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일메나이트 중 철의 선택적 염화와 선광된 TiO<sub>2</sub>의 추가 염화반응에 대한 글로벌 피팅함수
정동규,원용선,김용하,정은진,송덕용,Chung, Dong-Kyu,Won, Yong Sun,Kim, Yong-Ha,Jung, Eun-Jin,Song, Duk-Yong Materials Research Society of Korea 2019 한국재료학회지 Vol.29 No.7
Global fitting functions for Fe-selective chlorination in ilmenite($FeTiO_2$) and successive chlorination of beneficiated $TiO_2$ are proposed and validated based on a comparison with experimental data collected from the literature. The Fe-selective chlorination reaction is expressed by the unreacted shrinking core model, which covers the diffusion-controlling step of chlorinated Fe gas that escapes through porous materials of beneficiated $TiO_2$ formed by Fe-selective chlorination, and the chemical reaction-controlling step of the surface reaction of unreacted solid ilmenite. The fitting function is applied for both chemical controlling steps of the unreacted shrinking core model. The validation shows that our fitting function is quite effective to fit with experimental data by minimum and maximum values of determination coefficients of $R^2$ as low as 0.9698 and 0.9988, respectively, for operating parameters such as temperature, $Cl_2$ pressure, carbon ratio and particle size that change comprehensively. The global fitting functions proposed in this study are expressed simply as exponential functions of chlorination rate(X) vs. time(t), and each of them are validated by a single equation for various reaction conditions. There is therefore a certain practical merit for the optimal process design and performance analysis for field engineers of chlorination reactions of ilmenite and $TiO_2$.
정동규,정은진,이미선,김진영,송덕용,Chung, Dong-Kyu,Jung, Eun-Jin,Lee, Mi Sun,Kim, Jinyoung,Song, Duk-Yong 한국청정기술학회 2019 청정기술 Vol.25 No.2
2단 유동층 염화로에서 일메나이트광의 선택염화반응과 이산화티탄의 탄소염화반응의 염화도를 예측하기 위해서 shrinking core 모델과 유출률 및 입자파손을 고려한 수치 모델을 개발하였다. 입자분포를 고려하여 입자별 물질 수지와 염화반응을 반영할 수 있는 유동층 염화 반응 해석이 가능하다. 유동층 염화로의 실험값과 비교하여 약 6% 오차율의 정확성을 보였다. 입자 크기에 따라서는 입자 크기가 작을수록 염화도의 변화가 더 크게 나타났으며 염화도 1의 값에 도달하는 반응시간 차이가 약 100 min 정도로 나타났다. 온도의 변화($800{\sim}1000^{\circ}C$)에 대한 염화도의 변화는 염화도 0.9에 도달하는 반응시간이 약 10 min 차이로 크게 나타나지 않았다. 1단계 선택염화공정에서 일메나이트광의 질량감소율은 180 min 경과 시에 이론값인 0.4735 값에 근접하고, Fe 성분의 염화도는 $FeCl_2$ 또는 $FeCl_3$로 변환되어 180 min 경과 시에는 거의 1의 값을 보인다. 2단계 탄소염화공정에서 $TiO_2$의 염화도는 180 min 경과 시 0.98에 근접하고, 질량분율은 0.02에 도달하여 $TiCl_4$로 변환되는 것으로 나타났다. 1단계 선택염화공정에서 $TiO_2$는 180 min 경과 시에 98%까지 생성되었다가 연속적인 2단계 탄소염화공정에서 추가로 90 min 경과 시(총 경과 시간 270 min)에 99% $TiCl_4$로 전환되는 것으로 나타나고, 질량감소율도 99% 이상 감소하였다. Numerical model that considered the shrinking core model and elutriation and degradation of particles was developed to predict selective chlorination of ilmenite and carbo-chlorination of $TiO_2$ in a two stage fluidized bed chlorination furnace. It is possible to analyze the fluidized bed chlorination reaction to be able to reflect particle distribution for mass balances and the chlorination reaction. The numerical model showed an accuracy with error less than 6% compared with fluidized bed experiments. The chlorination degree with particle size change was greater with a smaller particle size, and there was a 100 min difference to obtain a chlorination degree of 1 between $75{\mu}m$ and $275{\mu}m$. This was not shown to such a great extent with variation of temperature ($800{\sim}1000^{\circ}C$), and there was only a 10 min difference to obtain a chlorination degree of 0.9. In the first selective chlorination process, the mass reduction rate approached to the theoretical value of 0.4735 after 180 min, and chlorination changed the Fe component into $FeCl_2$ or $FeCl_3$ and showed nearly 1. In the second carbo-chlorination process, the chlorination degree of $TiO_2$ approached 0.98 and the mass fraction reached 0.02 with conversion into $TiCl_4$. In the first selective chlorination process, 98% of $TiO_2$ was produced at 180 min, and this was changed into 99% of $TiCl_4$ after an additional 90 min. Also the mass reduction rate of $TiO_2$ was reduced to 99% in the second continuous carbo-chlorination process.
