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석탄회로 합성한 제올라이트에 대한 암모니아성 질소 흡착특성 조사
류완호,이원묵,백일현,배장순 한국화학공학회 2003 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.41 No.4
국내 석탄화력 발전소에서 폐기되는 석탄회를 이용하여 폐수 중 암모니아성 질소 제거용 흡착제를 제조하고자 NaOH를 반응물로 한 수열합성 반응을 이용, 제올라이트를 합성하였으며 제조된 제올라이트를 실제공정에 활용하기 위하여 흡착실험 및 공정모사를 수행하였다. 또한 흡착제를 구형으로 제조하여 암모니아성 질소의 등온 흡착 공정에 이용하였으며 이 결과 Langmuir식에 잘 일치함을 알 수 있었다. 고정층에서의 흡착 거동은 축 방향 분산흐름, 입자 내부에서의 표면 확산 및 Sips 흡착 등온식을 바탕으로 한 고정층 흡착모델의 주요 공정 변수에 대한 파과곡선을 잘 모사할 수 있음을 확인할 수 있었다. Zeolite was synthesized from coal fly ash produced by a domestic power plant and applied for the removal of ammonia from waste water. Zeolite was synthesized using a hydrothermal method involving an akaline reaction with NaOH, and adsorption experiments and simulations were conducted. Adsorption experiments with the pelletized spherical zeolite were carried out. The experimental data obtained from adsorption isotherms agreed well with the Langmuir equation. Also, most of the correlated results for the fixed bed model based on surface diffusion and Sips adsorption isotherms equation were consistent with the experimental data.
류완호,김새롬,김수한,정은숙,이광하 대한중환자의학회 2022 Acute and Critical Care Vol.37 No.1
Background: This study aimed to investigate the association between the Korean national health insurance coverage benefit extension policy and clinical outcomes of patients who were ventilated owing to various respiratory diseases.Methods: Data from 515 patients (male, 69.7%; mean age, 69.8±12.1 years; in-hospital mortality rate, 28.3%) who were hospitalized in a respiratory intensive care unit were retrospectively analyzed over five years.Results: Of total enrolled patients, 356 (69.1%) had one benefit items under this policy during their hospital stay. They had significantly higher medical expenditure (total: median, 23,683 vs. 12,742 USD, P<0.001), out-of-pocket (median, 5,932 vs. 4,081 USD; P=0.008), and a lower percentage of out-of-pocket medical expenditure relative to total medical expenditure (median, 26.0% vs. 32.2%; P<0.001). Patients without benefit items associated with higher in-hospital mortality (hazard ratio [HR], 2.825; 95% confidence interval [CI], 1.995–4.000; P<0.001). In analysis of patients with benefit items, patients with three items (“cancer”, “tuberculosis,” and “disability”) had significantly lower out-of-pocket medical expenditure (3,441 vs. 6,517 USD, P<0.001), and a lower percentage of out-of-pocket medical expenditure relative to total medical expenditure (17.2% vs. 27.8%, P<0.001). They were associated with higher in-hospital mortality (HR, 3.996; 95% CI, 2.535–6.295, P<0.001).Conclusions: Our study showed patients with benefit items had more medical resources and associated improved in-hospital survival. Patients with the aforementioned three benefit items had lower out-of-pocket medical expenditure due to the implementation of this policy, but higher in-hospital mortality.
