Comparative Study of Mass Transfer and Bubble Hydrodynamic Parameters in Bubble Column Reactor

Prajak Sastaravet,Chomthisa Chuenchaem,Nawaporn Thaphet,Nattawin Chawaloesphonsiya,Pisut Painmanakul 대한환경공학회 2014 Environmental Engineering Research Vol.19 No.4

In this paper, effects of physical configurations and operating conditions on bubble column performance were analyzed in terms of bubble hydrodynamic and mass transfer parameters. Bubble column with 3 different dimensions and 7 gas diffusers (single / multiple orifice and rigid / flexible orifice) were applied. High speed camera and image analysis program were used for analyzing the bubble hydrodynamic parameters. The local liquid-side mass transfer coefficient (kL) was estimated from the volumetric mass transfer coefficient (kLa) and the interfacial area (a), which was deduced from the bubble diameter (DB) and the terminal bubble rising velocity (UB). The result showed that the values of kLa and a increased with the superficial gas velocity (Vg) and the size of bubble column. Influences of gas diffuser physical property (orifice size, thickness and orifice number) can be proven on the generated bubble size and the mass transfer performance in bubble column. Concerning the variation of kL coefficients with bubble size, 3 zones (Zone A, B and C) can be observed. For Zone A and Zone C, a good agreement between the experimental and the predicted KL coefficients was obtained (average difference of 짹 15%), whereas the inaccuracy result (of 짹 40%) was found in Zone B. To enhance the high kLa coefficient and absorption efficiency in bubble column, it was unnecessary to generate numerous fine bubbles at high superficial gas velocity since it causes high power consumption with the great decrease of kL coefficients.

점성액체 기포탑에서 탑의 직경이 기포, wake 및 연속액상 체류량에 미치는 영향

임대호 ( Dae Ho Lim ),장지화 ( Ji Hwa Jang ),강용 ( Yong Kang ),전기원 ( Ki Won Jun ) 한국화학공학회 2011 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.49 No.5

Holdup characteristics of bubble, wake and continuous liquid phases were investigated in bubble columns with viscous liquid media. Effects of column diameter(0.051, 0.076, 0.102 and 0.152 m ID), gas velocity(U(G)=0.02~0.16 m/s) and liquid viscosity(μL=0.001~0.050 Pa·s) of continuous liquid media on the holdups of bubble, wake and continuous liquid phases were discussed. The three phase such as bubble, wake and continuous liquid phases were classified successfully by adapting the dual electrical resistivity probe method. Compressed filtered air and water or aqueous solutions of CMC(Carboxy Methyl Cellulose) were used as a gas and a liquid phase, respectively. To detect the wake as well as bubble phases in the bubble column continuously, a data acquisition system(DT 2805 Lab Card) with personal computer was used. The analog signals obtained from the probe circuit were processed to produce the digital data, from which the wake phase was detected behind the multi-bubbles as well as single bubbles rising in the bubble columns. The holdup of bubble and wake phases decreased but that of continuous liquid media increased, with an increase in the column diameter or liquid viscosity. However, the holdup of bubble and wake phases increased but that of continuous media decreased with an increase in the gas velocity. The holdup ratio of wake to wake to bubble phase decreased with an increase in the column diameter or gas velocity, however, increased with an increase in the viscosity of continuous liquid media. The holdups of bubble, wake and continuous liquid media could be correlated in terms of operating variables within this experimental conditions as: εB=0.043D(-0.18)U(G)(0.56)μL(-0.13), εW=0.003D(-0.85)U(G)(0.46)μL(-0.10), εC=1.179D(0.09)U(G)(-0.13)μL(0.04).

