytic processes are desired for more effective utilization of precious natural resources. In this review, we summarized the major descriptors of catalyst and reaction engineering of the SMR process and compared the SMR process with its derivative technologies, such as dry reforming with CO2 (DRM), partial oxidation with O2, autothermal reforming with H2O and O2. Finally, we discussed the new progresses of methane conversion: direct decomposition to hydrogen and solid carbon and selective oxidation in mild conditions to hydrogen containing liquid organics (i.e., methanol, formic acid, and acetic acid), which serve as alternative hydrogen carriers. We hope this review will help to achieve a whole picture of catalytic hydrogen production from methane.

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12

Ye, Jian Wen, Dong Lai Xie, Zhenhua Yang i Zhiyu Cao. "Simulation of Fluidized Bed Oxygen Permeable Membrane Reactors for Hydrogen Production from Natural Gas". Advanced Materials Research 608-609 (grudzień 2012): 1467–71. http://dx.doi.org/10.4028/www.scientific.net/amr.608-609.1467.

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Hydrogen is an important chemical commodity. Fluidized bed oxygen permeable membrane reactor is a novel technology for hydrogen production from natural gas reforming. An Aspen model is built for this novel reactor. Influences of reaction pressure, oxygen to carbon ratio, and steam to carbon ratio on the hydrogen concentration in syn-gas, hydrogen yield, and reaction temperature and methane conversion are studied. The results are compared with the ordinary fluidized bed reactor. It shows that the fluidized bed oxygen permeable membrane reactor has a higher methane conversion and a hydrogen yield and a higher hydrogen concentration in the syngas, due to its in-situ oxygen separation from air.

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Lu, Yi-heng, Kang Li i Yu-wei Lu. "Microwave-assisted direct synthesis of butene from high-selectivity methane". Royal Society Open Science 4, nr 12 (grudzień 2017): 171367. http://dx.doi.org/10.1098/rsos.171367.

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Methane was directly converted to butene liquid fuel by microwave-induced non-oxidative catalytic dehydrogenation under 0.1–0.2 MPa. The results show that, under microwave heating in a two-stage fixed-bed reactor, in which nickel powder and NiO x –MoO y /SiO 2 are used as the catalyst, the methane–hydrogen mixture is used as the raw material, with no acetylene detected. The methane conversion is more than 73.2%, and the selectivity of methane to butene is 99.0%. Increasing the hydrogen/methane feed volume ratio increases methane conversion and selectivity. Gas chromatography/electron impact ionization/mass spectrometry chromatographic analysis showed that the liquid fuel produced by methane dehydrogenation oligomerization contained 89.44% of butene, and the rest was acetic acid, ethanol, butenol and butyric acid, and the content was 1.0–3.0 wt%.

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Jomnonkhaow, Umarin, Sureewan Sittijunda i Alissara Reungsang. "Hybrid Process for Bio-hydrogen and Methane Production from Hydrogenic Effluent: A Mini Review". Jurnal Kejuruteraan 33, nr 3 (30.08.2021): 385–90. http://dx.doi.org/10.17576/jkukm-2021-33(3)-01.

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Hydrogenic effluent is the effluent from the bio-hydrogen production process via dark fermentation. It mainly consists of volatile fatty acids, residual sugars, and organic solid residues with a high carbon oxygen demand (COD), which prohibits direct discharge to the environment. Therefore, a post-process after dark fermentation to utilize the organic substances in the hydrogenic effluent is needed to complete the organic conversion and reduce the COD load. This review discussed the use of organic substances in the hydrogenic effluent to produce bioenergy, including bio-hydrogen, through photo fermentation and microbial electrolysis cells, and to produce methane by anaerobic digestion. Furthermore, the advantages and disadvantages of using hydrogenic effluent to generate bio-hydrogen and methane and the challenges and future perspectives on utilizing the hydrogenic effluent are discussed.

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Nagai, Masatoshi, i Kenji Matsuda. "Hydrogen Production from Methane Conversion on Molybdenum Nitride". JOURNAL OF CHEMICAL ENGINEERING OF JAPAN 39, nr 5 (2006): 575–79. http://dx.doi.org/10.1252/jcej.39.575.

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Yin, Fang, Wu Di Zhang, Ling Xu, Jing Liu, Hong Yang i Xing Ling Zhao. "Contribution of H₂ during the Two-Phase Anaerobic Digestion". Advanced Materials Research 908 (marzec 2014): 235–38. http://dx.doi.org/10.4028/www.scientific.net/amr.908.235.

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In the process of anaerobic digestion for methane production, one-third of which is from hydrogen, another two-thirds from acetic acid. From the point of material and energy recovery, the energy conversion efficiency of alone hydrogen or methane production is less than co-generation of hydrogen and methane production. Because hydrogen production is also accompanied by acidification and syntrophic acetogenic fermentation process, it is technically feasible for alone hydrogen or methane production. As the two-phase anaerobic digestion separate the acidifying bacteria and methanogens in different reactors, blocking the synergy of the two different microbial community, we should provide scientific and technological support for two-phase anaerobic application.

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Liu, Mengying, Zeai Huang, Yunxiao Zhou, Junjie Zhan, Kuikui Zhang, Mingkai Yang i Ying Zhou. "Optimized Process for Melt Pyrolysis of Methane to Produce Hydrogen and Carbon Black over Ni Foam/NaCl-KCl Catalyst". Processes 11, nr 2 (23.01.2023): 360. http://dx.doi.org/10.3390/pr11020360.

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Methane pyrolysis transforming CH4 into hydrogen without a CO2 byproduct is a potential hydrogen production process under the net-zero emission target. The melt pyrolysis of methane is a technology that could simultaneously obtain hydrogen and carbon products. However, its catalytic activity and stability are still far from satisfactory. In this work, a new strategy for the melt pyrolysis of methane to hydrogen production was proposed using Ni foam and molten NaCl-KCl. The increase in the amount of Ni foam was found to enhance the methane conversion rate from 12.6% to 18%. The process was optimized by the different amounts of catalysts, the height of the Ni foam layer, and the filling method of Ni foam, indicating that the methane conversion rate of the string method could reach 19.2% at 900 °C with the designed aeration device. Furthermore, we observed that the addition of molten salt significantly alleviated the carbon deposition deactivation of the Ni foam and maintained its macrostructure during the reaction. The analysis of the carbon products revealed that carbon black could be obtained.

