• Title, Summary, Keyword: Bubble Column

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Development of a Liquid-Phase Methanol Synthesis Process for Coal-derived Syngas (석탄가스 전환용 액상 메탄올 합성 공정 개발)

  • Shin, Jang-Sik;Jung, Heon;Lee, Jong-Dae
    • Journal of the Korean Applied Science and Technology
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    • v.19 no.4
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    • pp.251-257
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    • 2002
  • Liquid-phase methanol synthesis via methyl formate using coal-derived syngas was carried out in a bench-scale(diameter 173 mm and dispersion height 1200 mm) slurry bubble column reactor(SBCR) Under the condition of $180^{\circ}$. 61 atm, 30 L/min, $H_{2}$/CO=2 and a slurry mixture of 2 kg of copper chromite and 0.5 kg of $KOCH_{3}$ suspended in 14 L of methanol, the per pass conversions of syngas is 6 %, maximum concentration of methyl formate 3.088 mol% and maximum synthesis, rate of methanol 0.8 gmole/kg ${\cdot}$ hr. It is a significant evidence that copper chromite powder as heterogeneous catalyst didn't active for the hydrogenolysis of methyl formate to methanol, resulting copper chromite powder was not efficiently suspended in a slurry mixture. To enhance the hydrogenolysis of methyl formate in liquid-phase methanol synthesis process, the designed SBCR have need to use the higher specific gravity solvent and/or decrease the catalyst particle size.

KINEMATICS AND CHEMISTRY OF THE S140/L1204 MOLECULAR COMPLEX

  • Park, Yong-Sun;Minh, Young-Chul
    • Journal of The Korean Astronomical Society
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    • v.28 no.2
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    • pp.255-264
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    • 1995
  • The HII region S140 and the associated molecular cloud L1204 have been observed with 10 molecular transitions, CO (1-0), $^{13}CO$ (1-0), $C^{18}O$ (1-0), CS (2-1), $HCO^+$ (1-0), HCN (1-0), SO (${2_2}-{1_1}$), $SO_2(2_{20}-3_{13})$, OCS (8-7), and $HNCO\;(4_{04}-3_{03})$ with ${\sim}50"$ angular resolutions. More than 7,000 spectra were obtained in total. The morphology of this region shows a massive fragment (the S140 core) and the extended envelope to the northeast. Several gas condensations have been identified in the envelope, having masses of ${\sim}10^{3}M_{\odot}$ and gas number densities of ${\lesssim}10^{4}cm^{-3}$ to $3{\times}10^{5}cm^{-3}$ in their cores. The column densities of the observed molecular species toward the S140 core appear to be the typical warm clouds' abundances. It seems to be that the S140 core and L1204 have been swept up by an expanding shell called the Cepheus bubble. The large value of $L_{IR}$(embedded\;stars)/$M_{cloud}\;{\sim}\;5\;L_{\odot}$/$M_{\odot}$ of the S140 core may suggest that the star formation has been stimulated by the HII region, but the shock velocity and the pressure of the region seem to give a hint of the spontaneous star formation by the self gravity.

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Production of Tropane Alkaloids by Two-stage Culture of Scopolia parviflora Nakai Adventitious Root

  • Kim, Won-Jung;Jung, Hee-Young;Min, Ji-Yun;Chung, Young-Gwan;Lee, Cheol-Ho;Choi, Myung-Suk
    • Korean Journal of Medicinal Crop Science
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    • v.12 no.5
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    • pp.372-377
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    • 2004
  • Scopolia parviflora Nakai, a rare and endangered species, is the sole plant producing tropane alkaloids (TA) among the Korean native species. In order to enhance TA productivity the SP72 root line was selected by screening 100 of root line, and the optimal culture media for root growth and TA production were investigated with the SP72 roots. Based on the several media, SH and 2B5 medium were determined as growth medium and White and NN medium as production medium. Among the four combinations of two-stage culture, 2BN (2B5 as growth medium plus NN as production medium) showed more enhanced root growth and TA production as compared with production media of White and NN medium and growth media of SH and 2B5 medium, respectively. However, bubble column bioreactor (BCB) cultures applying two-stage culture did not reveal the effective results despite of the each successful operation of two-stage culture in conical flasks and BCB cultures.

