합성 천연가스의 하이드레이트 형성 거동 연구

이종원 ( Jong Won Lee ),이주동 ( Ju Dong Lee ) 한국화학공학회 2012 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.50 No.5

Gas hydrates are solid crystal structures formed by enclathration of gaseous guest species into 3-dimensional lattice structure of hydrogen-bonded water molecules. These compounds can be potentially used as an energy storage/transportation medium because they can hold a large amount of gas in a small volume of the solid phase. In addition, huge amount of natural gas, buried in seabeds or permafrost region in the form of the solid hydrate, is regarded as a future energy source. In this study, synthesized natural gas, whose composition is 90.0 mol% of methane, 7.0 mol% of ethane, and 3.0 mol% of propane, was used to identify formation behaviors of natural gas hydrates for the purpose of applying the gas hydrate to a storage/transportation medium of natural gas. According to the experimental results obtained by means of the solid-state NMR and high-resolution powder XRD methods, it is found that formed natural gas hydrates have crystal structure of the structure-II hydrate, and that methane occupies both small and large cages, while the others only occupy large ones, In addition, both the NMR spectroscopy and the gas chromatograph showed that there exists preferential occupation among the natural gas components during the hydrate formation, Compositional changes after the hydrate formation revealed that the preferential occupation is in order of propane, ethane, and methane (propane is the most preferential guest species when forming natural gas hydrates).

배기가스 온도 및 조성 변화에 따른 촉매코팅 DPF의 재생 특성에 관한 실험적 연구

허민(Min Heo),박영준(Young-Joon Park),조용석(Yong-Seok Cho),주재근(Jea-Gun Joo) 한국자동차공학회 2007 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-

As soot particles are loaded in a diesel particulate filter, the filter causes increase of back pressure in exhaust system. To minimize pressure drop due to DPF, the filter should be regenerated when it collects a certain quantity of soot. It is important to know characteristics of regeneration for DPF with variation of exhaust gas temperature and composition. This study presents characteristics of regeneration according to variable exhaust gas composition. Furthermore, the experiment were performed variable gas temperature of DPF inlet gas at each exhaust gas composition. Test-rig is used to control at each inlet gas temperature and composition during regeneration of DPF. Experimental results indicated that increased concentration of NOx and O₂ lead to regenerate more greatly. Also, higher exhaust gas temperature lead to make more clean DPF helpfully.

Effect of gas composition on dispersion characteristics of blowout gas on offshore platform

Yang, Dongdong,Chen, Guoming,Shi, Jihao,Li, Xinhong The Society of Naval Architects of Korea 2019 International Journal of Naval Architecture and Oc Vol.11 No.2

Gas composition has a significant impact on the dispersion behavior and accumulation characteristics of blowout gas. However, few public studies has investigated the corresponding effect of gas composition. Therefore, this study firstly builds the FLACS-based numerical model about an offshore drilling platform. Then several scenarios by varying the composition of blowout gas are simulated while the scenario with the composition of "Deepwater Horizon" accident is regarded as the benchmark. Furthermore, the effects of the gas composition on the flammable cloud volume, the influenced area of flammable cloud, the influenced area of hydrogen sulfide and the critical time of the hydrogen sulfide spreading to the living area are analyzed. The results demonstrate that gas composition is a driving factor for dispersion characteristics of blowout gas. All the results can give support to reduce the risk of the similar accidents incurred by real blowouts.

배기가스 온도 및 조성 변화에 따른 CDPF의 재생 특성에 관한 실험적 연구

조용석(Yong-Seok Cho),이정섭(Jung-Sub Lee),윤여빈(Yu-Bin Yoon),박영준(Young-Joon Park),이성욱(Seang-Wock Lee) 대한기계학회 2008 大韓機械學會論文集B Vol.32 No.8

The catalyzed diesel particulate filter (CDPF) is widely used for collecting soot from the exhaust gas of diesel engine. However, the CDPF need being regenerated after the soot accumulation. It is important to know characteristics of regeneration for CDPF with variation of exhaust gas temperature and composition. This study presents characteristics of regeneration according to variable exhaust gas composition. Furthermore, the experiment were performed variable gas temperature of CDPF inlet gas at each exhaust gas composition. Test-rig is used to control at each in let gas temperature and composition during regeneration of CDPF. Reaction intensity(Ic) is used to compare with each result. Experimental results indicated that increased concentration of NOx and O₂ lead to regenerate more greatly. Also, higher temperature of exhaust gas leads to make CDPF cleaner.