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Matus, Е. V., I. Z. Ismagilov, E. S. Mikhaylova i Z. R. Ismagilov. "Hydrogen Production from Coal Industry Methane". Eurasian Chemico-Technological Journal 24, nr 2 (25.07.2022): 69. http://dx.doi.org/10.18321/ectj1320.

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Coal industry methane is a fossil raw material that can serve as an energy carrier for the production of heat and electricity, as well as a raw material for obtaining valuable products for the chemical industry. To ensure the safety of coal mining, rational environmental management and curbing global warming, it is important to develop and improve methods for capturing and utilizing methane from the coal industry. This review looks at the scientific basis and promising technologies for hydrogen production from coal industry methane and coal production. Technologies for catalytic conversion of all types of coal industry methane (Ventilation Air Methane – VAM, Coal Mine Methane – CMM, Abandoned Mine Methane – AMM, Coal-Bed Methane – CBM), differing in methane concentration and methane-to-air ratio, are discussed. The results of studies on the creation of a number of efficient catalysts for hydrogen production are presented. The great potential of hybrid methods of processing natural coal and coal industry methane has been demonstrated.

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Konno, Katsuya, Kaoru Onoe, Yasuyuki Takiguchi i Tatsuaki Yamaguchi. "Effect of Coexistent Hydrogen on the Selective Production of Ethane by Dehydrogenative Methane Coupling through Dielectric-Barrier Discharge under Ordinary Pressure at an Ambient Temperature". Journal of Fuels 2014 (1.01.2014): 1–5. http://dx.doi.org/10.1155/2014/286392.

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The effect of coexistence of hydrogen on the product selectivity to ethane from methane by dielectric-barrier discharge (DBD) reactor was examined experimentally under ordinary pressure without use of catalyst and external heating. By the dilution of methane with hydrogen, both the increase of methane conversion and the decrease of alkene production were observed, improving the selectivities to ethane by ca. 70%.

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Karim, G. A., i G. Zhou. "The Uncatalyzed Partial Oxidation of Methane for the Production of Hydrogen With Recirculation". Journal of Energy Resources Technology 115, nr 4 (1.12.1993): 307–13. http://dx.doi.org/10.1115/1.2906437.

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The combustion of rich mixtures of methane representing natural gas in air or oxygenated air involving the uncatalyzed partial oxidation of methane is examined analytically with the view of hydrogen and/or synthesis gas (carbon monoxide and hydrogen) production from natural gas. This is carried out in turn for isothermal, constant pressure and constant volume combustion processes over the feed temperature range of 800–2000K and equivalence ratio of up to 3.5. The role of various operating parameters in establishing the yield of hydrogen is presented and discussed. The effectiveness of the controlled recirculation of combustion gases to the feed for enhancing the reaction and conversion rates of methane into hydrogen is examined. It is shown that there are some conditions that can be employed for such recirculation to yield significant increases in the conversion rate.

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Pinaeva, L. G., i A. S. Noskov. "The modern level of catalysts and technologies for natural gas conversion to syngas". Kataliz v promyshlennosti 21, nr 5 (21.09.2021): 308–30. http://dx.doi.org/10.18412/1816-0387-2021-5-308-330.

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The paper presents an analysis of the main catalysts and technologies applied for industrial conversion of natural gas to syngas, which is further used to produce ammonia, methanol and hydrogen. The analysis reveals the major trends in their development aimed to reduce the consumption of energy and resources; technological schemes of the processes as well as the catalysts and sorbents used in different steps of methane reforming and steam conversion of CO are described.

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Lee, Sunggeun, i Hankwon Lim. "Variation of the Number of Heat Sources in Methane Dry Reforming: A Computational Fluid Dynamics Study". International Journal of Chemical Engineering 2021 (24.11.2021): 1–15. http://dx.doi.org/10.1155/2021/4737513.

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To overcome the weak point of the gas type heating (failure in heating uniformly and persistently), liquid type molten salt as a concentration of solar energy was considered as a heat source for dry reforming. This high-temperature molten salt flowing through the center of the tubular reactor supplies necessary heat. The dependence on the number of heat source of the hydrogen production was investigated under the assumption of the fixed volume of the catalyst bed. By changing these numbers, we numerically investigated the methane conversion and hydrogen flow rate to find the best performance. The results showed that the methane conversion performance and hydrogen flow rate improved in proportion to the number of heating tubes. For the one heat source, the reactor surrounded by a heat source rather than that located in the center is the best in terms of hydrogen yield. In addition, this study considered the case in which the system is divided into several smaller reactors of equal sizes and a constant amount of catalyst. In these reactors, we saw that the methane conversion and hydrogen flow rate were reduced. The results indicate that the installation of as many heating tubes as possible is preferable.

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Yakovenko, R. E., V. B. Ilyin, A. P. Savostyanov, I. N. Zubkov, A. V. Dulnev i O. A. Semyonov. "Conversion of Liquefied Hydrocarbon Gases on Commercial Nickel Catalysts". Kataliz v promyshlennosti 19, nr 6 (14.11.2019): 455–64. http://dx.doi.org/10.18412/1816-0387-2019-6-455-464.

