• 전기학회논문지
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• 제56권5호
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• pp.921-925
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• 2007

Gas removal characteristics of an air clean system, consisted of a filter and a nonthermal discharge plasma reactor with a magnetic field, have been investigated with emphasis on the enhancing gas removal efficiency of the applied magnetic field. It is found that the magnetic field influenced significantly to the corona discharge characteristics, decreasing the corona onset voltage and increasing the corona current. As a result, the proposed air clean system with the magnetic field showed the higher removal efficiency of the gas (e.g., trimethlyamine) than that of without the magnetic field. This would be because the magnetic field applied to the discharge plasma reactor of the air clean system can elevate the corona characteristics, and activate the generation of ozone, thus the removal efficiency of the gas was concurrently enhanced. This reveals that the proposed air clean system with the magnetic field could be used as an effective means of removal an indoor pollutant gas.

• 기술사
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• 제12권4호
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• pp.26-31
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• 1979

천연가스는 그 생성을 석유원유와 같이 하고 있으며 이두 열에너지자원은 해성생물인 Plankton의 해저퇴적물이 심해저의 혐기성 환경하에서 생화학적 작용을 받으면서 매몰되어 탄화수소가스와 탄화수소유로 변질된 것이다. 이러한 자원의 부존지층은 주로 제삼기층의 수성퇴적암층으로 되어 있다. 천연가스의 부존형태는 유전성가스전 구조성가스트 및 수용성가스전의 세가지형태로서 구분될 수 있다.

• 한국대기환경학회지
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• 제17권2호
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• pp.223-231
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• 2001

In order to provide some insights into the influence of electric field, gas composition, and gas temperature on electron energy distribution and electron transport characteristics, the Boltzmann equation was solved by using cross section data for electron collisions, Critical electric fields for the corona development in dry air and flue gas are 150 and 80 Td, respectively. It was seen that the decrease of critical electric field in flue gas is mainly caused by the $H_2O$ addition through the comparison of ionization and attachment coefficients of gas components. Increase of $O_2$, $H_2O$, and $CO_2$ contents in gas affected discharge characteristics according to their reciprocal characteristics between lowering the ionization threshold and increasing the electro-negativity. As electric field increases, electrons with higher energies in the electron energy distribution also increase. The mean and characteristic electron energies also linearly increase with electric field. The variation of flue gas temperature did rarely affect on the electron energy distribution function and electron transport characteristics, because the gas temperature is several hundreds or thousands times lower than the electron temperature.

• Geomechanics and Engineering
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• 제12권3호
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• pp.465-481
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• 2017

Thermal effect has great influence on wellbore stability in Dongfang 1-1 (DF 1-1) gas field, a reservoir with high-temperature and high-pressure. In order to analyze the wellbore stability in DF1-1 gas field, the variation of temperature field after drilling was analyzed. In addition, the effect of temperature changing on formation strength and the thermal expansion coefficients of formation were tested. On this basis, a wellbore stability model considering thermal effect was developed and the thermal effect on fracture pressure and collapse pressure was analyzed. One of the main challenges in this gas field is the decreasing temperature of the wellbore will reduce fracture pressure substantially, resulting in the drilling fluid leakage. If the drilling fluid density was reduced, kick or blowout may happen. Therefore, the key of safe drilling in DF1-1 gas field is to predict the fracture pressure accurately.

• Journal of Electrical Engineering and Technology
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• 제5권4호
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• pp.631-636
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• 2010

Gas-insulated transmission lines (GITL) are valued as technological solutions in hydro-power stations due to their enormous power handling capabilities. The performance of GITL is a function of the size of metallic particles inside the gas-insulated chamber. Electrostatic field (E-field) enhancement is a common phenomenon in gas-insulated lines due to these metallic particles. In this study, the E-field enhancement factor is calculated by considering metallic particles at various locations in the gas-insulated line/bus section, such as high-tension (HT) conductor, high-voltage shields, support insulator, and inner surface of grounded enclosure. For this purpose, a two-dimensional model based on finite element (FE) method is developed. The length of the metallic particle is in the range of 1 to 10 mm while the diameter is between 1 to 3 mm. E-field enhancement is also computed for various particle configurations of the gas-insulated system, with focus on dielectric coating made of epoxy on HT conductor and inner surface of grounded enclosure.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2001년도 학술대회논문집
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• pp.187-191
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• 2001

