Influence of Coal Size on the Performance of Corex Process

Abstract

The size distribution of coal used in the Corex process is of prime importance. It controls the permeability and stability of the char bed and thus the performance of the furnace. The particle size of the coal is monitored by its mean particle size (MPS) and the fraction of -6.3 mm in coal charge. A lower fraction of -6.3 mm in coal and higher coal MPS are desirable for improved performance. The variation in MPS and fraction -6.3mm of coal influences the fuel rates making the furnace unstable and thereby decreases the production. Theoretical calculations have been attempted using the actual plant data to know the impact of coal size on the permeability of the bed in the melter gasifier (MG). Statistical analysis was employed to investigate the influence of coal size on the performance of the Corex process. Attempts were made to establish the relationship between the coal size charged and performance indicators of the Corex process. It was found that a stable and improved performance of the Corex process requires MPS of coal in the range of 19-22 mm and fraction -6.3 mm in coal less than 15 %. A regression equation for the fuel rate including coal size has been derived. The present paper discusses the influence of coal fines and MPS on the performance of the Corex process.