An emphasis on optimum fuel production for Indian coal preparation plants treating multiple coal sources

Optimization of operating parameters of integrated coal washing plants for achieving maximum clean coal yield at any desired clean coal ash level is a major problem. The problem is largely associated with processing of raw coal obtained from different seams/collieries with frequent variations in proportions and characteristics of individual coals. For large number of source coals or washing different size fractions there are no simple methods of optimization. This paper presents a numerical solution to the constrained non-linear optimization of a multivariable objective function utilizing Excel® spreadsheet. The method is capable of handling any number of source coals with different size fractions. Here the yield is optimized subject to constraints on both ash and specific gravity. It is shown that the operational constraints of different washeries in the integrated plant utilizing gravity separation methods can also be overcome. The method offers the plant operators an easy and straightforward way for determining the optimum cut points of separation for blended coals to produce a maximum overall product yield at specified level of ash content.