SciELO - Scientific Electronic Library Online

vol.108 issue10Applications of electrical tomography to improve the performance of crystallization, precipitation and mixing processesThree-dimensional measurement and simulation of the dewatering behavior of flocs and sediments using X-ray microtomography author indexsubject indexarticles search
Home Pagealphabetic serial listing  

Journal of the Southern African Institute of Mining and Metallurgy

On-line version ISSN 2411-9717
Print version ISSN 0038-223X

J. S. Afr. Inst. Min. Metall. vol.108 n.10 Johannesburg Oct. 2008




Measurement of suspension velocity in slurries and pastes using impedance imaging



R.A. Williams; G. Vilar

Institute of Particle Science and Engineering, School of Process, Environmental and Materials Engineering, University of Leeds, UK




Electrical impedance tomographic methods have been applied to a variety of mineral and chemical processes in the laboratory and on plant. This review paper surveys technical developments in measurement methods to enable quantitative extraction of key process information in the form of mapping of concentration profiles, mixture homogeneity and suspension velocity. The methods for determining velocity are summarized, since this is of especial interest when applied to opaque systems where most conventional optically based measurements fail. A recent significant development is the use of ultra-high speed measurement that now allows velocity vectors to be extracted for fast moving mixtures and fluids (up to several metres per second). New data are reported pertinent to low and high solids concentration flow in pipelines. Use of the methods offer improvements to design of such systems but also points to the use of tomographic electrical sensor as online flow measurement and fault detection. This offers new opportunities for applications and benefits in the design and monitoring of mineral slurries and sludges.



“Full text available only in PDF format”




1. WILLIAMS, R.A. and BECK, M.S. Process Tomography: principles, techniques, and applications. Butterworth-Heinemann Ltd 1995.         [ Links ]

2. WILLIAMS, R.A. Mineral and material processing, Process Imaging for Automatic Control, Scott DM, McCann H., Taylor and Francis, 2005. pp. 359-400.         [ Links ]

3. CULLIVAN, J.C., WILLIAMS, R.A. and CROSS, C.R. New insights into hydrocyclone operation, Particulate Science and Technology, vol. 21, 2003. pp. 83-103.         [ Links ]

4. FANGARY, Y.S., ABD EL GHANI, A.S., EL HAGGAR, S.M. and WILLIAMS, R.A. The effect of fine particles on slurry transport processes, Minerals Engineering, vol. 10, 1997. pp. 427-439.         [ Links ]

5. FANGARY, Y.S., WILLIAMS, R.A., NEIL, W.A., BOND, J. and FAULKS, I. Application of electrical resistance tomography to detect deposition in hydraulic conveying systems, Powder Technology, vol. 95, 1998. pp. 61-66.         [ Links ]

6. LUCAS, G.P., CORY, J., WATERFALL, R.C., LOH, W.W. and DICKIN, F.J. Measurement of the solids volume fraction and velocity distributions in solids-liquid flows using dual-plane electrical resistance tomography, Flow Measurement and Instrumentation, vol. 10, 1999. pp. 249-258.         [ Links ]

7. WANG, M., LUCAS, G., DAI, Y., PANAYOTOPOULOS, N. and WILLIAMS, R.A. Visualisation of bubbly velocity distribution in a swirling flow using electrical resistance tomography, Particle & Particle Systems Characterization, vol. 23, 2006. pp. 321-329.         [ Links ]

8. WANG, M., JONES, T.F. and WILLIAMS, R.A. Visualization of asymmetric solids distribution in horizontal swirling flows using electrical resistance tomography, Trans IChemE, 81, Part A, 2003. pp. 854-861.         [ Links ]

9. HALSEY, D.M. Flow meters in swirling flows, J Phys E: Sci Instrum, vol. 20, 1987. pp. 1036-1040.         [ Links ]

10. JONES, T.F. Pipe design for improved particle distribution and reduced wear, Directorate General Energy, ECSC 7220-EA/841, European Communities, Luxembourg. 1997.         [ Links ]

