Experimental analysis of the hydrodynamics of a three-phase system in a vessel with two impellers
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Anna Kiełbus-Rąpała
und
Joanna Karcz
Abstract
Results of experimental analysis concerning gas hold-up and average residence time of gas bubbles in a three-phase gas-solid-liquid system produced in a baffled, double-impeller vessel are presented. Measurements were carried out in a vessel with the internal diameter of 0.288 m. Two different double-impeller configurations were used for agitation: Rushton turbine (lower) — A 315 (upper) and Rushton turbine (lower) — HE 3 (upper). Upper impellers differed in the fluid pumping mode. Coalescing and non-coalescing systems were tested. Liquid phases were distilled water (coalescing system) and aqueous solutions of NaCl (non-coalescing systems). The ability of gas bubbles to coalesce in the liquid was described using parameter Y. Dispersed phases were air and particles of sea sand. The experiments were conducted at seven different gas flow rates and two particle loadings. Effects of the ability of gas bubbles to coalesce (liquid phase properties), operating parameters (superficial gas velocity, impeller speed, solids loadings), and of the type of the impeller configuration on the investigated parameters were determined. The results were approximated mathematically. For both impeller configurations tested, significantly higher gas hold-up values were obtained in the non-coalescing gas-solid-liquid systems compared to the coalescing one. Out of the tested impeller systems, the RT-A 315 configuration proved to have better performance ensuring good gas dispersion in the liquid in the three-phase systems.
[1] Alves, S. S., Maia, C. I., & Vasconcelos, J. M. T. (2003). Effect of bubble contamination on the liquid film mass transfer coefficient in stirred tanks. In Proceedings of the 11th European Conference on Mixing, October 14–17, 2003 (pp. 237–244). Bamberg, Germany: VDI-GVC. Suche in Google Scholar
[2] Chapman, C. M., Nienow, A. W., Cooke, M., & Middleton, J. C. (1983). Particle-gas-liquid mixing in stirred vessels. Part III: Three phase mixing. Chemical Engineering Research and Design, 61, 167–181. Suche in Google Scholar
[3] Cooke, M., Heggs, P. J., & Rodgers, T. L. (2008). The effect of solids on the dense phase gas fraction and gas-liquid mass transfer at conditions close to the heterogeneous regime in a mechanically agitated vessel. Chemical Engineering Research and Design, 86, 869–882. DOI: 10.1016/j.cherd.2007.10.022. http://dx.doi.org/10.1016/j.cherd.2007.10.02210.1016/j.cherd.2007.10.022Suche in Google Scholar
[4] Dohi, N., Matsuda, Y., Itano, N., Shimizu, K., Minekawa, K., & Kawase, Y. (1999). Mixing characteristics in slurry stirred tank reactors with multiple impellers. Chemical Engineering Communications, 171, 211–229. DOI: 10.1080/00986449908912758. http://dx.doi.org/10.1080/0098644990891275810.1080/00986449908912758Suche in Google Scholar
[5] Dohi, N., Takahashi, T., Minekawa, K., & Kawase, Y. (2004). Power consumption and solid suspension performance of large-scale impellers in gas-liquid-solid three-phase stirred tank reactors. Chemical Engineering Journal, 97, 103–114. DOI: 10.1016/s1385-8947(03)00148-7. http://dx.doi.org/10.1016/S1385-8947(03)00148-710.1016/S1385-8947(03)00148-7Suche in Google Scholar
[6] Dutta, N. N., & Pangarkar, V. G. (1995). Critical impeller speed for solid suspension in multi-impeller three phase agitated contactors. The Canadian Journal of Chemical Engineering, 73, 273–283. DOI: 10.1002/cjce.5450730302. http://dx.doi.org/10.1002/cjce.545073030210.1002/cjce.5450730302Suche in Google Scholar
[7] Dyląg, M., & Talaga J. (1994). Hydrodynamics of mechanical mixing in a three-phase liquid-gas-solid system. International Chemical Engineering, 34, 539–551. Suche in Google Scholar
