• 한국세라믹학회지
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• 제50권1호
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• pp.18-24
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• 2013

This study was conducted to recycle fly ash containing an abundance of CaO generated from combustion in a circulating layer as a carbon storage medium. The study utilized XRD, TG-DTA and XRF analyses during the hydration of fly ash and identified calcium substances within fly ash that could be used in a carbonation process. $Ca^{2+}$ ions in the calcium substances were easily converted to hydrates. A carbonation experiment was done, which used the method of $CO_2$ gas injection to produce suspensions by mixing fly ash with distilled water. The results were analyzed using TG-DTA, XRD, and pH meter measurements. The study was able to verify that the reaction was completed at a $CO_2$ flow rate of 300cc/min approximately 30 minutes after an injection into a solution with a solid-liquid ratio of 1 : 10 of fly ash and distilled water. Moreover, the stirring time of the suspensions did not influence the reaction, and the reaction time was found to diminish as the portion of the fly ash became smaller. Thus, this study produced carbon storage fly ash having a $CO_2$ storage rate of about 71% through the utilization of the CaO content contained within fly ash.

• 에너지공학
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• 제22권2호
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• pp.226-236
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• 2013

고온개질기를 이용한 수증기 메탄 개질반응에 대해 실험 및 전산해석 기법을 이용하여 실제 개질기의 효율 및 개질기의 형상의 변화에 따른 열 분포 및 내부 유동에 대해서 연구하였다. 수증기 개질에 대한 반응모델은 Xu & Froment에 의해 개발된 수증기 반응 모델을 사용하였고, 그 결과로 고온개질기내에서 일어나는 화학반응은 Steam Reforming(SR), Water Gas Shift(WGS), Direct Steam Reforming(DSR) 반응이 다른 반응을 지배한다고 가정하였다. 고온개질기를 이용한 수증기 메탄 개질 반응 실험 결과로는 Steam Carbon Ratio(SCR)이 증가함에 따라 수소 수득율 또한 증가하고 일산화탄소와 메탄은 감소하는것을 알 수 있었다. 또한 입구가 한 개인 디자인과 두 개인 디자인을 비교, 분석하였을 때 입구가 두 개인 개질기보다 입구가 한 개인 개질기에서 열 분포 및 내부유동, 수소 수득율이 우수하다는 결과를 얻게 되었다.

• 한국광물학회지
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• 제9권1호
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• pp.1-6
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• 1996

Woolastonite from Susan occurs as intercalations in limestone beds of Lower Paleozoic Joseon Supergroup. It is a thermal metamorphic product of impure limestone. Electron microprobe analysis shows that it is considerably pure wollastonite. It has triclinic cell with a=7.932$\AA$, b=7.328$\AA$, c=7.069$\AA$, $\alpha$=89.995$^{\circ}$, $\beta$=$95.255^{\circ}$, and $ \Upsilon=103.367^{\circ}$.Dissolution behaviors of wollastonite have been studied conducting three different dissolution experiments; two different reactions with HC1 (one batch and one re-initialization experiment) and one traction with distilled water. In the batch type powder wollastonite-HCl reaction, pH of solution rapidly increases in the early stage and then its rate of increase slows down to reach plateau resulting in parabolic relationship with time. It is represented by the early rapid rise and fall in pH giving a sharp pH-edge and succeeding slow rise in the re-initialization experiment. The early rapid rise in pH is due to the rapid sorption of H- in solution to oxygens on the reactive surface of wollastonite and the fall in pH means that all reactive surface sites are occupied by H- ions and no more H- adsorption occurs. The slow rise in pH following the pH- edge is due to the dissolution of wollastonite as evidenced by the correlation of pH variation and cation concentration. Dissolution of powder wollastonite in HCl shows linear trend with time. Si is dissolved predominantly over Ca at a constant rate. Ca is dissolved predominantly in the very early stage. Dissolution rate of coarse-grained wollastonite fragments in distilled water is parabolic with times howing a rapid reaction in the early stage and a slow reaction in the advanced stage. The Ca/Si ratio in solution is high in the case of coarse-grained wollastonite fragment as compared with powder wollastonite. The coarse-grained wollastonite fragment-water (acid) reaction resulted in the solution with an elevated constant pH value (alkaline) giving an important significance on the environmental view point.

