• 자원리싸이클링
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• 제27권1호
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• pp.45-54
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• 2018

플라이애시의 부유선별 과정에서 교반속도와 공기주입량과 같은 기계적 요소 변화에 따른 영향을 알아보고자 본 연구를 실시하였다. 본 연구에서는 미연탄소 함량이 약 3.4 ~ 3.7% 수준인 화력발전소 플라이애시를 사용하였다. 대표적인 부유선별의 선별 요소인 pH, 교반속도, 포수제 첨가량, 기포제 첨가량 변화에 따른 영향을 살펴보았을 때, Safflower oil을 포수제로 사용하여 첨가량을 800 g/ton, pH 7, 교반속도 1,200 rpm, 기포제 첨가량이 400 g/ton였을 때, 미연탄소 회수율과 미연탄소 함량이 각각 63%, 34%로 나타났다. 이 때 부상물 SEM/EDS 분석을 통해 알아본 결과, 구형의 플라이애시 미립자가 미연탄소 내에 고용되거나, 광액 내에 가라앉지 못하고 기포와 함께 부유함으로써 미연탄소의 함량을 낮추는 것으로 나타났다. 교반속도와 공기주입량과 같은 기계적 요소를 변화시킨 실험에서는 공기주입량 8L/min, 교반 속도 900 rpm에서 미연탄소 회수율 74%, 미연탄소 함량 67%인 것으로 나타났다. 이는 낮은 교반속도와 추가 공기주입으로 인하여 광액 내 와류의 강도가 낮아져, 미립의 플라이애시 입자가 미연탄소와 함께 부유되는 현상을 방지됨으로써, 미연탄소 회수율과 미연탄소 함량이 향상된 것으로 나타났다. 또한, 교반속도와 공기주입량을 각각 800 rpm, 6 L/min으로 설정하였을 때 미연탄소 회수율과 미연탄소 탄소함량이 각각 80%, 70%로 향상되어 가장 우수한 것으로 나타났다.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2002년도 제5회 압출 및 인발가공 심포지엄
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• pp.43-49
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• 2002

A7003 alloy has characteristics of their excellent weldability, high corrosion resistance and superior plastic working however the broadening of application for the alloy has been hampered by the lower extrudability associated by Mg content. For improvement of extrudability and enhanced recovery efficiency during Al scrap recyeling, it has been generally practiced to reduce Mg content in A7003 alloy. Therefore, it is necessary to investigate the influence of Mg content on mechanical strength and extrudability of A7003 alloy. For efficient material processing which has small amounts, life cycle assessment in material processing(MLCA) is evaluated. The quantitative analysis of energy requirements and $CO_2$ emission for production of A7003 extruded bar are estimated with different Mg content and billet pre-heating process (heating source by light oil or LPG). In particular, the estimation of energy requirements was performed within shipping and gating range (except the mining and extraction stages)to investigate the influence of the variables on energy requirements and $CO_2$ emission in detail. As Mg content increased, the flow stress and the extrusion pressure for A7003 alloy increased. It has been thought that an increment in extrusion pressure with increasing Mg content is caused by the solid solution hardening of Mg atoms in the matrix and increment in volume fraction of intermetallic compound, $Mg_2Si$. The extrudability and the tensile strength are equal to, or above that of conventional A 7003 alloy even the content of Mg varied from $1.1wt.\%\;to\;0.5wt.\%$ alloy. This means that minimizing the content of Mg in A7003 alloy can enhance recovery efficiency during Al scrap recycling. It can be quoted that rather than Mg content energy source for billet heating is a prime factor to determine the atmospheric $CO_2$ emission.

• 한국산학기술학회논문지
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• 제14권6호
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• pp.2588-2595
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• 2013

기존의 유압식 엘리베이터에서 엘리베이터 카의 하강행정 동안 손실 되는 유압 에너지를 회수하여 재사용하기 위하여 개발한 유압식 엘리베이터용 하이브리드 형 에너지 저감 장치에 대한 성능 특성에 관하여 연구하였다. 회수된 에너지는 축전지에 저장하여 재사용할 수 있도록 구성되어 있으며, 엘리베이터의 구동 조건에 따른 에너지 저감장치의 출력 특성, 효율 및 에너지 회수율 등에 관하여 실험을 통하여 규명하고자 하였다. 본 연구의 결과들은 하강행정 동안 버려지는 에너지의 회수율이 최대 약 54%로 에너지 저감 장치의 압력, 유량, 출력 전압과 전류, 효율 및 에너지 회수율 등과 같은 성능 특성들이 안정적이고 양호하다는 것을 보여주고 있으며, 본 연구를 통하여 유압식 엘리베이터의 에너지 저감 장치를 통하여 하강행정 동안 회수된 에너지를 재사용하데 매우 유용하며, 상용화 가능성이 충분하다는 것을 확인하였다.

