Adverse Operating Condition Monitoring of Dense Medium Cyclones by Acoustic Emissions

摘要

A robust, low-cost, non-intrusive contact Acoustic Emission (AE) passive monitoring system for Dense Medium Cyclone (DMC) adverse operating conditions is described. Elastic waves generated by particulate slurry flow through an operating DMC are simultaneously monitored by an array of accelerometers mounted at feed, mid-body, underflow and overflow shell locations. Both the hardware and software components of the contact AE monitoring and analysis system for DMCs are discussed in this paper. The system has been developed and tested by monitoring trials on DMCs of different types and wear states at a number of coal washeries in Australia, operating at a wide variety of operating conditions. Results are presented for detection of surging and clay ball formation adverse operating conditions in washery DMCs. Possible imbalance in the feed and product stream mass flow rates of parallel DMCs is also investigated. Contact AE process and condition monitoring of DMCs is readily implemented in operating coal preparation plants and amenable to further development as an on-line soft-sensor analysis system. It is expected that the combination of multiple sensor contact AE measurements, "feature" extraction signal processing and soft-sensor modelling based on calibrated experiments will lead to on-line soft-sensor alarms for adverse operating conditions, plus monitoring of DMC operating and separation performance variables and liner general wear state. It is further anticipated that contact AE monitoring coupled with soft-sensor modelling methods will be widely applicable for process and condition monitoring of other unit operations in coal washeries.