• Journal of Microbiology and Biotechnology
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• 제19권11호
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• pp.1369-1373
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• 2009

Succinic acid was produced by continuous fermentation of Actinobacillus succinogenes sp. 130Z in an external membrane cell recycle reactor to improve viable cell concentration and productivity. Using this system, cell concentration increased to 16.4 g/l at the dilution rate $0.2\;h^{-1}$, up to 3 times higher than that of batch culture, and the volumetric productivity of succinic acid increased up to 6.63 g/l/h at the dilution rate $0.5\;h^{-1}$, 5 times higher than that of batch fermentation. However, in the continuous culture using a high dilution rate, operational problems including severe membrane fouling and contamination by lactic acid producer were observed. Another succinic acid producer, Mannheimia succiniciproducens MBEL55E, was also utilized in this system, and the cell concentration and productivity of succinic acid at the dilution rate of $0.3\;h^{-1}$ were found to be above 3 and 2.3 times higher, respectively, compared with those obtained at the dilution rate of $0.1\;h^{-1}$. These observations give a deep insight into the process design for a continuous succinic acid production by microorganisms.

• 한국물환경학회지
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• 제21권6호
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• pp.602-608
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• 2005

A laboratory-scale experiment was conducted to investigate control of soluble microbial products (SMP) by the internal recycle rate in the submerged membrane separation activated sludge process. The internal recycle rate of the reactor RUN 1 and RUN 2 were 100 % and 200 %, respectively. SMP concentration was rapidly accumulated in the reactor (RUN 1). The variation of accumulated SMP concentration was related to the denitrification rate at the beginning experiment however SMP concentration decreased without correlatively to the denitrification rate during long operation time. The microbial kinetic model was rapidly presented in the both microbial growth and extinction in the reactor (RUN 1). In the SMP kinetic model, Internal recycle rate is the lower, value of UAP and BAP which SMP matter were presented low. The study about development of kinetic model is relatively well adjusted to the experiment exception SMP. In the future, SMP formation equation must be thought that continually research is necessary.

• 한국산업융합학회 논문집
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• 제15권3호
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• pp.83-86
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• 2012

This study have cross checked the change of internal sludge-recycle in Full-scale Anaerobic-Digestion, and researched about not only the improvement of Bio-gas production from the digested sludge but also the efficient method of sludge minimization. Ultimate aim of the study is to reduce the amount of sludge by the improved efficiency of contact with the organic-matter and the microbes in Anaerobic-Digestion. The sludge-recycle fluidized sludge layer and raised the activity of the sludge, The sludge-recycle ratio of optimum was 500%, VS and COD removal ratio respectively appeared with 67.8% and 70.4%. Through these result of this study, it may be positive view to treat waste sludge by the sludge-recycle ratio in terms of minimization and circulation of resources.

• 청정기술
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• 제9권1호
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• pp.29-35
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• 2003

기존의 Epichlorohydrin의 생산 공정을 개선하기 위해 중간 생성물인 dichlorohydrin생성 반응인 hypochlorination 반응에 대한 실험을 통해 개선방안을 조사하였다. 첫 번째로 이 반응에서 사용되고 있는 공업용수를 PVC 공장으로부터 방출된 폐수를 재활용하여 사용하였을 경우 반응 수율에 미치는 영향에 대해 실험하였고 실제적인 반응 생성물 조성에는 크게 영향을 미치지 않는 것으로 나타났다. 부반응물 중 거의 대부분을 차지하고 있는 TCPA를 정제공정 이전에 "추출제 A"를 사용하여 제거할 수 있다. 이를 이용하여 TCPA에 의한 부가적인 부반응을 억제하고 후단의 정제공정에서 분리하는데 소요되는 에너지를 절감할 수 있을 것이다. 또한 Allyl chloride와 반응하는 염소기체의 양을 감소시키면서 생성물의 조성변화를 관찰하였다. 주반응 생성물의 수율에 는 거의 영향을 미치지 않으면서 부반응물의 비율이 다소 감소하는 경향을 확인할 수 있었다.