Development of Pilot-Scale Scrubber for Simultaneous Removal of $SO_2/NO$

  • Jung, Seung-Ho;Jeong, Gwi-Taek;Lee, Gwang-Yeon;Park, Don-Hee;Cha, Jin-Myeong
    • 한국생물공학회:학술대회논문집
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    • pp.468-474
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    • 2005
  • SOx and NOx are known major precursors of acid rain and thus the abatement of their emissions is a major target in air pollution control. To obtain basic data on the removal process of simultaneous $SO_2/NO$, the optimal reaction condition and the composition of reaction solution for simultaneous removal of $SO_2/NO$, ware investigated using a bubble column reactor. Pilot scrubber was consisted of scrubber, filter and control box. Dust removal rate was 83, 92, and 97% with catalyst flux of 0.5, 0.8, 1.5 L/min, respectively Average dust removal efficiency with a kind of nozzle was about 94 and 90% in STS FF6.5 (5/8in.) and 14 of P.P W(1.0in.), respectively Dust and $SO_2$ were removed more than 98-96% regardless of reactor number. In the case of NO gas, removal yield of 83.3% was achieved after 48 hours in 1 stage, also removal yield of 95.7% was reached in 2 stages. In tile case of application of STS (5/8 in.) and P.P (1.0 in.) as used fill packing, removal efficiency was reached higher than 98% without related to of kind of fill packing.

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A Study on the Degradation Characteristics of 1,4-dioxane at Different Initial pHs with Advanced Oxidation Process Using $O_3/H_2O_2$ ($O_3/H_2O_2$ 고급산화공정에서 초기 pH 변화에 따른 1,4-dioxane의 제거 특성 연구)

  • Park, Jin-Do;Suh, Jung-Ho;Lee, Hak-Sung
    • Journal of Environmental Health Sciences
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    • v.31 no.5
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    • pp.404-410
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    • 2005
  • The pH efforts on the removal of 1,4-dioxane and the biodegradobility enhancement of dioxane contaminated water were investigated using $O_3/H_2O_2$ baled advanced oxidation process. Experiments were conducted using a bubble column reactor under different initial pH. The $O_3/H_2O_2$ process effectively converted 1,4-dioxane to more biodegradable intermediates which had a maximum $BOD_5$ enhancement at pH 11 within the experimental range, precisely, when the initial pH increased, $BOD_5$ enhanced. However, in case of removal efficiencies of 1,4-dioxane during $O_3/H_2O_2$ oxidation the optimum condition was shown at pH 9 compared with pH 6 and 11. TOC and COD values were not largely changed for all reaction time. From the results of 1,4-dioxane removal efficiency, TOC, COD, and $BOD_5$ enhancement with reaction time, it was surely observed that 1,4-dioxane was just converted to biodegradable materials, not completely oxidized to carbon dioxide.

Optimal Culturing and Enhancement of Lipid Accumulation in a Microalga Botryococcus braunii (미세조류 Botryococcus braunii의 배양조건 최적화 및 지질축적 향상)

  • Kwon, Sung-Hyun;Lee, Eun-Mi;Cho, Dae-Chul
    • Journal of Environmental Science International
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    • v.21 no.7
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    • pp.779-785
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    • 2012
  • Several tests and experimental work have been done for identifying the best growth conditions and accumulated amount of lipid moiety in B. braunii, a microalga(UTEX 572) in terms of media composition. The specific growth rate was found to be the highest at 0.15 g/L-day when the phosphorus concentration was doubled with the other ingredients at the normal level. Experiments for varied media compositions revealed that the accumulation of lipid was the highest at 48% (dry cell weight based) in the nitrogen deficient medium and its corresponding specific growth rate was comparative to that in the normal BG 11 medium. In the bubble column experiments, carbon dioxide containing air produced four times more cell mass than air only. Light and glucose addition also enhanced cell mass with maximum, 1.8 g/L and accordingly 42% of lipid composition, which turned out to be a better strategy for higher lipid-producing microalgal culture.

Prediction and Verification of Water-entry Traces Size of Small Falling Objects into the Sea (해상 소형 낙하물 입수흔적의 크기 예측 및 검증)

  • Min, Anki;Hwang, Tae-Won
    • Journal of the Korea Institute of Military Science and Technology
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    • v.18 no.2
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    • pp.146-153
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    • 2015
  • An unmanned aerial photography method by using an unmanned helicopter is useful method for measuring of the water-entry traces of small falling objects into the sea. Pixel sizes on the aerial photograph may be too large due to a limit of camcorder resolution and a wide shooting area. If the pixel size is too large, identification of water-entry trace is impossible. Thus an accurate prediction of water-entry trace size is required. The traces of water-entry could be classified into three types such as splash, water column, and bubble. Diameters of each trace are predicted by water-entry impact pressure theories, cavity theories, and trial test results. The results are verified by drop tests using an unmanned helicopter at two water-entry speeds. As a result, prediction and test results showed sufficient similarity to evaluate the identifiability of water-entry trace.