미립자공학,유동층,고분자,재료 : 무기, 유기 ; 점성슬러리 기포탑에서 작은 기포의 체류량 특성

진해룡 ( Hae Ryong Jin ),송양호 ( Yang Ho Song ),강용 ( Yong Kang ),정헌 ( Heon Jung ),이호태 ( Ho Tae Lee ) 한국화학공학회 2011 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.49 No.1

Holdup characteristics of small bubbles were investigated in a viscous slurry bubble column. The phase holdup of small bubbles was obtained from the knowledge of total bubble{gas) holdup and large bubble holdup, which were measured by mean of static pressure drop method and dual resistivity probe method, respectively. Effects of gas velocity, viscosity of continuous liquid phase and solid fraction in the slurry phase on the small bubble holdup as well as holdups of total bubble{gas) and large bubble in a viscous slurry bubble column. The small bubble holdup increased with increasing gas velocity but decreased with increasing liquid viscosity or solid fraction in the slurry phase. In addition the fraction of small bubble in the total bubble(gas) holdup increased with increasing gas velocity but decreased with increasing liquid viscosity or solid fraction in the slurry phase. It was revealed that the rising velocity of large bubble did not related to the holdup of small bubble in a viscous slurry bubble column.

벤치스케일(0.36 m × 22 m) 다단형 기포탑에서 다공판이 기포의 거동 및 기체 체류량에 미치는 영향

양정훈 ( Jung Hoon Yang ),허영걸 ( Young Gul Hur ),이호태 ( Ho Tae Lee ),양정일 ( Jung Ii Yang ),김학주 ( Hak Joo Kim ),천동현 ( Dong Hyun Chun ),박지찬 ( Ji Chan Park ),정헌 ( Heon Jung ) 한국화학공학회 2012 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.50 No.3

The gas hold-up has a strong relationship with the size distribution and rising velocities of bubbles in a bubble column. Therefore, many previous researchers have studied on the hydrodynamics focusing on the bubble size variation in bubble column. In this study, the bubble behavior was influenced by partitioning porous plates installed at a certain height in a trayed bubble column. The gas hold-up was increased in non-sparging region (H/D > 5) as well as sparging region. We identified the effect of the partitioning porous plate using three trayed bubble columns with different reactor geometries. Furthermore, the bubble break-up frequency and size distribution were observed before and after individual bubbles penetrated through the plate. The arrangement of the plates was also investigated using a 0.15-m-in-diameter bubble column. Based on the result, we applied this design concept to a 0.36-m-in-diameter, 22 m tall trayed bubble column and identified the effect of the partitioning porous plate on the gas hold-up increase.

기포탑에서 작은기포와 큰기포의 크기 구별

서명재 ( Myung Jae Seo ),진해룡 ( Hae Ryong Jin ),임대호 ( Dae Ho Lim ),임호 ( Ho Lim ),강용 ( Yong Kang ),전기원 ( Ki Won Jun ) 한국화학공학회 2012 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.50 No.2

Size verification of small and large bubbles in a bubble column was investigated by employing the dynamic gas disengagement (DGD) method and dual electrical resistivity probe (DRP) method, simultancously. The holdups of large and small bubbles in the bubble column in a given operating condition were obtained by means of the DGD method by measuring the pressure drop variation in the column with a variation of time after stopping the gas input into the column. The size and frequency of bubbles were measured by the DRP method in the same operating condition, from which the bubble holdup of each range of size was obtained. The verification of size in determining the large or small bubbles was decided by comparing the holdups of large or small bubbles measured by the DGD method with that measured by the DRP method. Filtered compressed air and tap water were used as a gas and a continuous liquid medium. The diameter and height of the bubble column were 0.102 m and 1.5 m, respectively. The demarcation size between the large and the small bubbles in the bubble column was 4.0~5.0 mm; the demarcation size was about 5.0 mm when the gas velocity was in the relatively low range, but about 4.0 mm when the gas velocity was in the relatively high range, within this experimental conditions.