[8] Fujasová, M., Linek, V., & Moucha, T. (2007). Mass transfer correlations for multiple-impeller gas-liquid contactors. Analysis of the effect of axial dispersion in gas liquid phases on “local” k La values measured by the dynamic pressure method in individual stages of the vessel. Chemical Engineering Science, 62, 1650–1669. DOI: 10.1016/j.ces.2006.12.003. http://dx.doi.org/10.1016/j.ces.2006.12.00310.1016/j.ces.2006.12.003Suche in Google Scholar
[9] Gogate, P. R., Beenackers, A. A. C. M., & Pandit, A. B. (2000). Multiple-impeller systems with special emphasis on bioreactors: a critical review. Biochemical Engineering Journal, 6, 109–144. DOI: 10.1016/s1369-703x(00)00081-4. http://dx.doi.org/10.1016/S1369-703X(00)00081-410.1016/S1369-703X(00)00081-4Suche in Google Scholar
[10] Jin, B., & Lant, P. (2004). Flow regime, hydrodynamics, floc size distribution and sludge properties in activated sludge bubble column, air-lift and aerated stirred reactors. Chemical Engineering Science, 59, 2379–2388. DOI: 10.1016/j.ces.2004.01.061. http://dx.doi.org/10.1016/j.ces.2004.01.06110.1016/j.ces.2004.01.061Suche in Google Scholar
[11] Kiełbus-Rąpała, A. (2011). The analysis of gas-liquid system hydrodynamics in a double-impeller agitated vessel. Inżynieria i Aparatura Chemiczna, 50(4), 18–19. (in Polish) Suche in Google Scholar
[12] Kiełbus-Rąpała, A., & Karcz, J. (2009). Influence of suspended solid particles on gas-liquid mass transfer coefficient in a system stirred by double impellers. Chemical Papers, 63, 188–196. DOI: 10.2478/s11696-009-0013-y. http://dx.doi.org/10.2478/s11696-009-0013-y10.2478/s11696-009-0013-ySuche in Google Scholar
[13] Kiełbus-Rąpała, A., & Karcz, J. (2010). Solid suspension and gas dispersion in gas-solid-liquid agitated systems. Chemical Papers, 64, 154–162. DOI: 10.2478/s11696-009-0104-9. http://dx.doi.org/10.2478/s11696-009-0104-910.2478/s11696-009-0104-9Suche in Google Scholar
[14] Laakkonen, M., Alopaeus, V., & Aittamaa, J. (2006). Validation of bubble breakage, coalescence and mass transfer models for gas-liquid dispersion in agitated vessel. Chemical Engineering Science, 61, 218–228. DOI: 10.1016/j.ces.2004.11.066. http://dx.doi.org/10.1016/j.ces.2004.11.06610.1016/j.ces.2004.11.066Suche in Google Scholar
[15] Lee, J. C., & Meyrick, D. L. (1970). Gas-liquid interfacial areas in salt solutions in an agitated tank. Transactions of the Institution of Chemical Engineers, 48, 37–45. Suche in Google Scholar
[16] Machoň, V., Vlček, J., & Kudrna, V. (1978). Gas hold-up in agitated aqueous solutions of strong inorganic salts. Collection of Czechoslovak Chemical Communications, 43, 593–603. http://dx.doi.org/10.1135/cccc1978059310.1135/cccc19780593Suche in Google Scholar
[17] Majířová, H., Příkopa, T., Jahoda, M., & Machoň, V. (2002). Gas hold-up and power input in two- and three-phase dualimpeller stirred reactor. In Proceedings of the 15th International Congress of Chemical & Processing Engineering CHISA, August 25–29, 2002. Prague, Czech Republic. Suche in Google Scholar
[18] Major-Godlewska, M., & Karcz, J. (2003). Gas hold-up and power consumption for gas-liquid system agitated in a stirred tank equipped with vertical coil. Chemical Papers, 57,6, 432–444. Suche in Google Scholar
[19] Major-Godlewska, M., & Karcz, J. (2011). Process characteristics for a gas-liquid system agitated in a vessel equipped with a turbine impeller and tubular baffles. Chemical Papers, 65, 132–138. DOI: 10.2478/s11696-010-0080-0. http://dx.doi.org/10.2478/s11696-010-0080-010.2478/s11696-010-0080-0Suche in Google Scholar