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The two-step conversion of industrial liquefied hydrocarbon gases (LHG) on NIAP-07-01 (NKM-1) and NIAP-03-01 catalysts for the production of hydrogen-containing gases was investigated. The experiments were carried out in flow reactors with a fixed catalyst bed at a pressure of 0.1 MPa under the following conditions: temperature 350–450 °C, gas hourly space velocity (GHSV) 1000–3000 h–1, steam-gas ratio 4 : 1–8 : 1 (pre-reforming); and temperature 700 °C, GHSV 2000 h–1, air-gas ratio 1.2 : 1 (steam-air reforming). Under the studied conditions, the concentrations of components of the converted gas correspond to the equilibrium values calculated within the Peng-Robinson model. The conversion of methane homologs in the pre-reforming step was found to be virtually 100 %; therewith, the methane concentration reached 32–54 %, and that of hydrogen, 24–47 %. To prevent the formation of elemental carbon (carbonization), pre-reforming of hydrocarbon gases with a high methane equivalent should be performed at H2O : C > 2. In the two-step reforming, the yield of hydrogen-containing gas reaches 15.6 m3 from 1 m3 of the initial LHG with the hydrogen content 41.81 %, and the total content of CO and H2 exceeds 52 %.

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Xiao, Yong Shan, Li Yu Chen, Run Xia Lu i Cheng Qian Tang. "Selective Oxidation of Methane to Methanol with Organic Oxidants Catalyzed by Iodine in Non-Aqueous Acetic Acid Medium". Applied Mechanics and Materials 723 (styczeń 2015): 624–28. http://dx.doi.org/10.4028/www.scientific.net/amm.723.624.

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Various organic oxidants including tert-butyl peroxybenzoate, tert-butyl hydroperioxide (TBHP), hydrogen peroxide-urea adduct, dicumyl peroxyide and peracetic acid solution were studied for the oxidation of methane to methanol via methyl acetate catalyzed by iodine in non-aqueous acetic acid medium. Among these organic oxidants investigated, tert-butyl hydroperioxide (TBHP) exhibited the highest methane conversion. The effects of various kinetic factors on the catalytic behavior of the TBHP-I2 system were investigated, and a quantitative yield of methyl acetate (18.9%) based on methane has been obtained under the optimized conditions. A possible mechanism involving electrophilic displacement has been suggested for this reaction.

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Rawool, Sushma A., Rajesh Belgamwar, Rajkumar Jana, Ayan Maity, Ankit Bhumla, Nevzat Yigit, Ayan Datta, Günther Rupprechter i Vivek Polshettiwar. "Direct CO2 capture and conversion to fuels on magnesium nanoparticles under ambient conditions simply using water". Chemical Science 12, nr 16 (2021): 5774–86. http://dx.doi.org/10.1039/d1sc01113h.

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We demonstrated the use of magnesium nanoparticles (and bulk) to convert CO₂ (pure & also from the air) to methane, methanol, formic acid and green cement without external energy within a few minutes, using only water as the sole hydrogen source.

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Rusdan, Nisa Afiqah, Sharifah Najiha Timmiati, Wan Nor Roslam Wan Isahak, Zahira Yaakob, Kean Long Lim i Dalilah Khaidar. "Recent Application of Core-Shell Nanostructured Catalysts for CO2 Thermocatalytic Conversion Processes". Nanomaterials 12, nr 21 (2.11.2022): 3877. http://dx.doi.org/10.3390/nano12213877.

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Carbon-intensive industries must deem carbon capture, utilization, and storage initiatives to mitigate rising CO2 concentration by 2050. A 45% national reduction in CO2 emissions has been projected by government to realize net zero carbon in 2030. CO2 utilization is the prominent solution to curb not only CO2 but other greenhouse gases, such as methane, on a large scale. For decades, thermocatalytic CO2 conversions into clean fuels and specialty chemicals through catalytic CO2 hydrogenation and CO2 reforming using green hydrogen and pure methane sources have been under scrutiny. However, these processes are still immature for industrial applications because of their thermodynamic and kinetic limitations caused by rapid catalyst deactivation due to fouling, sintering, and poisoning under harsh conditions. Therefore, a key research focus on thermocatalytic CO2 conversion is to develop high-performance and selective catalysts even at low temperatures while suppressing side reactions. Conventional catalysts suffer from a lack of precise structural control, which is detrimental toward selectivity, activity, and stability. Core-shell is a recently emerged nanomaterial that offers confinement effect to preserve multiple functionalities from sintering in CO2 conversions. Substantial progress has been achieved to implement core-shell in direct or indirect thermocatalytic CO2 reactions, such as methanation, methanol synthesis, Fischer–Tropsch synthesis, and dry reforming methane. However, cost-effective and simple synthesis methods and feasible mechanisms on core-shell catalysts remain to be developed. This review provides insights into recent works on core-shell catalysts for thermocatalytic CO2 conversion into syngas and fuels

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Ma, P. Y., Zhi Guo Tang, Y. L. Li, C. H. Nie, X. Z. He i Q. Z. Lin. "Conversion of Natural Gas to Hydrogen under Super Adiabatic Rich Combustion". Advanced Materials Research 105-106 (kwiecień 2010): 701–5. http://dx.doi.org/10.4028/www.scientific.net/amr.105-106.701.

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Interest in fuel cells in recent years has promoted the development of hydrogen sources. Methane (the main composition of natural gas) is an optimal fuel for hydrogen production due to its rich resource and its high ratio of hydrogen to carbon. In this work, several hydrogen processes, such as steam reforming of methane, partial oxidation, and auto thermal reforming, were reviewed. Different processes exhibit different importance for hydrogen production due to their diversity on usages. In this paper the special method of natural hydrogen production from natural gas with super adiabatic rich combustion is depicted in details. Some problems of this method were analyzed and discussed. In view of the existing problems, a new method was developed to be used for conversion of natural gas to hydrogen. The method can solve the problems of flame drift, heat preservation, product cooling, and low transform efficiency. Due to its simple and compact structure, it is attractive for distributing hydrogen production system and solving the transportation and storage problems of hydrogen.

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Weijma, J., i A. J. M. Stams. "Methanol conversion in high-rate anaerobic reactors". Water Science and Technology 44, nr 8 (1.10.2001): 7–14. http://dx.doi.org/10.2166/wst.2001.0452.