• 에너지공학
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• 제10권3호
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• pp.188-194
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• 2001

정유공장으로부터 발생하는 중잔사유를 이용하는 가스화 복합발전 플랜트에 대한 공정모사를 수행하였다. 가스화 복합사이클의 발전계통을 모델링하기 위해 본 연구는 MS7001FA 가스터빈이 공기분리장치와 연계되어 있고, 공기분리장치를 위한 공기 추출과 공기분리장치로 부터의 질소희석이 이루어진다고 가정하였다 가스터빈의 폐열은 삼중압력의 페열회수 증기발생장치로부터 회수하였다. 가스터빈의 합성가스 연료는 중잔사유가 Shell 가스화 및 Sulfinol-SCOT-Claus 공정을 거쳐 발생되는 것으로 가정하였다. 공정 최적화 결과로부터, 가스화 복합사이클의 효율이, 질소 희석이 없는 경우와 있는 경우에 대해, 공기추출비 20% 또는 40∼60%에서 가장 우수했다. 그리고, 연소지의 질소희석은 NOx 저감에 매우 바람직하고 현저한 효과를 가져오나, 반면에 가스터빈의 운전조건을 써지 조건에 가깝게 이동시킴을 알 수 있었다.

• Journal of Biosystems Engineering
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• 제25권3호
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• pp.221-226
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• 2000

Hot air heater with light oil burner is the most common heater for greenhouse heating in the winter season in Korea. However, since the thermal efficiency of the heater is about 80∼85%, considerable unused heat amount in the form of exhaust gas heat discharges to atmosphere. In order to capture this exhaust heat a heat recovery system for plant bed heating in the greenhouse was built and tested in the hot air heating system of greenhouse. The heat recovery system is made for plant bed or soil heating in the greenhouse. The system consisted of a heat exchanger made of copper pipes, ${\Phi}12.7{\times}0.7t$ located in the rectangular column of $330{\times}330{\times}900mm$, a water circulation pump, circulation plastic pipe and a water tank. The total heat exchanger area is 1.5$m^2$, calculated considering the heat exchange amount between flue gas and water circulated in the copper pipes. The system was attached to the exhaust gas path. The heat recovery system was designed as to even recapture the latent heat of flue gas when exposing to low temperature water in the heat exchanger. According to the performance test it could recover 45,200 to 51,000kJ/hr depending on the water circulation rates of 330 to $690\ell$/hr from the waste heat discharged. The exhaust gas temperature left the heat exchanger dropped to $100^{\circ}C$ from $270^{\circ}C$ by the heat exchange between the water and the flue gas, while water gained the difference and temperature increased to $38^{\circ}C$ from $21^{\circ}C$ at the water flow rate of $690\ell$/hr. By the feasibility test conducted in the greenhouse, the system did not encounter any difficulty in operations. And, the system could recover 220,235kJ of exhaust gas heat in a day, which is equivalent of 34% of the fuel consumption by the water boiler for plant bed heating of 0.2ha in the greenhouse.

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

• Membrane and Water Treatment
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• 제11권2호
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• pp.97-109
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• 2020

Membrane fouling is the main drawback of membrane technology. Frequent membrane cleaning and membrane replacement are, therefore, required to reduce membrane fouling that causes permeate flux reduction, lower rejection, or higher operating pressure. Studies have proved that the alteration of membrane properties is the key controlling factor in lessening membrane fouling. Among stimuli-responsive membranes, thermo-responsive membrane is the most popular, with a drastic phase transition and swelling-shrinking behavior caused by the temperature change. In this study, the thermo-responsive ability of two commercial membranes, PolyCera® Titan membrane and PolyCera® Hydro membrane, at different temperatures was studied on the antifouling function of the membrane in palm oil mill effluent (POME) treatment. The evaluation of the membrane's thermo-responsive ability was done through three cycles of adsorption (fouling) and desorption (defouling) processes in a membrane filtration process. The experimental result depicted that PolyCera® Hydro membrane had a higher membrane permeability of 67.869 L/㎡.h.bar than PolyCera® Titan membrane at 46.011 L/㎡.h.bar. However, the high membrane permeability of PolyCera® Hydro membrane was compensated with low removal efficiency. PolyCera® Titan membrane with a smaller mean pore size had better rejection performance than PolyCera® Hydro membrane for all tested parameters. On the other hand, PolyCera® Titan membrane had a better hydrodynamic cleaning efficiency than PolyCera® Hydro membrane regardless of the hydrodynamic cleaning temperature. The best hydrodynamic cleaning performed by PolyCera® Titan membrane was at 35℃ with the flux recovery ratio (FRR) of 99.17 ± 1.43%. The excellent thermo-responsive properties of the PolyCera® Titan membrane could eventually reduce the frequency of membrane replacement and lessen the use of chemicals for membrane cleaning. This outstanding exploration helps to provide a solution to the chemical industry and membrane technology bottleneck, which is the membrane fouling, thus reducing the operating cost incurred by the membrane fouling.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2011년도 춘계학술대회 초록집
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• pp.190-190
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• 2011

