• 제목/요약/키워드: Shell-and-tube

검색결과 224건 처리시간 0.021초

Feasibility Study of Employing a Catalytic Membrane Reactor for a Pressurized CO2 and Purified H2 Production in a Water Gas Shift Reaction

  • Lim, Hankwon
    • 청정기술
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    • 제20권4호
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    • pp.425-432
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    • 2014
  • 이 논문은 촉매막반응기(catalytic membrane reactor)에서의 중요한 두 요소인 수소선택도와 수소투과량 및 Ar sweep 유량과 압력이 수성가스전이반응의 성능에 미치는 영향에 대하여 1차원 반응기모델과 반응속도식에 근거한 연구결과를 나타내고 있다. 연소전 이산화탄소 포집의 한 방법으로서, 촉매막반응기를 사용하여 원통부분에서는 고압/고농도의 이산화탄소를 관부분에서는 고순도의 수소를 동시에 얻을 수 있는지에 대한 가능성을 검토하였다. 또한, 고농도의 이산화탄소와 고순도의 수소를 동시에 얻기 위해 필요한 수소투과량, 수소선택도, Ar sweep 유량 및 압력에 대한 지침을 나타내었다. 그 결과 $1{\times}10^{-8}molm^{-2}s^{-1}Pa^{-1}$의 수소투과량과 10000의 수소선택도를 가진 막을 장착한 촉매막반응기에서는 8 atm의 압력과 $6.7{\times}10^{-4}mols^{-1}$의 Ar sweep 유량의 조건하에서 약 90%의 농도를 가진 이산화탄소와 100%의 순도를 가진 수소가 동시에 얻어짐이 밝혀졌다.

설비공학 분야의 최근 연구 동향 : 2016년 학회지 논문에 대한 종합적 고찰 (Recent Progress in Air-Conditioning and Refrigeration Research : A Review of Papers Published in the Korean Journal of Air-Conditioning and Refrigeration Engineering in 2016)

  • 이대영;김사량;김현정;김동선;박준석;임병찬
    • 설비공학논문집
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    • 제29권6호
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    • pp.327-340
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    • 2017
  • This article reviews the papers published in the Korean Journal of Air-Conditioning and Refrigeration Engineering during 2016. It is intended to understand the status of current research in the areas of heating, cooling, ventilation, sanitation, and indoor environments of buildings and plant facilities. Conclusions are as follows. (1) The research works on the thermal and fluid engineering have been reviewed as groups of flow, heat and mass transfer, the reduction of pollutant exhaust gas, cooling and heating, the renewable energy system and the flow around buildings. CFD schemes were used more for all research areas. (2) Research works on heat transfer area have been reviewed in the categories of heat transfer characteristics, pool boiling and condensing heat transfer and industrial heat exchangers. Researches on heat transfer characteristics included the results of the long-term performance variation of the plate-type enthalpy exchange element made of paper, design optimization of an extruded-type cooling structure for reducing the weight of LED street lights, and hot plate welding of thermoplastic elastomer packing. In the area of pool boiling and condensing, the heat transfer characteristics of a finned-tube heat exchanger in a PCM (phase change material) thermal energy storage system, influence of flow boiling heat transfer on fouling phenomenon in nanofluids, and PCM at the simultaneous charging and discharging condition were studied. In the area of industrial heat exchangers, one-dimensional flow network model and porous-media model, and R245fa in a plate-shell heat exchanger were studied. (3) Various studies were published in the categories of refrigeration cycle, alternative refrigeration/energy system, system control. In the refrigeration cycle category, subjects include mobile cold storage heat exchanger, compressor reliability, indirect refrigeration system with $CO_2$ as secondary fluid, heat pump for fuel-cell vehicle, heat recovery from hybrid drier and heat exchangers with two-port and flat tubes. In the alternative refrigeration/energy system category, subjects include membrane module for dehumidification refrigeration, desiccant-assisted low-temperature drying, regenerative evaporative cooler and ejector-assisted multi-stage evaporation. In the system control category, subjects include multi-refrigeration system control, emergency cooling of data center and variable-speed compressor control. (4) In building mechanical system research fields, fifteenth studies were reported for achieving effective design of the mechanical systems, and also for maximizing the energy efficiency of buildings. The topics of the studies included energy performance, HVAC system, ventilation, renewable energies, etc. Proposed designs, performance tests using numerical methods and experiments provide useful information and key data which could be help for improving the energy efficiency of the buildings. (5) The field of architectural environment was mostly focused on indoor environment and building energy. The main researches of indoor environment were related to the analyses of indoor thermal environments controlled by portable cooler, the effects of outdoor wind pressure in airflow at high-rise buildings, window air tightness related to the filling piece shapes, stack effect in core type's office building and the development of a movable drawer-type light shelf with adjustable depth of the reflector. The subjects of building energy were worked on the energy consumption analysis in office building, the prediction of exit air temperature of horizontal geothermal heat exchanger, LS-SVM based modeling of hot water supply load for district heating system, the energy saving effect of ERV system using night purge control method and the effect of strengthened insulation level to the building heating and cooling load.

