National University of Science and Technology «MISIS» (Moscow, Russia):

P. I. Chernousov, Cand. Eng., Associate Prof., e-mail: p.chernou@yandex.ru
O. V. Golubev, Cand. Eng., Associate Prof., e-mail: olega-san@yandex.ru

Stoilensky Mining and Concentrating Works (Staryi Oskol, Russia):
S. N. Seregin, Director of Repair and Maintenance Complex, e-mail: seregin_sn@nlmk.com

Among the factors that determining the effectiveness of the technology of injection of pulverized coal (PC), the optimal choice of the used coal is playing an important role. Currently, a number of technical and economic criteria have been determined, which make it possible to evaluate the effectiveness of the use of any given coal as a PC. The main one is the «actual» coal-to-coke replacement ratio, which depends on many parameters, some of which are individual for particular enterprises and furnaces. Research analysis conducted in recent decades in the field of the influence of various parameters on the coke replacement ratio showed a signifi cant difference both in the employed approaches and in the obtained results. The high burning quality of coal used at the initial stage of the development of the PC technology made it possible to practice the technology of their use bypassing the problem of incomplete combustion of coal particles in the tuyere zone. With the accumulation of the practical experience and the development of theoretical foundations for the use of PC in the blast-furnace process, preference was given to coals with a low volatile. Coal size reduction and particle-size distribution of PC have a great significance in a practical use of PC. Preliminary assessment of the efficiency of using coal or a mixture of coal as a PC is a complex task. Ideally, the solution of this problem involves the use of laboratory equipment to study the efficiency of coal combustion and the subsequent use of the results obtained as inputs to a mathematical model that takes into account both technical and economic conditions. In the past two decades, not only research organizations, but also a number of metallurgical companies are developing integrated technical and economic models for calculating the efficiency of coal use as a PC. The use of empirical dependencies between efficiency of the use of PC and its quality indicators can lead to a significant fault in the result.

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