Selection Of The Degree Of Washing For Component Coals To Maximize The Yield Of The Blend

The percent ash in a coal blend is equal to the weighted average of the ash contents of the component coals. If the raw coals differ in washability characteristics, the total yield may be maximized by washing the component coals to different quality levels. A mathematical basis for blend maximization is developed and a computer program is described The program determines the component weights that maximize the yield, while meeting an individual coal-quality specification. The procedure is directly applicable to linear parameters of grade quality such as percent ash, percent sulfur and the calorific value. A transformation of variables permits program execution to meet a sulfur-compliance specification. Blends may consist of any number of component coals.