• Applied Chemistry for Engineering
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• v.35 no.2
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• pp.134-139
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• 2024

In the steam reforming of methane reactions, the effect of adding noble metals Ru and Pd to a Ni-based catalyst as promoters was analyzed in terms of catalytic activity and hydrogen production. The synthesized catalysts were coated on the surface of a honeycomb-structured metal monolith to perform steam methane reforming reactions. The catalysts were characterized by XRD, TPR, and SEM, and after the reforming reaction, the gas composition was analyzed by GC to measure methane conversion, hydrogen yield, and CO selectivity. The addition of 0.5 wt% Ru improved the reduction properties of the Ni catalyst and exhibited enhanced catalytic activity with a methane conversion of 99.91%. In addition, reaction characteristics were analyzed according to various process conditions. Methane conversion of over 90% and hydrogen yield of more than 3.3 were achieved at a reaction temperature of 800 ℃, a gas hourly space velocity (GHSV) of less than 10000 h^-1, and a ratio of H₂O to CH₄ (S/C) higher than 3.

• Journal of the Korean Society of Combustion
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• v.11 no.3
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• pp.1-7
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• 2006

A reaction mechanism of methane partial oxidation, which consists of thermal and plasma chemistry reaction pathways, has been investigated using with an arc-jet reactor. The reaction zone of the arc-jet reactor is spatially separated into thermal and non-thermal plasma zone. Methane conversion rates, selectivity of $H_2$ and $C_2$ chemicals in each zone are obtained, which reveals clearly different characteristics of reaction pathways depending on the temperature conditions. The conversion rates obtained in thermal plasma zone is higher than those in non-thermal plasma zone. The selectivity, however, obtained in non-thermal plasma zone is significantly higher than those in thermal plasma zone. Further parametric study on $O_2/C$ ratio, arc length and SED shows that the present process is mainly governed by thermal chemistry pathways.

• Journal of the Korean Applied Science and Technology
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• v.13 no.1
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• pp.67-74
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• 1996

This study was conducted to find a catalyst system which has high conversion and selectivity for the oxidative coupling of methane to produce ethane and ethylene. Various catalysts were tested in a fixed bed reactor ar $750^{\circ}C$, 1 atm, and the feed ratio($CH_4/O_2$) of 2/1. Under the reaction condition, 10wt%$PbSO_4/MgO$ catalyst showed the highest catalytic activity : methane conversion, $C_2$ selectivity and yield were 50, 40 and 20%, respectively. Catalysts containing sulfate compounds, 10wt%$PbSO_4/MgO$, 10wt%$MgSO_4/MgO$ and $Na_2SO_4/MgO$ revealed a moderate methane conversions such as 38, 50 and 50%, respectively and low $C_2$ selectivities such as 18, 5 and 9%, respectively. Catalysts containing carbonate compounds, 10wt%$PbCO_3/MgO$, 10wt%$Li_2CO_3/MgO$ and $NaCO_3/MgO$, also showed a moderate methane conversions such as 64, 44 and 51%, respectively and low $C_2$ selectivities such as 5, 6 and 2%, respectively. With the existence of chlorine and mercury, $C_2$ selectivity was decreased.

• New & Renewable Energy
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• v.4 no.2
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• pp.39-44
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• 2008

Partial oxidation of methane was carried out by ceria-promoted Ni-substituted hydrotalcite-derived catalysts ($Ce_xNi_3$-HTlc ; x=$0.3{\sim}1.2$) in a fixed-bed reactor. The Ce/Ni ratio of 0.3/3 in the catalyst showed the best catalytic activity but the Ce/Ni ratio became higher above 0.3/3, the catalyst became less active in short-term tests. No ceria promoted catalyst was started to decrease $CH_4$ conversion after 20 h but the Ce/Ni ratio 0.3/3 catalyst was kept its stability in long-term tests.

• Journal of the Korean Applied Science and Technology
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• v.28 no.3
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• pp.321-328
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• 2011

The autothermal reforming reaction of methane was investigated to produce hyd rogen with Ni/$CeO_2-ZrO_2$, Ni/$Al_2O_3$-MgO and Ni-Ru/$Al_2O_3$-MgO catalysts. Honeycomb metalli c monolith was applied in order to obtain high catalytic activity and stability in autothermal r eforming. The catalysts were characterized by XRD, BET and SEM. The influence of various catalysts on hydrogen production was studied for the feed ratio($O_2/CH_4$, $H_2O/CH_4$). The $O_2/CH_4$ and $H_2O/CH_4$ ratio governed the methane conversion and temperature profile of reactor. Th e reactor temperature increased as the reaction shifted from endothermic to exothermic reactio n with increasing $O_2/CH_4$ ratio. Among the catalysts used in the experiment, the Ni-Ru/$Al_2O_3$-MgO catalyst showed the highest activity. The 60% of $CH_4$ conversion was obtained, and th e reactor temperature was maintained $600^{\circ}C$ at the condition of GHSV=$10000h^{-1}$ and feed ratio S/C/O=0.5/1/0.5.

