Influence of impeller submergence depth on power consumption in stirred tank
Keywords:arrowhead impeller, power consumption, rotational speed, stirred tanks, submergence depth
Impeller submergence governs the performance of mixing tanks employed in chemical and biochemical operation. Present work experimentally investigates the effect of impeller submergence depths on power consumption when arrow head impeller has been used in the process. Arrowhead impeller performs better than the conventional Rushton impeller. It has been found that at higher range of impeller submergence, mixing tanks consume less power. Optimal range of submergence depth is 0.8 to 0.9 times the impeller diameter.
Key words: arrowhead impeller; power consumption; rotational speed; stirred tanks; submergence depth
Chemical Engineering Research Bulletin 15 (2011) 45-47
Oldshue JY, Fluid Mixing Technology, McGraw-Hill, New York, 1983.
Ulbrecht JJ and Patterson GK, Mixing of Liquids by Mechanical Agitation, Chemical Engineering Series: Concepts and Reviews, Volume 1, Gordon and Breach Science Publishers, London, 1985.
Bader FG, (1987). Modelling mass transfer and agitator performance in multiturbine fermentors, Biotechnol.Bioeng, 1987. 31: 3751
Charles M, Fermentation design and scale-up, In: Moo-Young M (ed) Comprehensive biotechnology. Pergamon Press, Oxford, 1985.
Rushton JH, Applications of fluid mechanics and similitude to scale-up problems-part1, Chem Engg Progress, 1952. 48: 33-38.
Nagata S, Mixing Principles and applications, John Wiley & sons, New York, 1975.
Ognean T, Dimensionless Criteria for Estimating Oxygen Transfer in Aeration systems. Biotechnol Bioeng, 1993. 41: 1014-1020.
Ciofalo M, Brucato A, Grisafi F and Torraca N, Turbulent flow in closed and free-surface unbaffled tanks, Chem Eng Sci, 1996. 51: 3557-3573.
Nienow AW, Hydrodynamics of stirred bioreactors, App Mech Rev 1998. 51:132.
Montante G, Lee KC, Brucato A and Yianneskis M, Numerical simulations of the dependency of flow pattern on impeller clearance in stirred vessels, Chem Eng Sci, 2001. 56: 37513770.
Li M, White G, Wilkinson D and Roberts KJ, LDA measurements and CFD modeling of a stirred vessel with a retreat curve impeller, Ind Eng Chem Res, 2004. 43: 65346547.
Assirelli M, Bujalski W, Eaglesham A and Nienow AW, Study of micromixing in a stirred tank using a Rushton turbine: comparison of feed position and other mixing devices, Trans Inst Chem Engg, 2002. 80: 855863.
Patil SS, Deshmukh NA and Joshi JB, Mass-Transfer Characteristics of Surface Aerators and Gas-Inducing Impellers, Ind Eng Chem Res, 2004. 43: 2765-2774
Backhurst JR, Harker JH and Kaul SN, The performance of pilot and full-scale vertical shaft aerators, Water Res, 1988. 22: 1239-1243.
Takase H, Unno H and Akehata T, Oxygen Transfer in a Surface Aeration Tank with Square Cross Section, Int Chem Eng 1984. 128-134.
Hwang HJ and Stenstrom MK, Evaluation of Fine-Bubble Alpha Factors in Near-Full Scale Equipment, JWPCF, 1985. 57: 1142-1150.
Vasel JL, Contribution á létude des transferts d'oxygène en gestion des eaux, Ph.D. Thesis, Fondation Universitaire Luxemourgeoise, Luxembourg, Arlon, 1988..
www.chemineer.com [accessed on 17th February, 2011]
Walas SM, Chemical Process Equipment - Selection and Design, Butterworth-Heinemann, Washington Street, Newton, MA, USA, 1990.
King RL, Hiller RA and Tatterson GB, Power consumption in a mixer. AIChE J, 1988. 34: 506-509
Nienow AW and Ulbrecht JJ, Mixing of liquids by mechanical agitation, Eds. Ulbrecht, J.J. and Patterson, G.K., Gordon and Breach, New York, Chapter 6, pp. 203-237, 1985.
Ascanio G, Castro B and Galindo E, Measurement of power consumption in stirred vesselsa review, Chem Eng Res Des, 2004. 82: 1282290.
Deshmukh NA and Joshi JB, Surface aerators: power number, mass transfer coefficient, gas hold up profiles and flow patterns, Chem Eng Res Des, 2006. 84: 116.