Agitation of a gas-solid-liquid system in a vessel with high-speed impeller and vertical tubular coil
-
Marta Major-Godlewska
and
Joanna Karcz
Abstract
Experimental results of gas hold-up, power consumption and residence time of gas bubbles in a gas-solid-liquid system produced in an agitated vessel equipped with a high-speed impeller and a vertical tubular coil are presented in this paper. Critical agitator speed, needed for the dispersion of gas bubbles and solid particles in liquid were also identified. The studies were carried out in an agitated vessel of the inner diameter D = 0.634 m and the working liquid volume of about 0.2 m3. A tubular coil of the diameter of 0.7D, consisting of 24 vertical tubes of the diameter of 0.016D, was located inside the flat-bottomed vessel. The agitated vessel was equipped with a Rushton turbine with six blades or an A 315 impeller with four blades. Both impellers had diameter, d, equal to 0.33D. The vessel was filled with liquid up to the height H = D. In this study, air and particles of sea sand with the mean diameter of 335 μm and the concentration of up to 3.0 mass % were dispersed in distilled water as the liquid phase. The measurements were carried out within the turbulent regime of the fluid flow in the agitated vessel. Results of the measurements were processed graphically and mathematically. Lower values of the critical agitator speed, n JSG, needed for simultaneous dispersion of gas bubbles and particles with the solids concentration from 0.5 mass % to 2 mass %, were obtained for the vessel equipped with the A 315 impeller. Higher values of the specific power consumption were reached for the vessel with the Rushton turbine. Higher values of the gas hold-up and residence time of the gas bubbles in the fluid were obtained for the system equipped with the Rushton turbine. Results of the gas hold-up as a function of the specific power consumption, superficial gas velocity and solids concentration were approximated with good accuracy using Eq. (5).
[1] Brunazzi, E., Di Festa, U., Galletti, C., Merello, C., Paglianti, A., & Pintus, S. (2002). Measuring volumetric phase fractions in a gas-solid-liquid stirred tank reactor using an impedance probe. The Canadian Journal of Chemical Engineering, 80, 688–694. DOI: 10.1002/cjce.5450800407. 10.1002/cjce.5450800407Search in Google Scholar
[2] Capuder, E., & Koloini, T. (1984). Gas hold-up and interfacial area in aerated suspensions of small particles. Chemical Engineering Research and Design, 62, 255–260. Search in Google Scholar
[3] 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. Search in Google Scholar
[4] Cieszkowski, J., & Dyląg, M. (1988). Gas-liquid-solid mixing in a stirred tank. In Proceedings of the 6th European Conference on Mixing, May 24–26, 1988 (pp. 421–426). Pavia, Italy. Search in Google Scholar
[5] Dohi, N., Matsuda, Y., Itano, N., Minekawa, K., Takahashi, T., & Kawase, Y. (2001). Suspension of solid particles in multi-impeller three-phase stirred tank reactors. The Canadian Journal of Chemical Engineering, 79, 107–111. DOI: 10.1002/cjce.5450790116. http://dx.doi.org/10.1002/cjce.545079011610.1002/cjce.5450790116Search in Google Scholar
[6] 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/10.1080/0098644990891275810.1080/00986449908912758Search in Google Scholar
[7] 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)00148-7Search in Google Scholar
[8] 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.5450730302Search in Google Scholar
[9] Greaves, M., & Loh, V. Y. (1985). Effect of high solids concentrations on mass transfer and gas hold-up in three-phase mixing. In Proceedings of the 5th European Conference on Mixing, June 10–12, 1985 (pp. 451–467). Wurzburg, Germany. Search in Google Scholar
[10] Harnby, N., Edwards, M. F., & Nienow, A. W. (1992). Mixing in the process industries (2nd ed., pp. 342). Oxford, UK: Butterworth-Heineman. Search in Google Scholar
[11] Jahoda, M., Machon, V., Veverka, P., & Majirova, H. (2000). Homogenisation of the liquid in three-phase multiimpeller stirred reactor. In Proceedings of the 14th International Congress of Chemical & Processing Engineering CHISA, August 27–31, 2000. Prague, Czech Republic. Search in Google Scholar
[12] Kamieński, J. (2004). Agitation of multiphase systems. Warsaw, Poland: WNT. (in Polish) Search in Google Scholar
[13] Kasat, G. R., & Pandit, A. B. (2005). Review on mixing characteristics in solid-liquid and solid-liquid-gas reactor vessels. The Canadian Journal of Chemical Engineering, 83, 618–643. DOI: 10.1002/cjce.5450830403. http://dx.doi.org/10.1002/cjce.545083040310.1002/cjce.5450830403Search in Google Scholar
[14] Kawase, Y., Shimizu, K., Araki, T., & Shimodaira, T. (1997). Hydrodynamics in three-phase stirred tank reactors with non-Newtonian fluids. Industrial & Engineering Chemistry Research, 36, 270–276. DOI: 10.1021/ie960452d. http://dx.doi.org/10.1021/ie960452d10.1021/ie960452dSearch in Google Scholar
