Mackay Manufacturer Develops State-of-the-Art Coal Quality Analyzer
Using sophisticated PGNAA (prompt gamma neutron activation analysis) technology the AllScan® provides real-time, continuous data on the chemical composition of coal including what elements make up the coal and in what concentrations. Material on the conveyor is bombarded with neutrons emitted from a radioactive isotope that is housed in a fail-safe stainless steel holder which sits above the conveyor belt. When neutrons collide with an element in the coal, gamma rays are emitted with a specific energy unique to that element – in effect, creating chemical signature for that element. The greater the amount of an element in the coal the greater the number of gamma rays emitted with the corresponding specific energy. By measuring the specific energy of the gamma rays that are emitted and the number of gamma rays, an accurate analysis of the chemistry of the coal is derived.
From this data, key coal quality parameters such at total ash, sulphur and combustible energy are accurately determined.
In addition, the AllScan® cross belt coal quality analyser identifies harmful and unwanted trace elements, such as mercury and arsenic, potentially present in coal at extremely low concentrations. Traditional laboratory methods of coal analysis cannot provide real time data on variation in ash content and harmful trace elements; hence plant operators cannot take immediate corrective action.
A Central Queensland coal mine recently installed four coal quality analysers to reduce penalty payments for supplying coal that was too high in ash content and contained unacceptable levels of mercury and arsenic. One AllScan® is installed on a conveyor from the mine. Once the coal on the belt is analysed by the AllScan® it is either sent to the wash plant stockpile or the product stockpile. If there is an unacceptable spike in mercury or arsenic an automatic alarm is sent to the plant control room. Another two analysers are installed on stackers to the product stockpile yards. The ash data from the PGNAA coal quality analyzer is used to build a detailed stockpile model that is then reclaimed automatically in predefined quality sections to achieve the desired coal quality specified by the customer. A forth analyzer is installed on the product belt to the train load-out as a final check that the product meets the customers quality requirements.
RTI has also recently sold a number of AllScan® PGNAA analysers to several coal mines in New South Wales and to a massive coal mining project in Mozambique.
Whilst there are a number of other online PGNAA elemental analysers on the market, Dr Asbury explains that the AllScan® has a number of distinct advantages that make it the most accurate and reliable analyser available.
In particular, RTI has developed a highly advanced algorithm that we have named Dura-G™. Dura-G™ ensures that accuracy is maintained irrespective of belt loading and variable profiling. A drop off in accuracy under varying belt loading and profiling conditions has always been a technical challenge for online elemental analysis. And a major concern for customers. The Dura-G™ neutron modelling software incorporated in the AllScan® separates the influence of profile and bed depth variation from elemental variation, thus enabling accurate results, even at very low bed depths and in situations of erratic profiling. This is a world-first. Additionally, the Dura-G™ neutron modelling software can identify and alarm on harmful and unwanted trace elements that might be present in coal, even at extremely low concentrations.
Coal companies, coal marketers and end-users stand to significantly benefit from integrating online coal quality analysis into their operations’, Dr Asbury said. “Using the AllScan® you get to really know your coal”. All the coal on the belt is analysed and the results are reported second-by-second. Compare this with traditional lab sampling where a small sample of coal is taken off the belt periodically and sent to a laboratory for analysis. Coal can be very heterogeneous so relying on periodic samples does not necessarily represent a true picture of the quality of the coal. The AllScan® gives accurate, real time, continuous data on coal quality. Operators have this valuable information at their fingertips.
The AllScan® is manufactured in Mackay, Australia. All parts are made from non-corrosive materials and fully ruggedized for harsh industrial application, ensuring a long field life and low maintenance costs.
“We’re very proud to be a high-technology manufacturer based in regional Queensland and exporting our products all over the world” said Dr Asbury
For more information on the AllScan® coal quality analyzer visit the RTI website.
For further information contact Ben Faa on +61 (7) 4955 5944 or Dr James Asbury on +61 (7) 4955 5944. Alternatively email benf[at]realtimegrp.com.