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An overview on methanol conversion in high-rate anaerobic reactors is presented, with the focus on technological as well as microbiological aspects. The simple C1-compound methanol can be degraded anaerobically in a complex way, in which methanogens, sulfate reducing bacteria and homoacetogens interact cooperatively or competitively at substrate level. This interaction has large technological implications as it determines the final product of methanol mineralization, methane or carbon dioxide. The degradation route of methanol may be entirely different when environmental conditions change. Direct methanogenesis from methanol seems the predominant mineralization route under mesophilic conditions both in the absence and the presence of sulfate. Under thermophilic conditions methanol oxidation to carbon dioxide and hydrogen appears to play an important role. The UASB technology for mesophilic digestion of methanolic waste has presently reached full-scale maturity. The potential of methanol as feedstock for anaerobic processes is discussed.

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Madon, Rais Hanizam, Mas Fawzi, Khairul Ilman Sarwani, Shahrul Azmir Osman, Mohd Azahari Razali i Abdul Wahab Mohammad. "Effect of Steam to Carbon Ratio (S:C) on Steam Methane Reforming’s yield over Coated Nickel Aluminide (Ni3Al) Catalyst in Micro Reactor". Jurnal Kejuruteraan 32, nr 4 (30.11.2020): 657–62. http://dx.doi.org/10.17576/jkukm-2020-32(4)-14.

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This work looks into the effect of Steam to Carbon ratio (S:C) on methane (CH4) conversion and hydrogen (H2) yield over coated Nickel Aluminide (Ni3Al) catalyst in micro reactor. The Ni3Al is an intermetallic alloy which known to have good catalytic activity and selectivity. The Ni3Al catalyst precursor was prepared through dip coating technique at 10wt% on top of substrate plate and characterized by X-Ray Diffraction (XRD), Scanning Electron Microscope-Energy Dispersive X-Ray Spectroscopy (SEM-EDX), Temperature Programming Reduction (TPR), activated by H2 reduction, and catalytic activity test in steam methane reforming (SMR) reaction in micro reactor at S:C 2, S:C 3 and S:C 4 with 650°C reaction temperature and 300 minutes reaction time. The characterization showed the presence of Ni3Al on top of the coating surface and successfully been activated at 500°C and 46 minutes. The CH4 conversion and H2 yield in the product of the reaction were quantified using the Gas Chromatograph technique. From the series of experiments, it was found that S:C 4 produced the highest methane conversion of 65.56% and S:C 3 produced the highest hydrogen yield of 41.34%. The S:C 2, showed faster and smoother stability trend conversion as early as 180 minutes from the start of the reaction. However, S:C 3 showed the most optimum methane conversion and hydrogen yield and achieved stability trend conversion within the defined reaction time range of 300 minutes. It is inferred that the S:C 3 is the best steam to carbon ratio for the developed catalyst in these settings.

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Garduño, M., Marquidia Pacheco, Joel Pacheco, Ricardo Valdivia, Alfredo Santana, Benoîte Lefort, Nadia Estrada i C. Rivera-Rodríguez. "Hydrogen production from methane conversion in a gliding arc". Journal of Renewable and Sustainable Energy 4, nr 2 (marzec 2012): 021202. http://dx.doi.org/10.1063/1.3663876.

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Yao, Shuiliang, Akira Nakayama i Eiji Suzuki. "Acetylene and hydrogen from pulsed plasma conversion of methane". Catalysis Today 71, nr 1-2 (listopad 2001): 219–23. http://dx.doi.org/10.1016/s0920-5861(01)00432-1.

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Yamani, Zain H. "Clean Production of Hydrogen via Laser-Induced Methane Conversion". Energy Sources 27, nr 8 (czerwiec 2005): 661–68. http://dx.doi.org/10.1080/00908310490449351.

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Andersen, Arnfin, Ivar M. Dahl, Klaus-Joachim Jens, Erling Rytter, Åse Slagtern i Åge Solbakken. "Hydrogen acceptor and membrane concepts for direct methane conversion". Catalysis Today 4, nr 3-4 (luty 1989): 389–97. http://dx.doi.org/10.1016/0920-5861(89)85035-7.

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Msheik, Malek, Sylvain Rodat i Stéphane Abanades. "CFD Simulation of a Hybrid Solar/Electric Reactor for Hydrogen and Carbon Production from Methane Cracking". Fluids 8, nr 1 (2.01.2023): 18. http://dx.doi.org/10.3390/fluids8010018.

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Methane pyrolysis is a transitional technology for environmentally benign hydrogen production with zero greenhouse gas emissions, especially when concentrated solar energy is the heating source for supplying high-temperature process heat. This study is focused on solar methane pyrolysis as an attractive decarbonization process to produce both hydrogen gas and solid carbon with zero CO2 emissions. Direct normal irradiance (DNI) variations arising from inherent solar resource variability (clouds, fog, day-night cycle, etc.) generally hinder continuity and stability of the solar process. Therefore, a novel hybrid solar/electric reactor was designed at PROMES-CNRS laboratory to cope with DNI variations. Such a design features electric heating when the DNI is low and can potentially boost the thermochemical performance of the process when coupled solar/electric heating is applied thanks to an enlarged heated zone. Computational fluid dynamics (CFD) simulations through ANSYS Fluent were performed to investigate the performance of this reactor under different operating conditions. More particularly, the influence of various process parameters including temperature, gas residence time, methane dilution, and hybridization on the methane conversion was assessed. The model combined fluid flow hydrodynamics and heat and mass transfer coupled with gas-phase pyrolysis reactions. Increasing the heating temperature was found to boost methane conversion (91% at 1473 K against ~100% at 1573 K for a coupled solar-electric heating). The increase of inlet gas flow rate Q0 lowered methane conversion since it affected the gas space-time (91% at Q0 = 0.42 NL/min vs. 67% at Q0 = 0.84 NL/min). A coupled heating also resulted in significantly better performance than with only electric heating, because it broadened the hot zone (91% vs. 75% methane conversion for coupled heating and only electric heating, respectively). The model was further validated with experimental results of methane pyrolysis. This study demonstrates the potential of the hybrid reactor for solar-driven methane pyrolysis as a promising route toward clean hydrogen and carbon production and further highlights the role of key parameters to improve the process performance.