[20] Moucha, T., Linek, V., & Prokopová, E. (2003). Gas holdup, mixing time and gas-liquid volumetric mass transfer coefficient of various multiple-impeller configurations: Rushton turbine, pitched blade and Technmix impeller and their combinations. Chemical Engineering Science, 58, 1839–1846. DOI: 10.1016/s0009-2509(02)00682-6. http://dx.doi.org/10.1016/S0009-2509(02)00682-610.1016/S0009-2509(02)00682-6Suche in Google Scholar
[21] Nienow, A. W., & Bujalski, W. (2002). Recent studies on agitated three phase (gas-solid-liquid) systems in the turbulent regime. In Proceedings of the 7th UK Conference on Mixing, Fluid Mixing 7, July 10–11, 2002. Bradford, UK. 10.1205/026387602321143363Suche in Google Scholar
[22] Nocentini, M., Fajner, D., Pasquali, G., & Magelli, F. (1993). Gas-liquid mass transfer and holdup in vessels stirred with multiple Rushton turbine: water and water-glycerol solutions. Industrial & Engineering Chemistry Research, 32, 19–26. DOI: 10.1021/ie00013a003. http://dx.doi.org/10.1021/ie00013a00310.1021/ie00013a003Suche in Google Scholar
[23] Paglianti, A., Takenaka, K., Bujalski, W., & Takahashi, K. (2000). Estimation of gas hold-up in areated vessel. The Canadian Journal of Chemical Engineering, 78, 386–392. DOI: 10.1002/cjce.5450780214. http://dx.doi.org/10.1002/cjce.545078021410.1002/cjce.5450780214Suche in Google Scholar
[24] Panneerselvam, R., Savithri, S., & Surender, G. D. (2009). Computational fluid dynamics simulation of solid suspension in a gas-liquid-solid mechanically agitated contactor. Industrial & Engineering Chemistry Research, 48, 1608–1620. DOI: 10.1021/ie800978w. http://dx.doi.org/10.1021/ie800978w10.1021/ie800978wSuche in Google Scholar
[25] Rewatkar, V. B., Raghava Rao, K. S. M. S., & Joshi, J. B. (1991). Critical impeller speed for solid suspension in mechanically agitated three-phase reactors. 1. Experimental part. Industrial & Engineering Chemistry Research, 30, 1770–1784. DOI: 10.1021/ie00056a013. http://dx.doi.org/10.1021/ie00056a01310.1021/ie00056a013Suche in Google Scholar
[26] Zhang, L. F., Pan, Q. M., & Rempel, G. L. (2006). Liquid phase mixing and gas hold-up in multistage-agitated contactor with co-current upflow of air/viscous fluids. Chemical Engineering Science, 61, 6189–6198. DOI: 10.1016/j.ces.2006.06.001. http://dx.doi.org/10.1016/j.ces.2006.06.00110.1016/j.ces.2006.06.001Suche in Google Scholar
[27] Zhu, Y. G., & Wu, J. (2002). Critical impeller speed for suspending solids in aerated agitation tanks. The Canadian Journal of Chemical Engineering, 80, 1–6. DOI: 10.1002/cjce.5450800417. http://dx.doi.org/10.1002/cjce.545080041710.1002/cjce.5450800417Suche in Google Scholar
[28] Zwietering, T. N. (1958). Suspending of solids particles in liquid by agitators. Chemical Engineering Science, 8, 244–253. DOI: 10.1016/0009-2509(58)85031-9. http://dx.doi.org/10.1016/0009-2509(58)85031-910.1016/0009-2509(58)85031-9Suche in Google Scholar
© 2012 Institute of Chemistry, Slovak Academy of Sciences
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Artikel in diesem Heft
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- Investigation of kinetics of anaerobic digestion of Canary grass
- Extractive distillation modeling of the ternary system 2-methoxy-2-methylpropane-methanol-butan-1-ol
- Agitation of a gas-solid-liquid system in a vessel with high-speed impeller and vertical tubular coil
- Experimental analysis of the hydrodynamics of a three-phase system in a vessel with two impellers
- Influence of the ionic form of a cation-exchange adsorbent on chromatographic separation of galactooligosaccharides
- Mixed oxides of transition metals as catalysts for total ethanol oxidation
- Speciation of heavy metals in sewage sludge after mesophilic and thermophilic anaerobic digestion
- Oxidation of ammonia using modified TiO2 catalyst and UV-VIS irradiation
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