• 한국환경과학회지
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• 제14권2호
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• pp.231-240
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• 2005

The number of cases exceeding environmental standards of atmospheric ozone in the major cities in Korea has steadily increased during the past decades. In order to understand and analyze the atmospheric reactions in the atmosphere, especially the secondary photochemical reactions, smog chambers studies have been performed very actively by many research groups worldwide. However, these studies have focused on the mechanism of photochemical reactions in high concentration conditions, not at the ambient levels. Therefore, in-depth studies in these conditions are essentially needed to realize exact mechanism in the atmosphere near the earth surface, especially at Korean atmospheric conditions. In this experiment, the mechanism of photochemical smog was examined through a comparative experiment of smog chambers under sun light and black light conditions. The results of our study indicated that concentrations of ozone, aldehyde, and PAN increased as the radiation of light source increases. Photochemical reaction patterns can be considered quite similar for both black light and sun light experiments. Based on our experiments using toluene as a reactant which is present at significant high levels in ambient air relative to other VOCs, it was found that toluene could contribute notably to oxidize NO to $NO_2$, this reaction can eventually generate some other photochemical oxidants such as ozone, aldehyde, and PAN. The results of simulation and experiments generally showed a good agreement quite well except for the case of $O_3$. The restriction of oxidization of NO to $NO_2$ seems to cause this difference, which is mainly from the reaction of peroxy radical itself and other reactants in the real gas.

• 한국지구물리탐사학회:학술대회논문집
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• 한국지구물리탐사학회 2003년도 Proceedings of the international symposium on the fusion technology
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• pp.573-580
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• 2003

In Taiwan there are 21 Municipal Solid Waste Incinerators (MSWI) built to treat 80% of the MSW nationwide. Approximately 2,000 tons of incineration ashes of municipal waste contain reaction ash and fly ash (3:1 by weight)will be produced daily, and this may cause a serious waste problem. According to EPA regulations, reaction ash and fly ash produced after incineration should be properly treated. Landfill capacity barely meets the general demands. More efficient actions should be planned and taken. The study found 'reclamation' should be the optimal solution to this problem. Only limited research and previous successful experiences are available among other countries. An incinerator in Northern Taiwan is chosen for this study to make environmental bricks from the reaction ash and fly ash. From the previous tests, the results of strength test were measured. From the previous test results, the fly ash products have not reached the desired strength; hence, reaction ash is chosen for further pilot study. In the experiment, incineration ashes, cement and gravel are mixed in the ratio of 1:1:1(by weight), to ground concretization aggregate and pelletization aggregate, the concrete products made from the aggregates were of the strength of 108 $kgf/cm^2$ and 142 $kgf/cm^2$ individually. For the purpose of making nonstructural walls which met the State Building Standards. In the study, 50 tons of concrete products was yielded from aggregate and environmental bricks. Further observation and supervision are recommended to ascertain the resource recycling and reclamation. EPA has planned to build three 'Recycling Plants' in northern, middle and southern Taiwan to develop efficient techniques to produce concrete products, sub-base course, soundproofing wall, gravel, artificial fishing reefs, tiles, drainage, bricks and etc. This experiment of the demonstrative plant solves the problem of the incineration ashes and opens another opportunity to reclaim them.

• 콘크리트학회지
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• 제9권1호
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• pp.115-121
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• 1997

본 연구는 NaCl 수용액 중에서 고로 슬래그미분말의 알칼리실리카반응에 대한 팽창억제 특성 및 그의 메카니즘에 관한 것이다. 실험에 사용된 NaCl 수용액의 농도는 0%(수도수), 2.8% 및 20%였으며, 골재는 안산암을 사용하였다. 슬래그는 비표면적이 $4,100cm^2/g.\;5,960cm^2/g$ 및 $7,950cm^2/g$인 3종류를 사용하였고 치환율은 시멘트중량에 대하여 40%, 60%, 70% 및 80%로 하였다. NaCl 수용액에 있어서 슬래그를 첨가한 공시체는 치환율이 많을수록 수축률은 높게 되었고 그의 값은 비표면적이 클수록 높게 나타났다. 슬래그에 의한 알카리실리카반응의 유해한 팽창의 억제는 슬래그의 첨가에 의한 경화 콘크리트의 화학적 수축에 의해서도 달성됨이 확인되었다.

