電解質溶液의 氣泡塔에서 氣體滯留量 및 氣泡群의 速度에 關한 硏究

咸榮敏 단국대학교 1986 論文集 Vol.20 No.-

Gas hold-up, relative velocity, and settling velocity of bubbles have been measured in a bubble column of 5.4 cm diameter in which ionic solutions (in the range of concentration of 0.001N to 0.1N) were employed in order to determine the effects of ionic characteristics. The relative velocity and the settling velocity are important in determining the ultimate bubbly flow regime, which is transited to turbulent flow. Effects of gas velocity (1.3~9.7cm/sec), liquid velocity (0.5~2.1cm/sec) and especially ionic characteristics on gas hold-up and bubble velocity are determined.

電解質 溶液의 脫收氣泡塔에서 物質傳達에 관한 硏究

咸榮敏,李相鳳 단국대학교 1984 論文集 Vol.18 No.-

Expermental data on the gas hold-up and oxygen mass transfer coefficient K_La in 5㎝ I.D. continuous countercurrent bubble column with porous gas distributor were obtained with various aqueous electrolyte solution in order to determine the effect of ionic strength on the objective parameters. The data were obtained in a countercurrent flow system in the ranges of gas velocity of 1.1㎝/sec to 5㎝/sec and liquid velocity of 0.3㎝/sec to 0.9㎝/sec. The electrolyte solutions were: K1, KBr, KCl, NaCl, MgCl_2, CaCl_2, MgSO_4, Na_2SO_4, FeCl_3, K_3PO_4. Desorption of oxygen was studied by measuring the concentration of oxygen in the liquid phase. The results showed a definite dependence of gas velocity, liquid flow rate and especially ionic strength on the gas hold-up and oxygen mass transfer in the range of dilute electrolyte solution (I<0.2). A correlation for ε_G and K_La was developed and was shown to correlate the experimental data with an average deviation of 5.3%, 6.7%, respectively.

졸-겔법에 의한 ZnO/TiO_2 복합 미립자의 제조 및 UV 차단 효과

함영민,이창우 단국대학교 1998 論文集 Vol.32 No.-

ZnO/TiO_2 composite fine powder were prepared by Sol - Gel processing and their surface electrical and UV protection properties were investigated. TiO_2 fine powders were coated by ZnO sol fabricated using zinc acetate and 2 - methoxye-thanol as a solvent with DEA (Diethanolamine, solubility improver). The effect of experimental parameter such as hydrolysis time of starting material on the UV protection of Zn/TiO_2 composite powder was discussed. As a result, ZnO/TiO_2 composite fine powder could protect UV - A and B. And we could control the coating thickness and average particle size of ZnO/TiO_2 composite fine powder. It was also shown good dispersibility in aqueous solution. The obtained powders were observed to be included the range of maximum UV scattering at 200∼250nm average particle size.

斷熱 氣-液 流動化 再循環 反應器에서 離脫된 溫度의 制御

咸榮敏,洪英浩,李暢祐 단국대학교 1994 論文集 Vol.28 No.-

This study was carried out to investigate the effect of the control action, recycle ratio and the position(top, middle and bottom) of set temperature and controlled temperature within the reactor on temperature control in adiabatic ebullated recycle reactor when the disturbance was occured. Estimation of th solution were performed numerically using the finite difference method. It was assumed that heat of reaction and the physical properties(density, heat capasity and viscosity…. etc) of the flowing fluid are not nearly varied within the reactor. It was shown that the response time was shorter at higher recycle ration and the PI-control for middle point temperature of the reactor as controlled temperature was available.

金綱 充塡管을 통한 氣體-固體의 輸送에 관한 硏究

咸榮敏,趙熙俊,洪英浩,張潤鎬 단국대학교 1987 論文集 Vol.21 No.-

This study was carried out to investigate the effect of solid mass flow rate and mean particle diameter on minimun carrying velocity, which was defined as the superficial gas velocity of the upper limit of choking phenomenon, when vertical pneumatic conveying was made through a screen-packed pipe whose inner diameter and length were 4.6cm and 180cm respectively. It was also examined the effect of superficial gas velocity, solid mass flow rate and mean particle diameter on pressure drop. And these minimum carrying velocity and pressure drop were compared with those in an empty pipe. Superficial gas velocity was taken 3.0m/sed to 5.5m/sec. Solid mass flow rate was controlled by five orifices which had different opening dimensions and its range was 2.90g/sec to 16.35g/sec. Silica sand of three sizes (mean diameter; 425㎛, 280㎛, 180㎛) was used as solid particle. The pressure drop in a screen-packed pipe increased as superficial gas velocity, solid mass flow rate and mean particle diameter increased. And the pressure drop in an empty pipe also increased according to the increase of solid mass flow rate, but it decreased though superficial gas velocity increased within the range of experimental conditions. In the case of minimum carrying velocity, it increased as solid mass flow rate and mean particle diameter increased. The pressure drop in a screen-packed pipe was far higher than that in an empty pipe. However, the minimum carrying velocity in the former was slightly lower than that in the latter.