축류형 송풍기 설계 과정에서 공력 - 음향학적 성능 예측을 위한 전산 프로그램의 개발
정동규(Dong-Kyu Chung),홍순성(Soon-Seong Hong),이찬(Chan Lee) 한국유체기계학회 2000 유체기계 연구개발 발표회 논문집 Vol.- No.-
Developed is a computer program for the prediction of the aero-acoustic performance characteristics such as discharge pressure, efficiency, power and noise level in the basic design step of axial flow fan. The flow field and the aerodynamic performance of fan are analyzed by using the streamline curvature computing scheme with total pressure loss and flow deviation models. Fan noise is assumed to be generated due to the pressure fluctuations induced by wake vortices of fan blades and to radiate via dipole distribution. The vortex-induced fluctuating pressure on blade surface is calculated by combining thin airfoil theory and the predicted flow field data. The predicted aerodynamic performances, sound pressure level and noise directivity patterns of fan by the present computer program are favorably compared with the test data of actual fan. Furthermore, the present computer program is shown to be very useful in optimizing design variables of fan with high efficiency and low noise level and in analyzing their design sensitivities.
성능 및 소음 해석 기능이 수반된 전산화된 축류 송풍기 설계 체제
정동규(Dong-Kyu Chung),노준구(Jun-Gu Noh),서제영(Jae-Young Seo),이찬(Chan Lee) 한국유체기계학회 2001 유체기계 연구개발 발표회 논문집 Vol.- No.-
A computerized axial flow fan design system is developed with the capabilities for predicting the aerodynamic performance and the noise characteristics of fan. In the present study, the basic fan blading design is made by combining vortex distribution scheme with camber line design, airfoil selection, blade thickness distribution and stacking of blade elements. With the designed fan blade geometry, the through-flow field and the performance of fan are analyzed by using the streamline curvature computing scheme with spanwise total pressure loss and flow deviation models. Fan noise is assumed to be generated due to the pressure fluctuation induced by wake vortices of fan blades and to radiate as dipole distribution. The vortex-induced fluctuating pressure on blade surface is calculated by combining thin airfoil theory and the predicted flow field data. The predicted performances, sound pressure level and noise directivity patterns of fan by the present method are favorably compared with the test data of actual fans. Furthermore, the present method is shown to be very useful in designing the blade geometry of new fan and optimizing design variables of the fan to achieve higher efficiency and lower noise level.
정동규(Dong Kyu Chung) 한국생약학회 1978 생약학회지 Vol.9 No.2
The constituents of Ranunculaceae plants are summerized from more than one hundred of papers. Fifteen steroidal alkaloids, thirty two of terpenoids (diterpenes and triterpenes), fifty four isoquinoline alkaloids are recorded. Thirty three papaverines, eighteen berberines, and three hydrastines belong to isoquinoline group. Besides, of alkaloids a number of glycosides are also found. Adonis glycoside, famous cardiotonics, from Adonis and cyanogenin glycoside and calthoside D were identified from the leaves of Thalicutrum aquilegifolum and Caltha silvestris. Anemonin, the irritating substance, found in Pulsatilla grandiz WENDER. Kaempferol and dihydrokaempferol were isolated and identified from the leaves of Clematis brachyura MAXIMOWICZ by author in 1968.
항암성자원생약개발에 관한 연구 : 미국산 개미취근의 성분연구(Ⅱ)
정동규(Dong Kyu Chung) 한국생약학회 1978 생약학회지 Vol.9 No.2
We had previously reported that five compounds were obtained from fraction A of Aster divaricatus by using column chromatography and presumed them to be alkanes CH₃ (CH₂)n CH₃. In this investigation, compound (II) out of above five compounds was identified as hydrocarbon C_(l6)H<sub>34</sub>, m.w. 258 belonging to alkane, by using nmr spectra, mass spectra and the elementary analysis. It was also found that compound (IV) is the same compound as the campound (II).