• 한국유체기계학회 논문집
• /
• 제19권6호
• /
• pp.68-74
• /
• 2016

Hydraulic fracturing of wells during oil and gas (O&G) exploration consumes large volumes of fresh water and generates larger volumes of contaminated wastewater with high salinity. It is critical to treat and reuse the O&G wastewater in a cost-effective and environmentally sound manner for sustainable industrial development and for meeting stringent regulations. Recently, forward osmosis (FO) has been examined if it is a promising solution for treatment and desalination of complex industrial streams and especially fracturing flowback and produced waters. In the present study, the performances of a plate-and-frame FO membrane element and a module (6 elements combined in series) were investigated for concentrating high TDS wastewater. An FO module has achieved up to 64 % water recovery (i.e., concentration factor of 2.76) from 10,000 ppm wastewaters and can concentrate feed streams salinities to greater than 30,500 ppm.

• KSBB Journal
• /
• 제14권1호
• /
• pp.109-113
• /
• 1999

이산화탄소를 용매로하는 초임계유체 크로마토그래퍼(SFC)방법을 이용하여 어유로부터 EPA및 DHA를 고순도로 분리정제하는 연구를 하였다. 질산은 칼럼을 이용하는 초임계 이산화탄소의 초기 압력조건 변화가 저 지방산의 용해도 및 분리도에 미치는 영향을 조사하였는데 압력이 증가될수록 저지방산의 용해도는 증가되었고, 반면에 EPA와의 분리도는 감소하는 경향을 나타내었다. EPA의 분리정제 효율을 높이기 위해 초임계 이산화탄소에 대한 단계별 밀도구매 방법을 적용하였다. 적용 결과 초기에 저지방산이 먼저 분리되었고, 계속해서 92.1%~97.8%EPA 순도를 갖는 분획들을 얻을 수 있었다. 순도가 높은 3개의 분획의 평균 순도는 95.6%이었고 회수율은 30%에 달하였다.

• Environmental Engineering Research
• /
• 제16권1호
• /
• pp.11-18
• /
• 2011

The aim of this research was to introduce a new rapid analysis method (heating of the multi-layer silica gel column/alumina column) for polychlorinated biphenyls in insulating oils, and to compare our new method with the analytical method currently used in Korea. The entire pretreatment procedure was completed within 2 hr, using about only 20 mL of solvents via our rapid analytical method. Furthermore, the pretreatment procedure can always be uniformly performed, regardless of oil type (JIS 1~JIS 7 and KS 1~KS 7). The recovery rates were more than 89%, with relative standard deviations below 6.0%. In conclusion, this rapid analytical method could reduce the pretreatment time and solvent usage by 1/10 and between 1/25 and 1/50, respectively, compared to analytical method currently used in Korea.

• 자원리싸이클링
• /
• 제13권3호
• /
• pp.27-36
• /
• 2004

수소화 반응용 니켈 폐촉매를 배소하여 산화니켈을 회수한 다음, 회수한 산화니켈을 산처리하고 침전법으로 Kieselguhr에 담지 된 니켈 촉매로 재생시켰다. 폐촉매의 배소 조건이 니켈산화물의 회수에 미치는 영향을 조사하였다. 니켈 폐촉매의 재생 과정에서 $1,000^{\circ}C$의 온도에서 배소 하였을 경우에 대부분 니켈산화물로 회수할 수 있었다. 산화니켈을 산처리하여 얻은 질산니켈을 사용하여 Kieselguhr에 담지 된 니켈 촉매를 제조하였다. 이때 조촉매의 첨가, 침전 조건 및 환원 조건 등이 재생된 촉매의 식물성 오일의 수소화 반응 성능에 미치는 영향을 조사하였다. 알카리 금속인 CaO와 희토류 금속인 $Ce_2$$O_3$를 조촉매로 첨가했을 때 수소화 반응의 활성이 증가하였다.

• 한국항공우주학회지
• /
• 제34권10호
• /
• pp.61-70
• /
• 2006

마하 4 비행 조건에서 작동하는 고성능 램제트와 듀얼모드 스크램제트 엔진의 초음속 공기 흡입구 모델을 설계하였다. 배압, 받음각, 요각 등 비행 변수의 변화에 따른 내부 유동 특성을 파악하기 위하여 규슈대학교의 불어내기식 초음속 풍동을 이용한 실험을 수행하였다. 유동 가시화를 위하여 쉴리렌 기법, 오일 가시화 기법을 이용하였으며, 정량적 성능 분석을 위하여 표면 압력 및 전압력을 측정하였다. 실험의 결과는 전산 유체 해석과 비교하였다. 본 연구는 기본적이지만 찾기 힘든 고 마하수 초음속 공기 흡입구 유동의 실험 결과를 제시한다.

