Effects of the particle residence time and the spray droplet size on the particle removal efficiencies in a wet scrubber

Abstract

A new type of scrubbing system equipped with air-atomized spray nozzles, full cone type spray nozzles and the maze shape channels has been developed and the mass transfer mechanism to remove sub-micron particles is analyzed. There is a minimal time duration for the mixture of air and sprayed water droplets should remain in the scrubbing zone for the sub-micron particles and hydrogen fluoride (HF) gas to diffuse and be captured by water droplets. The grown water droplets enter the maze shape channels which have sharp corners and bends to eliminate the water droplets by collision with the walls. As a result of applying the developed design methodology, the sub-micron particle removal efficiencies of the scrubber are found to be above 99% for the particles of 0.5–1 μm, 96% for those of 0.3–0.5 μm, and 86% for those smaller than 0.3 μm in diameter under the optimum operating condition.