연속 혼합 흐름 반응기에서 평균 체류 시간에 관한 연구

함영민,이창일,차윤호 단국대학교 1999 산업기술연구 Vol.1 No.-

Mean residence time has been measured in a continuous stirred tank reactor by the analysis of age distribution function in order to determine the effect of agitator speed and liquid flow rate. The data were obtained in the ranges of agitator speed from 50 rpm to 100 rpm and liquid flow rate from 50 ml/min to 150 ml/min. Age-distribution curve was studied by measuring the conductivity of KCl as a tracer. The effect of agitator speed and liquid flow rte on the mean residence time are determined. The parameter f(t￣_exp / t￣_p) represents the degree of deviation from perfect mixing. The parameter f was found to be strongly affected by agitator speed but little affect by liquid flow rate.

단열 기-액 유동순환반응기에서 이탈온도의 제어에 관한 연구

咸榮敏 단국대학교 1989 論文集 Vol.23 No.-

This study was carried out to investigate the effect of control actions, types of recycles, recycle ratio, and feed temperature for the control of temperature excursion in an adiabatic ebulluated-bed recycle reactor. When there is a rise is feed temperature , it is desirable to use proportional integral control and to recycle from the bottom section of reactor. However, when the value of recycle ratio in recycle reactor is changed, disturbances of temperature in bed cannot be controlled by control actions or types of recycle.

金剛 充塡 垂直管에서 固體 粒子의 氣壓 輸送에 관한 硏究

咸榮敏,洪英浩 단국대학교 1993 論文集 Vol.27 No.-

This study was carried out to investigate the effects of solid mass flow rate, mean particle diameter and mesh number of screen packing material on minimum carrying velocity, which was defined as the superficial gas velocity of the upper limit of chocking phenomenon. Vertical pneumatic conveying was studied in a 4.6cm I.D. pipe, 180cm in length. Experiments were performed in both the empty and the screen-packed pipe. It was also examined the effect of superficial gas velocity, solid masss flow, mean particle diameter, and mesh number of packing material on pressure drop. Minimum carrying velocity in screen packed-pipe was lower than that in an empty pipe, besides minimum carrying velocity was decreased with increase in mesh number of screen packing material. The pressure drop in vertical packed-pipe was increased with increase in superficial gas velocity, mean particle diameter, and mesh number of screen packing material.

가축사료의 분진폭발 위험성에 관한 연구

이창우,함영민,김정환,현성호 韓國火災 ·消防學會 1998 한국화재소방학회논문지 Vol.12 No.2

가축사료 분진의 열적 안정성 실험결과 본 연구에서 사용한 시료 입도의 경우 발열개시온도 및 발열량에는 별 차이가 없었으나, 승온속도가 증가함에 따라 발열개시온도가 낮아지고, 입도가 미세해질수록 분해열이 증가함을 알 수 있었다. 한편, 분위기 기체를 조연성 기체인 O_2로 사용할 경우 불활성 기체인 N_2를 사용하는 경우보다 발열개시온도는 현저히 낮아지며, 반면에 발열량도 20배 이상 증가하였다. 또한 본 연구에서 사용한 시료중 비교적 미세입자가 대기중에 부유하기 쉽고, 외부에서 점화에너지가 주어질 경우 공기중의 산소와 쉽게 순간적으로 반응하여 폭발하는 것을 볼 수 있다. 본 연구에서의 시료입도중 80/100 mesh의 경우 평균 최대폭발압력은 6.88 Kgf/㎠ 로 구해졌다. According to the results for thermodynamic stability of feed-stuff dust, there are little change of initiation temperature of heat generation and heating value for used particle size. But initiation temperature of heat generation decreased with high heating rate whereas decomposition heat increased with particle size. Using the supporting gas, O_2, initiation temperature of heat generation decreased remarkably than using the inert gas, N_2, and heating value increased as twenty times under the same condition. When the ignition energy is given from the outside, used fine particle which can float in the air easily reacted tremendously with oxygen. Average maximum explosion pressure was 6.88 Kgf/㎠ for 80/100 mesh.

콜로이드 응집법으로 제조된 구형 실리카 입자의 액체 크로마토그래피 컬럼 충진물로의 응용

이창일,이융,함영민 한국공업화학회 2003 응용화학 Vol.7 No.1

The surface of porous spherical silica particles prepared by colloid-aggregation method modified with various silane coupling agents for application of column packing materials in reverse phase liquid chromatography. Hydrophobicity and carbon loading of modified silica was increased according to reactivity and the length of alkyl group of silane coupling agents and surface modification time. Aromatic compound mixture used as samples for application of liquid chromatography with the preparative silica and commercial packing column. Both colimns were on the same separation properties. Optimum separation condition determined by controlled flow rate and composition of mixed solvent used as mobile phase.