• 한국환경과학회지
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• 제9권5호
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• pp.389-392
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• 2000

In this study a packed tower was selected for the treatment apparatus of $NH_3$ gas produced in industry. Formerly latticework packing has been used in preventive facility of treatment of $NH_3$ gas. However recently metallic Ralu-Pack 250YC. structured packing is usually being used in petrochemical production plant. This study is for the application the packing to the $NH_3$ gas treatment in wet scrubbing process. In Air/water system hydraulic pressure drop dependent of specific liquid load and gas capacity factor was continuous and parallel from graph. The tower height can be determuined by the number of transfer unit and the height of transfer unit influenced on liquid distribution.

• 한국대기환경학회지
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• 제14권6호
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• pp.537-544
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• 1998

We selected Spathiyhyllum patinii and Pachira aqkatica, since the former has high O3 absorption while the latter low absorption, and analyzed physiological factors such as diffusive coefficient, transpiration rate, photosynthetic rate, and CO2 absorption rate, which affected O3 absorption capacity There was significant relationship between gas absorption capacity and the other factors; photosynthetic rate, diffusive resistance, stomatal resistance and CO2 absorption rate. Therefore model formula for estimation of O3 absorption rate in plant was formulated by making use of these factors. There was difference for the estimation of O3 absorption rate according to plant species. In case of Spathiphyllum patinii, photosynthetic rate is an optimal factor for estimation of O3 absorption capacity. On the other hand, stomatal resistance and diffusive resistance are optimal factors of Pachira aquatica among various physiological ones. And we knew that CO2 absorption rate is a potential factor to evaluate gas absorption capacity regardless of plant species. But considering efficiency and practicality, diffusive resistance was the most effective factor for the estimation of O3 gas absorption.

• 한국통신학회논문지
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• 제33권11A호
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• pp.1079-1086
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• 2008

본 논문을 통해 GAS-CP-CDMA(우수한 자기상관 특성의 시퀀스를 사용하는 순한확장 CDMA) 시스템이 제안되었고 그 시스템의 상향링크의 신호대 잡음비 성능이 분석되었다. 다른 사용자를 구분하기 위해 위상이 편이된 시퀀스가 사용된다. GAS-CP-CDMA 시스템의 신호는 좋은 자기상관 특성 덕분에 동일 셀내의 다른 사용자 신호와 거의 간섭을 일으키지 않는다. 그러나 인접셀의 사용자 신호는 간섭을 일으킨다. CDMA 시스템에서 주파수 재사용율은 0.6 정도이다. 따라서 기존 CDMA 방식에서 인접셀로 부터 유입되는 간섭은 전체 간섭의 40% 정도가 된다. 수치분석은 주파수 재사용율에 대한 신호대 잡음비와, 사용자 수에 따른 신호대 잡음비 성능에 대해 수행되었으며, GAS-CP-CDMA 시스템은 기존 CDMA 시스템보다 우수한 성능을 가지는 것으로 분석되었다. 제안된 시스템의 상향링크 사용자 용량은 기존 CDMA 시스템의 약 2배로 증가됨을 확인하였다.

• 청정기술
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• 제26권2호
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• pp.102-108
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• 2020

