• 한국대기환경학회지
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• 제12권4호
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• pp.487-494
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• 1996

Simultaneous effects of $C_2H_4$ injection and heterogeneous chemical reactions on non-thermal plasma process to remove $SO_2$ and NOx from flue gas were investigated in the present experimental study. The present results showed that 40% of the electrical power can be reduced in $C_2H_4$ injection and heterogeneous chemical reaction are simultaneously included in the non-thermal plasma precess. As an effort to apply the non-thermal plasma technique to practical flue gas treatment system, a wire-plate type reactor which has technically similar geometry of industrial electrostatic precipitators is used instead of other types of reactors, such as wire-cylinder, packed-bed and surface discharge which are inappropriate to industrial application. In the present study, the photo pictures of positive streamer corona taken by ICCD camera, voltage and current oscillograms, and design criteria of a wire-plate type reactor are also shown, which are needed for industrial application of the non-thermal plasma process.

• 한국연소학회:학술대회논문집
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• 한국연소학회 1998년도 제17회 KOSCI SYMPOSIUM 논문집
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• pp.31-36
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• 1998

An experimental study has been performed to characterize fundamental aspects of VOCs removal using non-thermal palsma technique. The removed VOCs in the present study are toluene ($C_6H_5CH_3$), ethene ($C_2H_4$), propene ($C_3H_6$) which are typical air pollutants generated from industry and automobile engines. The non-thermal plasma used in the present experiments has been produced in a wire-cylinder reactor with pulsed corona or a packed-bed reactor filled with ceramic bead. These differently generated non-thermal plasma have been visualized with an intensified CCD. The images of non-thermal plasma have been used for optimal design of a corona reactor used in the present study. The experimental results show that the removal efficiencies of VOCs with non-thermal plasma are dependant on the reactivity of VOCs with OH, O, and $O_3$. The results also show that the removal efficiencies of VOCs decrease significantly when VOCs are treated with NO that is also oxidized in the presence of OH, O, and $O_3$.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제53권7호
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• pp.377-381
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• 2004

A discharge plasma reactor using a ferroelectric pellet packed bed is now used as a removal means of pollutant gases, such as NOx, SOx and VOCs. When an ac voltage is applied to this plasma reactor, then the pellets are polarized, and great electric fields are formed at each top and bottom contact points of the ferroelectric pellets. Thus the points of each pellet become covered with intense corona discharges, where an electrophysicochemical reaction is taking place strongly However these strong discharges also elevate the temperature of the pellets greatly and concurrently decrease the output ozone generation, as a result, the overall removal efficiency of gas becomes decreased greatly A new configuration of discharge plasma reactor using a ferroelectric pellet layer and a wire-to-wire electrode has been proposed and investigated experimentally. It is found that an intensive microdischarge is taking place on the surface of ac corona-charged ferroelectric pellet layer of the proposed reactor, which concurrently enhances the efficiency of plasma generation greatly And, this type of configuration of plasma reactor utilizing a wire-to-wire electrode and a ferroelectric pellet layer could be used as one of effective plasma reactors to remove pollutant gas.

• KSBB Journal
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• 제8권4호
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• pp.336-340
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• 1993

생물고분자 생산을 위하여 오니에서 slime을 생산하는 Zoogloea ramigera 115를 선택하였다. 추출한 생물고분자는 카드뮴, 아연 같은 금속에 대해서 높은 흡착성능을 나타냈다. 특히 발효조 broth는 높은 흡착성능을 나타냄으로써 부가적인 분리공정없이 생물흡착제로서 사용 가능할 것이다. 생물고분자는 calcium alginate bead 형태로 고정화되어 유가금속 회수를 위하여 충전층 반응기에 사용되었다. 생물흡착제는 구리, 카드뮴, 망간, 아연에 대하여 80% 또는 그이상의 높은 제거율을 나타냈으며 흡착-탈착-재흡착 실험에서 높은 안정성을 나타냈다. 고정화된 생물고분자 시스템은 이온교환수지와 같은 다른 중금속 제거 시스템과 경쟁력 및 잠재적인 산업상 응용 가능성을 보였다.

• KSBB Journal
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• 제7권1호
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• pp.79-83
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• 1992

Erwinia rhapontici를 Ca-alginate에 고정화시켜 고정화 세포의 반응특성을 고찰하고, STR, PBR을 이용하여 Palatinose의 생산을 검토하였다. Free cell과 고정화 세포의 반응최적 pH는 5.5-6.0, 반응 최적온도는$30-35^{\circ}C$로 동일하였으나 고정화에 의해 pH 및 온도 범위가 보다 넓어졌고, 이때 Free cell및 고정화 세포의 겉보기 Km갑슨 각각 0.13, 0.28M이었다. STR을 이용한 Palatonose 생산시 고정화 세포의 반감기는 약 380 시간으로 낮았으나, PBR을 통해 30일까지 안정운전이 가능하였다. PBR 운전시의 운전온도 30, $33^{\circ}C$에서 Palatinose수율 및 고정화 세포의 안정성은 거의 동일한 결과를 나타내었으며 이때 PBR생산성은 약 120g/l$\cdot$h이었고, Pilot scale인 50L 까지 성공적으로 Scale up 되었다.

