The new Ash Eye is a much improved instrument based upon the previous Bretby Gammatech Natural Gamma Coal Quality Monitor (NGCQM). It is a non-contacting, fully on-line ash monitor providing second-by-second information on the ash content of conveyed coal.
The Ash Eye contains no radio active sources as it uses Natural Gamma Technology.
The Ash Eye incorporates a new and improved algorithm leading to greater consistency in ash measurement.
The Ash Eye often pays for itself in a few weeks!
Operation
The dirt associated with coal contains a higher concentration of radioactive material than the coal itself. The signal from a natural gamma detector mounted under the conveyor belt contains ash information. When this signal is combined with the mass of the material from a belt weigher a measurement of the ash content can be obtained.
Ash Eye data flow diagram
In order to counter the effects of changes in background radiation, signals from a small background sensor are also included in the ash calculation.
Accuracy
The accuracy of the Ash Eye will depend upon the site and the belt weigher.
Accuracies (1σ) of better than 0.5% ash on final product and 1-3% on run-of-mine have regularly been achieved. A precision of 0.5% ash can be achieved with final product systems (measured to ISO/DIS 15239).
More details in this
World Coal paper (Jan 2000).
Reprints are available upon request.
Features
Real time graphical and numerical display of instantaneous and shift ash
Local numerical display of instantaneous ash, shift ash, tph & shift tonnes (new feature)
Simple, secure, menu-driven operation
User-definable quality parameters
User configurable shift patterns
Optional batch operation with end-of-batch reporting
Comprehensive end of shift (and batch) reporting
User selectable graphical displays of archived trend information with user configurable
overlays (new feature)
Analogue outputs of any two measured parameters
Serial (RS232) output of measured parameters (up to 10km with long line drivers and radio modems (new feature)
Automatic restart upon restoration of power
Up to eight user nominated coal sources - automatic or manual switching being
available (new feature)
Up to four automatically or manually activated calibrations (new feature)
Automated scaling of background compensation leading to greater consistency (new feature)
Applications
Run-of-Mine (ROM) Monitoring
In dirt bunkering systems
Monitoring face or satellite mine ash
Monitoring screened coal
Blending control systems
Final product monitoring
Monitoring deliveries of coal
Monitoring boiler feed
Benefits
In run-of-mine applications the Ash Eye is being used to identify the source of dirty production enabling managers to tackle the problem.
In a large mining complex a network of monitors was successfully used to apportion the proceeds on the basis of ash content and tonnage.
In blending control systems the good use of the Ash Eye information leads to a more consistent blend leading to higher financial proceeds for the coal producer.
In power station applications the Ash Eye is often used to identify dirty coal prior to it entering the boilers thus saving costly downtime and boiler cleaning.
In final product applications the Ash Eye has, in many cases, eliminated the requirement for hourly control samples - significant Heat Error improvements have been achieved - thereby reducing costs and increasing revenue to the user.
In many in-plant applications the Ash Eye information can be used to give advance warning of problems e.g. changes in gravity levels, blocked shutes etc.
If you would like more information please download the
Ash Eye brochure.
Printed brochure available upon request.