Effect of gas composition on dispersion characteristics of blowout gas on offshore platform

Dongdong Yang,Guoming Chen,Jihao Shi,Xinhong Li 대한조선학회 2019 International Journal of Naval Architecture and Oc Vol.11 No.2

Gas composition has a significant impact on the dispersion behavior and accumulation characteristics of blowout gas. However, few public studies has investigated the corresponding effect of gas composition. Therefore, this study firstly builds the FLACS-based numerical model about an offshore drilling platform. Then several scenarios by varying the composition of blowout gas are simulated while the scenario with the composition of “Deepwater Horizon” accident is regarded as the benchmark. Furthermore, the effects of the gas composition on the flammable cloud volume, the influenced area of flammable cloud, the influenced area of hydrogen sulfide and the critical time of the hydrogen sulfide spreading to the living area are analyzed. The results demonstrate that gas composition is a driving factor for dispersion characteristics of blowout gas. All the results can give support to reduce the risk of the similar accidents incurred by real blowouts.

Implementation of alternative gas compositions and effects on discharge properties of atmospheric pressure plasma in decomposition of CHF₃

Nguyen, Duc Ba,Lee, Won Gyu THE KOREAN SOCIETY OF INDUSTRIAL AND ENGINEERING 2017 Journal of Industrial and Engineering Chemistry Vol.52 No.-

<P><B>Abstract</B></P> <P>Discharge properties of atmospheric pressure plasma depend on the composition of the plasma gas. The effects of gas composition on the discharge properties of the atmospheric pressure plasma were investigated in a dielectric barrier discharge reactor immersed in an oil bath for CHF<SUB>3</SUB> decomposition. A variation of the CHF<SUB>3</SUB> fraction of several thousandths (0–0.8%) in the feed led to a significant change in the electrical properties of the plasma discharge when N<SUB>2</SUB> was a dilution gas; however, it did not occur with Ar or He as a dilution gas. Moreover, N<SUB>2</SUB> dilution gas showed high-energy photons in the visible spectrum.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Effects of gas compositions on the discharge properties of atmospheric pressure plasma for the CHF<SUB>3</SUB> decomposition. </LI> <LI> There is a significant change of the electrical properties due to the variation of CHF<SUB>3</SUB> fraction when N<SUB>2</SUB> a dilution gas. </LI> <LI> Analyzing visible spectra of atmospheric pressure plasma for the CHF<SUB>3</SUB> decomposition. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>Effects of gas composition on the electrical parameters of an atmospheric plasma discharge.</P> <P>[DISPLAY OMISSION]</P>

Mechanistic Analysis of MWCNT/ZnO Composite Film Gas Sensor Based on NOx Gas Detection Characteristics

김현수 대한설비관리학회 2023 대한설비관리학회지 Vol.28 No.4

A NOx gas sensor was fabricated using a multi-walled carbon nanotube (MWCNT)/zinc oxide composite film. Gas sensors require characteristics such as high speed, sensitivity, and selectivity. Thus, carbon nanotubes (CNTs) having good electronic properties, chemical stability, and great conductivity and zinc oxide, a wide band-gap semiconductor with a large exciton binding energy, were selected in this study. The fabricated gas sensor was used to detect NOx gas at different concentrations. The gas sensor absorbed NOx gas molecules with an associated increase in the sensitivity. The sensitivity of the gas sensor increased with increasing gas concentration. By varying the temperature inside the chamber of the MWCNT/ZnO composite film gas sensor, the sensitivity and normalized response for detecting NOx gas was determined. Based on comparative analysis with ZnO, the MWCNT film gas sensor is excellent for detecting NOx gas. The experimental data confirmed the enhanced gas sensing properties and sensor performance derived from the electronic interaction between the MWCNTs and ZnO film.

