The capture of aerosol in a granular moving bed

Flue gas from process plants usually contains contaminants which require scrubbing prior to discharging to atmosphere. There are various techniques used to scrub the exit gas, such as packed columns, spray scrubbers, fluidised beds, filters, etc. One of the key design parameters required in order to select and design a scrubber is the capture efficiency. This efficiency is dependent on a number of factors such as the contacting mode, feed composition and operating conditions. This paper describes an experimental technique to quantify the efficiency of liquid aerosol capture in a bed of moving particles. The experimental technique provides an effective means of generating and capturing the tracer aerosol and determination of the overall aerosol capture efficiency. The results show the influence of the superficial gas and particle velocity, bed height, as well as the aerosol concentration, on the overall capture efficiency. Three possible predictive methods are considered to describe or quantify the aerosol capture efficiency. These are a capture parameter based on the available surface area, a capture parameter based on dimensionless groupings, and a dispersion model based on aerosol particle filtration by fixed bed porous filters. Each method is applied to the experimental data to determine their effectiveness in describing the capture in the granular moving bed. The dispersion model method showed good potential in quantifying the experimental capture efficiency. Crown Copyright (C) 2011 Published by Elsevier B.V. on behalf of The Institution of Chemical Engineers. All rights reserved.