Comparative strength analysis of two popular options of the radial centrifugal fan impeller design used in horizontal conveyor dryer for fine-grained raw materials is presented. Three types of materials for impeller manufacturing—ASTM A36 steel, Hardox 450 steel and aluminium alloy 6061-T6 are considered. The finite element method (FEM) has been used to investigate stresses and deformations of the impeller within the operational speed range. Analysis shows that the better design is the impeller made of Hardox 450 steel with a central disk. Although the maximum stress is slightly higher in the blades slot for central disk fitting for this design option, it has greatly reduced stresses in contact edges with two other disks (by 22–38%) and blades bending deformation (by 51%). For this design, the maximum operational rotation speed is 1135 min${}^{-1}$ according to the yield strength with a 15% safety factor, while for basic design, it is 1225 min${}^{-1}$. The rational choice of material depends on maximum value of the yield stress to density ratio as well as taking into account the operating conditions and required fan performance. Recommendations for manufacturing the centrifugal fan impeller related to chosen material are given.

This article presents a description of three decision support systems (DSS) in the mode of an adviser to the technological personnel of blast furnaces (BF), which were implemented by the Iron and Steel Institute of Z.I. Nekrasov (Dnipro, Ukraine) or underwent pilot testing as part of the automated control system of the BF shop of PrJSC “Kamet-steel” (Kamianske, Ukraine). The first DSS for managing the thermal state was implemented in 2021; it includes the entire list of information necessary for personnel in a convenient and compact form, generates recommendations in case of technology deviations, and, in the case of incorrect actions by the personnel, signals the need for correct actions. The main recommendations from the DSS are to correct the raceway adiabatic flame temperature, coke consumption when its characteristics are specified in (indicators of strength and abrasion, fractional composition, humidity, ash and sulfur), and ore load change. Using the system allows both reducing the specific coke consumption and preventing unplanned downtime. The second DSS for controlling the distribution of fuel additives over air tuyeres is based on information on thermal loads determined on water-cooled elements of tuyere tools. The main recommendations from the DSS are to adjust the amount of injected pulverized coal fuel on individual tuyeres in order to ensure a uniform distribution of the raceway adiabatic flame temperature around the circumference of the BF and, as a result, the energy efficiency of BF smelting. The third DSS for adjusting the parameters of the charging mode is based on information from the means of controlling the temperatures of the gas flow above the surface of the charge in the BF. The functioning of this DSS is based on determining the reference curves for the distribution of the gas flow along the BF radii, corresponding to the minimum consumption of coke and maximum productivity, and on the search for solutions by direct and iterative optimization methods, which allow one, by adjusting the charging parameters, to ensure a rational distribution of charge materials and gas flow in the BF.

The screw feeder design for the pre-compaction of bulk materials to be briquetted in a roll press is considered to increase the overall reliability. The relationship between the parameters of the screw feeder and its technological characteristics is investigated by the example of two fine-grained materials. A new mathematical model and design algorithm have been developed, which takes into account the properties of materials, the roller press parameters, the shape of the briquettes, and their deformation after compaction. The relationship between the pre-compaction pressure and the material stack height at the inlet is determined. The relations between the torque, the screw pitch, and the material stack height above the inlet, as well as the drive power and the screw pitch on productivity, are investigated. In experiments, using the proposed design, the compaction ratio of the peat increases by 22-27%, and hydrolyzed lignin – by 14-17%. The proposed approach allows for preventing drive overloading and ensures the reliable operation of pre-compaction devices for the roller presses.