Effect of Light Quality on Growth and Fatty Acid Production in Chlorella vugaris Using Light Emitting Diodes (발광다이오드를 이용한 광파장에 따른 Chlorella vulgaris의 생장과 지방산 생산에 미치는 효과)

  • Kim, Z-Hun;Kim, Dong Keun;Lee, Choul-Gyun
    • Journal of Marine Bioscience and Biotechnology
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    • v.8 no.1
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    • pp.24-29
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    • 2016
  • Microalgae are considered as superior biodiesel producers, because they could effectively produce high amount of lipid with fast growth rate. In this study, Chlorella vulgaris was exposed to various light wavelengths (${\lambda}_{max}$ 470 nm, ${\lambda}_{max}$ 525 nm, and ${\lambda}_{max}$ 660 nm) using light emitting diodes (LEDs) to examine effect of light quality on their growth and fatty acid production in 0.4-L bubble column photobioreactors. Fluorescent lamps were also used as polychromatic light sources (control). From the results, biomass productivity was varied by light wavelength from 0.05 g/L/day to 0.30 g/L/day. Maximum biomass productivity was obtained from red LED among tested ones. We also observed that contents of oleic acid and linolenic acid, which affect biodiesel properties, were significantly changed depending on supplied wavelength. These results indicated that production of algal biomass, and fatty acid content and productivity could be improved or controlled by supplying specific light wavelength.

A Study on Ozonation of Sulfamethoxazole (Sulfamethoxazole의 오존산화처리에 관한 연구)

  • Lee, Cheal-Gyu
    • Journal of Korean Society on Water Environment
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    • v.35 no.6
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    • pp.459-469
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    • 2019
  • The ozonation of sulfamethoxazole (SMX) was performed at 20℃ using a pilot scale countercurrent bubble column reactor. Ozonation systems were combined with UV irradiation and TiO2 addition. As the oxidation reaction proceeded in each treatment system, the pH of the sample decreased and in the O3/UV/TiO2 system, the pH change was the largest from 4.54 to 2.02. Under these experimental conditions, the scavenger impact of carbonate is negligible. The highest COD and TOC removal rate was observed in the O3/UV/TiO2 system due to the UV irradiation and the photocatalytic effect of TiO2. Also, the highest mineralization ratio(ε) value is 0.2 in the O3/UV/TiO2 system, which means theoxidation capacity of the systems. The highest SMX degradation rate constants calculated by COD and TOC values (COD and TOC) were 2.15 × 10-4 sec-1 and 1.00 × 10-4 sec-1 in the O3/UV/TiO2 system, respectively. The activation energy (Ea) of ozone treatment follows the Arrhenius law. It was calculated based on COD and TOC. Each activation energy decreased in order of single O3> O3/TiO2> O3/UV > O3/UV/TiO2 system. The result showed that ΔH≠ is more effective than ΔS≠ in each SMX ozontaionsystem, that is characteristic of the common oxidation reaction.

Treatment of Malodorous Waste Air by a Biofilter Process Equipped with a Humidifier Composed of Fluidized Aerobic and Anoxic Reactor (폐가스 가습조(유동상호기 및 무산소조)를 포함한 바이오필터공정을 이용한 악취폐가스의 처리)

  • Lim, Kwang-Hee
    • Korean Chemical Engineering Research
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    • v.56 no.1
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    • pp.85-95
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    • 2018
  • In this research, a biofilter system equipped with a biofilter process and a humidifier composed of a fluidized aerobic and an anoxic reactor, was constructed to treat odorous waste air containing hydrogen sulfide, ammonia and VOC, frequently generated from pig and poultry housing facilities, compost manufacturing factories and publicly owned facilities. Its optimum operating condition was revealed and discussed. In the experiment of complex feed, the ammonia of fed-waste air was removed by ca. 75% and more than 20% at the stage of the humidifier and the biofilter, respectively. The toluene of the fed-waste air was removed by ca. 20% and more than 70% at the stage of the humidifier and the biofilter, respectively. Therefore the water-soluble ammonia and the water-insoluble toluene were treated mainly at the stage of the humidifier and the biofilter, respectively. In addition, hydrogen sulfide was almost absorbed at the stage of the humidifier so that it was not detected at the biofilter process. In the experiment of ammonia-containing feed, the ammonia of fed-waste air was removed by ca. 65% and 35% at the stage of the humidifier and the biofilter, respectively. Its removal efficiency of ammonia at the stage of the humidifier was 10% less than that in the experiment of complex feed, due to no supply of such carbon source as toluene required in the process of denitrification. In the experiments of complex feed, ammonia-containing feed with and without (instead, glucose) the addition of yeast extract, the absorption rates of ammonia-nitrogen were ca. 0.28 mg/min, 0.23 mg/min and 0.27 mg/min, respectively. The corresponding denitrification rates in the anoxic reactor were 0.42 mg/min, 0.55 mg/min and 0.27 mg/min, respectively. In addition, in the modeling of bubble column(the fluidized aerobic reactor of the humidifier) process, the value of specific surface area(a) of bubbles multiplied by enhanced mass transfer coefficient (E $K_y$) was evaluated to be 0.12/hr.