• Journal of the Society of Naval Architects of Korea
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• v.55 no.2
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• pp.161-168
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• 2018

This paper presents the design procedure of the suction bucket used to support a subsea manifold. The soil-suction bucket interaction numerical analysis technique was verified by comparing the present results with a reference data. In order to simulate the soil-bucket interaction analyses of a subsea manifold structure, various material data such as undrained shear strength, elastic modulus, and poisson ratio of soft clay in Gulf of Mexico were collected from reference survey. We proposed vertical and horizontal design loads based on system weights and current-induced drag forces. Under the assumption that diameter of the suction bucket was 3.0 m considering real dimension of the subsea manifold frame structures, aspect ratio was decided to be 3.0 based on reference survey. The ultimate bearing load components were determined using tangent intersection method. It was proved that the two design load components were less than ultimate bearing loads.

• Journal of Ocean Engineering and Technology
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• v.25 no.5
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• pp.21-26
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• 2011

Seawater lift pump systems are responsible for maintaining open canal levels to provide the suction flow of circulating water pumps at the set point. The objective of this paper is to design a 2-stage mixed flow pump (for seawater lifting), investigate the new impeller modeling method, and performance improvements of the impeller by using a commercial CFD code. The rotating speed of the impeller is 1,750 rpm with a flow rate of 2,700 m3/h. A finite volume method with a structured mesh and realized k-${\varepsilon}$ turbulent model is used to guarantee a more accurate prediction of turbulent flow in the pump impeller. The performance variables such as the static head, brake horsepower, and efficiency of the mixed flow pump are compared based on changes in the impeller blade shape.

• Journal of Ocean Engineering and Technology
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• v.29 no.3
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• pp.207-216
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• 2015

Amanifold is one of the essential subsea oil and gas production components to simplify the subsea production layout. It collects the production fluid from a couple of wellheads, transfers it to onshore or offshore storage platforms, and even accommodates water and gas injection flowlines. This paper presents the basic design procedure for a manifold frame structure with novel structural verification using in-house unity check codes. Loads and load cases for the design of an SIL 3 class-manifold are established from a survey of relevant industrial codes. The basic design of the manifold frame is developed based on simple load considerations such as the self weights of the manifold frame and pipeline system. In-house software with Eurocode 3 embedded, called INHA-SOLVER, makes it possible to carry out code checks on the yield and buckling unities. This paper finally proves that the new design of the manifold frame structure is effective to resist a permanent and environment load, and the in-house code is also adaptively combined with the commercial finite element code Nastran.

• Journal of Ocean Engineering and Technology
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• v.30 no.4
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• pp.253-259
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• 2016

This study demonstrates the result of mooring analysis for five spread-moored FPSOs having different length-to-breadth (L/B) ratios from 4.5–6.5. FPSOs are subjected to four metocean conditions, ones from the Gulf of Mexico (Hurricane/Loop current condition), West Africa, Nigeria, and Brazil Campos Basin, which are amongst the most typical offshore oil and gas fields. With change in design parameters of OBA (Outer bundle angle) and IBA (Inner bundle angle) combinations, a change in the line tension is demonstrated and the OBA-IBA combinations having the smallest line tension are presented for each L/B ratio and sea, respectively. This study is expected to influence the preliminary design layout of an FPSO spread-mooring system as a function of the L/B ratio and metocean conditions.

• Transactions of the Korean hydrogen and new energy society
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• v.32 no.1
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• pp.53-62
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• 2021

Batch type reduction-oxidation tests were performed to check effects of temperature, pressure, gas velocity, and capacity on reduction characteristics of mass produced particle in a 0.5 MWth chemical looping combustion system. The fuel conversion and the CO2 selectivity increased as the temperature increased and as the gas velocity decreased. However the CO2 selectivity showed the maximum and decreased as the capacity increased because the CO emission increased. The results show that high temperature, low gas velocity and low inert gas concentration are preferable to ensure high reactivity of oxygen carrier in the fuel reactor.