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Nichols, Eva M., Joseph J. Gallagher, Chong Liu, Yude Su, Joaquin Resasco, Yi Yu, Yujie Sun, Peidong Yang, Michelle C. Y. Chang i Christopher J. Chang. "Hybrid bioinorganic approach to solar-to-chemical conversion". Proceedings of the National Academy of Sciences 112, nr 37 (24.08.2015): 11461–66. http://dx.doi.org/10.1073/pnas.1508075112.

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Natural photosynthesis harnesses solar energy to convert CO2and water to value-added chemical products for sustaining life. We present a hybrid bioinorganic approach to solar-to-chemical conversion in which sustainable electrical and/or solar input drives production of hydrogen from water splitting using biocompatible inorganic catalysts. The hydrogen is then used by living cells as a source of reducing equivalents for conversion of CO2to the value-added chemical product methane. Using platinum or an earth-abundant substitute, α-NiS, as biocompatible hydrogen evolution reaction (HER) electrocatalysts andMethanosarcina barkerias a biocatalyst for CO2fixation, we demonstrate robust and efficient electrochemical CO2to CH4conversion at up to 86% overall Faradaic efficiency for ≥7 d. Introduction of indium phosphide photocathodes and titanium dioxide photoanodes affords a fully solar-driven system for methane generation from water and CO2, establishing that compatible inorganic and biological components can synergistically couple light-harvesting and catalytic functions for solar-to-chemical conversion.

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Ghasemzadeh, Kamran, Ehsan Andalib i Angelo Basile. "Modelling Study of Palladium Membrane Reactor Performance during Methan Steam Reforming using CFD Method". Chemical Product and Process Modeling 11, nr 1 (1.03.2016): 17–21. http://dx.doi.org/10.1515/cppm-2015-0055.

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Abstract The main aim of this study is the investigation of dense palladium membrane reactor (MR) performance during methane steam reforming (MSR) reaction using computational fluid dynamic (CFD). To this purpose, a two-dimensional isothermal CFD model was developed and its validation was realized by comparing the theoretical results with our experimental data achieved in ITM of Italy. In this work, the CFD model was presented by COMSOL- Multiphysics software version 5. The reaction rate expressions and kinetics parameters were used from literatures. According to validation results, a good agreement between modeling results and experimental data was found. After model validation, the effect of the some important operating parameters (temperature and pressure) on the performance of palladium MR was studied in terms of methane conversion and hydrogen recovery. The CFD model presented velocity and pressure profiles in both side of MR and also molar fraction of different species in permeate and retentate streams. The modeling results showed that the palladium MR presents comparable performance with respect to traditional reactor (TR) in terms of the methane conversion, especially, at lower temperatures and higher pressures. In fact, CFD results indicated that palladium MR performance was improved by increasing the reaction pressure, while this parameter had negative effect on the TR performance. This result related to increasing the hydrogen permeance through the palladium membrane by enhancement of pressure gradient. Indeed, this shift effect can provide a higher methane conversion in lower temperatures in the palladium MR. In particular, 99% methane conversion and 43% hydrogen recovery was achieved at 500°C and 1.5 atm.

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Vavilin, V. A., L. Ya Lokshina, S. V. Rytov, O. R. Kotsyurbenko, A. N. Nozhevnikova i S. N. Parshina. "Modelling methanogenesis during anaerobic conversion of complex organic matter at low temperatures". Water Science and Technology 36, nr 6-7 (1.09.1997): 531–38. http://dx.doi.org/10.2166/wst.1997.0633.

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Low temperature consumption of H2/CO2 by microflora of tundra wetland soil and pond silt were simulated using the modified <METHANE> model with consideration of homoacetogens or hydrogen consuming methanogens as hydrogenotrophs. Simulations show that the model with homoacetogens was able to fit the data closely. Under the conditions of high initial hydrogen concentrations acetate was the main precursor of methane. Inhibition of acetoclasic methanogens proved to be significant for tundra soil samples. Methane formation from organic matter contained in the samples of tundra soil was modeled in the wide range of temperature conditions. It was concluded that hydrolysis is the rate-limiting step at 10–28°C, but at 6°C the rate of acetoclastic methanogenesis becomes the rate-limiting stage in methane production. To describe the low temperature methane formation from organic matter by microflora of pond silt, cattle's and pig's manure the alternative pathways with participation of homoacetogens or hydrogenotrophic methanogens were verified. It was shown that the both pathways fit the measured data comparatively well.

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Wnukowski, Mateusz, Julia Gerber i Karolina Mróz. "Shifts in Product Distribution in Microwave Plasma Methane Pyrolysis Due to Hydrogen and Nitrogen Addition". Methane 1, nr 4 (15.11.2022): 286–99. http://dx.doi.org/10.3390/methane1040022.

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Methane pyrolysis can produce many valuable products besides hydrogen, e.g., C2 compounds or carbon black. In the conditions provided by microwave plasma, the distribution of these products might be shifted by the addition of hydrogen and nitrogen. In this work, different ratios of H2:CH4, ranging from 0:1 to 4:1, were tested. The most unambiguous and promising result was obtained for the highest H2:CH4 ratio. For this ratio, a significant improvement in methane conversion rate was observed (from 72% to 95%) along with the increase in C2H2 and C2H4 yield and selectivity. The results support the hypothesis that the H radicals present in the plasma are responsible for improving methane conversion, while the presence of molecular hydrogen shifts the product distribution towards C2 compounds. Based on the carbon balance, the increase in the output of C2 compounds was obtained at the cost of solid carbon. At the same time, the addition of hydrogen resulted in the formation of bigger carbon particles. Finally, with the addition of both nitrogen and hydrogen, the formation of carbon was completely inhibited. Hydrogen cyanide was the main product formed instead of soot and some of the acetylene.

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Hong, Kyungpyo, Stephanie Nadya Sutanto, Jeong A. Lee i Jongsup Hong. "Ni-based bimetallic nano-catalysts anchored on BaZr0.4Ce0.4Y0.1Yb0.1O3−δ for internal steam reforming of methane in a low-temperature proton-conducting ceramic fuel cell". Journal of Materials Chemistry A 9, nr 10 (2021): 6139–51. http://dx.doi.org/10.1039/d0ta11359j.

