• Journal of the Korean Applied Science and Technology
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• v.30 no.4
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• pp.649-655
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• 2013

Methanol was directly produced by the partial oxidation of methane with perovskite and mixed oxide catalysts. Perovskite ($ABO_3$) catalysts were prepared by the malic acid method with changing A and B site components. Three-component mixed oxide catalysts that have Mo and Bi as a main component were prepared by the co-precipitation method. Among the perovskite catalysts, $SrCrO_3$ showed the highest methanol selectivity of 11% at $400^{\circ}C$. For the three-component mixed oxide catalysts, there were no remarkable changes in methane conversion. Among the mixed oxide catalysts, Mo-Bi-Cr mixed oxide catalyst showed the highest methanol selectivity of 15.3% at $400^{\circ}C$. The catalytic activity and methanol selectivity of the three-component mixed oxide catalysts were directly proportional to the surface area of the catalysts.

• Journal of the Korean Chemical Society
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• v.36 no.1
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• pp.147-156
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• 1992

Supported lead oxide catalysts were prepared by using ${\alpha}-,{\beta}-{\gamma}$-alumina, and MgO as a support. Among the supported lead oxide catalysts, MgO-supported catalyst showed the highest $C_2^+$ hydrocarbon selectivity for the methane conversion into $C_2^+$ hydrocarbons, but ${\gamma}$-alumina-supported PbO catalyst gave the highest $CO_2$ selectivity. And ${\alpha}$-alumina-supported catlyst showed the midium activity, whereas ${\beta}$-alumina-supported catalyst gave little activity. These reaction characteristics seemed to be largely dependent on the acticity of lattice oxygens in supported catalysts, which would be influnto be largely dependent on the activity of lattice oxygens in supported catalysts, which would be influenced in the interaction between the supports and lead oxides and the properties of supports. Especially, much higher ration of (002)/(111) peak intensities for PbO phase on MgO support than on the other supports in X-ray diffraction analysis was considered to be ab evidence that methane oxidative coupling of methane might be so-called structure-sensitive reaction, and this seemed to be an example of surface oxide-support interaction (SOSI) in the oxidative coupling reaction.

• 한국신재생에너지학회:학술대회논문집
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• 2005.06a
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• pp.231-234
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• 2005

수소 기반의 에너지 사회는 중소규모 분산 발전과 연료 전지 자동차에서 시작될 거라는 예측이 지배적이다. 가정용 고분자 연료전지 시스템은 상업화에 가장 가까운 소규모 분산 발전 시스템중의 하나이며, 에너지기술연구위원에서는 가정용 고분자 연료전지에 수소를 공급하기 위한 천연가스 수증기 개질시스템의 개발을 진행해 왔다. 효율 향상과 제작의 용이성, 그리고 소형화에 초점을 맞추어 개발된 prototype-I은 $2.0Nm^3/hr$의 순수 수소 생산 용량을 가지고 있으며, 수증기 개질기와 수성가스 전이 반응기 수중기 생성 장치, 그리고 반응열 공급에 필요한 버너 등을 이중 동심원관에 통합한 형태이다. 수중기 개질과 수성가스 전이 반응을 거쳐 나오는 개질 가스의 조성은 $72.3\%\;H_2,\;4.8\%\;CH_4,\;0.7\%\;CO,\;22.2\%\;CO_2$이며, 이때 S/C 비율은 2.5였다. 고분자 연료 전지 공급 시 요구되는 CO 농도가 10ppm 이하이기 때문에, 본 시스템에는 선택적 산화 반응기를 2단으로 설치하여 CO. 농도를 10ppm 이하로 낮추어주었다. 전체 시스템의 열효율은 LHV 기준으로 $68\%$. Prototype-I의 운전을 통해 설계 개선안을 도출하였으며, 이를 적용해 제작한 prototype-II가 시험 운전 중이다,. 통합된 개질 시스템에서는 각 단위 반응기사이의 열교환을 최적화하여 단위 반응들이 적정 온도 범위에서 일어나도록 유도하는 것이 중요하다. Prototype-II는 수증기 개질 반응기와 WGS 반응기, 수증기 생성 장치 사이의 열교환율을 향상시켜 농도를 $2.5\%$로 감소시키면서 CO의 농도는 $1\%$이하로 유지하였다. 이 결과를 바탕으로 얻어진 메탄 전환율은 $87\%$이고, 열효율은 LHV 기준으로 $75\%$이다. 아울러 개선점을 적용한 선택적 산화 반응기를 제작하였다. 개질 가스와 산소의 혼합을 유도하고, 반응기 온도의 제어를 통해 선택적 산화 반응의 속도와 선택성을 향상시키고자 한다. 시스템의 운전을 통해 메탄 전환율과 열효율의 개선을 진행할 예정이다.