가물치의 위장내 기생하는 흡충(Azygia속) 및 선충(Pingus속)의 동정과 감염상황 (Identification and prevalence of trematode(Gen Azygia) and nematode(Gen Pingus) in Ophicephalus argus)

  • 문무홍;이은우
    • 대한수의학회지
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    • 제38권1호
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    • pp.147-159
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    • 1998
  • A survey of the internal parasites in 115 fishes of Ophicephalus argus was carried out in Kyungpook province during the period from January 1995 to November 1997. A species of trematode from the stomach and a species of nematode from the caeca of the fishes was discovered respectively. The trematode was identified as Azygia hwangtsinyi (Tsin, 1993) and the nematode as Pingus sinensis ($Hs\ddot{u}$, 1993). The fluke was pressed at thick of 0.1mm~0.2mm between slide glasses and fixed in 70% ethyl alcohol solution. The fluke was washed with tap water after fixation and stained with hematoxylin-carmin and mounted in balsam through routine methods. The nematode was fixed in 5% formalin solution and mounted with lactophnol or glycerine jelly. Morphology : Arygia hwantsinyi ; The fluke is elongate body with approximately parallel margins and rounded extremities in pressed preparations(Fig 1). The cuticle is unarmed. The oral sucker is ventro-subterminal in position. The ventral sucker is slightly smaller than oral sucker and positioned at 14.2% of body length from the oral sucker. The cirrus sac and genital pore is in mid-ventral line, slightly anterior to the ventral sucker. The oral sucker is succeeded by a well developed muscular pharynx. It is succeeded by a short inverted Y-shaped oesophagus. The inner wall of oesophagus is consisted of many fine folded membrane. The fine tubes of esophagus pass into the intestinal heads which are distended and presented a marked borderline between the fine tube and intestinal heads. The Intestinal heads start at level of pharynx and pass caudad in a zigzag course to end quite near caudal margin. The uterine coils occupy the intercecal area between the level of the cephalic margin of the ovary and about the level of the ventral sucker. The uterus is filled with many eggs. The testes are round or oval and placed one behind the other generally a little diagonally. The posterior testis is placed at level of 75.1% of body length. The ovary is oval, placed ahead the anterior testis. The shell gland not discernible outline is contacted with ovary ahead it. The vitelline glands are consisted of small oval vesicles. The vesicles occupy extracecal regions and between a little posterior of the ventral sucker and near caudal margin. Pingus sinensis : Female ; The cuticle is smooth and the cervical alae are well developed. The mouth opening is small, triangular, and without lips. The anterior end bears four sub-medial papillae. The oesophagus is divided into a muscular and glandular portion. The nerve ring is situated just at the junction of the muscular and glandular portions of the oesophagus. The vulva which has a prominent flap, is placed behind the middle of the body about one-third of the length of the worm from the posterior extremity. The vagina is strongly muscularised and after running anteriorly about $68{\mu}$, divides itself into two broad uterine tubes with an anterior and a posterior one. There are a few eggs in the uterine tubes. The tail is slender, straight and pointed. The ovary extends almost to the posterior extremity. Male : Male is smaller than female. The tail is pointed, curved and carrying well-developed caudal alae. A prominent muscular precloacal sucker is characteristic. The spicules are equal and short. There are four pairs of pedunculated pre-anal papillae, of which the most anterior pair are situated just at the level anterior to the muscular sucker. Two pairs of pedunculated papillae are present before the anus. There are five pairs of post-anal papillae of which the most anterior pair and the second counted from the posterior end are ventral and more marked than the ones which are situated laterally.