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Ni–Rh and Ni–Co nano-scale alloys exhibit high methane conversion, hydrogen yield, resistance to carbon formation, and long-term stability at low temperatures, allowing them to cope with the various operating conditions of direct methane-fueled PCFCs.

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Arutyunov, V. S., L. N. Strekova i A. V. Nikitin. "Partial Oxidation of Light Alkanes as a Base of New Generation of Gas Chemical Processes". Eurasian Chemico-Technological Journal 15, nr 4 (15.10.2013): 265. http://dx.doi.org/10.18321/ectj231.

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Recent developments in unconventional natural gas production increase the need for principally new small-scale technologies for gas processing and transportation. The promising way for small-scale gas processing is its autothermal partial oxidation to syngas or direct partial oxidation to chemicals. The paper considers some prospective gas chemical processes based on the partial oxidation of light alkanes. Among them are the conversion of natural gas to syngas in volumetric (3D) matrix burners made of a gas permeable material and direct conversion of methane to methanol without its preliminary conversion to syngas (DMTM). As a more simple technology that lets to use fat associated oil gas often flaring in remote sites, it can be suggested the selective oxidative cracking of heavier components of natural gas. This process converts heavy methane homologues from propane to pentane and heavier into ethylene, methane, ethane, hydrogen, and carbon monoxide, thus increasing methane index (octane number) of gas and making it suitable for feeding modern gas piston and gas turbine power engines. One more interesting prospect is the creation of technologies making use of the subsequent processing of valuable oxycracking products, such as olefins, CO, and hydrogen, for example, by their catalytic co-polymerization without preliminary separation from gas phase. The co-polymerization of CO and ethylene, followed by the separation of resulting liquid products, can considerably improve the economic attractiveness of the oxycracing process. Thus, despite the absence of economically proved and industrial-scale tested smallcapacity direct and indirect gas chemical technologies, intensive efforts to develop such alternative technologies let to expect near bright future for them.

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Ravil Mustafin i Igor Karpilov. "Effect of the Catalyst Shapes and the Packed Bed Structure on the Efficiency of Steam Methane Reforming". Journal of Advanced Research in Fluid Mechanics and Thermal Sciences 104, nr 1 (3.04.2023): 124–40. http://dx.doi.org/10.37934/arfmts.104.1.124140.

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One of the promising technologies for on-board hydrogen production is methane steam reforming in reactor with packed bed. The study of the effect of various catalytic packing arrangements on the steam methane reforming process is of considerable interest. The present article analyses the influence of catalyst shapes and packing arrangement on steam methane reforming reactions efficiency. The reformer tube contains several packings with a changing relative position; additionally, two forms of catalysts, a ball and a cylinder, are also used. The pressure drop depending on the packing location, methane conversion and hydrogen yield were analysed. It was found that the packing arrangement with spacing allows better distribution of the supplied heat. Due to the distance between the packing sections flow becomes more turbulent after each section, which intensifies the heat transfer and mixing of the mixture. The highest hydrogen yield is observed on catalytic packings located at a distance of 40 mm from each other and consisting of cylindrical catalysts. The most uniform pressure drop occurs at a packing arrangement without spacing. The increase in methane conversion observed with the increment in spacing distance, but the difference is insignificant. Therefore, the arrangement of catalysts with spacing can be used for the improvement of steam methane reforming process.

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Trianto, Azis, Ira Santrina J. C i Susilo Yuwono. "Simulasi produksi hidrogen melalui CO₂ methane reforming pada reaktor membran". Jurnal Teknik Kimia Indonesia 6, nr 3 (2.10.2018): 666. http://dx.doi.org/10.5614/jtki.2007.6.3.2.

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Hydrogen is a promising alternative fuel to establish environmentally friendly energy generation system. One of the methods for producing hydrogen is C02 methane reforming (CMR) process. Despite producing H2, this process also consumes CO2 enabling it to be used as a scheme for mitigating CO2. Conventionally, the hydrogen production via CMR is conducted in a fixed bed reactor. However low conversion is usually found in this kind of reactor. To increase conversion, a membrane reactor can be used. Two types of membrane may be employed to conduct this reaction, i.e. prorous vycor and nanosil membrane reactor. This study evaluated the performances of CMR con 1ucted in membrane ractors andfixed-bed reactor. The results show that the conversion obtained in nanosil membrane reactor is higher than those obtained in porous vycor membrane reactor and fixed-bed reactor. With the change in reactant flowrate, it is obtained that the conversions in membrane reactors are more stable than those infixed bed reactors.Keywords: Hydrogen Production, Membrane Reactor, Methane Reforming AbstrakHidrogen merupakan bahan bakar alternatif yang sangat menjanjikan untuk sistem pembangkitan energi yang lebih ramah lingkungan. Salah satu rute produksi hidrogen adalah melalui reformasi metana dengan karbondioksida (C02 Methane Reforming/CMR). Saat ini telah dikembangkan proses CMR menggunakan membran yang mampu meningkatkan laju produksi H2• Pada makalah ini dikaji dua tipe reaktor membran untuk maksud peningkatan produksi hidrogen tersebut, yakni reaktor membran dengan basis membran porous vycor dan nanosil. Sebagai pembanding, dilakukanjuga evaluasi unjuk kerja reaksi CMRpada reaktorfzxe-bed. Hasil kajian ini menurljukkan bahwa reaktor nanosil danporous vycor mampu memberikan konversiyang lebih besar dibanding reaktor fixed-bed. Lebihjauh, reaktor membran dengan nanosil membran mampu memberikan laju produksi hidrogen yang lebih tinggi dibanding reaktor membran dengan membran porous vycor. Lebih jauh, pada perubahan laju molar reaktan, reaktor membran menurijukkan stabilitas yang lebih baik dibanding reaktor fixed-bed.Kata Kunci: Produksi Hidrogen, Reaktor Membran, Reformasi Metana

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Mel, Maizirwan, Fouad Riyad Hussein Abdeen, Hamzah Mohd Salleh, Sany Izan Ihsan, Fazia Adyani Ahmad Fuad i Roy Hendroko Setyobudi. "Simulation Study of Bio-Methane Conversion into Hydrogen for Generating 500 kW of Power". MATEC Web of Conferences 164 (2018): 01027. http://dx.doi.org/10.1051/matecconf/201816401027.

