• 공업화학
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• 제18권1호
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• pp.84-89
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• 2007

본 연구에서는 열플라즈마 직접분해법에 의해 메탄과 프로판으로부터 수소와 카본 블랙을 생성하는 공정에 대해 조사하였다. 메탄과 프로판의 직접분해 시 열역학적 평형조성을 깁스 자유에너지의 최소화에 근거하여 계산하였으며, 이를 바탕으로 직접분해 실험을 수행하였다. 탄화수소의 직접분해에 의해 생성된 수소의 순도는 분해가스 유량에 의존하는 것으로 나타났으며, 고순도의 수소를 얻기 위한 분해 조건을 조사하였다. 메탄을 분해가스로 사용한 경우 프로판의 경우보다 높은 수소의 순도를 나타내는데, 이는 열플라즈마에 의해 생성된 라디칼의 재결합 등으로 인한 메탄이나 에탄, 그리고 아세틸렌과 같은 부산물이 프로판의 경우에 더욱 많이 생겨나기 때문인 것으로 조사되었다. 생성된 카본블랙은 X선 회절분석과 Raman Spectroscopy 분석을 통해 결정성을 조사하였으며, SEM 분석 및 입도 분석을 통해 카본블랙의 입자 모양과 크기를 조사하였다. 그 결과 구형이며 결정성이 양호한 카본블랙이 생성되었음을 확인하였으며, 메탄으로부터 생성된 카본 블랙이 프로판으로부터 생성된 카본블랙보다 평균 입자 크기가 작은 것으로 나타났다.

• 신재생에너지
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• 제17권2호
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• pp.40-49
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• 2021

This paper explains the development process of methane decomposition to hydrogen and carbon black using solar thermal energy. It also demonstrates the advantages and disadvantages of five different reactors for each development stage, including the reactor's experimental results. Starting with the initial direct heating type reactor, the indirect heating type reactor was developed through five modifications. The 40-kWth solar furnace installed at the Korea Institute of Energy Research was used for the experiment. In the experiment using the developed indirect heating reactor, an 89.0% methane to hydrogen conversion rate was achieved at a methane flow rate of 40 L/min, obtained at about twice the flow rate compared to previous advanced studies.

• 한국수소및신에너지학회논문집
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• 제13권2호
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• pp.101-109
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• 2002

This work was focused on the thermal decomposition of methane into hydrogen and carbon black without emitting carbon dioxide. Extensive experimental investigation on the thermal decomposition of methane has been carried out using a continuous flow reaction system with tubular reactor. The experiments were conducted at the atmospheric pressure condition in the wide range of temperature ($950-1150^{\circ}C$) and flow rate (250 - 1500 ml/min) in order to study their dependency on hydrogen yield. During the experiments the carbon black was successfully recovered as an useful product. Undesirable pyrocarbon was also formed as solid film, which was deposited on the inside surface of tubular reactor. The film of pyrocarbon in the reactor wall became thicker and thicker, finally blocking the reactor. The design of an efficient reactor which can effectively suppress the formation of pyrocarbon was thought to be one of the most important subjects in the thermal cracking of methane.

• 신재생에너지
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• 제17권1호
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• pp.40-49
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• 2021

In this study, the optical properties, heat transfer capabilities and chemical reaction performance of a methane thermal decomposition reactor using solar heat as a heat source were numerically analyzed on the basis of the cavity shape. The optical properties were analyzed using TracePro, a Monte Carlo ray tracing-based program, and the heat transfer analysis was performed using Fluent, a CFD program. An indirect heating tubular reactor was rotated at a constant speed to prevent damage by the heat source in the solar furnace. The inside of the reactor was filled with a porous catalyst for methane decomposition, and the outside was insulated to reduce heat loss. The performance of the reactor, based on cavity shape, was calculated when solar heat was concentrated on the reactor surface and methane was supplied into the reactor in an environment with a solar irradiance of 700 W/㎡, a wind speed of 1 m/s, and an outdoor temperature of 25℃. Thus, it was confirmed that the heat loss of the full-cavity model decreased to 13% and the methane conversion rate increased by 33.5% when compared to the semi-cavity model.

• 한국산학기술학회논문지
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• 제9권2호
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• pp.487-492
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• 2008

본 논문은 유동층반응기에서 메탄 열분해에 의한 수소 생산과 탄소 생성에 대한 연구를 수행하였다. 환경에 대한 영향을 최소화한 상태에서 one-step에 의한 메탄의 전환반응을 메탄 분해촉매활성에 영향을 미치는 인자에 대하여 연구하였다. 측정된 압력요동특성치의 해석을 통하여 유동층 열분해촉매의 유동화현상을 측정하였으며, 유동화특성에 따른 메탄열분해능을 측정하였다. 메탄의 분해능는 생성되는 수소의 농도로부터 측정하였다. 유동층의 특성인 층내 입자 이동성, U-Umf, 마모, 비산유출, 유동화가스의 효율밀도에 따른 분해효율에 미치는 영향을 고찰하였다.