• Proceedings of the KSME Conference
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• 2008.11b
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• pp.2892-2897
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• 2008

Plasma techniques have been proposed to generate a hydrogen enrich gas to investigate a feasibility of plasma techniques on a fuel reforming, we considered a dry reforming and a partial oxidation with methane in the atmospheric pressure. For these experiments, we employed an arc jet plasma reactor. The effects of input power and oxidizer in each process were investigated by product analysis, including carbon monoxide, hydrogen, ethylene, propane, and acetylene as well as methane and carbon dioxide. In both processes, input electrical power activated the reactions significantly. The increased ratio of the carbon dioxide to methane in the dry reforming doesn't affect to a methane conversion, whereas increased ratio of oxidizer to methane in the partial oxidation was very effective for the reaction. Moreover, for a simultaneous treatment of methane and carbon dioxide, a feasibility of a dry reforming combined with partial oxidation also has been investigated.

• Korean Chemical Engineering Research
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• v.48 no.6
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• pp.776-783
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• 2010

Co and Ni catalysts supported on $Al_2O_3$ for partial oxidation of methane producing hydrogen were synthesized using impregnation to incipient wetness. The activities of these catalysts for the partial oxidation of methane was investigated at 1 atm and $CH_4/O_2=2.0$ in the temperature range of $450{\sim}650^{\circ}C$. The reaction activity of $Ni/Al_2O_3$ and $Co/Al_2O_3$ catalysts with different loading was investigated. And the beneficial effects of Ni addition to $Co/Al_2O_3$ and the promotional effects of Ce and La addition to $Ni/Al_2O_3$ and $Co/Al_2O_3$ were investigated. These catalysts were characterized by XRD and SEM/EDX. Comparing catalyst loadings, 10 wt% Co and 10 wt% Ni were found to be optimal at the experimental conditions. The 10 wt% $Ni/Al_2O_3$ and 10 wt% $Co/Al_2O_3$ catalysts in partial oxidation of methane showed $CH_4$ conversions and CO selectivity close to the thermodynamic equilibrium levels, but showed lower $H_2$ selectivity than equilibrium level. The addition of Ni to $Co/Al_2O_3$ exhibited higher $H_2$ selectivity but beneficial effect was not observed in the $CH_4$ conversion. Addition of Ce to $Co/Al_2O_3$ and addition of La to $Ni/Al_2O_3$ a improved the $CH_4$ conversion level and $H_2$ selectivity.

• Applied Chemistry for Engineering
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• v.10 no.4
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• pp.557-562
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• 1999

The reaction properties of Pd. Pd-Ce and Pd-La catalysts supported on ${\gamma}-Al_2O_3$ were investigated in the oxidation reaction of methane($CH_4$) exhausted from the compressed natural gas vehicle in a U-tube flow reactor with gas hourly space velocity of $72,000h^{-1}$. The catalysts were characterized by X-ray diffraction(XRD), X-ray photoelectron spectroscopy(XPS), BET surface area and hydrogen chemisorption. Pd catalyst prepared by $Pd(NO_3)_2$ as a palladium precursor and calcined at $600^{\circ}C$ showed the highest activity for a methane oxidation. Catalytic activity of calcined $Pd/{\gamma}-Al_2O_3$ in which most of palladium was converted into palladium oxide species was higher than that of reduced $Pd/{\gamma}-Al_2O_3$ in which most of palladium existed in palladium metal by XRD. As increasing the number of reaction cycles in the wide range of redox, the catalytic activity of $Pd/{\gamma}-Al_2O_3$ was decreased and the highly active window became narrower. Lanthanum oxide promoted Pd catalyst, $Pd/La/{\gamma}-Al_2O_3$ showed enhanced thermal stability compared with $Pd/{\gamma}-Al_2O_3$ even after aging at $1000^{\circ}C$, which was ascribed to the role of La as a promoter to suppress the sintering of palladium metal and ${\gamma}-Al_2O_3$ support. Almost all of methane was removed by the reaction with NO at the redox ratio of 1.2 in case of oxygen excluded steam, but that activity was significantly decreased in the steam containing oxygen.