NO_X 가스 검출 특성을 이용한 MWCNT/ZnO 복합체 필름 가스 센서의 메커니즘 분석

손주형,김현수,박용서,장경욱,Son, Ju-Hyung,Kim, Hyun-Soo,Park, Yong-Seo,Jang, Kyung-Uk 한국전기전자재료학회 2018 전기전자재료학회논문지 Vol.31 No.3

In this study, we fabricated an $NO_X$ gas sensor using a composite film of multi-walled carbon nanotubes (MWCNT)/zinc oxide (ZnO). Carbon nanotubes (CNTs) show good electronic conductivity and chemical-stability, and zinc oxide (ZnO) is a wide band gap semiconductor with a large exciton binding energy. Gas sensors require characteristics such as high speed, sensitivity, and selectivity. The fabricated gas sensor was used to detect $NO_X$ gas at different $NO_X$ concentrations. The sensitivity of the gas sensor increased with increasing gas concentrations. Additionally, while changing the temperature inside the chamber containing the MWCNT/ZnO gas sensor, we obtained the sensitivity and normalized responses for detecting $NO_X$ gas in comparison to ZnO and MWCNT film gas sensors. From the experimental results, we confirmed that the gas sensor sensing mechanism was enhanced in the composite-film gas-sensor and that the electronic interaction between MWCNT and ZnO contributed to the improved sensor performance.

NOX 가스 검출 특성을 이용한 MWCNT/ZnO 복합체 필름 가스 센서의 메커니즘 분석

손주형,김현수,박용서,장경욱 한국전기전자재료학회 2018 전기전자재료학회논문지 Vol.31 No.3

In this study, we fabricated an NOX gas sensor using a composite film of multi-walled carbon nanotubes(MWCNT)/zinc oxide (ZnO). Carbon nanotubes (CNTs) show good electronic conductivity and chemical-stability, and zincoxide (ZnO) is a wide band gap semiconductor with a large exciton binding energy. Gas sensors require characteristicssuch as high speed, sensitivity, and selectivity. The fabricated gas sensor was used to detect NOX gas at different NOXconcentrations. The sensitivity of the gas sensor increased with increasing gas concentrations. Additionally, while changingthe temperature inside the chamber containing the MWCNT/ZnO gas sensor, we obtained the sensitivity and normalizedresponses for detecting NOX gas in comparison to ZnO and MWCNT film gas sensors. From the experimental results, weconfirmed that the gas sensor sensing mechanism was enhanced in the composite-film gas-sensor and that the electronicinteraction between MWCNT and ZnO contributed to the improved sensor performance.

아르곤 가스를 효율적으로 사용하기 위한 GMA 용접 토치 구조 Part 1 : AMAG와 DMAG 토치가 아르곤 조성에 미치는 영향

최상균,문명철,유중돈 대한용접접합학회 1999 대한용접·접합학회지 Vol.17 No.6

Shielding gas has significant effects on arc stability, metal transfer and weld quality in the gas metal arc welding (GMAW) process. The double gas-shielded MAG(DMAG) and auxiliary gas-shielded MAG (AMAG) torches are investigated for their capability to provide argon-rich gas mixture using small amount of argon gas through the inner and auxiliary nozzles, respectively. Argon composition with the DMAG torch is calculated numerically, and compared with the measured data using the gas chromatogrphy. Gas flow pattern of the DMAG torch is calculated to change from the laminar to turbulent flow when total gas flow rate becomes larger than 4.5 liter/min at room temperature. While argon-rich shielding gas was obtained using both the AMAG and DMAG torches, the AMAG torch provides higher argon composition than the DMAG torch, which demonstrates that argon gas can be utilized more efficiently with the AMAG torch.