Coal Preparation » Process Control
A proof-of-concept robust, low-cost, non-intrusive contact Acoustic Emission (AE) monitoring and soft-sensor analysis system has been developed for monitoring of coal washery Dense Medium Cyclone (DMC) process state and machine condition. AE sensors are mounted on the external shell of an operating DMC, typically at feed, mid-body, underflow and overflow locations, with data logged at intervals to a computer in the plant control room for later analysis and prediction of key DMC operating and performance variables, and unit wear state.
Contact AE process and condition monitoring systems suitable for DMCs are relatively low-cost and can be readily installed in an operating washery. The current system has been successfully trialled on industrial DMCs at two NSW coal washeries and on a hydrocyclone in the laboratory.
The most significant outcome of the project is the demonstrated ability of a robust, low-cost, non-intrusive multiple sensor contact AE monitoring and analysis system to quantitatively predict changes in DMC operating conditions and qualitatively predict changes in DMC wear state.
Specific findings of the project of significance to plant operators include:
- ?Back-up' soft-sensors can be formulated for robust quantitative prediction of washery DMC operating variables including module dry feed rate, Specific Gravity (SG) of feed dense medium and DMC inlet pressure, based on suitably processed contact AE signals.
- DMC general wear state can be qualitatively predicted from suitably processed contact AE signals.
- There are strong indications that feed imbalance to parallel DMCs can be predicted from suitably processed contact AE signals associated with the DMC feed monitoring locations.
- There are indications that spigot overload can be predicted from suitably processed contact AE signals associated with the DMC feed and underflow monitoring locations.
The next step in the development of a contact AE monitoring system for DMCs (already commenced in ACARP project C14063) is to construct a proof-of-concept software alarm module for detection of adverse operating conditions, such as incipient surging, clay ball build-up and spigot overload. An additional project could involve developing a prototype low-cost AE monitoring and analysis system that includes operating and performance variable, general wear state and adverse operating condition alarm modules, suitable for long-term, on-line process and condition monitoring of DMCs at washeries. A conceptual design for an industrial prototype on-line contact AE monitoring system suitable for long-term use in coal preparation plants has already been developed as part of the current project.