• Korean Chemical Engineering Research
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• 제40권6호
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• pp.681-686
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• 2002

산업 현장에서 이론적인 건조방법이 실제와는 차이가 많고 또한 배기가스의 재순환이 폐열을 이용하는 목적으로 열원의 절감에는 경제적이지만 이들 파라미터에 따른 요소수지 성형화에 미치는 영향을 연구한바가 없다. 따라서 요소 수지 성형재료의 경화 특성을 건조와 성형 공정 중의 건조온도와 시간, 배기가스 재 순환률 및 성형온도에 따라 실험하여 다음과 같은 결과를 얻었다. 성형재료의 수분함량은 건조 시간과 건조 온도가 증가함에 감소하고, 건조속도는 배기가스 재 순환률이 증가하면 감소한다. 특히 경화유동도는 배기가스의 재 순환량, 건조온도 및 성형온도가 증가하면 감소한다. 또한 건조온도, 건조시간, 배기가스의 재 순환량 및 성형온도에 따라 수분함량과 경화유동도에 대한 상관식을 구하여 재현성있는 최적의 조건을 구명하였다.

• 자원리싸이클링
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• 제19권2호
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• pp.63-72
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• 2010

폐플라스틱 관련 재활용 기술 동향을 조사하기 위하여 특허 검색을 실시하였다. 특허 검색 테이터베이스는 국내 WIPS사의 특허 검색 사이트를 이용하였으며, 특허검색범위는 2009년 9월까지 미국, 유럽연합, 일본과 한국에서 출원 및 공개된 특허로 제한하였다. 본 연구에서는 검색된 특허의 요약문을 분석하여 최종 4,795건의 특허를 대상으로 분석하였으며, 폐플라스틱 재활용 기술동향을 연도별, 국가별, 출원인별로 분석하여 조사하였다. 일본의 특허 출원점유율은 65%으로 전체 특허의 과반수 이상을 차지하고 있었으며, 화학적 재활용 기술에 높은 출원 집중률을 보였다. 한국의 경우, 폐플라스틱 재활용 관련 특허는 물질 재활용에 집중되어 있었다.

• 한국환경과학회지
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• 제6권4호
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• pp.409-415
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• 1997

In order to Investigate the possibility as a simple technique of wastewater treatment for recirculating aquaculture system, the experiment by a biofilter unfit was carried out. The high and stable removal efficiency of nitrogen could be obtained by selecting the optimum recycle ratio and DO concentration. It was found that the proper combination of nitrifacation and denitrfication step in the reactor would be required for increasing the removal efficiency. The extent of nitrogen removal gradually decreased UO the rise of re- cycle ratio since the depression of denitrificatlon by the lack of hydrogen donor. The depression of nitrogen removal was overcome by increasing the CIN ratio In the wastewater. The extent of phosphorus removal was increased slightly with the increase of DO concentration and recycle ratio, but high removal efficiency was not observed. However, the extent of COD removal was not affected by recycle ratio and DO concentration and showed the stable removal of above 90%.

• 한국건축시공학회지
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• 제4권3호
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• pp.143-151
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• 2004

The purpose of this study is development of technique to use cementitious powder as recycle cement produced from deteriorated Concrete waste which has a large quantity of calcium carbonate. Therefore, after having theoretical consideration based on the properties of high-heated concrete and concerning about neutralization of Concrete, we analysis chemical properties of ingredients of cementitious powder. After making origin cement paste, then processing the accelarated carbonation, we consider the properties of hydration and chemical properties of cementitious powder under various temperature conditions. As a result of the thermal analysis, the $CaCO_3$ content of cementitious powder would affect decision of heat temperature to recover its hydrated ability because $CaCO_3$ content is increased when neutralization is progressed. And as a result of XRD analysis, in case of origin powder of non-neutralized paste, CaO peak is found at $700^{\circ}C$. but, heat temperature to generate CaO would increase when the content of neutralized ingredients is increased. Finally, recycle cement heated at $700^{\circ}C$ 120min. shows the best compressive strength when the content of neutralized ingredients in recycle cement is less then 50%.

• 제어로봇시스템학회논문지
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• 제9권3호
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• pp.236-241
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• 2003

This paper addresses the optimal design of dividing wall distillation column which is rapidly applied in a variety of chemical processes over recent several years because of its high energy saving efficiency. A general dividing wall column model which can cope with the heat transfer through the dividing wall is developed using rigorous computer simulation. Based on the simulation model, the effects of the internal recycle flow distribution around the dividing wall and the heat transfer across the dividing wall on overall system performance are investigated. An improved column design method is suggested to utilize the heat transfer through the wall. The suggested method is compared with the existing method via simulation study in which the proposed design shows improved energy saving result.

• Bulletin of the Korean Chemical Society
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• 제28권8호
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• pp.1422-1424
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• 2007