• Applied Chemistry for Engineering
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• v.4 no.4
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• pp.807-813
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• 1993

Oxidative coupling of methane(OCM), one of the methods of direct methane conversion, was performed. Metal oxide catalysts used were Li/MgO and Pb/MgO. To investigate the reactivity of the catalysts with temperature, the reaction was carried out at 600, 700 and $800^{\circ}C$; and to investigate the effect of the feed ratio of the reactants($CH_4:O_2$) on reactivity, conversion, and selectivity the reaction was performed at $700^{\circ}C$ with the feed ratio of 2:1 and 1:1. The results indicate that 7wt% Li/MgO catalyst is a good catalyst for OCM reaction with 20% conversion and 65% selectivity at $700^{\circ}C$ with the feed ratio of 2:1. As feed ratio was 1:1, methane conversion was increased to 30% while $C_2$ selectivity decreased to 45% at $700^{\circ}C$ with 7wt% Li/MgO catalyst. The Pb/MgO catalyst showed less selectivity(25%) than Li/MgO did.

• Journal of Korean Society of Environmental Engineers
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• v.22 no.5
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• pp.971-980
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• 2000

Mixed methanotrophs (MM) secreting soluble methane monooxygenase(sMMO) were immobilized on celite R-635 to degrade trichloroethylene(TCE) in methanotrophic consortium biofilm reactor(MCBR) system. Further neutralization of celite R-635 was not needed for immobilization because effluent pH was stabilized at neutral after 4 hour washing. It took 130 days to develop biofilm on celite R-635 and the color of the celite changed gradually from white to red. After biofilm developed, influent methane and oxygen were decreased from 2.5~4 and 8~10 ppm to 0.5~1 and 1~2 ppm, respectively, With influent 2 ppm of TCE and 10 hours of retention time, 79.9% of TCE was degraded in the MCBR system.

• Korean Chemical Engineering Research
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• v.51 no.3
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• pp.319-324
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• 2013

The partial oxidation reaction of methane was investigated to produce syngas with $Ni/CeO_2-ZrO_2$, $Ni-Ru/CeO_2-ZrO_2$ and $Ni-Pd/CeO_2-ZrO_2$ catalysts. Honeycomb metallic monolith was applied in order to obtain high catalytic activity and stability in partial oxidation reforming. The catalysts were characterized by XRD and FE-SEM. The influence of various catalysts on syngas production was studied for the feed ratio (O/C), GHSV and temperature. Among the catalysts used in the experiment, the $Ni-Pd/CeO_2-ZrO_2$ catalyst showed the highest activity. The 99% of $CH_4$ conversion was obtained at the condition of T=$900^{\circ}C$, GHSV=10,000 $h^{-1}$ and feed ratio O/C=0.55. It was confirmed that $H_2$ yield increased slightly as O/C ratio increased, while CO yield remained almost constant. Also, $CH_4$ conversion decreased as GHSV increased. It was found that the safe range of GHSV for high $CH_4$ conversion was estimated to be less than 10,000 $h^{-1}$.

• Applied Chemistry for Engineering
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• v.5 no.4
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• pp.580-587
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• 1994

The oxidative coupling of methane was studied kinetically using $Na^+(50wt%)/MgO$ catalyst at 710, 730, 750, 770 and $790^{\circ}C$ in a fixed bed flow reactor at the atmospheric pressure under differential conversion conditions. Through curve fitting, it was found that the Langmuir-Hinshelwood type mechanism was fitted to this reaction rather than Rideal-Redox type or Eley-Rideal type mechanism. Therefore, it was proposed that the $O_2{^-}$ or $O_2{^{2-}}$ species on the surface was related to the production of $CH_3{\cdot}$. The estimated activation energy of $CH_3{\cdot}$ production was about 39.3kcal/mol. Moreover, as the result of curve fitting, the stoichiometric coefficient of $O_2$ for the production of $CH_3{\cdot}$ to produce $CO_x$was approximately 1.5. Accordingly, it could be concluded that the $CH_3O_2{\cdot}*$ was prouduced through the partial oxidation of $CH_3{\cdot}$ with the surface oxygen.