Venturi Scrubber Development and Implementation to Industry Scale

Emission limits are tightening globally. This affects also smelting industry and more efficient gas cleaning solutions are needed for ferroalloys production in submerged arc furnaces (SAF). In SAF’s, gas cleaning is commonly conducted with wet scrubbers, such as Venturi Scrubber. Advantages of venturi scrubbers are safety and robustness. However, meeting current emission limits with conventional wet scrubbers is challenging. Therefore, a development program was launched for improving the performance and gas cleaning efficiency of Venturi Scrubbers. In the development program, the effect of an additional cleaning stage (auxiliary venturi) and droplet separation on the scrubber performance was studied with Computational Fluid Dynamics (CFD) studies and pilot-scale test scrubbers. Test results indicated that the auxiliary venturi increased dust removal efficiency and enhanced pressure generation. Furthermore, the effective droplet separation turned out to be a key factor to the effective gas cleaning. Results and findings from the development work and the pilot-scale tests were implemented and validated in the industry scale. Operational experiences and emission measurements, from industry, indicated that enhanced performance and lower emissions were achieved with the improved scrubber design. Future challenges like decreasing gas handling water consumption, energy recovery and handling SOx, NOx and other harmful emissions will be discussed also.