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Research and development sectors have made great efforts for finding cleaner and greener supplements for fossil fuels. The uses of POME (Palm oil Mill Effluent) as feedstock of biogas production has attracted many industries to produce energy because this source (waste) is abundance and not fully utilised. Methane from biogas production has shown to have a significant potential to replace the depleting sources as it can be produced from renewable feed stocks. The main objective of this study is to produce hydrogen from methane obtained by digesting of POME and to transform bio-methane into hydrogen for generating 500 kW of electric power using a simulation software of SuperPro Design.

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Mori, Tohru, Shunichi Hoshino, Arthit Neramittagapong, Jun Kubo i Yutaka Morikawa. "Novel Activity of SnO2for Methanol Conversion: Formation of Methane, Carbon Dioxide, and Hydrogen". Chemistry Letters 31, nr 3 (marzec 2002): 390–91. http://dx.doi.org/10.1246/cl.2002.390.

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Kumar, Gopalakrishnan, i Chiu-Yue Lin. "Biogenic Hydrogen Conversion of De-Oiled Jatropha Waste via Anaerobic Sequencing Batch Reactor Operation: Process Performance, Microbial Insights, andCO2Reduction Efficiency". Scientific World Journal 2014 (2014): 1–9. http://dx.doi.org/10.1155/2014/946503.

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We report the semicontinuous, direct (anaerobic sequencing batch reactor operation) hydrogen fermentation of de-oiled jatropha waste (DJW). The effect of hydraulic retention time (HRT) was studied and results show that the stable and peak hydrogen production rate of 1.48 L/L*d and hydrogen yield of 8.7 mL H2/g volatile solid added were attained when the reactor was operated at HRT 2 days (d) with a DJW concentration of 200 g/L, temperature 55°C, and pH 6.5. Reduced HRT enhanced the production performance until 1.75 d. Further reduction has lowered the process efficiency in terms of biogas production and hydrogen gas content. The effluent from hydrogen fermentor was utilized for methane fermentation in batch reactors using pig slurry and cow dung as seed sources. The results revealed that pig slurry was a feasible seed source for methane generation. Peak methane production rate of 0.43 L CH4/L*d and methane yield of 20.5 mL CH4/g COD were observed at substrate concentration of 10 g COD/L, temperature 30°C, and pH 7.0. PCR-DGGE analysis revealed that combination of celluloytic and fermentative bacteria were present in the hydrogen producing ASBR.

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Biswas, Saheli, Shambhu Singh Rathore, Aniruddha Pramod Kulkarni, Sarbjit Giddey i Sankar Bhattacharya. "A Theoretical Study on Reversible Solid Oxide Cells as Key Enablers of Cyclic Conversion between Electrical Energy and Fuel". Energies 14, nr 15 (26.07.2021): 4517. http://dx.doi.org/10.3390/en14154517.

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Reversible solid oxide cells (rSOC) enable the efficient cyclic conversion between electrical and chemical energy in the form of fuels and chemicals, thereby providing a pathway for long-term and high-capacity energy storage. Amongst the different fuels under investigation, hydrogen, methane, and ammonia have gained immense attention as carbon-neutral energy vectors. Here we have compared the energy efficiency and the energy demand of rSOC based on these three fuels. In the fuel cell mode of operation (energy generation), two different routes have been considered for both methane and ammonia; Routes 1 and 2 involve internal reforming (in the case of methane) or cracking (in the case of ammonia) and external reforming or cracking, respectively. The use of hydrogen as fuel provides the highest round-trip efficiency (62.1%) followed by methane by Route 1 (43.4%), ammonia by Route 2 (41.1%), methane by Route 2 (40.4%), and ammonia by Route 1 (39.2%). The lower efficiency of internal ammonia cracking as opposed to its external counterpart can be attributed to the insufficient catalytic activity and stability of the state-of-the-art fuel electrode materials, which is a major hindrance to the scale-up of this technology. A preliminary cost estimate showed that the price of hydrogen, methane and ammonia produced in SOEC mode would be ~1.91, 3.63, and 0.48 $/kg, respectively. In SOFC mode, the cost of electricity generation using hydrogen, internally reformed methane, and internally cracked ammonia would be ~52.34, 46.30, and 47.11 $/MWh, respectively.

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Mrakin, Anton N., Olga V. Afanaseva i Oleg Yu Kuleshov. "CALCULATION OF HEAT TRANSFER INTENSITY OF GAS FUEL COMBUSTION PRODUCTS". Bulletin of the Tomsk Polytechnic University Geo Assets Engineering 334, nr 5 (31.05.2023): 109–15. http://dx.doi.org/10.18799/24131830/2023/5/3987.

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Link for citation: Mrakin A.N., Afanaseva O.V., Kuleshov O.Yu. Calculation of heat transfer intensity of gas fuel combustion products. Bulletin of the Tomsk Polytechnic University. Geo Аssets Engineering, 2023, vol. 334, no. 5, рр.109-115. The relevance of the research is determined by the modern trend in the field of thermal power engineering and heat engineering for the transition from traditional gaseous fuel (methane) to the use of hydrogen, methane-hydrogen mixtures, as well as thermochemical conversion gases. Switching to new non-design fuel is justified by considerations of reducing the negative impact on the environment and increasing the thermal efficiency of fuel combustion plants. In this case, the use of fuels with a composition different from the design one will affect the heat transfer processes. The main aim: carrying out a comparative analysis of indicators of the intensity of radiant and convective heat transfer of combustion products of non-design fuels, such as hydrogen, methane-hydrogen mixture and thermochemical conversion gases. As an assumption in the formulation of the problem and objectives of the study, the constancy of the heat release power in the apparatus due to changes in the amount of fuel burned was taken. Objects: heat exchange surface of a fire-tube hot water boiler. Methods: carrying out numerical calculation using traditional approaches to determine the indicators of the intensity of heat transfer in the system «combustion products – metal wall of the pipe of thermal power plants». We also used the relations tested earlier by other authors to calculate the thermophysical parameters of gas mixtures. Results. According to the results of the performed comparative calculations, we can conclude that the transition from the use of conventional fuel (natural gas/methane) to its thermochemical conversion gases under the considered conditions has almost no effect on the integral heat transfer performance. To a greater extent, this transition is caused by changes in the intensity of heat transfer for products of combustion of hydrogen and methane-hydrogen mixture, which will affect the operation of thermal power and heat technological installations. At the same time, it is necessary to conduct additional research on the combustion kinetics of thermochemical methane conversion gases, their thermophysical properties, etc., because the hardware design, type of the catalyst used and operating parameters of the process will affect the composition of obtained synthesis gas.