In South Korea the gross generation and heated effluent of power generation plant was 259 TWh and 4.73 billion tons in 2008. And then the waste heat from power generation was 388 TWh. It shows that the efficiency of thermal power generation plant is about 40%. Therefore to reduce $CO_2$ emission from thermal power generation plant, the energy of this heated effluent must be reused to heat buildings or farm facilities. In South Korea horticultural facilities of about 25% are heated in winter season. Total area of greenhouses which are heated is about 13,000 ha. Total heat amount needed to warm greenhouse of 13,000 ha in winter season is only 3.4% of total waste heat from power generation plant. In this study a heat pump system was designed to reuse the waste heat from power generation. Especially new heat exchanger was developed to recover the thermal energy from waste water and this model considered anti-corrosion against sea water and low cost for economic feasibility. This heat recovery system was installed in mango growing greenhouse around thermal power generation plant in Seogwipo-city, Jeju Special Self-Governing Province. The result of preliminary test shows that the heating cost of about 90% is saved as compared to boiler using tax free light oil as a fuel.

• 한국지역지리학회:학술대회
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• 한국지역지리학회 2009년도 하계학술대회 발표집
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• pp.108-115
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• 2009

An increase in oil and gas plants caused by development of process industry have brought into the increase in use of flammable and toxic materials in the complex process under high temperature and pressure. There is always possibility of fire and explosion of dangerous chemicals, which exist as raw materials, intermediates, and finished goods whether used or stored in the industrial plants. Since there is the need of efforts on disaster damage reduction or mitigation process, we have been conducting a research to relate explosion model on the background of real 3D terrain model. By predicting the extent of damage caused by recent disasters, we will be able to improve efficiency of recovery and, sure, to take preventive measure and emergency counterplan in response to unprepared disaster. For disaster damage prediction, it is general to conduct quantitative risk assessment, using engineering model for environmentaldescription of the target area. There are different engineering models, according to type of disaster, to be used for industry disaster such as UVCE (Unconfined Vapor Cloud Explosion), BLEVE (Boiling Liquid Evaporation Vapor Explosion), Fireball and so on, among them.we estimate explosion damage through UVCE model which is used in the event of explosion of high frequency and severe damage. When flammable gas in a tank is released to the air, firing it brings about explosion, then we can assess the effect of explosion. As 3D terrain information data is utilized to predict and estimate the extent of damage for each human and material. 3D terrain data with synthetic environment (SEDRIS) gives us more accurate damage prediction for industrial disaster and this research will show appropriate prediction results.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2008년도 International Symposium on Remote Sensing
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• pp.3-5
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• 2008

An increase in oil and gas plants caused by development of process industry have brought into the increase in use of flammable and toxic materials in the complex process under high temperature and pressure. There is always possibility of fire and explosion of dangerous chemicals, which exist as raw materials, intermediates, and finished goods whether used or stored in the industrial plants. Since there is the need of efforts on disaster damage reduction or mitigation process, we have been conducting a research to relate explosion model on the background of real 3D terrain model. By predicting the extent of damage caused by recent disasters, we will be able to improve efficiency of recovery and, sure, to take preventive measure and emergency counterplan in response to unprepared disaster. For disaster damage prediction, it is general to conduct quantitative risk assessment, using engineering model for environmental description of the target area. There are different engineering models, according to type of disaster, to be used for industry disaster such as UVCE (Unconfined Vapour Cloud Explosion), BLEVE (Boiling Liquid Evaporation Vapour Explosion), Fireball and so on, among them, we estimate explosion damage through UVCE model which is used in the event of explosion of high frequency and severe damage. When flammable gas in a tank is released to the air, firing it brings about explosion, then we can assess the effect of explosion. As 3D terrain information data is utilized to predict and estimate the extent of damage for each human and material. 3D terrain data with synthetic environment (SEDRIS) gives us more accurate damage prediction for industrial disaster and this research will show appropriate prediction results.