Optimization Studies on a Multi-Gravity Separator Treating Ultrafine Coal

ABSTRACT

The present article outlines the tests carried out on an ultrafine coal sample collected from an operating washery using a multi-gravity separator (MGS) for its beneficiation. Influence of the most significant operational parameters of MGS, such as drum speed, tilt angle, and shaking amplitude, were varied for modelling and optimization purposes during the study to generate empirical correlations for prediction of yield and ash content with the help of a three-level Box-Behnken factorial design combined with response surface methodology (RSM). Equations of the second order were developed from response functions expressed as functions of these three operating parameters of MGS. The influence of the process variables of MGS on yield and ash content of the coal were presented as three-dimensional response surface graphs. Taking advantage of the mathematical-software-optimized levels of the process variables that have been determined as optimum levels to achieve the maximum yield of 61.3% and minimum ash of 17.5% product was predicted (from a feed ash of 33.5%). Further optimization test was carried out by targeting the minimum ash and yield product of above 60% and found a yield of 63.48% with an ash content of 17.25%.

KEYWORDS:

• Multi-gravity separator
• box-behnken design
• response surface methodology
• ultrafine coal beneficiation
• modelling and optimization