[15] Kiełbus-Rąpała, A., & Karcz, J. (2010). Solid suspension and gas dispersion in gas-solid-liquid agitated systems. Chemical Papers, 64,2, 154–162. DOI: 10.2478/s11696-009-0104-9. http://dx.doi.org/10.2478/s11696-009-0104-910.2478/s11696-009-0104-9Search in Google Scholar
[16] 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, 432–444. Search in Google Scholar
[17] 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/s11696-010-0080-0Search in Google Scholar
[18] 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. Search in Google Scholar
[19] Martin, M., Montes, F. J., & Galan, M. A. (2009). Physical explanation of the empirical coefficients of gas-liquid mass transfer equations. Chemical Engineering Science, 64, 410–425. DOI: 10.1016/j.ces.2008.10.035. http://dx.doi.org/10.1016/j.ces.2008.10.03510.1016/j.ces.2008.10.035Search 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, piched 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)00682-6Search in Google Scholar
[21] Murthy, B. N., Ghadge, R. S., & Joshi, J. B. (2007). CFD simulations of gas-liquid-solid stirred reactor: Prediction of critical impeller speed for solid suspension. Chemical Engineering Science, 62, 7184–7195. DOI: 10.1016/j.ces.2007.07.005. http://dx.doi.org/10.1016/j.ces.2007.07.00510.1016/j.ces.2007.07.005Search in Google Scholar
[22] Murthy, B. N., Kasundra, R. B., & Joshi, J. B. (2008). Hollow self-inducing impellers for gas-liquid-solid dispersion: Experimental and computational study. Chemical Engineering Journal, 141, 332–345. DOI: 10.1016/j.cej.2008.01.040. http://dx.doi.org/10.1016/j.cej.2008.01.04010.1016/j.cej.2008.01.040Search in Google Scholar
[23] Murugesan, T. (2001). Critical impeller speed for solid suspension in mechanically agitated contactors. Journal of Chemical Engineering of Japan, 34, 423–429. DOI: 10.1252/jcej.34.423. http://dx.doi.org/10.1252/jcej.34.42310.1252/jcej.34.423Search in Google Scholar
[24] Nagata, S. (1975). Mixing: principles and applications (pp. 350). Tokyo, Japan: Kodansha. Search in Google Scholar
[25] Nienow, A.W., & Bujalski, W. (2001). Studies on agitated three phase systems. In Proceedings of the 6th World Congress of Chemical Engineering, September 23–27, 2001. Melbourne, Australia. Search in Google Scholar
[26] 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. 10.1205/026387602321143363Search in Google Scholar
[27] Panneerselvam, R., Savithri, S., & Surender, G. D. (2008). CFD modeling of gas-liquid-solid mechanically agitated contactor. Chemical Engineering Research and Design, 86, 1331–1344. DOI: 10.1016/j.cherd.2008.08.008. http://dx.doi.org/10.1016/j.cherd.2008.08.00810.1016/j.cherd.2008.08.008Search in Google Scholar
[28] 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/ie800978wSearch in Google Scholar
[29] Pinelli, D., Nocentini, M., & Magelli, F. (1994). Hold-up in low viscosity gas-liquid systems stirred with multiple impellers. Comparison of different agitators types and sets. IChemE Symposium Series, 136, 81–88. Search in Google Scholar
[30] Roman, R. V., & Tudose, R. Z. (1997a). Studies on transfer processes in mixing vessels: effect of particles on gas-liquid hydrodynamics using modified Rushton turbine agitators. Bioprocess and Biosystems Engineering, 16, 135–144. DOI: 10.1007/s004490050300. 10.1007/s004490050300Search in Google Scholar
[31] Roman, R. V., & Tudose, R. Z. (1997b). Studies on transfer processes in mixing vessels: power consumption of the modified Rushton turbine agitators in three-phase systems. Bioprocess and Biosystems Engineering, 17, 307–316. DOI: 10.1007/s004490050390. 10.1007/s004490050390Search in Google Scholar
[32] Takenaka, K., Ciervo, G., Monti, D., Bujalski, W., Etchells, A. W., & Nienow, A. W. (2001). Mixing of three-phase system at high solids kontent (up to 40 % w/w) using radial and mixed flow impellers. Journal of Chemical Engineering of Japan, 34, 606–612. DOI: 10.1252/jcej.34.606. http://dx.doi.org/10.1252/jcej.34.60610.1252/jcej.34.606Search in Google Scholar
[33] Vasconcelos, J. M. T., Orvalho, S. C. P., Rodrigues, A. M. A. F., & Alves, S. S. (2000). Effect of blade shape on the performance of six-bladed disc turbine impellers. Industrial & Engineering Chemistry Research, 39, 203–213. DOI: 10.1021/ie9904145. http://dx.doi.org/10.1021/ie990414510.1021/ie9904145Search in Google Scholar
[34] 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.5450800417Search in Google Scholar
[35] 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)85031-9Search in Google Scholar
© 2012 Institute of Chemistry, Slovak Academy of Sciences
Articles in the same Issue
- Mathematical model of aerobic stabilization of old landfills
- 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
- Antioxidant potential and authenticity of some commercial fruit juices studied by EPR and IRMS
- Etching and recovery of gold from aluminum substrate in thiourea solution
Articles in the same Issue
- Mathematical model of aerobic stabilization of old landfills
- 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
- Antioxidant potential and authenticity of some commercial fruit juices studied by EPR and IRMS
- Etching and recovery of gold from aluminum substrate in thiourea solution