• 대한기계학회논문집B
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• 제32권8호
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• pp.636-644
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• 2008

The objective of this paper is to investigate characteristics of an autothermal reformer at various operating conditions. Numerical method has been used, and simulation model has been developed for the analysis. Pseudo-homogeneous model is incorporated because the reactor is filled with catalysts of a packed-bed type. Dominant chemical reactions are Full Combustion reaction, Steam Reforming(SR) reaction, Water-Gas Shift(WGS) reaction, and Direct Steam Reforming(DSR) reaction. Simulation results are compared with experimental results for code validation. Operating parameters of the autothermal reformer are inlet temperature, Oxygen to Carbon Ratio(OCR), Steam to Carbon Ratio(SCR), and Gas Hourly Space Velocity(GHSV). Temperature at the reactor center, fuel conversion, species at the reformer outlet, and reforming efficiency are shown as simulation results. SR reaction rate is improved by increased inlet temperature. Reforming efficiency and fuel conversion reached the maximum at 0.7 of OCR. SR reaction and WGS reaction are activated as SCR increases. When GHSV is increased, reforming efficiency increases but pressure drop from the increased GHSV may decrease the system efficiency.

• Biotechnology and Bioprocess Engineering:BBE
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• 제6권6호
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• pp.376-385
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• 2001

Considerable attention has been focused in recent years upon the field of biosorption for the removal of metal ions from aqeous effluents. Compared to other technologies, the advan-tages of biosortption are the high purity of the treated waste water and the cheap raw material. Really, the first major challenge for the biosorption field is to select the most promising types of biomass. Abundant biomass types either generated as a waste by-product of large-scale industrial fermentations particularly fungi or certain metal-binding seaweeds have gained importance in re-cent years due to their natural occurrence, low cost and, of course good performance in metal biosorption. Industrial solutions commonly contain multimetal systems or several organic and in organic substances that form complexes with metals at relatively high stability forming a very complex environment. When several components are present, interference and competition phe-nomena for sorption sites occur and lead to a more complex mathematical formulation of the process. The most optimal configuration for continuous flow-biosorption seems to the packed-bed column which gets gradually from the feed to the solution exit end. Owing to the com-petitive ion exchange taking place in the column, one or more of the metals present even at trace levels may overshot the acceptable limit in the column effluent before the breakthrough point of the trargeted metal. Occurrence of 'overshoot's and impact on havey metal removal has not been analyzed enough. New trends in biosorption are discussed in this review.

• 한국분무공학회지
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• 제24권1호
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• pp.8-14
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• 2019

The purpose of this study is to develop a packing-free wet scrubber to prolong the maintenance interval compared with the conventional packed bed wet scrubbers with which frequent operation stops are unavoidable to clean the packing materials. The main- and interaction-effects were quantitatively analyzed by regression analysis for the measured ammonia scrubbing data from the experiments prepared by experimental design. The scrubbing efficiency of the newly developed wet scrubber was found to be over 95% under the condition of flue gas flow rate of 90CMM and liquid-to-gas ratio $2l/m^3$ for all considered trials of experimental design. The interaction effect between the inlet duct spray and the filter was found to be important, which controls the droplet growth due to the droplet collisions between the duct- and scrubbing tower-spray. The presented methodology to analyze the impacts of operational and design factors on the scrubber efficiency showed potential for applications to optimize the future flue gas abatement process in semiconductor plants.

• 한국지진공학회논문집
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• 제25권6호
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• pp.283-292
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• 2021

In this study, a structural health monitoring system for cable-stayed bridges is developed. In the system, condition assessment of the structure is performed based on measured records from seismic accelerometers. Response indices are defined to monitor structural safety and serviceability and derived from the measured acceleration data. The derivation process of the indices is structured to follow the transformation from the raw data to the outcome. The process includes noise filtering, baseline correction, numerical integration, and calculation of relative differences. The system is packed as a condition assessment program, which consists of four major processes of the structural health evaluation: (i) format conversion of the raw data, (ii) noise filtering, (iii) generation of response indices, and (iv) condition evaluation. An example set of limit states is presented to evaluate the structural condition of the test-bed and cable-stayed bridge.

• Nuclear Engineering and Technology
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• 제54권4호
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• pp.1343-1354
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• 2022

Experiments were performed to measure the critical heat flux (CHF) on a vertical surface abutting a coarse packed bed of spherical particles. This geometry is representative of a CANDU reactor calandria tubesheet facing the end shield cavity during the in-vessel retention (IVR) phase of a severe accident. Deionized light water was used as the working fluid. Low carbon steel shielding balls with diameters ranging from 6.4 to 12.7 mm were used, allowing for the development of an empirical correlation of CHF as a function of shielding ball diameter. Previously published data is used to develop a more comprehensive empirical correlation accounting for the impacts of both shielding ball diameter and heating surface height. Tests using borosilicate shielding balls demonstrated that the dependence of CHF on shielding ball thermal conductivity is insignificant. The deposition of iron oxide particles transported from shielding balls to the heating surface is verified to increase CHF non-trivially. The results presented in this paper improve the state of the knowledge base permitting quantitative prediction of CHF in the CANDU end shield, refining our ability to assess the feasibility of IVR. The findings clarify the mechanisms governing CHF in this scenario, permitting identification of potential future research directions.