• Ocean Systems Engineering
• /
• 제4권3호
• /
• pp.215-241
• /
• 2014

Steel catenary riser (SCR) is a popular/economical solution for the oil/gas production in deep and ultra-deep water. The behavioral characteristics of SCR have a high correlation with the motion of floating production facility at its survival and operational environments. When large motions of surface floaters occur, such as FPSO in 100-yr storm case, they can cause unacceptable negative tension on SCR near TDZ (touch down zone) and the corresponding elastic deflection can be large due to local dynamic buckling. The generation, propagation, and decay of the elastic wave are also affected by SCR and seabed soil interaction effects. The temporary local dynamic buckling vanishes with the recovery of tension on SCR with the upheaval motion of surface floater. Unlike larger-scale, an-order-of-magnitude longer period global buckling driven by heat and pressure variations in subsea pipelines, the sub-critical local dynamic buckling of SCR is motion-driven and short cycled, which, however, can lead to permanent structural damage when the resulting stress is greatly amplified beyond the elastic limit. The phenomenon is extensively investigated in this paper by using the vessel-mooring-riser coupled dynamic analysis program. It is found that the moment of large downward heave motion at the farthest-horizontal-offset position is the most dangerous for the local dynamic buckling.

• 신재생에너지
• /
• 제4권4호
• /
• pp.37-43
• /
• 2008

Three properties of food waste are water 80%, ash 3%, volatile matter 17%. When food waste goes through treatment process such as removal of foreign substances, removal of water as well as sodium, dryness, and pulverization, it transforms into 4,000 Kcal/kg purverized fuel if moisture content is below 13%. Fuel ratio (fixed carbon/volatile matter) of purverized fuel is low compared with bituminuous coal. Ignition temperature measured by thermogravimetry analyzer is about $460^{\circ}C$. Combustion test of purverized fuel have been performed using energy recovery facility which include storage tank of dewatered cake, dryer, hammer mill, combuster including burner, boiler, flue gas treatment equipment. When 160-180 kg/hr of fuel is steadily supplied to burner for 3 hours, combustor temperature reaches about $1000^{\circ}C$ and CO is 77-103 ppm at 1.55 excess air ratio and SOx and Cl are under 2 ppm and 1ppm, respectively. This experiment demonstrate that purverized fuel made from food waste could be an alternative clean energy at the age of high oil price.

• 대한전자공학회:학술대회논문집
• /
• 대한전자공학회 2001년도 The 6th International Symposium of East Asian Resources Recycling Technology
• /
• pp.215-219
• /
• 2001

Impurities removal from waste carbon black was carried out to produce high-grade carbon black. A lot of hydrophilic carbon black is produced as a byproduct of the hydrogen production process by flame decomposition of water. Due to its impurity content such as sulphur, iron, ash and etc., it can only be used as low-grade carbon or burnt out. High-grade hydrophilic carbon black is 3-5 times more expensive than oil-based carbon black because of its process difficulties and requires pollutant treatment. Hydrophilic carbon is normally used far conductive materials for batteries, pigment for plastics, electric wire covering, additives for rubber, etc.. In these applications, hydrophilic carbon must maintain its high purity. In this study magnetic separation, froth flotation and ultrasonic treatment were employed to remove impurities from the low-grade hydrophilic carbon black. As results, the ash, iron and sulphur content of product decreased to less than 0.01wt.%, 0.0lwt.% and 0.3wt.% respectively, and the surface area of product was about 930 $m^2$/g.

• 소성∙가공
• /
• 제25권2호
• /
• pp.116-123
• /
• 2016

Press-brake bending is used to shape flat and thick plates into a targeted circular configuration without excessive localized thinning or thickening. A brake bending press called 'a knife press bending apparatus' has been widely adopted to manufacture thick, large and long pipe from initially thick plate. Submerged Arc Welded (SAW) pipes are also produced by employing press-brake bending. These pipes are mainly used for oil, natural gas and water pipelines. The principal process variables for press-brake bending can be summarized as stroke of the press-brake knife, the distance between both roll in the lower die, and the feeding length of the plate. Many combinations of these process variables are available, thus various pipe diameters can be realized. In the current study, a series of repetitive numerical simulations by feeding a thick plate with initial thickness of 25.4mm were conducted with the consideration of elastic recovery. Furthermore, an index for SAW pipe production is proposed which can be widely used in industry.

• 조명전기설비학회논문지
• /
• 제23권5호
• /
• pp.1-8
• /
• 2009

자동차의 자동변속기에는 변속을 하기 위한 솔레노이드 밸브가 장착되어 있으며, 이 솔레노이드 밸브는 자동변속기의 고장 원인 중 상당부분을 차지하므로 이 밸브를 세척하기 위하여 솔레노이드 밸브 세척기를 사용한다. 그러나 현재 사용되고 있는 세척기는 슬러지를 제거하는 효과가 적고 세척 속도가 느린 단점을 가지고 있다. 본 논문에서는 솔레노이드 오프시에 잔류전류를 신속하게 제거하여 플런저의 동작속도를 증가시킴으로써 세척력을 증가시키고 세척 속도를 빠르게 하는 방법을 제안하였으며, 그 성능을 실험을 통해 증명하였다.