• Journal of Korean Society of Environmental Engineers
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• v.30 no.9
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• pp.933-938
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• 2008

In the present study, carbon dioxide was converted to methane, using bio-hydrogen. Here, the bio-hydrogen was produced from organic waste. The anaerobic microorganism was cultured using only carbon dioxide and hydrogen for duration of 3 months. Therefore methane was not produced with acetogenotrophs. During methane production, carbon dioxide and hydrogen are taken in different ratios; among which 1 : 5 ratio has shown the highest methane yield. Carbon dioxide and hydrogen were introduced into the reactor at the rate of 8 mL/min and 40 mL/min, respectively. In this case, 92% of carbon dioxide was reduced and 2.2 m$^3$/m$^3$ day amount of methane was produced. Thus, the process has been successful in conversion of carbon dioxide into methane by purging it into methane fermentation reactor with bio-hydrogen using batch process.

• Korean Chemical Engineering Research
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• v.47 no.1
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• pp.17-23
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• 2009

The catalytic behavior of $Ni/Ce_XZr_{(1-X)}O_2$ loaded on the alumina coated honeycomb monolith was studied for the autothermal reforming reaction of methane. Among the catalysts with the different Ce/Zr ratios, the $Ni/Ce_{0.80}Zr_{0.20}O_2$ Catalyst showed the highest conversion of methane. By investigating the effect of Ni content on the $Ni/Ce_{0.80}Zr_{0.20}O_2$ catalysts, the catalyst loaded with 15wt% Ni had the highest activity. Also, $H_2$ yield was increased as $H_2O/CH_4$ ratio increased. Methane conversion was improved as $O_2/CH_4$ ratio was increased, whereas the yield of $H_2$ was decreased. Among the catalysts tested for 30 hours, $Ni(15wt%)/Ce_{0.80}Zr_{0.20}O_2$ showed the excellent conversion(${\geq}99%$) of methane and the stability at the condition of $GHSV=30,000h^{-1}$, feed ratio S/C/O=2/1/0.5 and reaction temperature $800^{\circ}C$.

• Transactions of the Korean hydrogen and new energy society
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• v.22 no.1
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• pp.100-108
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• 2011

The use of biogas as an energy source reduces the chance of possible emission of two greenhouse gases, $CH_4$ and $CO_2$, into the atmosphere at the same time. Its nature of being a reproducible energy source makes its use even more attractive. This research if for the hydrogen production through the steam reforming of the biogas. The biogas utilized 3D-IR matrix burner in which the surface combustion is applied. The nickel catalyst was used inside a reformer. Parametric screening studies were achieved as Steam/Carbon ratio, biogas component ratio, Space velocity and Reformer temperature. When the condition of Steam/Carbon ratio, $CH_4/CO_2$ ratio, Space velocity and Refomer temperature were 3.25, 60%:40%, 19.32L/$g{\cdot}hr$ and $700^{\circ}C$ respectively, the hydrogen concentration and methane conversion rate were showed maximum values. Under the condition mentioned above, $H_2$ concentration was 73.9% and methane conversion rate was 98.9%.

• Applied Chemistry for Engineering
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• v.25 no.5
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• pp.497-502
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• 2014

The conversion reaction of methane and carbon dioxide at an atmospheric pressure plasma reactor filled with Ni-$Al_2O_3$ and Ni-$MgAl_2O_4$ catalyst was performed. Effects of various process parameters such as the applied electric power, reaction gas flow rate, reactor temperature, mixing ratio of reactants and the presence of the catalyst on the reaction between methane and carbon dioxide were analyzed. From the analysis of the contribution of the catalyst in the reaction step, even if the temperature raised to $400^{\circ}C$, there was no spontaneous catalytic conversion of methane and carbon dioxide without plasma discharges. When the catalysts for the conversion of methane and carbon dioxide would be adopted to the plasma reactor, the careful selection of suitable catalysts and process parameters should be essential.

• Clean Technology
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• v.26 no.1
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• pp.72-78
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• 2020

The use of fossil fuel and biogas production causes air pollution and climate change problems. Research endeavors continue to focus on converting methane and carbon dioxide, which are the major causes of climate change, into quality energy sources. In this study, a novel plasma-carbon converter was proposed to convert biogas into high quality gas, which is linked to photovoltaic and wind power and which poses a problem on generating electric power continuously. The characteristics of conversion and gas production were investigated to find a possibility for biogas conversion, involving parametric tests according to the change in the main influence variables, such as O₂/C ratio, total gas feed rate, and CO₂/CH₄ ratio. A higher O₂/C ratio gave higher conversions of methane and carbon dioxide. Total gas feed rate showed maximum conversion at a certain specified value. When CO₂/CH₄ feed ratio was decreased, both conversions increased. As a result, the production of solar fuel by plasma oxidation destruction-carbon material gasification conversion, which was newly suggested in this study, could be known as a possibly useful technology. When O₂/C ratio was 0.8 and CO₂/CH₄ was 0.67 while the total gas supply was at 40 L min^-1 (VHSV = 1.37), the maximum conversions of carbon dioxide and methane were achieved. The results gave the highest production for hydrogen and carbon dioxide which were high-quality fuel.