• 공업화학
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• 제18권2호
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• pp.136-141
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• 2007

본 연구에서는 열플라즈마를 이용하여 클로로메탄 즉 사염화탄소($CCl_4$), 삼염화탄소($CCl_3H$), 이염화탄소($CCl_2H_2$)를 분해하는 실험을 수행하였으며 열플라즈마분해공정의 특성에 대한 연구를 진행하였다. Factsage program을 이용하여 열역학적 평형조성을 알아보았으며, 또한 Gas chromatography를 이용하여 농도, 캐리어 가스의 유량 및 quenching 속도등 세가지 변수의 변화에 따른 분해율을 살펴보았다. 실험 결과 92%이상의 높은 분해율을 얻었다. FT-IR을 이용하여 최종 생성물을 확인한 결과 중성 분위기에서는 주로 카본, 염소, 염화수소가 생성되었고 산화 분위기에서는 카본의 생성이 억제되었으며 주로 이산화탄소, 염화수소, 염소가 생성되었다. FT-IR생성물에 대한 분석과 Factsage program에 의한 온도 분포 별 생성된 라디칼 및 기타 입자의 종류와 결부하여 이에 따른 분해 메커니즘에 대해 알아보았다. 분해 경로는 주로 라디칼에 의한 산화반응과 전자 부착에 의한 분해 반응으로 이루어짐을 확인하였다.

• 신재생에너지
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• 제2권4호
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• pp.70-77
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• 2006

The butane decomposition over the catalyst is an attractive method for the hydrogen production. The objective of the work was investigated the catalysis of carbon black in butane decomposition reaction. The Butane decomposition was performed over carbon black catalyst in a range of $500-1100^{\circ}C$. The butane conversion of thermal decomposition and catalytic decomposition were increased with increasing the reaction temperature The butane conversion of the thermal decomposition was higher than the butane conversion of the catalytic decomposition. Hydrogen and methane were mostly observed in the butane decomposition over $1000^{\circ}C$. Especially, the hydrogen yield was steadily increased with raising the reaction temperature, It could be known that the hydrogen yield of the catalytic decomposition was higher than one of the thermal cracking because the hydrogen productivity was improved by the catalyst. The deactivation of the catalyst was not observed in the reactivity test. The surface and crystalline of the fresh and used catalysts were characterized by TEM, BET surface area and XRD analysis, respectively. The fresh carbon black particles had mostly smoothly round-shaped surfaces. In the surface of the carbon black after the reaction, the deposited carbon was formed as the protrusion-shaped carbon and the cone-shaped. The proper peaks of carbon black appeared in XRD analysis.

• 청정기술
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• 제10권4호
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• pp.203-213
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• 2004

천연가스의 열분해법은 천연가스 (CH4)를 고온에서 분해 시켜 수소와 탄소로 전환시키는 기술이다. 천연가스 열분해법의 가장 큰 장점은 이산화탄소의 발생 없이 수소와 탄소를 만드는 것이다. 본 연구에서는 이와같이 천연가스 고온 열분해법을 이용하여 메탄으로부터 수소와 탄소의 생성을 연구하였다. 실험을 통하여 메탄의 고온 열분해시 pyrocarbon이 반응관 내벽에 생성되며 그 위에 탄소가 퇴적되는 plugging 현상이 발생한다는 것을 알 수 있었다. 이 문제를 해결하기 위하여 본 연구에서는 이중관 반응기법, 반응 중간에 주기적으로 $O_2$나 $CO_2$로 퇴적된 탄소를 산화시키는 방법 등을 시도하였으며, 그 결과 어느 정도의 탄소 퇴적 현상을 해결할 수 있었다. 또한 SEM (Scanning Electron Microscope) image를 사용하여 탄소 입자의 크기를 측정하였으며 그 크기는 약 200 nm정도였다.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2007년도 추계학술대회 논문집
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• pp.93-96
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• 2007

Catalytic activities of color and conductive carbon blacks in ethane decomposition for $CO_2-free$ hydrogen production were investigated. The ethane decomposition was carried out in a conventional fixed bed reactor under atmospheric pressure at 973-1173 K for 2 hours. When the decomposition in the presence of carbon black was compared with the non-catalytic thermal decomposition, the former exhibited significantly higher ethane conversion, higher C(s) selectivity and lower ethylene selectivity with small increase of the methane selectivity, which resulted in higher hydrogen yield. This indicates that carbon black is catalytically effective for dehydrogenation of ethane as well as subsequent decomposition of ethylene. All the carbon blacks exhibited stable catalytic activity with time. In durability tests, fluffy N-330 and BP2000 maintained their activities for 36 hours.

• Carbon letters
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• 제13권2호
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• pp.99-108
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• 2012

The sol-gel technique has been studied to fabricate a homogeneous Fe-Mo/MgO catalyst. Ambient effects (air, Ar, and $H_2$) on thermal decomposition of the citrate precursor have been systematically investigated to fabricate an Fe-Mo/MgO catalyst. Severe agglomeration of metal catalyst was observed under thermal decomposition of citrate precursor in air atmosphere. Ar/$H_2$ atmosphere effectively restricted agglomeration of bimetallic catalyst and formation of highly-dispersed Fe-Mo/MgO catalyst with high specific surface-area due to the formation of Fe-Mo nanoclusters within MgO support. High-quality thin-multiwalled carbon nanotubes (t-MWCNTs) with uniform diameters were achieved on a large scale by catalytic decomposition of methane over Fe-Mo/MgO catalyst prepared under Ar-atmosphere. The produced t-MWCNTs had outer diameters in the range of 4-8 nm (average diameter ~6.6 nm) and wall numbers in the range of 4-7 graphenes. The as-synthesized t-MWCNTs showed product yields over 450% relative to the utilized Fe-Mo/MgO catalyst, and indicated a purity of about 85%.