류완호,이원묵,박성하,양천회 한밭대학교 에너지청정기술연구소 2004 에너지청정기술논문집 Vol.4 No.1
국내 석탄화력 발전소에서 폐기되는 석탄회를 이용하여 폐수 중 암모니아성 질소 제거용 흡착제를 제조하고자 NaOH를 반응물로 한 수열합성 반응을 이용, 제올라이트를 합성하였으며 제조된 제올라이트를 실제공정에 활용하기 위하여 흡착실험 및 공정모사를 수행하였다. 또한 흡착제를 구형으로 제조하여 암모니아성 질소의 등온 흡착 공정에 이용하였으며 이 결과 Langmuir, Freundlich 및 Sips 식에 잘 일치함을 알 수 있었다. 고정층에서의 흡착 거동은 축 방향 분산흐름, 입자 내부에서의 표면확산 및 Sips 흡착 등온식을 바탕으로 한 고정층 흡착 모델의 주요 공정 변수에 대한 파과곡선을 잘 모사할 수 있음을 확인할 수 있었다. Zeolite was synthesized from coal fly ash produced by a domestic power plant and applied for the removal of ammonia from waste water. Zeolite was synthezied using a hydrothermal method involving an akaline reaction with NaOH, and adsorption experiments and simulations were performed with the pellectized zeolite. The experimental data obtained from adsorption isotherms were consistent with the Langmuir, Freundlich and Sips equation. Also, most of the correlated results for the fixed bed model based on surface diffusion and Sips adsorption isotherms equation were consistent with the experimental data.
석탄회를 이용한 제올라이트의 합성 및 암모니아성 질소 흡착
류완호,박찬교,배장순 한국공업화학회 2004 공업화학 Vol.15 No.1
국내 석탄 화력발전소에서 폐기되는 석탄회를 이용하여 제올라이트를 합성하였으며, 이를 이용하여 폐수 중 암모니아성 질소 제거용 흡착제로서의 활용가능성을 조사하였다. 실험결과 산에 의한 전처리 과정이 중요하고, 4M-NaOH, 반응시간 4 h, pH 7~9.5에서 합성한 제올라이트가 가장 우수한 흡착성능을 보였으며, 이는 상업용 5A형 제올라이트와 비슷한 80%의 흡착성능을 보였다. Synthetic zeolite was prepared from coal fly ash which had been abandoned from a domestic power plant as wastes, and was investigated as an absorbent for removed of ammonia from the waste water. The results suggest that pH control step in the synthesis process was an important factor for the removal capacity due to the presence of alkaline materials such as CaO and MgO in fly ash. Accordingly the zeolite synthesized at 4 M-NaOH and 4 hrs under controlling the pH7-9.5 showed the removal efficiency of 80% as much as the commertial one at its highest ate.
류완호,이원묵,홍필선,양천희,안재영,백일현,이병노 한국화학공학회 2003 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.41 No.5
석탄회를 이용, 중금속 제거용 흡착제 제조를 목적으로 NaOH를 반응물로 한 수열합성 반응으로 제올라이트를 합성하였으며, 이에 대한 성능특성 및 중금속 흡착실험을 수행하였다. SiO₂와 Al₂O₃를 주성분으로 한 석탄회를 NaOH에 의한 수열합성 반응으로 폐수 중에 포함되어 있는 중금속에 대한 제거능력이 높은 제올라이트를 합성하고자 하였다. 따라서 NaOH 농도, 시간을 변화시키면서 제올라이트를 합성하여 실험한 결과 4 M-NaOH, 4시간에서 최적의 조업조건을 얻을 수 있었다. 산에 의한 전처리 과정을 거친 합성 제올라이트는 pH 7-9.5로 중성을 나타내었다. 또한 산처리 합성 제올라이트를 이용하여 중금속인 P, Pb, Cd, Cr, Mn등의 흡착능을 비교한 결과 P, Pb, Cd 등은 비교적 흡착능이 우수하게 나타났지만 Cr과 Mn 등은 pH가 너무 높기 때문에 거의 흡착이 이루어지지 않았다. Zeolite was synthesized from coal fly ash produced by a domestic power plant and has applications in the removal of heavy metal from waste water. Zeolite was synthesized using a hydrothermal method involving an alkaline reaction with NaOH. The NaOH concentration and reaction times were varied in order to synthesize zeolite showing the maximum removal efficiency of heavy metal from waste water. The synthesis conditions were optimized at the concentration of 4M-NaOH and the reaction time of 4hn. The synthesized zeolite needed washing with HCI solution to improve the removal efficiency of P, Pb. Cd. Cr. Mn and it was maximized at pH 7-9.5 in leaching solution of synthesized zeolite.