Selegej A. Development of scientific fundamentals for charging blast furnace burden with account for the particle sizes thereof

The doctoral thesis is dedicated to the study of the charging blast furnace burden as well as to the development of scientific fundamentals for the automatic blast-furnace melting operation. The thesis contains theoretical insights and tests on the dynamics of the burden flow through the modern blast furnace conveyor lines, as well as the development of fundamentals of the automatic self-adjustment for blast-furnace melting operation on the basis of the data on the gasdynamics in the blast-furnace mouth. For the first time, there has been revealed the regularities of dependence of the surface texture variability of loading in the blast-furnace mouth on the size consistence of the blast furnace burden flow when utilizing bell-type charging and bell-less charging. The regularities of this type have been unknown before which allows to improve the prediction accuracy for the gasdynamic regime of a blast furnace, to reduce coke and natural gas consumption, and to increase blast furnace life extension by 15-20%. There also have been first defined the regularities for the complex effect of structural and operational parameters for the blast furnace charging systems on the burden surface texture in the blast-furnace mouth. This enabled the on-line correction of the burden relief in the blast-furnace mouth, leading to the energy source consumption decrease by 1.5%. For the first time, integral regularities between the kinematic parameters of the burden flow have been determined according to the elements of charging systems and flow capacity thereof. Similar data used to be inconsistent. Thus, the research allowed to increase the blast furnace charging efficiency, consequently resulting in general blast-furnace productivity index enhancement. Due to the experimental test results, it has been first theoretically justified that the correction of the burden relief in the blast-furnace mouth can be carried out both by means of the hopper mechanism angle change and the hopper gate opening size of the bell-less top, as well as via the change of the described parameters. Application of the doctoral thesis results involves the following stages: -the scientific foundations for the correction of the blast furnace charging programmes that provide rational melting conditions for the particular type of the blast furnace burden; -it has been found out and experimentally confirmed that the efficient control of burden flows in the blast furnace conveyor lines involves both the change of the hopper mechanism angle of the bell-less top, and the opening angle of the storage hopper sliding gate. It allows the most accurate ore load distribution along the radial ring zones of the blast furnace mouth; -there has been suggested a new technique to define rational parameters of blast furnace burden layers in the dry zone of the blast furnace, thus providing the greatest gasdynamics under the given burden conditions; -a new operation algorithm has been suggested for the automatic operating system of the blast furnace charging that enables the charging programme correction for particular conditions, and the active change thereof; -the efficiency of the monitoring technique for the dynamic change of the load profile of the burden in the blast-furnace mouth via the radar technology has been confirmed. Moreover, the developed pilot algorithm for the charging and its correction has been implemented in the system of automatic control of the blast furnace charging and successfully tested on a model. The conceptual issues of the doctoral thesis are used in the academic process by the students of the National Metallurgical Academy of Ukraine when working on Master’s theses and Bachelor’s theses. Suggested techniques and engineering solutions on the defining the rational parameters for blast furnace charging, melting techniques and the main properties of the charging mechanism allow to analytically determine the parameters for the charging programme correction and create a basis for the full automation of the charging processes. The techniques and engineering solutions proposed in the doctoral thesis were implemented at PJSC “DniproHidroMash”, and at Zolotonosha Machine-Building Plant named after I.I. Lepse; they are used when designing modern charging mechanisms for blast furnaces that are supposed to be utilized at PC Dnipro Metallurgical Complex, PC “Azovstal”, and PC “Zaporizhstal”.