11. YIN, W., WANG, M., JONES, T.F., GANESHALINGAM, J., WILLIAMS, R.A., MILES, NJ., LI, D., LAI, Y. and WU, Y. Measurement of swirling flow in hydraulic conveying using electrical resistance tomography, Proceedings of the World Congress on Particle Technology IV, Sydney, 21-25 July. 2002.         [ Links ]

12. NOWAKOWSKI, A.F., CULLIVAN, J.C., WILLIAMS, R.A. and DYAKOWSKI, T. Application of CFD to modelling of the flow in hydrocyclones. Is this a realizable option or still a research challenge?, Minerals Engineering, vol. 17, 2004. pp. 661-669.         [ Links ]

13. CULLIVAN, J.C., WILLIAMS, R.A., DYAKOWSKI, T. and CROSS, C.R. New understanding of a hydrocyclone flow field and separation mechanism from computational fluid dynamics, Minerals Engineering, vol. 17, 2004. pp. 651-660.         [ Links ]

14. BENNETT, M.A. and WILLIAMS, R.A. Monitoring the operation of an oil/water separator using impedance tomography, Minerals Engineering, vol. 17, 2004. pp. 605-614.         [ Links ]

15. WILLIAMS, R.A., JIA, X., WEST, R.M., WANG, M., CULLIVAN, J.C., BOND, J., FAULKS, I., DYAKOWSKI, D., WANG, S.J., CLIMPSON, N., KOSTUCH, J.A. and PAYTON, D. Industrial monitoring of hydrocyclone operation using electrical resistance tomography, Minerals Engineering, vol. 12, 1999. pp.1245-1252.         [ Links ]

16. BRENNAN, M., HOLTHAM, P., KHANAL, M. and MORRISON, R. Comparing ERT Measurements with CFD Predictions for an Industrial Scale hydrocyclone classifier, 5th World Congress on Industrial Process Tomography, Bergen, Norway. 2007.         [ Links ]

17. WEST, R.M., JIA, X. and WILLIAMS, R.A. Parametric modelling in industrial process tomography, Chem. Eng. J., vol. 77, 2000. pp. 31-36.         [ Links ]

18. WEST, R.M., SCOTT, D.M., SUNSHINE, G., KOSTUCH, J., HEIKKINEN, L., VAUHKONEN, M., HOYLE, BS., SCHLABERG, H.I., HOU, R., and WILLIAMS, R.A. In-situ imaging of paste extrusion using electrical impedance tomography, Meas. Sci. Technol. vol. 13, 2002. pp. 1890-1897.         [ Links ]

19. BENNETT, M.A., WEST, R.M., LUKE, S.P., JIA, X. and WILLIAMS, R.A. Measurement and analysis of flows in a gas-liquid column reactor, Chemical Engineering Science. vol. 54, 1999. pp. 5003-5012.         [ Links ]

20. VILAR, G., WILLIAMS, R.A., WANG, M. and TWEEDIE, R.J. On Line Analysis of Structure of Dispersions in an Oscillatory Baffled Reactor using Electrical Impedance Tomography, Chem. Eng. J., vol. 141, 2007. pp. 58-66.         [ Links ]

21. WANG, M., MA, Y., HOLLIDAY, N., DAI, Y., WILLIAMS, R.A. and LUCAS, G. A High-Performance EIT System, IEEE Sensors Journal, vol. 5, 2005. pp. 289-299.         [ Links ]

22. WILKINSON, A.J., RANDALL, E.W., DURRETT, D.R., NAIDOO, T. and CILLIERS, J.J. The design of a 1000 frames/second ERT Data Capture System and Calibration Techniques Employed, 3rd World Congress on Industrial Process Tomography, Banff, Canada. 2003.         [ Links ]

23. SCHLABERG, H.I., JIA, J., QIU, C., WANG, M. and LI, H. Development and application of the Fast Impedance Camera-a high performance dual-plane electrical impedance tomography system, Proceedings of the 5th International Symposium on Process Tomography, Zakopane, Poland. 2008.         [ Links ]

Creative Commons License All the contents of this journal, except where otherwise noted, is licensed under a Creative Commons Attribution License