다양한 생물반응기 형태가 인삼(Panax ginseng C.A. Meyer) 부정근의 생장과 Ginsenoside 생산에 미치는 영향

김윤수,한은주,백기엽,Kim, Yun-Soo,Hahn, Eun-Joo,Paek, Kee-Yoeup 한국식물생명공학회 2004 식물생명공학회지 Vol.31 No.3

생물반응기의 형태에 따른 인삼부정근의 생장과 ginsen-side의 생산능력에 대하여 조사한 결과, 원형의 상부와 하부에 5 cm의 bubble column을 가진 bulb type bubble bioreactor (BU)에서 건물중은 41.92 g으로 가장 많이 증가하였으며, cylindric tube bioreactor (CT)에서 건물중이 38.55g으로 가장 낮게 나타났다. 이들 두 생물반응기의 초기 kLa 값은 BU 생물반응기에서 6.98 h$^{-1}$로 가장 높게 측정되었고, 반대로 bubble column이 없는 CT 생물반응기에서 5.25 h$^{-1}$으로 가장 낮게 측정되었다. 그러나 이와 같은 초기 kLa값의 차이는 부정근내의 이차대사산물인 ginsenoside의 함량에는 영향을 주지 않는 것으로 나타났다. 또한 BU 생물반응기에서 bubble column의 길이를 기존의 5 cm에서 10 cm로 연장시켰을 때, 초기 kLa값이 6.52 h$^{-1}$에서 7.80 h$^{-1}$로 증가하면서 인삼부정근의 생장을 42.13 g에서 50.30 g으로 약 16% 증가시킨 것으로 나타났다. The type of air lift bioreactor affected the root growth in ginseng adventitious root cultures. Among bioreactors used in this experiment, bulb type bubble bioreactor (BU) was the best to increase root growth (41.92 g dry weight). The kLa value representing the oxygen transfer capacity from medium to explants (6.98 h$^{-1}$ ) in BU with 5 cm bubble column was higher than other bioreactors. On the other hand, cylindric tube bioreactor (CT) without bubble column resulted in minimum root growth (38.55 g dry weight) and kLa value (5.25 h$^{-1}$ ). Furthermore, the root growth (50.30 g dry weight) in BU with 10 cm bubble column more increased than 5 cm bubble column. However, the kLa value do not affected the secondary metabolite such as ginsenosides. These results show that the bubble column in air lift bioreactor increase kLa value and increased kLa value stimulate the growth of ginseng adventitious roots.

A Study of the Bubble Properties in the Column Flotation System

Lee, Jung-Eun,Choi, Woo-Sik,Lee, Jae-Keun 한국화학공학회 2003 Korean Journal of Chemical Engineering Vol.20 No.5

The bubble properties in the column flotation system are deeply affected by the bubble-generator type, frother dosage, and superficial gas velocity. This study is to determine the bubble-generator type, which effectively produces micro-bubbles to affect the flotation efficiency. Characteristics for two types of bubble generators like the in-line mixer and sparger are examined by bubble properties such as bubble diameter, holdup and bubble velocity. Micro bubbles generated from an in-line mixer were more effective for operating the flotation system than that of the sparger. It means that the in-line mixer bubble generator is more effective than a sparger in designing or operating the column flotation system.

Using a Lagrangian-Lagrangian approach for studying flow behavior inside a bubble column

손영우,안철오,이상환 한국원자력학회 2023 Nuclear Engineering and Technology Vol.55 No.12

Bubble columns are widely encountered in several industries, especially in the field of nuclear safety. The Eulerian-Eulerian and the Eulerian-Lagrangian methods are commonly used to investigate bubble columns. Eulerian approaches require additional tasks such as strict volume conservation at the interface and a predefined well-structured grid. In contrast, the Lagrangian approach can be easily implemented. Hence, we introduce a fully Lagrangian approach for the simulation of bubble columns using the discrete bubble model (DBM) and moving particle semi-implicit (MPS) methods. Additionally, we propose a rigorous method to estimate the volume fraction accurately, and verified it through experimental data and analytical results. The MPS method was compared with the experimental data of Dambreak. The DBM was verified by analyzing the terminal velocity of a single bubble for each bubble size. It agreed with the analytical results for each of the four drag correlations. Additionally, the improved method for calculating the volume fraction showed agreement with the Ergun equation for the pressure drop in a packed bed. The implemented MPS-DBM was used to simulate the bubble column, and the results were compared with the experimental results. We demonstrated that the MPS-DBM was in quantitative agreement with the experimental data.

