A Method to Justify Process Control Systems in Mineral Processing Applications

Document Type : Research Article

Authors

1 Mining Engineering Goup, Shahid Bahonar University of Kerman, P.O. Box 76175-133 Kerman, I.R. IRAN

2 Mining Engineering Group, ValiAsr University of Rafsanjan, P.O. Box 518 Rafsanjan, I.R. IRAN

Abstract

The impact of installing process control systems can be expected in terms of performance improvements through reduced operating costs.  Since these installations impose considerable capital expenditure, the profitability of the new systems should be economically justified. Controlled variable trend was reconstructed by a combination of simple waves, which provided a means to simulate the effect of installing a control system (feedback) by removing disturbance waves with high periods (> one cycle per hour).  A method was proposed to evaluate the impact of installing a control system either by a reduction of difference between concentrate target quality and operating quality (i.e., bias reduction) or by reduction of scatter of product quality (i.e., variance reduction).  Installing automatic control systems not only reduces operating costs, but also may increase revenue from washed coal sales by maintaining plant performance on designed or desired target. It was found that if an appropriate feedback control system is used at the flotation circuit of the Zarand coal washing plant, the variance of concentrate ash content could be decreased from the current value of 0.38 to 0.06. based on the predicted metallurgical improvement, the payback time of installing a conventional control system for the flotation circuit of the Zarand plant size with the approximate cost of $1,000,000 was found to be 2 years.The impact of installing process control systems can be expected in terms of performance improvements through reduced operating costs.  Since these installations impose considerable capital expenditure, the profitability of the new systems should be economically justified. Controlled variable trend was reconstructed by a combination of simple waves, which provided a means to simulate the effect of installing a control system (feedback) by removing disturbance waves with high periods (> one cycle per hour).  A method was proposed to evaluate the impact of installing a control system either by a reduction of difference between concentrate target quality and operating quality (i.e., bias reduction) or by reduction of scatter of product quality (i.e., variance reduction).  Installing automatic control systems not only reduces operating costs, but also may increase revenue from washed coal sales by maintaining plant performance on designed or desired target. It was found that if an appropriate feedback control system is used at the flotation circuit of the Zarand coal washing plant, the variance of concentrate ash content could be decreased from the current value of 0.38 to 0.06. based on the predicted metallurgical improvement, the payback time of installing a conventional control system for the flotation circuit of the Zarand plant size with the approximate cost of $1,000,000 was found to be 2 years.  

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References

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Iranian Journal of Chemistry and Chemical Engineering
Volume 32, Issue 4 - Serial Number 68
December 2013
Pages 105-115

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