Project Title: PERFORMANCE OPTIMIZATION OF A COAL PREPARATION PLANT USING GENETIC ALGORITHMS

It is well understood that the high cost of producing coal is a more significant parameter than the high sulfur content when considering the declining trend in Illinois coal sales. Hence, the reversal of this trend will require stringent cost cutting measures in all relevant cost components, including the coal preparation cost. One way to reduce coal preparation cost, which is expressed on the basis of cost per ton of clean coal, is to increase the amount of clean coal recovered from a given amount of raw coal without adding to the total cost incurred in the preparation of that coal. The main objective of this project was to develop a plant optimization model to maximize the clean coal yield from an operating plant while satisfying the multiple product quality constraints, such as upper limits on ash, sulfur and moisture contents. An innovative approach using genetic algorithms (GA) was utilized for the first time to maximize the plant yield while satisfying multiple product quality constraints. The continuous parameter GA approach was used for the optimization process for which a suitable objective function was developed by simultaneously considering the overall plant yield and the individual quality constraints. The coal preparation plant that participated in this study belongs to the American Coal Company’s Galatia Mine. The hostplant treats 2,100 tph of raw coal to produce mass yields of 52.1% and 58.0% for two different blends of raw coal while satisfying the product quality constraints of 6.75% ash, 1.20% sulfur and 13,600 Btu/lb of heating value. A detailed plant sampling program was conducted for each unit operation, including heavy media vessel, heavy media cyclone, spirals and flotation banks, operating in the plant to generate input data for the optimization model. The maximum plant yield achieved by the plant optimization model developed using genetic algorithms was 54.6% and 59.2% for the two coal blends while satisfying the aforementioned product quality constraints. A minimum increase of nearly 1.2% in the overall plant yield for the Galatia plant may translate to increased production of more than 20 tph of clean coal and over $2 million in annual revenue.