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제주도 우도 지역 내 지질유산의 다양성과 가치 (Natural Heritage Values and Diversity of Geoheritages on Udo Island, Jeju Province)

  • 우경식;윤석훈;손영관;김련;이광춘;임종덕
    • 헤리티지:역사와 과학
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    • 제46권1호
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    • pp.290-317
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    • 2013
  • 우도 내에 분포하는 여러 지질명소에 대해 자연유산적 학술적 가치를 조사하여, 이들의 보전가치와 세계자연유산으로서의 자격을 평가하였다. 우도는 작은 제주도라고 불릴 만큼 제주도 섬 내에 나타나는 다양한 지질유산적 특징을 가진다. 우도 내에는 우도를 형성한 수성화산체인 소머리오름과 소머리오름이 만들어지면서 형성된 여러 화산지형이 분포한다. 이들은 수성화산 분출에 의해 형성된 응회구와 그 위에 흐른 용암, 그리고 용암 내에 발달되어 있는 용암동굴과 화산 분화 후 재동되어 퇴적된 화산쇄설물이다. 플라이스토세에 이르러 수십 차례에 걸쳐 빙하기와 간빙기가 교호하면서 우도는 섬과 육지환경이 계속적으로 반복해 왔다. 마지막 최대 빙하기 이후에 해수면이 현재와 같이 상승한 약 6000년 전부터 우도 주변의 천해환경에서는 많은 탄산염 퇴적물이 형성되기 시작하였다. 특히 우도와 제주도 사이에 존재하는 수심이 20m 이내의 넓은 천해환경은 홍조단괴가 만들어지는 최적의 환경을 제공하였으며, 현재에도 많은 홍조단괴가 자라고 있다. 이렇게 만들어진 홍조단괴는 태풍에 의해 지속적으로 해안가로 운반되어 홍조단괴로만 이루어져 세계 유일이라고 판단되는 해빈퇴적물을 형성하였다. 하지만 이 해빈퇴적물은 전통적으로 학계에 알려진 해빈퇴적물과는 그 성인적 측면에서 구별된다. 전형적인 해빈퇴적물로는 탄산염 퇴적물로만 이루어진 하얀 모래의 하고수동 해빈, 화산쇄설물이 침식되어 퇴적된 검은 모래의 검멀레 해빈, 그리고 주변의 현무암이 침식되어 커다란 자갈로만 이루어진 톨칸이 해빈이 나타난다. 과거 바람에 의해 탄산염 해빈퇴적물이 육지로 운반되어 형성된 사구층이 나타나며, 우도의 북쪽 해안가 세배곶 지역에는 전형적인 해빈의 형성과 태풍의 영향으로 퇴적된 복합적인 성인을 가진 퇴적물도 나타난다. 화산쇄설물로 이루어진 퇴적층을 따라 발달한 해안 절벽에는 파도의 침식에 의해 형성된 해식동굴이 여러 개 발견된다. 특히 수심 10m 부근에 나타나는 수중 해식동굴은 해수면의 변화를 반영하는 뛰어난 지형으로 평가된다. 이러한 우도의 다양한 지질유산은 우도가 매우 뛰어난 지질다양성을 보여주는 장소임을 지시한다. 전 세계에서 우도의 홍조단괴 해빈과 같이 거의 모든 퇴적물이 홍조단괴로만 이루어진 지역은 매우 드물며, 수중폭발에 의해 형성된 소머리오름은 제주도 내에 나타나는 다른 수성화산체인 성산일출봉, 수월봉, 송악산, 용머리 등과 함께 세계자연유산으로 등재될 자격이 있는 것으로 판단된다. 현재 홍조단괴 해빈은 국가지정 천연기념물로 지정되어 있으나 그 지정 지역 밖에도 더 넓은 지역에 홍조단괴가 형성되고 있으므로 보전지역의 확장이 필요하다. 또한 소머리오름도 그 지질유산적 가치의 보전을 위해 천연기념물로 지정할 필요가 있다.