Spray Tower Scrubber Optimization for Hydrofluoric Acid Mist Capture in Aluminum Smelter Off-Gas

Abstract

Hydrofluoric acid (HF) mist emissions from aluminum smelter off-gas streams present significant environmental and occupational health concerns due to their corrosive nature and toxic effects on human health and surrounding ecosystems. This study investigates the optimization of a spray tower scrubber system for efficient capture of hydrofluoric acid mist from aluminum smelting exhaust gases under varying operational conditions. The research focuses on improving gas–liquid contact efficiency, pollutant removal performance, and process stability through systematic evaluation of scrubber operating parameters. Experimental analyses were conducted to examine the influence of liquid-to-gas ratio, droplet size distribution, spray nozzle configuration, gas flow rate, scrubbing liquid concentration, pressure drop, and tower height on HF mist removal efficiency. Results demonstrated that optimized spray tower operation significantly enhanced hydrofluoric acid capture through improved mass transfer and effective droplet–particle interaction mechanisms. The scrubber system achieved high removal efficiency while maintaining stable hydraulic performance and reduced operational energy consumption. Kinetic and fluid dynamic analyses revealed that gas residence time and droplet dispersion characteristics strongly influence absorption efficiency and pollutant capture behavior within the spray tower. The use of appropriate scrubbing conditions minimized secondary emissions and improved process reliability during continuous industrial operation. Comparative assessment with conventional gas cleaning systems indicated that optimized spray tower scrubbers provide cost-effective and environmentally sustainable control of fluoride emissions in aluminum production facilities. The findings highlight the importance of process optimization and equipment design in achieving effective acid mist abatement and regulatory compliance in industrial air pollution control applications.