오늘날 석유화학, 정밀화학, 대기오염 방지산업 등에서 증류, 흡수, 추출, 탈거 등 물질분리 단위공정으로 주로 충전탑을 사용해 왔다. 충전탑은 가스-액체, 가스-가스 시스템에서의 물질들과의 접촉에 의해 운전되어 진다. 이러한 충전탑은 낮은 압력손실, 경제적 효율, 고온성 액체물질 적용, 유지보수 용이, 유해가스 처리 등의 운영에서 장점들을 가진다. 충전탑의 성능은 충진물을 통해 가스와 액체를 고르게 분산함으로써 우수한 성능을 보이며, 이는 충전탑 설계에 있어 중요한 인자로 고려되어진다. 본 실험에서는 충진물에 대한 액체부하 및 가스용량인자에 따른 건조압력손실, 수력학적 압력손실, 액체함량 변화에 대한 기하학적 특성에 대하여 연구하였다. 결과로부터 설계인자와 운전조건 등의 유해가스 처리에 필요한 인자를 도출하였다. 임의 충진물인 raschig super-ring에 대한 건조압력손실을 측정한 결과, 가스용량인자가 증가할수록 일정하게 선형적으로 증가하였고, 가스용량인자가 0.630 ~ 3.448 kg^-1/2 m^-1/2 S^-1에서 건조압력손실은 1.892 ~ 47.312 mmH₂O m^-1로 기존 산업현장에서 보편적으로 사용되는 35 mm pall-ring보다도 낮은 압력손실을 보였다. 그리고 raschig super-ring에 대한 수력학적 압력손실을 측정한 결과, 고유 액체부하에 대하여 가스용량인자가 증가할수록 압력손실도 함께 증가함을 확인하였고, 액체부하 변화에 따른 가스용량인자가 1.855 ~ 2.323 kg^-1/2 m^-1/2 S^-1으로 20% 증가할 때, 압력손실은 약 17% 증가하는 것으로 나타났다. 마지막으로, 충진물 체적에 관한 액체함량은 가스용량인자에 의존된 액체부하 매개변수로서 액체부하 변화에 따른 가스용량인자 약 3.84 kg^-1/2 m^-1/2 S^-1까지는 거의 일정한 액체함량을 보였으나, 그 이상에서는 급격하게 증가하였다.

• Geosystem Engineering
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• 제21권6호
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• pp.318-325
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• 2018

Eight tight sandstone reservoir samples from $He_8$ and $Shan_1$ Formations of the Sulige Gas field were selected to perform gas-water micro-displacement experiment based on authentic sandstone micro-model. The gas pressure-relief experiment was proposed for the first time to simulate the pressure change and gas-water percolation characteristics in the process of gas exploitation. The experiment results show that: (1) In the process of gas accumulation, the gas preferentially flows into the well-connected pores and throats with large radius, but rarely flows into the area without pores and throats. (2) Under sufficient gas drive, the water in pores and throats usually exists in the forms of 'thin water film', 'thick water film', and 'water column', but under insufficient gas drive, gas fails to flow into new pathways in time, so that the reservoirs with large pores and throats are high in water cut. (3) Under the same water saturation, the reservoirs with better petrophysical properties has higher gas recovery factor within unit time. Under the same petrophysical conditions, the reservoirs with lower water saturation show higher gas recovery factor within unit time. The higher the permeability, the stronger the liquid carrying capacity of reservoirs.

• 설비공학논문집
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• 제8권2호
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• pp.279-287
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• 1996

A cycle analysis is performed to investigate how the non-ideal gas behavior of helium reduces the heating capacity of VM heat pumps. Since the operating pressures of VM heat pumps are as high as 1 to 20 MPa, the compressibility factor of helium becomes clearly greater than 1 and the non-ideal behavior always represents a thermal loss in heating. To calculate the amount of the losses, an adiabatic cycle analysis is performed with the real properties of helium and the net enthaply flows through the two regenerators are numerically obtained. It is shown that the non-ideal gas losses could be as much as 8% in the heating capacity when the operating pressures are greater than 10MPa. The effects of the operating temperatures and the dead volumes on the loss are presented.

• 한국가스학회지
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• 제20권3호
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• pp.46-51
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• 2016