• 혜화의학회지
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• 제15권2호
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• pp.263-272
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• 2006

Purpose Brain vessles have autoregulation function, so even when perfusion pressure drops, cerebral blood flow remain stable by vasodilation. Latest research on this reserve of cerebral vessels is being done using TCD, which measures the reserve of the vessels. We did a research comparing cerebral vessel and peripheral vessel reserve between Taeumin, who are more likely to suffer CVA, and the normal. We observed blood flow of Internal carotid artery siphon and radial indicis artery of the two group with TCD. Method We picked 20 people out of patients diagnosed as cerebral infarction at Cheon-An Oriental hospital of Daejeon University. They were diagnosed as Taeumin with QSCCII questionnaire and constitutional differentiation. Using TCD, we measured highest blood flow rate, mean blood flow and asymmetric counting blood flow of Internal carotid artery siphon and radial indicis artery at rest. And then we measured again after stimulating cerebral vessels, by triggering hypercapnia by self apnea and peripheral vessels by palm heating. Result At rest, mean blood flow rate of Internal carotid artery siphon showed significant decrease compared to control group. Blood flow rate of Internal carotid artery siphon after hypercapnia showed significant decline in highest blood flow rate and mean blood flow compared to control group. Cerebral vessel reaction after the hypercapnia induction showed great change in experiment group than the control group. Peripheral vessel reaction after palm heating showed significant decline in experiment group compared to control group. Conclusion In conclusion, measuring the alteration of blood flow used in diagnosing cerebral infarction, is more sensitive when vessel stimulation is done. Non-invasive TCD is effective especially in case of Taeumin who are more likely to suffer vascular disorder than others.

• 한국지하수토양환경학회지:지하수토양환경
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• 제21권1호
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• pp.86-93
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• 2016

Fenton is the reaction using the OH· radicals generating by interaction between hydrogen peroxide and Fe²⁺ which can oxidize the contaminants. Fe²⁺ ions are oxidized to Fe³⁺ ions by reaction with H₂O₂ and formed OH· radicals. UV-Fenton process includes the additional reaction that generates the OH· radicals by photodegradation of H₂O₂. In methylorange (MO) decolourization experiment with UV-Fenton, optimal Fe²⁺: H₂O₂ ratio was obtained at 1 : 10. Based on the obtained condition (H₂O₂= 10mM, Fe²⁺ = 1 mM) with/without UV-fenton experiment was carried out. Removal efficiency and sludge production were measured at 30 min. The case of w/o UV irradiation and only H₂O₂ was hardly treated and only Fe²⁺ showed 65% removal owing to coagulation. When UV-Fenton process in optimal ratio (Fe²⁺: H₂O₂ = 1 : 10), UV irradiation showed better removal efficiency than of w/o UV irradiation. Also, MO decolourization was a function of the hydrogen peroxide concentration (x₁), Fe²⁺:H₂O₂ ratio (x₂), and numbers of UV lamp (x₃) from the application of the response surface methodology. Statistical results showed the order of significance of the independent variables to be hydrogen peroxide concentration > numbers of UV l amp > Fe²⁺: H₂O₂ ratio.

• 한국수소및신에너지학회논문집
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• 제34권6호
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• pp.601-607
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• 2023

Pyrolysis oil (C5-C20) produced using plastic non-oxidative pyrolysis technology produces naphtha oil (C5-C10) through a separation process, and naphtha oil produces hydrogen through a reforming reaction to secure economic efficiency and social and environmental benefits. In this study, waste plastic pyrolysis oil was subjected to a steam reforming reaction on a commercialized catalyst of 46-3Q And it was found that the 46-3Q catalyst reformed the pyrolysis oil to produce hydrogen. Therefore, an experiment was performed to increase hydrogen yield and minimize the byproduct of ethylene. The reaction experiment was performed using actual waste plastic oil (C8-C11) with temperature, steam/carbon ratio (S/C) ratio, and space velocity as variables. We studied reaction conditions that can maximize hydrogen yield and minimize ethylene byproducts.

• 한국환경과학회지
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• 제6권2호
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• pp.133-139
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• 1997

말로네이트 제조 공정에서 발생되는 폐액으로부터 용매추출법을 적용하여 코발트 회수 연구를 하였다 용매 추출에서의 주요 변수는 용매의 선택, pH, 코발트 농도, 역추출 온도 등이며 이러한 변수들의 영향을 조사하였다. 용매로써 DEHPA와 PC88A가 사용되었으며 이들 용매의 평형추출 곡선을 구하였다. 공장설계 조건을 찾기 위하여 Mccabe-Tiele 선도를 작성하였고, 연속 공정인 믹서-세틀러 장치를 가동하였다. 본 연구 결과 폐액 중에서 코발트는 99.9% 이상 회수되었고, 회수된 황산코발트의 순도는 99.9% 이상이었다.