Assessment of a Multi-Stage Wet Scrubber Performance Based on Characteristics of Scrubbing Solution

This paper presents the wet scrubber performance on acid gas absorption based on pH and conductivity measurements. The waste combustion system comprised of a CFB combustor in which mainly plastics waste was loaded into the riser (15 cm ID x 1.5 m long). The scrubbing experiments were conducted using a two-stage wet scrubber used as air pollution control device. The performance of the wet scrubber system was assessed by studying the changes in the pH and conductivity. The scrubbing solution was prepared using lime. The optimum lime concentration was obtained from bench experiments, giving an initial pH of up to 13. The scrubbing solution samples were collected from the solution tanks after every 2 minutes for 40 minutes. The scrubbing solution flow rate ranged from 0.53 to 0.95 L/s while the gas flow rate from the blower was kept constant at 16 m/s. It was observed that the pH of the scrubbing solution for both stages decreased to neutral range with increasing operation time. The decrease in pH and conductivity was initially faster before increasing slightly due to deposition of fly ash. It was concluded that the multi- stage wet scrubber is capable of removing toxic acid gas and particulate matter