Monitoring bed formation in a pipeline: a comparative study of two measurement methods

Authors: Chryss, AG; Zheng, E Download Paper Open access courtesy of:

DOI https://doi.org/10.36487/ACG_repo/2455_34

Cite As:
Chryss, AG & Zheng, E 2024, 'Monitoring bed formation in a pipeline: a comparative study of two measurement methods', in AB Fourie & D Reid (eds), Paste 2024: Proceedings of the 26th International Conference on Paste, Thickened and Filtered Tailings, Australian Centre for Geomechanics, Perth, pp. 431-440, https://doi.org/10.36487/ACG_repo/2455_34



Abstract:
Transport of tailings via pipeline is a common practice between mineral processing sites and a tailings storage facility. To operate these typically turbulent multiphase-flows safely at high solids loadings with minimum energy and water consumption is not a simple task. Monitoring of tailings pipelines is often restricted to pressure drop measurements. Monitoring could be enhanced by effective, non-radiometric instrumentation for solids concentration or concentration profile. Two possible options for such an instrument are electrical resistance tomography (ERT) and thermal bed load detection (BLD). ERT represents a non-intrusive method suitable for monitoring solid-liquid suspension flows. While ERT has shown its capability to generate good qualitative images, it faces challenges including limited spatial resolution, sensitivity to electric noise and the inherent difficulty of calculating concentration distributions. For suspensions with a settled bed, ERT reconstruction projects an incorrect smooth transition at the bed interface and typically underestimates the concentration, with a discrepancy up to 25% (v/v) at the highest bed level. Thermal BLD provides a method of measuring the depth of a settled bed via changes in rate of heat transfer. The BLD consists of multiple sensors around the pipe circumference which combine a heater with a thermocouple to maintain a constant surface temperature. The power required to maintain a set temperature is proportional to the heat lost to the fluid or bed that is in contact with the sensor. The change in rate of heat transfer is then used to infer bed depth. A comparison is made between the results from both methods at laboratory and pilot scales. The data is assessed for its accuracy and the robustness of measurements for field deployment.

Keywords: solids settling, pipeline transport, electrical resistance tomography, thickened tailings, settled bed

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