In this paper, the ac breakdown characteristics of Ar/$N_2$and Kr/$N_2$gas mixtures with gas pressure range of 58.8~137.3[kPa] under uniform and non-uniform fields were investigated. Summarizing the experimental results, the breakdown voltages of Ar/$N_2$ gas mixtures were decreased with decreasing the mixture ratio of pure $N_2$gas. In case of Ar(85%)/$N_2$(15%) and Ar(70%)/$N_2$(30%) gas mixtures comparing to the pure Ar gas, the breakdown voltages under uniform field were increased about 1.8 and 2.2 times, and under non-uniform field were increased about 1.1 and 1.3 times at the pressure of 101.3[kPa]. Also, in case of Kr(85%)/$N_2$(15%) and Kr(70%)/$N_2$(30%) gas mixtures comparing to the pure Kr gas, the breakdown voltages under uniform field were increased about 1.7 and 2.0 times, and under non-uniform field were increased about 1.0 and 1.2 times.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 1996년도 춘계 학술대회논문집
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• pp.131-136
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• 1996

The numerical method for the flow field of a gas atomization process is presented. For the analysis of the compressible supersonic jet flow of a gas. an axisymmetric Navier-Stokes equations are solved using a LU-factored upwind method. The MUSCL type TVD scheme is used for the discretization of inviscid flux, whereas Steger-Warming splitting and LU factorization is applied to the implicit operator. For the validation of the present method, we computed the flow field around the simple gas atomizer proposed by Issac. The numerical results has shown excellent agreement with the experimental data.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1993년도 하계학술대회 논문집 B
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• pp.601-604
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• 1993

The effect of an insulator inserted along the axis of a red-to-plane gap on an ion flow field in $SF_6$ gas is investigated experimentally in the pressure region where a proceeding corona discharge exists. Without the insulator, the calculated electric field on the plane electrode agrees fairly well with the measured one. With the insulator, the ion flow field characteirstics may be attributed to the change in the electric field distribution by the accumulated charge, the increase in the ratio of the dielectric strength in gas gap to that along the insulator surface with the gas pressure, and the thermal diffusion of ions near the insulator.

• 한국가스학회지
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• 제14권4호
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• pp.51-55
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• 2010

전 세계적으로 온실가스인 이산화탄소 배출을 감축하기 위하여 다양한 노력이 이루어지고 있다. 이러한 상황에서 이산화탄소가 함유된 중소규모 가스전은 LNG로 개발하기에는 경제성이 떨어진다. 특히 가스전에 포함된 이산화탄소를 분리하기 위하여 분리설비가 추가로 설치되어야 한다. 따라서 플랜트 건설비용이 증가하고, 분리된 이산화탄소는 대기중으로 배출되어 온실가스 감축과는 상반되는 결과를 가져온다. 이러한 비경제적인 가스전에 KOGAS DME Process를 적용하면 가스전에 포함된 이산화탄소를 천연가스와 함께 원료가스로 활용할 수 있어 경제성이 높아진다. KOGAS DME Process는 합성가스를 제조하는 Tri-reformer(삼중개질반응기)를 통하여 $H_2$와 CO로 이루어지는 합성가스를 제조하는데 원료가스로 천연가스와 산소, 스팀, 이산화탄소를 활용한다. 여기서 사용되는 이산화탄소는 공정상 발생하는 이산화탄소를 회수하여 원료가스로 활용하게 된다. 따라서 본 연구에서는 공정상 발생하는 이산화탄소의 발생량과 원료가스로 사용되는 이산화탄소의 사용량 그리고 가스전에 포함된 이산화탄소의 함량을 분석하여 가스전에 포함된 이산화탄소의 활용범위를 연구하고자 한다.

• 대한자원환경지질학회:학술대회논문집
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• 대한자원환경지질학회 2000년도 춘계 공동학술발표회
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• pp.99-100
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• 2000