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Kuang, Xiao-Gang, Li Zhang, Yan-Lun Ren i Xing-Wei Wang. "Process intensification of hydrogen production by steam reforming of methane over structured channel packing catalysts". E3S Web of Conferences 385 (2023): 02018. http://dx.doi.org/10.1051/e3sconf/202338502018.

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The industrial methane steam reforming reaction usually employs particulate catalyst that are easy to prepare and cost-effective, but suffer from problems such as high reactor pressure drop and low overall catalyst utilization. In this study, the Ni-Al2CaO4 powder prepared by the equal volume impregnation method was subjected to particle size control using a pressing method, and was made into catalyst particles of different sizes. Some of the catalysts were filled into honeycomb structures with cordierite and metal substrates, respectively, to prepare regular channel packing catalysts. The differences in methane steam reforming conversion rate, H2/CO selectivity, and overall pressure drop among the three catalysts were compared, and the influence of particle size and regular channel on reaction performance was systematically explored. The results showed that under the same conditions, as the catalyst particle size increased, the methane conversion rate and pressure drop increased. The regular channel packing catalysts with the two substrates showed similar pressure drop levels, but the metal substrate exhibited a higher methane conversion rate due to its excellent thermal conductivity. Compared with single-particle catalysts of the same size, the pressure drop of the metal substrate regular channel packing catalysts was reduced by more than 25%. Under the conditions of a gas hourly space velocity of 2000 h-1, a reaction temperature of 700 °C, and a water-to-carbon ratio of 3, the 40-60 mesh metal substrate regular packing catalysts showed a 7% increase in methane conversion rate, reaching 95.2%.

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Mitoura dos Santos Junior, Julles, Jan Galvão Gomes, Antônio Carlos Daltro de Freitas i Reginaldo Guiradello. "An Analysis of the Methane Cracking Process for CO2-Free Hydrogen Production Using Thermodynamic Methodologies". Methane 1, nr 4 (7.10.2022): 243–61. http://dx.doi.org/10.3390/methane1040020.

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The thermal cracking process of methane does not present the emissions of polluting gases, forming only hydrogen with a high degree of purity and solid carbon that can be commercialized for other industrial purposes globally. Thermodynamic methodologies based on Gibbs energy minimization and entropy maximization are used in the present study to simulate operating conditions of isothermal and adiabatic reactors, respectively. The chemical equilibrium and combined phases problem were written in a non-linear programming form and optimized with the GAMS software using the CONOPT 3 solver. The results obtained by the methodology described in this study present a good agreement with the data reported in the literature, with mean relative deviations lower than 1.08%. High temperatures and low pressures favor the decomposition of methane and the formation of products. When conditioned in an isothermal reactor, total methane conversions are obtained at temperatures above 1200 K at 1 bar. When conditioned to an adiabatic reactor, due to the lack of energy support provided by the isothermal reactor and taking into account that it is an endothermic process, high methane-conversion rates are obtained for temperatures above 1600 K at 1 bar. As an alternative, the combined effects of the addition of hydrogen to the feed combined with a system of extreme pressure variation indicate a possibility of conducting the thermal cracking process of methane in adiabatic systems. Setting the CH4/H2 ratio in the system feed at 1:10 at 1600 K and 50 bar, following severe depressurization through an isentropic valve, varying the pressure from 50 to 1 bar, the methane conversion varies from 0 to 94.712%, thus indicating a possible operational conformation for the process so that the amount of carbon generated is not so harmful to the process, taking into account that the formation of the same occurs only after the reaction and heating processes. Under the same operating conditions, it is possible to use about 40.57% of the generated hydrogen to provide energy for the process to occur.

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Scheiblehner, David, Helmut Antrekowitsch, David Neuschitzer, Stefan Wibner i Andreas Sprung. "Hydrogen Production by Methane Pyrolysis in Molten Cu-Ni-Sn Alloys". Metals 13, nr 7 (21.07.2023): 1310. http://dx.doi.org/10.3390/met13071310.

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Hydrogen is an essential vector for transitioning today’s energy system. As a fuel or reactant in critical industrial sectors such as transportation and metallurgy, H2 can diversify the energy mix and supply and provide an opportunity to mitigate greenhouse-gas emissions. The pyrolysis of methane in liquid catalysts represents a promising alternative to producing hydrogen, as its energy demand is comparable to steam methane reforming, and no CO2 is produced in the base reaction. In this work, methane pyrolysis experiments were conducted using a graphite crucible filled with liquid ternary Cu-Ni-Sn alloys at 1160.0 °C. A statistical design of experiments allowed the generation of a model equation that predicts the achievable conversion rates in the ranges of the experiments. Furthermore, the experimental results are evaluated considering densities as well as surface tensions and viscosities in the investigated system, calculated with Butler and KRP equations, respectively. The highest methane conversion rate of 40.15% was achieved utilizing a melt of pure copper. The findings show that a combination of high catalytic activity with a high density and a low viscosity and surface tension of the melt results in a higher hydrogen yield. Furthermore, the autocatalytic effect of pyrolysis carbon is measured.

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