Microclimate and heat exchange in steelmaking shops

Aim: To examine the specific characteristics of the industrial microclimate in steelmaking shops, analyse the heat balance of thermal units, and justify engineering solutions aimed at improving microclimatic conditions using an electric arc furnace as an example. Methodology: An analysis of existing scientific publications on occupational safety in metallurgy, occupational hy-giene, and heat engineering has been carried out. Calculations were performed to assess the thermal balance of the steelmaking furnace and the aspiration system for gas and dust extraction. Results: It has been established that in modern steelmaking shops the air temperature at workplaces during the warm season often exceeds the maximum permissible levels by 2–14 °C, reaching 31–35 °C, with reduced humidity of 33–55 % and significant thermal radiation of up to 8000 W/m². During the cold season, the temperature in certain open areas de-creases to 3–18 °C. It has been determined that 70–75 % of the total heat emission in a steelmaking shop is generated by in-frared radiation from molten metal and heated surfaces, which leads to worker overheating. The heat balance of an electric steelmaking furnace is characterised by substantial losses: only about 50–60 % of the supplied energy is retained as the heat of the produced steel, while the remainder is dissipated through slag, cooling water, refractory lining and exhaust gases. The latter carry away up to 10 % of the energy and reach temperatures of approximately 1500 °C, with dust concentrations of 1.5–8 g/m³. A comparison of ventilation schemes has been performed. Conventional shop aeration does not ensure adequate removal of excess heat or harmful emissions. A combined aspiration system for the electric furnace has been proposed, inte-grating a local hood above the furnace and an extraction duct in the furnace roof. The optimal parameters of this system have been calculated: a gas velocity in the duct of approximately 6 m/s, an exhaust gas volume of around 24 000 m³/h, and a pipeline diameter of 0.5–0.55 m. Scientific novelty: For the first time in the context of a steelmaking shop, the application of a combined aspiration method with an adjustable mobile duct has been substantiated. This solution enables effective capture of hot gases and dust while maintaining pressure beneath the furnace roof close to the regulatory level. Practical significance: The implementation of the proposed ventilation system in a steelmaking shop will reduce the air temperature in the working area, as well as dust and gas pollutant concentrations, to regulatory levels, thereby improving working conditions and reducing occupational risks for personnel.