International Society for Industrial Process Tomography

Electrical Resistance Rheometry – The Application of
Multi-scale Tomography Sensors to Provide in-pipe Rheology
in Complex Processes

Thomas D. Machin^1,2*, K. Wei², R.W. Greenwood¹, M.J.H Simmons¹

¹University of Birmingham,Birmingham, UK

²Industrial Tomography Systems PLC,Manchester, UK

^*Email: tom.machin@itoms.com

ABSTRACT

The rheology of a fluid system is a vital property in a wide range of physical and chemical industrial processes as it governs process quality and efficiency. Conventionally, rheological properties are measured off-line with the removal of a sample from the process stream required. Off-line measurements are applied to flows within real processes; however, the majority of attempts have been unsatisfactory as it only offers a retrospective characterisation. Accordingly, there is an ever-increasing demand for the development of in-line rheometers as most industrial fluids exhibit complex rheological behaviour. A novel, in-line Electrical Resistance Rheometry technique is outlined in this paper which utilises a combination of multi-scalar microelectrical tomography sensors to perform in-situ measurements on process fluids. By cross-correlating fluctuations of computed conductivity pixels across and along a pipe, the rheological behaviour of a fluid is able to be obtained directly through the measurement of the velocity profile. The measurement of a flow profile with Electrical Tomography is well-established; however, the resolution in the near-wall region of the pipe has limited its application to monitor rheology. This has been overcome with the inclusion of multi-scalar arrays permit the specific targeting of the electrical field to a desired region of interest, in this instance near to the pipe-wall. Across a range of well characterised materials, the measured velocity profile and extracted rheological parameters have been verified with Particle Image Velocimetry and rotational rheometry, respectively. The manipulation of array length, and consequently electrical field penetration, has been utilised for the first time within this study and has further applications in other unit operations, for example stirred tanks.

Keywords multi-scaled sensing, in-line, rheology, process optimisation

Industrial Application General