• 한국신재생에너지학회:학술대회논문집
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• 2010.06a
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• pp.205.1-205.1
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• 2010

국내에서 발생하는 생활폐기물 발열량이 최근 3,000 kcal/kg 정도를 웃돌고 있고 사업장 폐기물의 경우는 4,000~7,000 kcal/kg 정도로 높아 이러한 가연성 폐기물 들은 자원화하여 에너지원으로 사용가능하다. 폐기물 자원화 기술의 하나인 가스화 기술을 적용하면 폐기물 내의 가연분은 CO, $H_2$가 주성분인 합성가스로 전환되어 화학원료 또는 발전원료로서 활용이 가능하다. 본 연구에서는 합성가스의 다양한 활용분야 중에서도 메탄올과 CO의 합성을 통해 얻어지는 초산제조 공정에서 폐기물의 가스화를 통해 발생되는 합성가스 내의 CO를 적용하여 기존 초산제조공정에서 필요한 CO를 생산하기 위해 소모되는 고가의 납사 원료를 절감하고자 하는 방안이 검토되고 있다. 초산은 CO와 메탄올($CH_3OH$)을 금속이온계 귀금속촉매 상에서 메탄올카본닐레이션(Methanol carbonylation)반응으로부터 합성되는 것으로, 초산에스테르, 염료, 안료, 의약품 등의 원료로 사용되는 화학원료이다. 일반적으로 초산을 제조하기 위해 사용되는 CO를 생산하기 위하여 납사(Naptha)를 가스화하는 부분산화공정을 이용하거나 촉매를 사용한 Steam reforming공정을 적용하고 있는데, 가스화 및 Steam reforming의 원료가 되는 납사가 고가이고, 원유가가 상승하면 납사의 가격도 상승할 수 있고, 결국 초산제조 비용의 상승을 초래할 수 있다. 폐기물의 가스화를 통해 발생하는 합성가스 내의 CO를 활용하여 초산제조의 원료로 사용할 수 있다면 초산제조 공정에서의 CO 제조 비용 절감 및 폐기물 자원화의 효과를 동시에 달성할 수 있을 것으로 생각된다. 본 연구에서는 초산제조의 원료로 폐기물의 가스화를 통해 발생한 합성가스 내의 CO를 적용가능성을 검토하기 위하여 사업장 폐기물 및 사업장폐기물과 폐유, 건조슬러지 등을 혼합한 복합폐기물의 가스화를 통해 CO의 발생 특성을 분석하였다.

• 한국신재생에너지학회:학술대회논문집
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• 2010.06a
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• pp.83.2-83.2
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• 2010

최근, 원유 가격의 상승으로 인해 태양에너지에 대한 관심이 크게 증가되고 있다. 그러나 이러한 태양전지용 Si(SoG-Si)의 대부분을 차지하는 태양전지급 다결정 실리콘 원료를 대부분 수입에 의존하고 있는 실정이다. 이에 대한 기술적 대응으로서 최근에는 고비용의 기상법을 해결하기 위하여 야금학적인 정련법을 이용한 제조기술 개발이 세계적으로 주목받고 있으며, 야금학적 정련기술은 지적재산권에 관한 기술적 배타성을 제고 할 수 있을 뿐 만 아니라 기상법의 Si 대비 낮은 품위 에도 불구하고 태양전지용 실리콘의 사용가능성을 제시함으로서 활발한 연구와 함께 실용화기술로 대두되고 있다. 그러므로 본 연구는 기존 사용 중인 고가의 기상법 폴리실리콘 제조와 달리, 생산 가격경쟁력이 있는 규석광으로부터 고순도금속 및 태양전지급 폴리실리콘 생산 연속 종전기술을 개발하고자 하였다. 금속급 Si(이하 MG-Si)으로부터 경제적인 SoG-Si을 제조하기 위한 공정 개발을 일환으로 MG-Si 중 불순물인 P 원소를 효과적으로 정련할 수 있는 슬래그 정련기술 개발과 슬래그설계 기술개발을 기본목표로 설정하여 고찰하였다. 용융 Silicon과 슬래그계면에 설정되는 산소분압제어에 따른 슬래그의 P의 이온 안정성을 변화시킴으로서, MG-Si중 P를 분리제거를 기본개념으로 설정하였다. 염기성 산화물로 산소이온이 공급됨을 이용하여 염기도에 따른 분배비를 고찰한 결과, CaO의 활동도가 증가함에 따라 슬래그 중 $O^{2-}$의 활동도와 함께 phosphide 이온의 안정성이 증가함을 확인하였다. 그리고 슬래그로부터 실리콘 중 Ca의 용해도에 따른 분배비를 확인하기 위해 실험 후 Si에서 Ca의 성분을 분석한 결과, 실리콘 중 Ca 용해도는 염기도($a_{CaO}/\sqrt{a_{SiO_2}}$)의 증가와 함께 증가하였으며, Ca의 용해도 증가는 탈린능을 증가시킨다는 것을 알 수 있었다. 또한 수소분압을 변화시켜 인의 증기압변화 및 기화정련 효과를 알 수 있었으며, acid leaching을 통해 잔존해있는 불순물을 추가적으로 정련될 수 있는 가능성을 확인할 수 있었다.