천연가스 액화공정은 극저온에서 운전되며, 에너지 집약적이다. 따라서 에너지 소모량을 최소화하기 위한 최적화 연구가 많이 진행되고 있으나, 천연가스 액화공정의 용량에 따른 비용 최적화는 많이 이루어지지 않고 있다. 본 연구에서는 다양한 천연가스 액화공정 중 SMR (Single Mixed Refrigerant) 공정을 대상으로, 용량별 설치비용과 운전비용을 분석하였다. SMR 공정의 용량은 1 MTPA (million ton per annum)부터 0.5 MTPA 단위로 증가하여 2.5 MTPA까지 설정하였다. 플랜트 용량의 증가에 따라 천연가스와 냉매의 유량만을 증가시켰으며, 온도, 압력, 조성 등 다른 운전조건은 모든 용량에서 동일하게 적용하였다. 비용 분석을 위해 Aspen Economic Evaluator(v8.7)를 사용하였으며, 비용 정보를 얻기 힘든 다중 흐름 열교환기의 경우에는 six tenths factor rule을 적용하여 계산하였다. 또한 용량별 SMR 공정의 비용 연구결과를 2천만 톤, 4천만 톤 및 8천만 톤 규모의 소규모 가스전에 대하여 적용한 결과, 가스전 규모에 따라 최적의 플랜트 용량을 찾을 수 있었다. 이러한 비용 분석을 통해 비용기반 최적화의 발판을 마련하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2009년도 제40회 하계학술대회
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• pp.468_469
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• 2009

The application of renewable energy in electric power systems is growing rapidly in order to make provision for the inequality of the climate, the dwindling supplies of coal, oil and natural gas and a further rise in oil prices. Solar cell generators(SCG) is one of the fastest growing renewable energy. A study on the renewable energy is getting more important for the application of renewable energy. This paper presents the capacity factor of SCG by calculating the probabilistic production energy of SCG.

• 공학논문집
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• 제6권2호
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• pp.85-98
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• 2004

The adsorption equilibrium data for the binary gas mixture system from the pure gas adsorption data of carbon dioxide and ethylene on ZSM-5 prepared were predicted. The binary gas mixture adsorption data have been examined against predicted values by two models-the vacancy solution model(VSM) and the statistical thermodynamic model(STM), using parameters obtained from the single component isotherm. The binary gas mixture data for the carbon dioxide-ethylene system were obtained for cation exchanged forms of ZSM-5 for the gas phase carbon dioxide mole fraction of 0.752 at $37^{\circ}C$ and 1 atm. The experimental adsorption phase diagrams were obtained for carbon dioxide-ethylene on sodium form ZSM-5 synthesized. The single component adsorption isotherms for carbon dioxide and ethylene were also obtained for this zeolite. The single component data were used to obtain parameters derived in two models. These parameters were, in turn, used to predict the binary mixture isotherms for this zeolite. Both the vacancy solution and the statistical thermodynamic models give satisfactory predictions of adsorption phase diagrams for the binary gas mixtures of carbon dioxide and ethylene on sodium exchanged ZSM-5. Also the correlation between the experimental data and the predicted values is generally in good agreement. The system appears to show ideal behavior with a relatively constant separation factor. The slight increase in adsorption capacity with an increase in ionic radius is due, in part, to the higher polarizability associated with larger cations.

• Structural Engineering and Mechanics
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• 제53권5호
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• pp.881-896
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• 2015

In this study, a method for fatigue performance estimation of deepwater steel catenary riser (SCR) under short-term vortex-induced vibration was investigated for selected S-N curves. General tendency between S-N curve capacity and fatigue performance was analysed. SCRs are generally used to transport produced oil and gas or to export separated oil and gas, and are exposed to various environmental loads in terms of current, wave, wind and others. Current is closely related with VIV and it affects fatigue life of riser structures significantly. In this regards, the process of appropriate S-N curve selection was performed in the initial design stage based on the scale of fabrication-related initial imperfections such as welding, hot spot, crack, stress concentration factor, and others. To draw the general tendency, the effects of stress concentration factor (SCF), S-N curve type, current profile, and three different sizes of SCRs were considered, and the relationship between S-N curve capacity and short-term VIV fatigue performance of SCR was derived. In case of S-N curve selection, DNV (2012) guideline was adopted and four different current profiles of the Gulf of Mexico (normal condition and Hurricane condition) and Brazil (Amazon basin and Campos basin) were considered. The obtained results will be useful to select the S-N curve for deepwater SCRs and also to understand the relationship between S-N curve capacity and short-term VIV fatigue performance of deepwater SCRs.