Investigating the Operational Parameters Affecting the Acid-Base Reaction Inside the Stirred Tank by PIV/PLIF Technique

Document Type : Original Article

Authors

Sahand University of Technology

Abstract

In this study, the acid-base neutralization reaction of acetic acid and ammonium hydroxide reaction inside a mixing tank to study the mixing interaction and chemical reaction by using simultaneous planar laser-induced fluorescence (PLIF)[1] and particle image velocimetry (PIV)[2] methods has been examined. The blade rotation speed, the blade distance from the bottom of the tank, the presence of buffers and the rheological properties of the fluid inside the tank are all the parameters that can be changed and optimized to improve the conditions of performance of mixed tanks which they are investigated to test them effects. The results showed that the progress of the acid-base neutralization reaction in the studied conditions was under the control of the mixing conditions of the reactants. To investigate the effect of blade distance from the tank floor, the ratios
C/T = 0.25, C/T = 0.5 and C/T = 0.75 were selected which C is the distance of the blade from the tank floor and T is the diameter of the tank. Also the experiments were repeated at three speeds of 100 rpm, 150rpm and 200rpm. The results showed that by increasing the distance of the blade from the bottom of the tank, which is equivalent to increasing the
C/T ratio, the reaction time was significantly reduced. In addition, at constant C/T ratios, the reaction time decreases sharply by increasing blade rotation speed. Also, in order to investigate the effect of the number of buffles in the tank, a buffleless,
2 buffles and 4 buffles blades were used at speeds of 100 rpm, 150rpm and 200rpm. Based on the results, it was found that as the number of buffles in the tank increased, the reaction time decreased. Also, a comparison of experiments performed in each tanks with three different speeds showed that the time-reduction ratios in tanks with fixed number of buffles at different speeds have a similar downward trend. Another parameter studied in this study was fluid viscosity, which was tested in
µ= 35 mPa.s, µ=55 mPa.s, µ=75 mPa.s. The results of these experiments showed that with increasing fluid viscosity from µ=35 mPa.s to µ=55 mPa.s, the reaction time increased significantly, However, increasing the fluid viscosity by µ=75 mPa.s has less effect on the reaction time.



[1]. Planar Laser-Induced Fluorescence


[2]. Particle Image Velocimetry

Keywords

References

Xiaoxia, X., Feng , Z. S., "Numerical simulation of reactive mixing process in a stirred reactor with the DQMOM-IEM model". chemical engineering journal, (2018).
[2]        Faes, M., Glasmacher, B., "Measurements Of Micro-And Macromixing In Liquid Mixtures Of Reacting Components Using Two-Colour Laser Induced Fluorescence". Chemical Engineering Science, (2008).
[3]        Cui, Y., Zhang, H., Li, X., Yang, M., "Computational and experimrntal investigation of laminar flow mixing system in a pitched – blade turbine stirred tank". Int J Agric & boil eng, (2018).
[4]        Aydin, O., Yapici, S., "A method for measurement of mixing time; A new application of electrochimical limiting diffusion current technique". Experimental thermal and Fluid Science, (2018).
[5]        Cheng, D., Feng, X., Cheng, J., Yang, C., "Experimental study on the disperesed phase macro-mixing in an immiscible Liquid-liquid stirred reactor". Chemical Engineering Science, (2015).
[6]        Thakur, S., Chauhan, M. S., "Removal of Malachite green dye from aqueous by Fenton Oxidation". International Research Journal of Engineering and Technology, (2016).
[7]        Chang, G., Peng, J., Yu, X., "Visualization study on vortex structure over an airfoil using planar laser induced fluorescence". International Journal for repid communication, (2018).
 
 
 
[8]        Lozano, A., Yip, B., "Acetone: a tracer for concentration measurement in gaseous flows by planar laser induced fluorescence". Experimental in Fluids, (1992).
[9]        Cruyningen, I. V., Lozano, A., Hanson, R. K., "Quantitative imaging of concentration by planar laser induced fluorescence". Experimental in Fluids, (1990).
[10]      Cetegen, B. M., Mohamad, N., "Expriments on liquid mixing and reaction in a vortex". Mechanical Engeering Department, (1992).
[11]      Gaskey, S., Vacus, P., David, R., "A method for turbulant mixing using flourecence spectroscopy". Experimental in Fluids, (1990).
[12]      Andre, C., David, R., Andre, J. C., Villermaux, J., "A New Fluorescence Method for measuring cross- fluctuations of two Non- reactive Component in a mixing Device". Chem. Eng. Techhnol, (1992).
[13]      Houcine, I., Vivier, H., Plasari, E., David, R., "Planar laser induced fluorescence technique for measurements of concentration fields in continuous stirred tank reactors". Experiments in Fluids, (1996).
[14]      Distelhoff, M. F. W., Marquis, A. J., "Scalar Mixing Measurement in batch operated stirred tank". Chemical Engineering, (1997).
[15]      Guillard, F., "Mixing patterns in rushton-tuorbine-agitated reactors". Lund University Publication, (2003).
[16]      Fall, A., Lecoq, O., David, R., "Chaaracterization of mixing in a stirred tank by planar laser induced fluorescence (PLIF) ". Institution of chemical engineers, (2001).
[17]      Hall, J. F., Barigou, M., Simmons, M. J. H., "Mixing in Unbaffled High-Throughput Experimenation Reactors". Ind. Eng. Chem, (2004).
[18]      Chung, K. H. K., Barigou, M., "Reconstruction of 3-D field inside miniature stirred vessels using A 2-D PIV Technique". Departement of Chemical Engineering, (2007).
 
[19]      Moghaddas, J.S., "An Experimental study of fluid dynamics and mixing in bubbly gas-liquid flow systems". Lund University Publication, (2004).
[20]      Zadghaffari, R., Moghaddas, J. S., Revstedt, J., "A mixing study in a double- rushton stirred tank". Computers and Chemical Engineering, (2009).
[21]      Collignon, M. L., Dossin, D., "Quality of mixing in a stirred bioreactor used for animal cells culture: heterogeneities in a lab scale bioreactor and evolution of mixing time with scale up". Biotechnol. Agron. Soc . environ, (2010).
[22]      Busciglio, A., Grisafi, F., Ippolito, F., "mixing time in unbaffled stirred tank". European Conference on mixing Warszawa, (2012).
[23]      Jordan, L. E., Amaro, A., "Introducing the planar laser- induced fluorescence techniqu (PLIF) to measure mixing time in gas- stirred ladles". The minerals, Metal & Materials Society, (2019).
[24]      Sancho, I., Varela, S., Vernet, A., Pallares, J., "Characterization Of The Reacting Laminar Flow In a Cylindrical Cavity With a Rotating Endwall Using Numerical Simulations And a Combined PIV/PLIF Technique". International Journal Of Heat And Mass Transfer, (2016).
[25]      Ibarra, R., Zadrazil, I., "Dyanamics of Liquid-Liquid flows in a horizontal pipes using simultaneous two- line planar laser-induced fluorescence and particle velocimetry". Multiphase Flow, (2017).
[26]      Ascacanio, G., "mixing time in stirred vessel; A reviw of expermental tecniques". Chmical Engineering, (2015).
[27]      Jordan, L. E., Rivera, C. G., Ramirez, M. A., "Effect of model size and water chemical composition on mixing time measurments using PLIF in a gas stirred ladle".Sciences Technology Conference, (2019).
Iranian Chemical Engineering Journal
Volume 19, Issue 110
September and October 2020
Pages 6-18

Files

Share

How to cite

Statistics