• Journal of Energy Engineering
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• v.20 no.2
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• pp.123-142
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• 2011

Coal Gasification Technology is one of the best alternatives among clean fossil fuel utilization. Major technology holding companies are devoting their efforts to develop more advanced technology to dominate the market in advance because of its importance on the applications such as IGCC, CTL, coal to SNG, various chemicals and so on. Japan and China, as well as America and European countries, have developed couple of thousands ton/day-class coal gasification technology. However, our gasification technology remains in the development stage with couple of ton/day-class pilot plant. So, we should be interested in developing this technology considering that we are heavily dependent of coal energy. In this paper, we summarized the trend and status of coal gasification technology development and commercial deployment of major technology holding companies mainly from the presentation materials of 'Gasification Technology Conference 2010', which is the biggest place of information exchange for recent coal gasification technology.

• Korean Journal of Microbiology
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• v.42 no.4
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• pp.286-293
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• 2006

Three hundred thirty two bacterial colonies which were able to degrade crude oil were isolated from soil samples that were contaminated with oil in Daejon area. Among them, one bacterial strain was selected for this study based on its low surface tension ability, and this selected bacterial strain was identified as Pseudomonas sp. G314 through physiological-biochemical tests and analysis of its 16S rRNA sequence. Pseudomonas sp. G314 showed a high resistance to antibiotics such as ampicillin, chloramphenicol, spectinomycin, and streptomycin, and heavy metals such as Li, Cr, and Mn. It was found that the optimal pH and temperature for biosurfactant production of Pseudomonas sp. G314 were pH 7.0 and $30^{\circ}C$, respectively. After seven hours of inoculated, the biosurfactant activity reached the maximum, and surface tension of the culture broth was decreased from 72 to 25 dyne/cm. The crude biosurfactant was obtained from the culture broth by acid precipitation, followed by solvent extraction, evaporation and then freeze drying. The CMC (critical micelle concentration) value of the crude biosurfactant was 20 mg/L.

• Clean Technology
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• v.8 no.1
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• pp.11-17
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• 2002

Petcokes is the final product obtained from a refinery process. This petcokes includes high percentage of inorganic and sulfur compounds. Currently, the petcokes produced from domestic refinery plants include more than 6% of sulfur. To use petcokes as valuable raw materials, the weight percentage of sulfur must be lower than 2% of sulfur. Solvent extraction, thermal desulfurization, and hydro-desulfurization have been used to remove the sulfur. In this study, we attempted new approach to remove the sulfur introducing microwave energy. Microwave increase the reaction rates by providing the fast heating and disconnecting the bonding structure of the molecules. The experiments of microwave thermal desulfurization and microwave plus hydrogen gas were carried out to remove the sulfur. We obtained 68.3% of sulfur removal rate with the 2 hours of reaction time and 1835 W of microwave powder. In the experiment of microwave with hydrogen gas, we obtained 86.4% of sulfur removal rate with the 1.5 hours of reaction time and 1835 W of microwave power. If we increase reaction time or decrease the particle size of petcokes, we expect more than 90% of sulfur removal.