MAXIMIZATION OF YIELDS OF CLEAN COAL FROM COAL PREPARATION PLANTS

A computer simulation model of coal preparation plants has been developed with provisions for crushers, screens, and washers, and a capability of interconnecting plant components into any desired configuration. The model predicts yield of clean coal, Btu recovery, and ash and sulfur levels. An efficient optimization method utilizes the simulation model for maximizing clean coal yields, within ash and sulfur level restrictions. The method, based on classical nonlinear search techniques, enhances its efficiency by exploiting special characteristics of coal preparation processes. Results obtained with the method compare favorably with theoretical results for ideal washers. Agreement between predicted and actual performance for entire plants is less satisfactory. Nevertheless, use of the optimizer is shown to result in significant improvements in the yield of clean coal. In one case featuring a crusher, two screens, and three washers, the clean coal yield increased by approximately 2 %, and the annual net revenue by over $500 000 for 600 tons per hour of feed. © 1979, American Chemical Society. All rights reserved.