이미지 분석시스템을 이용한 부선컬럼에서 기포크기의 측정

안기선,전호석,박철현 한국자원리싸이클링학회 2020 資源 리싸이클링 Vol.29 No.6

Bubble size in froth flotation has long been recognized as a key factor which affects the bubble residence time, the bubble surface area flux (Sb) and the carrying rate (Cr). This paper presents method of bubble size measurement, relationship between operating variables and gas dispersion properties in flotation column. Using high speed camera and image analysis system, bubble size has been directly measured as a function of operating parameters (e.g., superficial gas rate (Jg), superficial wash water rate (Jw), frother concentration) in flotation column. Relationship compared to measured and estimated bubble size was obtained within error ranges of ±15~20% and mean bubble size was 0.718mm. From this system the empirical relationship to control the bubble size and distribution has been developed under operating conditions such as Jg of 0.65~1.3cm/s, Jw of 0.13~0.52cm/s and frother concentration of 60~200ppm. Surface tension and bubble size decreased as frother concentration increased. It seemed that critical coalescence concentration (CCC) of bubbles was 200ppm so that surface tension was the lowest (49.24mN/m) at frother concentration of 200ppm. Bubble size tend to increase when superficial gas rate (Jg) decreases and superficial wash water rate Jw and frother concentration increase. Gas holdup is proportional to superficial gas rate as well as frother concentration and superficial wash water rate (at the fixed superficial gas rate). 기포크기는 컬럼부선에서 기포체류시간, 기포표면적플럭스(Sb) 및 운송율(Cr)에 영향을 미치는 중요 변수로 인식되고 있다. 본 논문은 부선컬럼에서 기포크기의 측정방법, 가동변수들의 관계 그리고 가스분산특성을 논한다. 기포크기는 고속카메라와 이미지 분석 시스템을 이용하여 가동변수들(가스속도, 세척수속도, 기포제농도)의 조건에 따라 부선컬럼에서 직접적으로 측정되었다. 각 측정과 산정된 기포크기 값들을 비교한 관계식이 ±15~20의 오차범위 내에서 도출되었고 평균 기포크기(Sauter mean diameter)는 0.718mm로 확인되었다. 본 시스템으로부터 기포크기 및 분포를 조절할 수 있는 경험식이 가동조건들(Jg: 0.65~1.3cm/s, JW: 0.13~0.52cm/s, frother concentration: 60~200ppm) 하에서 개발되었다. 기포제농도의 증가는 표면장면과 기포크기를 감소시킨다. 임계병합농도는 표면장력이가장 낮은 49.24mN/m일 때인 기포제농도 200ppm이라고 판단된다. 공기속도의 감소, 기포제농도 및 세척수속도의 증가에 따라 기포크기가 감소하는 경향을 보였다. 가스홀드업은 가스속도와 비례관계에 있으며 고정된 가스속도 조건에서 기포제농도 및 세척수속도와 비례관계였다.

Gas holdup in packed bubble column with fibrous polyethyelene media

윤용수,( Sa Dong Kim ),정용석 한국공업화학회 2015 한국공업화학회 연구논문 초록집 Vol.2015 No.0

Gas holdup is one of the most important parameters in bubble column system. as increasing of gas holdup as increase of the interfacial area between gas and liquid, which enhances the mass transfer rate. Enhancement of gas holdup during aeration and maintaining of gas hold-up after stopped supply of gas in bubble column by fibrous polypropylene media were investigated in this study. The gas holdup in bubble column were determined with tap water and synthesized dye wastewater with changing number of media line from 0 to 5 lines, the length of media line from 200 mm to 1000 mm versus supplied gas flow rate from 0.3 L/min to 1.1 L/min. Maintaining characteristics of gas hold-up in bubble column after stopped gas supply was observed during 60 min. The results indicate that the fibrous polypropylene media enhanced gas holdup and held gas inside column by bubbles attached on media``s surface with high level and stability for a long time after discontinuing supply of gas. This result is an important phenomenon in chemical reaction of gas and liquid phases that will be able to appllied to improve reaction efficiency in bubble column.