Coal Preparation » Process Control
A commercial prototype Acoustic Emission (AE) analyser has been developed for monitoring performance of washery Dense Medium Cyclones (DMCs), in particular the detection of adverse DMC operating conditions. The analyser consists of an electronics module and multiple accelerometer sensors which are non-intrusively mounted on a DMC shell at feed, underflow and overflow locations. These sensors acquire passive (natural) AE signals representative of the local internal flow stream process state. The AE signals are fed to the analyser computer for real time analysis. Process variable information from the plant control system is combined with derived AE measures to provide rapid information on the DMC performance to the plant control room. This will allow rapid remedial action to be taken by the plant if required.
This project follows on from the previous ACARP projects C12052 and C14063. The previous projects demonstrated proof-of-concept of the passive AE monitoring approach for determination of DMC process state and adverse operating conditions. Under the current project a robust analyser suitable for permanent industrial deployment, and capable of outputting alarms in real time has been developed, and manufactured. The analyser was installed, commissioned and tested in a five month trial at Hunter Valley Operations (HVO) No. 1 Coal Handling and Preparation Plant in NSW.
The analyser has been developed to advise of the following DMC conditions:
- Spigot/vortex overload
- Feed imbalance for parallel DMCs
- Discharge stream blockage
- Clay Ball formation
Overload and surging conditions occurred during the trial and were detected by the AE analyser. Feed imbalance between parallel DMCs was routinely detected. Although not part of the scope of the current project, the analyser was also shown to be capable of providing an estimate of DMC yield variation with coal feed type, specific gravity of the feed dense medium and solids feed rate. A DMC on-line yield indicator clearly has great potential for optimisation of washery separation performance.
CSIRO Minerals has established a strategy to supply AE Analysers to the Australian coal industry for deployment on DMCs. A commercial on-line analyser based on passive AE signals is easy to install and maintain in an operating washery. Designs are available for four or eight channel AE Analysers to monitor both single and dual DMC modules. The commercial prototype AE monitoring and alarm system for DMC adverse operating conditions is now available to the Australian coal industry.